{"id":1,"date":"2024-11-24T16:04:35","date_gmt":"2024-11-24T08:04:35","guid":{"rendered":"http:\/\/www.shoubashou.com\/?p=1"},"modified":"2025-06-03T09:58:25","modified_gmt":"2025-06-03T01:58:25","slug":"hello-world","status":"publish","type":"post","link":"https:\/\/www.shoubashou.com\/?p=1","title":{"rendered":"\u5b66\u4e60\u9605\u8bfb\u548c\u7ba1\u7406 OceanBase \u6570\u636e\u5e93 SQL \u6267\u884c\u8ba1\u5212"},"content":{"rendered":"\n<p>from \uff1a<a href=\"https:\/\/www.oceanbase.com\/docs\/community-tutorials-cn-1000000001390068\">https:\/\/www.oceanbase.com\/docs\/community-tutorials-cn-1000000001390068<\/a><\/p>\n\n\n\n<p>\u6267\u884c\u8ba1\u5212\uff08Execution Plan\uff09\u662f\u5bf9\u4e00\u6761 SQL \u67e5\u8be2\u8bed\u53e5\u5728\u6570\u636e\u5e93\u4e2d\u6267\u884c\u8fc7\u7a0b\u7684\u63cf\u8ff0\u3002<\/p>\n\n\n\n<p>\u7528\u6237\u53ef\u4ee5\u901a\u8fc7 EXPLAIN \u547d\u4ee4\u67e5\u770b\u4f18\u5316\u5668\u9488\u5bf9\u6307\u5b9a SQL \u751f\u6210\u7684\u6267\u884c\u8ba1\u5212\u3002\u5982\u679c\u8981\u5206\u6790\u67d0\u6761 SQL \u7684\u6027\u80fd\u95ee\u9898\uff0c\u901a\u5e38\u9700\u8981\u5148\u67e5\u770b SQL \u7684\u6267\u884c\u8ba1\u5212\uff0c\u6392\u67e5\u6bcf\u4e00\u6b65 SQL \u6267\u884c\u662f\u5426\u5b58\u5728\u95ee\u9898\u3002\u6240\u4ee5\u8bfb\u61c2\u6267\u884c\u8ba1\u5212\u662f SQL \u4f18\u5316\u7684\u5148\u51b3\u6761\u4ef6\uff0c\u800c\u4e86\u89e3\u6267\u884c\u8ba1\u5212\u7684\u7b97\u5b50\u662f\u7406\u89e3 EXPLAIN \u547d\u4ee4\u7684\u5173\u952e\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">EXPLAIN \u547d\u4ee4\u683c\u5f0f<\/h2>\n\n\n\n<p>\u8be5\u8bed\u53e5\u7528\u4e8e\u89e3\u91ca SQL \u8bed\u53e5\u7684\u6267\u884c\u8ba1\u5212\uff0c\u53ef\u4ee5\u662f SELECT\u3001DELETE\u3001INSERT\u3001REPLACE \u6216 UPDATE \u8bed\u53e5\u3002<\/p>\n\n\n\n<p>EXPLAIN \u4e0e DESCRIBE\u3001DESC \u4e92\u4e3a\u540c\u4e49\u8bcd\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u8bed\u6cd5<\/h3>\n\n\n\n<pre class=\"wp-block-code\"><code>{EXPLAIN &#91;INTO table_name ] &#91;SET statement_id = string]}\n&#91;explain_type] &#91;PRETTY | PRETTY_COLOR] dml_statement;\n\nexplain_type\uff1a\n    BASIC\n  | OUTLINE\n  | EXTENDED\n  | EXTENDED_NOADDR\n  | PARTITIONS\n  | FORMAT = {TRADITIONAL| JSON}\n\ndml_statement:\n    SELECT statement\n  | DELETE statement\n  | INSERT statement\n  | REPLACE statement<\/code><\/pre>\n\n\n\n<figure class=\"wp-block-image\"><img decoding=\"async\" src=\"https:\/\/obbusiness-private.oss-cn-shanghai.aliyuncs.com\/doc\/img\/tutorials\/V4.x\/70.diagnosis-and-tuning-of-oceanbase\/50.management-execution-plan-01.png\" alt=\"EXPLAIN\"\/><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\">\u53c2\u6570\u89e3\u91ca<\/h3>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th><strong>\u53c2\u6570<\/strong><\/th><th><strong>\u63cf\u8ff0<\/strong><\/th><\/tr><\/thead><tbody><tr><td>INTO table_name<\/td><td>\u8868\u793a\u5c06 EXPLAIN \u7684\u8ba1\u5212\u4fe1\u606f\u4fdd\u5b58\u5230\u6307\u5b9a\u8868\u5185\u3002\u5982\u679c\u6ca1\u6709\u6307\u5b9a <code>INTO table_name<\/code>\uff0c\u9ed8\u8ba4\u67e5\u8be2\u5230 PLAN_TABLE \u8868\u5185\u3002<\/td><\/tr><tr><td>SET statement_id<\/td><td>\u8868\u793a\u5f53\u524d\u67e5\u8be2\u4f7f\u7528\u5b57\u7b26\u4e32\u6807\u8bb0\uff0c\u4ee5\u65b9\u4fbf\u540e\u7eed\u67e5\u8be2\u8be5 SQL \u7684\u8ba1\u5212\u4fe1\u606f\u3002\u5982\u679c\u6ca1\u6709\u6307\u5b9a <code>SET statement_id<\/code>\uff0c\u9ed8\u8ba4\u4f7f\u7528\u7a7a\u5b57\u7b26\u4e32\u4f5c\u4e3a\u4fe1\u606f\u6807\u8bb0\u3002<\/td><\/tr><tr><td>PRETTY | PRETTY_COLOR<\/td><td>\u5c06\u8ba1\u5212\u6811\u4e2d\u7684\u7236\u8282\u70b9\u548c\u5b50\u8282\u70b9\u4f7f\u7528\u6811\u7ebf\u6216\u5f69\u8272\u6811\u7ebf\u8fde\u63a5\u8d77\u6765\uff0c\u4f7f\u5f97\u6267\u884c\u8ba1\u5212\u5c55\u793a\u66f4\u65b9\u4fbf\u9605\u8bfb\u3002<\/td><\/tr><tr><td>BASIC<\/td><td>\u6307\u5b9a\u8f93\u51fa\u8ba1\u5212\u7684\u57fa\u7840\u4fe1\u606f\uff0c\u5982\u7b97\u5b50 ID\u3001\u7b97\u5b50\u540d\u79f0\u3001\u6240\u5f15\u7528\u7684\u8868\u540d\u3002<\/td><\/tr><tr><td>OUTLINE<\/td><td>\u6307\u5b9a\u8f93\u51fa\u7684\u8ba1\u5212\u4fe1\u606f\u5305\u542b OUTLINE \u4fe1\u606f\u3002<\/td><\/tr><tr><td>EXTENDED<\/td><td>\u5c55\u793a\u9644\u52a0\u4fe1\u606f\u3002<\/td><\/tr><tr><td>EXTENDED_NOADDR<\/td><td>\u4ee5\u7b80\u7ea6\u7684\u65b9\u5f0f\u5c55\u793a\u9644\u52a0\u4fe1\u606f\u3002<\/td><\/tr><tr><td>PARTITIONS<\/td><td>\u663e\u793a\u5206\u533a\u76f8\u5173\u4fe1\u606f\u3002<\/td><\/tr><tr><td>FORMAT = {TRADITIONAL| JSON}<\/td><td>\u6307\u5b9a EXPALIN \u7684\u8f93\u51fa\u683c\u5f0f\u3002<code>TRADITIONAL<\/code>\uff1a\u8868\u683c\u8f93\u51fa\u683c\u5f0f\uff1b<code>JSON<\/code>\uff1a<code>KEY:VALUE<\/code> \u8f93\u51fa\u683c\u5f0f\uff0c<code>JSON<\/code> \u663e\u793a\u4e3a JSON \u5b57\u7b26\u4e32\uff0c\u5305\u62ec <code>EXTENDED<\/code> \u548c <code>PARTITIONS<\/code> \u4fe1\u606f\u3002<\/td><\/tr><tr><td>dml_statement<\/td><td>DML \u8bed\u53e5\u3002<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>\u5bf9\u4e8e OceanBase \u6570\u636e\u5e93\u7684\u4f7f\u7528\u8005\u6765\u8bf4\uff0c\u6700\u5e38\u7528\u7684\u662f EXPLAIN \u547d\u4ee4\u548c EXPLAIN EXTENDED_NOADDR \u547d\u4ee4\u3002<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>EXPLAIN \u6240\u5c55\u793a\u7684\u4fe1\u606f\u53ef\u4ee5\u5feb\u901f\u5e2e\u52a9\u666e\u901a\u7528\u6237\u4e86\u89e3\u6574\u4e2a\u8ba1\u5212\u7684\u6267\u884c\u65b9\u5f0f\u3002\u4f8b\u5982\uff1a<\/li>\n<\/ul>\n\n\n\n<pre class=\"wp-block-code\"><code>  create table t1(c1 int, c2 int);\n\n  create table t2(c1 int, c2 int);\n\n  -- \u5411 t1 \u8868\u63d2\u5165 10 \u884c\u6d4b\u8bd5\u6570\u636e\uff0cc1 \u5217\u7684\u503c\u662f\u4ece 1 \u5230 1000 \u7684\u8fde\u7eed\u6574\u6570\u3002\n  insert into t1 with recursive cte(n) as (select 1 from dual union all select n + 1 from cte where n &lt; 1000) select n, n from cte;\n\n  -- \u5411 t2 \u8868\u63d2\u5165 10 \u884c\u6d4b\u8bd5\u6570\u636e\uff0cc1 \u5217\u7684\u503c\u662f\u4ece 1 \u5230 1000 \u7684\u8fde\u7eed\u6574\u6570\u3002\n  insert into t2 with recursive cte(n) as (select 1 from dual union all select n + 1 from cte where n &lt; 1000) select n, n from cte;\n\n  -- \u6536\u96c6\u6307\u5b9a\u8868 t1 \u7684\u7edf\u8ba1\u4fe1\u606f\n  analyze table t1 COMPUTE STATISTICS for all columns size 128;\n\n  -- \u6536\u96c6\u6307\u5b9a\u8868 t2 \u7684\u7edf\u8ba1\u4fe1\u606f\n  analyze table t2 COMPUTE STATISTICS for all columns size 128;\n\n  explain select * from t1, t2 where t1.c1 = t2.c1 and t1.c1 &lt; 500;\n  +------------------------------------------------------------------------------------+\n  | Query Plan                                                                         |\n  +------------------------------------------------------------------------------------+\n  | =================================================                                  |\n  | |ID|OPERATOR         |NAME|EST.ROWS|EST.TIME(us)|                                  |\n  | -------------------------------------------------                                  |\n  | |0 |HASH JOIN        |    |498     |315         |                                  |\n  | |1 |\u251c\u2500TABLE FULL SCAN|t1  |499     |76          |                                  |\n  | |2 |\u2514\u2500TABLE FULL SCAN|t2  |499     |76          |                                  |\n  | =================================================                                  |\n  | Outputs &amp; filters:                                                                 |\n  | -------------------------------------                                              |\n  |   0 - output(&#91;t1.c1], &#91;t1.c2], &#91;t2.c1], &#91;t2.c2]), filter(nil), rowset=256          |\n  |       equal_conds(&#91;t1.c1 = t2.c1]), other_conds(nil)                               |\n  |   1 - output(&#91;t1.c1], &#91;t1.c2]), filter(&#91;t1.c1 &lt; 500]), rowset=256                  |\n  |       access(&#91;t1.c1], &#91;t1.c2]), partitions(p0)                                     |\n  |       is_index_back=false, is_global_index=false, filter_before_indexback&#91;false],  |\n  |       range_key(&#91;t1.__pk_increment]), range(MIN ; MAX)always true                  |\n  |   2 - output(&#91;t2.c1], &#91;t2.c2]), filter(&#91;t2.c1 &lt; 500]), rowset=256                  |\n  |       access(&#91;t2.c1], &#91;t2.c2]), partitions(p0)                                     |\n  |       is_index_back=false, is_global_index=false, filter_before_indexback&#91;false],  |\n  |       range_key(&#91;t2.__pk_increment]), range(MIN ; MAX)always true                  |\n  +------------------------------------------------------------------------------------+<\/code><\/pre>\n\n\n\n<p>OceanBase \u6570\u636e\u5e93\u6267\u884c\u8ba1\u5212\u4e2d\u7684\u5404\u5217\u7684\u542b\u4e49\u5982\u4e0b\u8868\u6240\u793a\u3002<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th><strong>\u5217\u540d<\/strong><\/th><th><strong>\u542b\u4e49<\/strong><\/th><\/tr><\/thead><tbody><tr><td>ID<\/td><td>\u6267\u884c\u6811\u6309\u7167\u524d\u5e8f\u904d\u5386\u7684\u65b9\u5f0f\u5f97\u5230\u7684\u7f16\u53f7\uff08\u4ece 0 \u5f00\u59cb\uff09\u3002<\/td><\/tr><tr><td>OPERATOR<\/td><td>\u64cd\u4f5c\u7b97\u5b50\u7684\u540d\u79f0\u3002<\/td><\/tr><tr><td>NAME<\/td><td>\u5bf9\u5e94\u8868\u64cd\u4f5c\u7684\u8868\u540d\uff08\u7d22\u5f15\u540d\uff09\u3002<\/td><\/tr><tr><td>EST. ROWS<\/td><td>\u4f18\u5316\u5668\u4f30\u7b97\u8be5\u64cd\u4f5c\u7b97\u5b50\u7684\u8f93\u51fa\u884c\u6570\uff0c\u4ec5\u4f5c\u4e3a\u53c2\u8003\u3002<br>\u4f8b\u5982\u4e0a\u56fe\u4e2d\u6700\u4e0b\u65b9\u7684 1 \u53f7\u7b97\u5b50 <code>TABLE FULL SCAN<\/code>\uff0c\u56e0\u4e3a\u8fc7\u6ee4\u6761\u4ef6\u6709 <code>t1.c1 &lt; 500<\/code>\uff0c\u6240\u4ee5\u4f18\u5316\u5668\u6839\u636e\u8fd9 1000 \u884c\u6570\u636e\u7684\u7edf\u8ba1\u4fe1\u606f\uff0c\u53ef\u4ee5\u4f30\u7b97\u51fa\u8fc7\u6ee4\u4e4b\u540e\u9700\u8981\u8f93\u51fa\u7684\u6570\u636e\u884c\u6570\u4e3a 499 \u884c\u3002<\/td><\/tr><tr><td>EST.TIME<\/td><td>\u4f18\u5316\u5668\u4f30\u7b97\u8be5\u64cd\u4f5c\u7b97\u5b50\u7684\u6267\u884c\u4ee3\u4ef7\uff08\u5fae\u79d2\uff09\uff0c\u4ec5\u4f5c\u4e3a\u53c2\u8003\u3002<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>\u5728\u8868\u64cd\u4f5c\u4e2d\uff0c<code>NAME<\/code> \u5b57\u6bb5\u4f1a\u663e\u793a\u8be5\u64cd\u4f5c\u6d89\u53ca\u7684\u8868\u7684\u540d\u79f0\uff08\u522b\u540d\uff09\uff0c\u5982\u679c\u662f\u4f7f\u7528\u7d22\u5f15\u8bbf\u95ee\uff0c\u8fd8\u4f1a\u5728\u540d\u79f0\u540e\u7684\u62ec\u53f7\u4e2d\u5c55\u793a\u8be5\u7d22\u5f15\u7684\u540d\u79f0\uff0c\u4f8b\u5982 <code>t1(t1_c2)<\/code> \u8868\u793a\u4f7f\u7528\u4e86\u7d22\u5f15 <code>t1_c2<\/code>\u3002\u5982\u679c\u626b\u63cf\u7684\u987a\u5e8f\u662f\u9006\u5e8f\uff0c\u8fd8\u4f1a\u5728\u540e\u9762\u4f7f\u7528 RESERVE \u5173\u952e\u5b57\u6807\u8bc6\uff0c\u4f8b\u5982 <code>t1(t1_c2,RESERVE)<\/code>\u3002<\/p>\n\n\n\n<p>OceanBase \u6570\u636e\u5e93 EXPLAIN \u547d\u4ee4\u8f93\u51fa\u7684\u7b2c\u4e00\u90e8\u5206\u662f\u6267\u884c\u8ba1\u5212\u7684\u6811\u5f62\u7ed3\u6784\u5c55\u793a\u3002\u5176\u4e2d\u6bcf\u4e00\u4e2a\u64cd\u4f5c\u5728\u6811\u4e2d\u7684\u5c42\u6b21\u901a\u8fc7\u5176\u5728\u7b97\u5b50\u4e2d\u7684\u7f29\u8fdb\u4e88\u4ee5\u5c55\u793a\u3002\u6811\u7684\u5c42\u6b21\u5173\u7cfb\u7528\u7f29\u8fdb\u6765\u8868\u793a\uff0c\u5c42\u6b21\u6700\u6df1\u7684\u4f18\u5148\u6267\u884c\uff0c\u5c42\u6b21\u76f8\u540c\u7684\u7b97\u5b50\u4ee5\u6307\u5b9a\u7b97\u5b50\u7684\u6267\u884c\u987a\u5e8f\u4e3a\u6807\u51c6\u6765\u6267\u884c\u3002\u4e0a\u8ff0\u793a\u4f8b\u67e5\u8be2\u7684\u8ba1\u5212\u5c55\u793a\u6811\u5982\u4e0b\u56fe\u6240\u793a\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><img decoding=\"async\" src=\"https:\/\/obbusiness-private.oss-cn-shanghai.aliyuncs.com\/doc\/img\/tutorials\/V4.x\/70.diagnosis-and-tuning-of-oceanbase\/50.management-execution-plan-02.png\" alt=\"\u8ba1\u5212\u5c55\u793a\"\/><\/figure>\n\n\n\n<p>\u5176\u4e2d\uff0c0 \u53f7\u7b97\u5b50\u662f\u4e00\u4e2a hash join\uff08HJ\uff09 \u7b97\u5b50\uff0c\u5b83\u6709\u4e24\u4e2a\u5b50\u8282\u70b9\uff0c\u5206\u522b\u662f 1 \u548c 2 \u53f7 table scan \u7b97\u5b50\uff08TSC\uff09\u30020 \u53f7 hash join \u7b97\u5b50\u7684\u6267\u884c\u903b\u8f91\u5982\u4e0b\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u8bfb\u53d6\u5de6\u5b50\u8282\u70b9\u7684\u6570\u636e\uff0c\u6839\u636e\u8054\u63a5\u5217\u8ba1\u7b97\u54c8\u5e0c\u503c\uff0c\u6784\u5efa\u4e00\u5f20\u54c8\u5e0c\u8868\u3002<\/li>\n\n\n\n<li>\u8bfb\u53d6\u53f3\u5b50\u8282\u70b9\u7684\u6570\u636e\uff0c\u6839\u636e\u8054\u63a5\u5217\u8ba1\u7b97\u54c8\u5e0c\u503c\uff0c\u5c1d\u8bd5\u4f7f\u7528\u901a\u8fc7\u5de6\u652f\u6570\u636e\u6784\u5efa\u7684\u54c8\u5e0c\u8868\u8fdb\u884c\u54c8\u5e0c\u63a2\u6d4b\uff0c\u5b8c\u6210\u8054\u63a5\u8ba1\u7b97\u3002 OceanBase \u6570\u636e\u5e93 EXPLAIN \u547d\u4ee4\u8f93\u51fa\u7684\u7b2c\u4e8c\u90e8\u5206\u662f\u5404\u64cd\u4f5c\u7b97\u5b50\u7684\u8be6\u7ec6\u4fe1\u606f\uff0c\u5305\u62ec\u8f93\u51fa\u8868\u8fbe\u5f0f\u3001\u8fc7\u6ee4\u6761\u4ef6\u3001\u5206\u533a\u4fe1\u606f\u4ee5\u53ca\u5404\u7b97\u5b50\u7684\u72ec\u6709\u4fe1\u606f\uff08\u5305\u62ec\u6392\u5e8f\u952e\u3001\u8054\u63a5\u952e\u3001\u4e0b\u538b\u6761\u4ef6\u7b49\uff09\u3002\u5373\u4e0a\u8ff0\u8ba1\u5212\u4e2d\u7684\u4e0b\u534a\u90e8\u5206\uff1a<\/li>\n<\/ol>\n\n\n\n<pre class=\"wp-block-code\"><code>   Outputs &amp; filters:                                                                 \n   -------------------------------------                                              \n     0 - output(&#91;t1.c1], &#91;t1.c2], &#91;t2.c1], &#91;t2.c2]), filter(nil), rowset=16           \n         equal_conds(&#91;t1.c1 = t2.c1]), other_conds(nil)                               \n     1 - output(&#91;t1.c1], &#91;t1.c2]), filter(&#91;t1.c1 &gt; 10]), rowset=16                    \n         access(&#91;t1.c1], &#91;t1.c2]), partitions(p0)                                     \n         is_index_back=false, is_global_index=false, filter_before_indexback&#91;false],  \n         range_key(&#91;t1.__pk_increment]), range(MIN ; MAX)always true                  \n     2 - output(&#91;t2.c1], &#91;t2.c2]), filter(&#91;t2.c1 &gt; 10]), rowset=16                    \n         access(&#91;t2.c1], &#91;t2.c2]), partitions(p0)                                     \n         is_index_back=false, is_global_index=false, filter_before_indexback&#91;false],  \n         range_key(&#91;t2.__pk_increment]), range(MIN ; MAX)always true<\/code><\/pre>\n\n\n\n<p>\u7b2c\u4e8c\u90e8\u5206\u7684\u5185\u5bb9\u8ddf\u7b2c\u4e00\u90e8\u5206\u6709\u5173\uff0c\u4e3b\u8981\u662f\u63cf\u8ff0\u7b2c\u4e00\u90e8\u5206\u7b97\u5b50\u7684\u5177\u4f53\u4fe1\u606f\u3002\u5176\u4e2d\u4e00\u4e9b\u516c\u5171\u7684\u4fe1\u606f\u5982\u4e0b\u3002<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>output : \u8be5\u7b97\u5b50\u7684\u8f93\u51fa\u8868\u8fbe\u5f0f\u3002<\/li>\n\n\n\n<li>filter : \u8be5\u7b97\u5b50\u7684\u8fc7\u6ee4\u8c13\u8bcd\u3002 \u5982\u679c\u7b97\u5b50\u6ca1\u6709\u8bbe\u7f6e\u8fc7\u6ee4\u6761\u4ef6\uff0c\u5219\u4e3a nil\u3002 \u4e3a\u4e86\u66f4\u597d\u5730\u8bfb\u61c2 OceanBase \u6570\u636e\u5e93 EXPLAIN \u8ba1\u5212\u4e2d\u5404\u4e2a\u7b97\u5b50\u7684\u7b2c\u4e8c\u90e8\u5206\uff0c\u9700\u8981\u7528\u6237\u5bf9\u5404\u4e2a\u7b97\u5b50\u7684\u4f5c\u7528\u6709\u4e00\u4e2a\u521d\u6b65\u7684\u4e86\u89e3\uff0c\u5177\u4f53\u4ecb\u7ecd\u53ef\u53c2\u89c1\u5b98\u7f51\u300aOceanBase \u6570\u636e\u5e93\u300b\u6587\u6863 <a href=\"https:\/\/www.oceanbase.com\/docs\/common-oceanbase-database-cn-1000000000510550\">\u53c2\u8003\u6307\u5357\/\u6027\u80fd\u8c03\u4f18\/SQL \u8c03\u4f18\u6307\u5357\/SQL \u6267\u884c\u8ba1\u5212\/\u6267\u884c\u8ba1\u5212\u7b97\u5b50<\/a> \u7ae0\u8282\u3002 \u4f8b\u5982\u4e0a\u9762\u8fd9\u4e2a\u8ba1\u5212\uff0c\u7528\u6237\u9700\u8981\u901a\u8fc7\u5b98\u7f51\u300aOceanBase \u6570\u636e\u5e93\u300b\u6587\u6863\u4e2d <a href=\"https:\/\/www.oceanbase.com\/docs\/common-oceanbase-database-cn-1000000000510550\">\u53c2\u8003\u6307\u5357\/\u6027\u80fd\u8c03\u4f18\/SQL \u8c03\u4f18\u6307\u5357\/SQL \u6267\u884c\u8ba1\u5212\/\u6267\u884c\u8ba1\u5212\u7b97\u5b50\/TABLE SCAN<\/a> \u5185\u5bb9\u548c <a href=\"https:\/\/www.oceanbase.com\/docs\/common-oceanbase-database-cn-1000000000510551#2-title-HASH%20JOIN%20(HJ)\">\u53c2\u8003\u6307\u5357\/\u6027\u80fd\u8c03\u4f18\/SQL \u8c03\u4f18\u6307\u5357\/SQL \u6267\u884c\u8ba1\u5212\/\u6267\u884c\u8ba1\u5212\u7b97\u5b50\/JOIN<\/a> \u4e00\u6587\u4e2d\u7684 <strong>HASH JOIN<\/strong> \u5185\u5bb9\u7684\u4ecb\u7ecd\u6765\u8bfb\u61c2\u4e0a\u9762\u8fd9\u90e8\u5206\u5185\u5bb9\uff0c\u5927\u5bb6\u4e0d\u59a8\u4e00\u8bd5\u3002<\/li>\n<\/ol>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p><strong>\u8bf4\u660e<\/strong><\/p>\n\n\n\n<p>\u4e0a\u8ff0\u8ba1\u5212\u4e2d\u7684 <code>rowset=16<\/code> \u548c OceanBase \u6570\u636e\u5e93\u6267\u884c\u5f15\u64ce\u7684\u5411\u91cf\u5316\u6267\u884c\u6280\u672f\u76f8\u5173\u3002\u8868\u793a\u5728\u7279\u5b9a\u7b97\u5b50\u4e2d\uff0c\u4f1a\u6309\u7167 16 \u884c\u4e00\u7ec4\u5206\u6279\u8fdb\u884c\u8ba1\u7b97\u3002<\/p>\n\n\n\n<p>\u7528\u6237\u53ef\u4ee5\u901a\u8fc7 <code>_rowsets_enabled<\/code> \u5bf9\u5411\u91cf\u5316\u5f00\u5173\u8fdb\u884c\u6253\u5f00\u6216\u5173\u95ed\uff0c\u4f8b\u5982\u901a\u8fc7 a<code>lter system set _rowsets_enabled = 0;<\/code> \u5173\u95ed\u5411\u91cf\u5316\u5f00\u5173\u3002\u7528\u6237\u4e5f\u53ef\u4ee5\u901a\u8fc7 <code>_rowsets_max_rows<\/code> \u5bf9\u5411\u91cf\u5316\u6267\u884c\u4e2d\u4e00\u6279\u5904\u7406\u7684\u884c\u6570\u8fdb\u884c\u8bbe\u7f6e\uff0c\u4f8b\u5982\u901a\u8fc7 <code>alter system set_rowsets_max_rows = 4;<\/code> \u5c06\u5411\u91cf\u5316\u6267\u884c\u4e2d\u4e00\u6279\u6570\u636e\u7684\u884c\u6570\u6539\u4e3a <code>4<\/code>\u3002<\/p>\n\n\n\n<p>\u5411\u91cf\u5316\u66f4\u8be6\u7ec6\u7684\u5185\u5bb9\u4e0d\u5728\u8fd9\u91cc\u5c55\u5f00\uff0c\u611f\u5174\u8da3\u7684\u7528\u6237\u53ef\u4ee5\u9605\u8bfb OceanBase \u793e\u533a\u535a\u5ba2<a href=\"https:\/\/open.oceanbase.com\/blog\/7499489568\">\u300aOceanBase \u8f7b\u91cf\u7ea7\u6570\u4ed3\u5173\u952e\u6280\u672f\u89e3\u8bfb\u300b<\/a>\u4e2d\u7684 <strong>\u5411\u91cf\u5316\u6267\u884c\u6280\u672f<\/strong> \u90e8\u5206\u3002<\/p>\n<\/blockquote>\n\n\n\n<ul class=\"wp-block-list\">\n<li>EXPLAIN EXTENDED_NOADDR \u547d\u4ee4\u7528\u4e8e\u8fdb\u884c\u8be6\u7ec6\u7684\u8ba1\u5212\u5c55\u793a\u3002\u901a\u5e38\u7528\u6237\u5728\u6392\u67e5 SQL \u6027\u80fd\u95ee\u9898\u65f6\uff0c\u4f1a\u4f7f\u7528\u8fd9\u79cd\u5c55\u793a\u6a21\u5f0f\u3002<\/li>\n<\/ul>\n\n\n\n<pre class=\"wp-block-code\"><code>  CREATE TABLE `t1` (\n    `c1` int, `c2` int,\n    KEY `idx` (`c1`));\n\n  insert into t1 values(1, 2);\n\n  explain EXTENDED_NOADDR select * from t1 where c1 &gt; 10;\n  +--------------------------------------------------------------------------+\n  | Query Plan                                                               |\n  +--------------------------------------------------------------------------+\n  | ===================================================                      |\n  | |ID|OPERATOR        |NAME   |EST.ROWS|EST.TIME(us)|                      |\n  | ---------------------------------------------------                      |\n  | |0 |TABLE RANGE SCAN|t1(idx)|1       |7           |                      |\n  | ===================================================                      |\n  | Outputs &amp; filters:                                                       |\n  | -------------------------------------                                    |\n  |   0 - output(&#91;t1.c1], &#91;t1.c2]), filter(nil), rowset=16                   |\n  |       access(&#91;t1.__pk_increment], &#91;t1.c1], &#91;t1.c2]), partitions(p0)      |\n  |       is_index_back=true, is_global_index=false,                         |\n  |       range_key(&#91;t1.c1], &#91;t1.__pk_increment]), range(10,MAX ; MAX,MAX),  |\n  |       range_cond(&#91;t1.c1 &gt; 10])                                           |\n  | Used Hint:                                                               |\n  | -------------------------------------                                    |\n  |   \/*+                                                                    |\n  |                                                                          |\n  |   *\/                                                                     |\n  | Qb name trace:                                                           |\n  | -------------------------------------                                    |\n  |   stmt_id:0, stmt_type:T_EXPLAIN                                         |\n  |   stmt_id:1, SEL$1                                                       |\n  | Outline Data:                                                            |\n  | -------------------------------------                                    |\n  |   \/*+                                                                    |\n  |       BEGIN_OUTLINE_DATA                                                 |\n  |       INDEX(@\"SEL$1\" \"test\".\"t1\"@\"SEL$1\" \"idx\")                          |\n  |       OPTIMIZER_FEATURES_ENABLE('4.0.0.0')                               |\n  |       END_OUTLINE_DATA                                                   |\n  |   *\/                                                                     |\n  | Optimization Info:                                                       |\n  | -------------------------------------                                    |\n  |   t1:                                                                    |\n  |       table_rows:1                                                       |\n  |       physical_range_rows:1                                              |\n  |       logical_range_rows:1                                               |\n  |       index_back_rows:1                                                  |\n  |       output_rows:1                                                      |\n  |       table_dop:1                                                        |\n  |       dop_method:Table DOP                                               |\n  |       avaiable_index_name:&#91;idx, t1]                                      |\n  |       unstable_index_name:&#91;t1]                                           |\n  |       stats version:0                                                    |\n  |       dynamic sampling level:0                                           |\n  |   Plan Type:                                                             |\n  |       LOCAL                                                              |\n  |   Note:                                                                  |\n  |       Degree of Parallelisim is 1 because of table property              |\n  +--------------------------------------------------------------------------+\n  47 rows in set<\/code><\/pre>\n\n\n\n<p>\u4e0a\u56fe\u4e2d\u7684 Optimization Info \u5f80\u5f80\u53ef\u4ee5\u7528\u4e8e\u5206\u6790\u4e00\u4e9b SQL \u7684\u6027\u80fd\u95ee\u9898\uff0c\u5176\u4e2d\u91cd\u8981\u4fe1\u606f\u7684\u4ecb\u7ecd\u5982\u4e0b\u3002<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>Optimization Info<\/th><th>\u542b\u4e49\u89e3\u91ca<\/th><\/tr><\/thead><tbody><tr><td>table_rows<\/td><td>\u4e0a\u4e00\u4e2a\u5408\u5e76\u7248\u672c SSTable \u4e2d\u7684\u8868\u7684\u884c\u6570\uff0c\u53ef\u4ee5\u7b80\u5355\u7406\u89e3\u4e3a <code>t1<\/code> \u8868\u7684\u884c\u6570\uff0c\u53ea\u5177\u6709\u53c2\u8003\u610f\u4e49\u3002<\/td><\/tr><tr><td>physical_range_rows<\/td><td><code>t1<\/code> \u8868\u9700\u8981\u626b\u63cf\u7684\u7269\u7406\u884c\u6570\u3002\u5982\u679c\u8d70\u4e86\u7d22\u5f15\u7684\u8bdd\uff0c\u542b\u4e49\u4e3a <code>t1<\/code> \u8868\u5728\u7d22\u5f15\u4e0a\u9700\u8981\u626b\u63cf\u7684\u7269\u7406\u884c\u6570\u3002<\/td><\/tr><tr><td>logical_range_rows<\/td><td><code>t1<\/code> \u8868\u5728\u9700\u8981\u626b\u63cf\u7684\u903b\u8f91\u884c\u6570\u3002\u5982\u679c\u8d70\u4e86\u7d22\u5f15\u7684\u8bdd\uff0c\u542b\u4e49\u4e3a <code>t1<\/code> \u8868\u5728\u7d22\u5f15\u4e0a\u9700\u8981\u626b\u63cf\u7684\u903b\u8f91\u884c\u6570\u3002\u5728\u4e0a\u9762\u8fd9\u4e2a\u8ba1\u5212\u4e2d\uff0c\u56e0\u4e3a\u626b\u63cf\u4e86 <code>idx<\/code> \u7d22\u5f15\uff0c\u6240\u4ee5\u80fd\u770b\u5230\u626b\u63cf\u8303\u56f4\u90fd\u662f <code>range(10,MAX ; MAX,MAX),range_cond([t1.c1 &gt; 10])<\/code>\u3002\u5982\u679c\u6ca1\u6709\u7d22\u5f15\uff0c\u5219\u9700\u8981\u626b\u63cf\u5168\u8868\uff0c\u8fd9\u65f6\u626b\u63cf\u7684\u8303\u56f4\u4f1a\u53d8\u4e3a <code>range(MIN ; MAX)<\/code>\u3002<strong>\u6ce8\u610f<\/strong><br><code>physical_range_rows<\/code> \u548c <code>logical_range_rows<\/code> \u8fd9\u4e24\u4e2a\u6307\u6807\u4e00\u822c\u6765\u8bf4\u662f\u76f8\u8fd1\u7684\uff0c\u770b\u4efb\u610f\u4e00\u4e2a\u90fd\u53ef\u4ee5\u3002\u4ec5\u5728\u4e00\u4e9b\u7279\u6b8a\u7684 Buffer \u8868\u573a\u666f\u4e0b\uff0c<code>physical_range_rows<\/code> \u53ef\u80fd\u4f1a\u8fdc\u5927\u4e8e <code>logical_range_rows<\/code>\u3002Buffer \u8868\u8868\u793a\u9891\u7e41\u63d2\u5165\u3001\u5220\u9664\u7684\u8868\u3002\u5f53 LSM tree \u4e2d\u7684\u589e\u91cf\u6570\u636e\u4e2d\u79ef\u7d2f\u4e86\u5927\u91cf\u6807\u8bb0\u5220\u9664\u7684\u6570\u636e\u65f6\uff0c\u4ece\u4e0a\u5c42\u5e94\u7528\u89c6\u89d2\u5b9e\u9645\u5b58\u5728\u7684\u884c\u5f88\u5c11\uff0c\u4f46\u8303\u56f4\u67e5\u8be2\u65f6\u53ef\u80fd\u9700\u8981\u5904\u7406\u8f83\u591a\u7684\u6807\u8bb0\u5220\u9664\u7684\u6570\u636e\uff0c\u8fd9\u79cd\u573a\u666f\u4e0b\uff0c<code>physical_range_rows<\/code> \u53ef\u80fd\u4f1a\u8fdc\u5927\u4e8e <code>logical_range_rows<\/code>\uff0c\u4ece\u800c\u5bfc\u81f4 SQL \u8017\u65f6\u4e0d\u591f\u7406\u60f3\u3002\u540c\u65f6 Buffer \u8868\u573a\u666f\u4e0b\u4e5f\u5bb9\u6613\u5bfc\u81f4\u4f18\u5316\u5668\u751f\u6210\u975e\u6700\u4f18\u6267\u884c\u8ba1\u5212\u3002Buffer \u8868\u7684\u4ecb\u7ecd\u3001\u68c0\u6d4b\u903b\u8f91\uff0c\u4ee5\u53ca\u89c4\u907f\u65b9\u6cd5\u8be6\u89c1\u5b98\u7f51\u300aOceanBase \u6570\u636e\u5e93\u300b\u6587\u6863 <a href=\"https:\/\/www.oceanbase.com\/docs\/common-oceanbase-database-cn-1000000000510482\">\u7ba1\u7406\u6570\u636e\u5e93\/\u6027\u80fd\u8c03\u4f18\/\u8bc6\u522b\u7ec4\u4ef6\u5185\u7684\u74f6\u9888\/OBServer \u7aef\u6027\u80fd\u74f6\u9888\/\u975e\u6700\u4f18\u8ba1\u5212\/Buffer \u8868<\/a>\u3002<\/td><\/tr><tr><td>index_back_rows<\/td><td>\u5982\u679c\u7d22\u5f15\u9700\u8981\u56de\u8868\uff0c\u8fd9\u4e2a\u503c\u8868\u793a\u7d22\u5f15\u56de\u8868\u7684\u884c\u6570\u3002\u5f53\u5168\u8868\u626b\u63cf\u6216\u8005\u7d22\u5f15\u626b\u63cf\u4f46\u4e0d\u9700\u8981\u56de\u8868\u65f6\uff0c\u8be5\u503c\u4e3a <code>0<\/code>\u3002\u7d22\u5f15\u56de\u8868\u7684\u6982\u5ff5\u8be6\u89c1\u5b98\u7f51\u300aOceanBase \u6570\u636e\u5e93\u300b\u6587\u6863 <a href=\"https:\/\/www.oceanbase.com\/docs\/common-oceanbase-database-cn-1000000000510550\">\u53c2\u8003\u6307\u5357\/\u6027\u80fd\u8c03\u4f18\/SQL \u8c03\u4f18\u6307\u5357\/SQL \u6267\u884c\u8ba1\u5212\/\u6267\u884c\u8ba1\u5212\u7b97\u5b50\/TABLE SCAN<\/a>\u3002\u7b80\u5355\u6765\u8bf4\uff0c\u8fd9\u4e2a\u8ba1\u5212\u4e2d\u7d22\u5f15\u9700\u8981\u56de\u4e3b\u8868\u7684\u539f\u56e0\u662f\u7d22\u5f15 <code>idx<\/code> \u4e2d\u53ea\u6709 <code>c1<\/code> \u5217\u7684\u6570\u636e\uff0c\u9700\u8981\u6839\u636e\u7d22\u5f15\u4e2d\u8fc7\u6ee4\u51fa\u6765\u7684\u6570\u636e\u5bf9\u5e94\u5230\u4e3b\u8868\u4e2d\u7684\u9690\u85cf\u4e3b\u952e\u4fe1\u606f\uff0c\u56de\u5230\u4e3b\u8868\u4e2d\u67e5\u51fa <code>c2<\/code> \u5217\u7684\u6570\u636e\u3002\u5982\u679c\u8fd9\u4e2a\u67e5\u8be2\u4e0d\u662f <code>select * from t1 where c1 &gt; 10<\/code>\uff0c\u800c\u662f <code>select c1 from t1 where c1 &gt; 10<\/code>\uff0c\u56e0\u4e3a\u7d22\u5f15\u4e2d\u5df2\u7ecf\u5305\u542b\u4e86\u9700\u8981\u67e5\u8be2\u7684\u5168\u90e8\u4fe1\u606f\uff0c\u5219\u4e0d\u9700\u8981\u7d22\u5f15\u56de\u8868\u3002<\/td><\/tr><tr><td>output_rows<\/td><td>\u9884\u4f30\u8f93\u51fa\u884c\u6570\u3002\u5728\u4e0a\u9762\u7684\u8ba1\u5212\u4e2d\uff0c\u8868\u793a <code>t1<\/code> \u8868\u7ecf\u8fc7\u8fc7\u6ee4\u4e4b\u540e\u7684\u884c\u6570\u3002<\/td><\/tr><tr><td>table_dop<\/td><td><code>t1<\/code> \u8868\u626b\u63cf\u65f6\u7684\u5e76\u884c\u5ea6\uff08\u5e76\u884c\u6267\u884c\u65f6\u6240\u4f7f\u7528\u7684\u5de5\u4f5c\u7ebf\u7a0b\u6570\uff09\u3002<\/td><\/tr><tr><td>dop_method<\/td><td>\u51b3\u5b9a\u8868\u626b\u63cf\u5e76\u884c\u5ea6\u7684\u539f\u56e0\u3002\u53ef\u4ee5\u662f TableDOP\uff08\u8868\u5728\u5b9a\u4e49\u65f6\u6307\u5b9a\u7684\u5e76\u884c\u5ea6\uff09\u3001AutoDop\uff08\u4f18\u5316\u5668\u57fa\u4e8e\u4ee3\u4ef7\u9009\u62e9\u7684\u5e76\u884c\u5ea6\uff0c\u9700\u8981\u6253\u5f00 auto dop \u529f\u80fd\uff09\u3001global parallel\uff08parallel hint \u6216\u7cfb\u7edf\u53d8\u91cf\u8bbe\u7f6e\u7684\u5e76\u884c\u5ea6\uff09\u3002<\/td><\/tr><tr><td>avaiable_index_name<\/td><td><code>t1<\/code> \u8868\u53ef\u7528\u7684\u7d22\u5f15\u5217\u8868\u3002\u8fd9\u91cc\u9664\u4e86\u7d22\u5f15\u8868\u4ee5\u5916\uff0c\u8fd8\u5305\u62ec\u4e3b\u8868\u3002\u5982\u679c\u6ca1\u6709\u5408\u9002\u7684\u7d22\u5f15\uff0c\u8ba1\u5212\u4f1a\u9009\u62e9\u5728\u4e3b\u8868\u4e0a\u8fdb\u884c\u5168\u8868\u626b\u63cf\u3002<\/td><\/tr><tr><td>pruned_index_name<\/td><td>\u5f53\u524d\u7684\u67e5\u8be2\u57fa\u4e8e\u4f18\u5316\u5668\u7684\u89c4\u5219\uff0c\u8ba4\u4e3a\u4e0d\u5e94\u8be5\u4f7f\u7528\u7684\u7d22\u5f15\u5217\u8868\u3002OceanBase \u6570\u636e\u5e93\u4f18\u5316\u5668\u7684\u7d22\u5f15\u526a\u679d\u89c4\u5219\u8be6\u89c1\u5b98\u7f51\u300aOceanBase \u6570\u636e\u5e93\u300b\u6587\u6863 <a href=\"https:\/\/www.oceanbase.com\/docs\/common-oceanbase-database-cn-1000000000511145\">\u53c2\u8003\u6307\u5357\/\u6027\u80fd\u8c03\u4f18\/SQL \u8c03\u4f18\u6307\u5357\/SQL \u4f18\u5316\/\u67e5\u8be2\u4f18\u5316\/\u8bbf\u95ee\u8def\u5f84\/\u57fa\u4e8e\u89c4\u5219\u7684\u8def\u5f84\u9009\u62e9<\/a>\u3002<\/td><\/tr><tr><td>unstable_index_name<\/td><td>\u8fd9\u4e2a\u5982\u679c\u5b58\u5728\uff0c\u5219\u4e00\u5b9a\u662f\u88ab\u88c1\u526a\u7684\u4e3b\u8868\u8def\u5f84\uff0c\u88ab\u88c1\u526a\u901a\u5e38\u662f\u56e0\u4e3a\u5b58\u5728\u5176\u4ed6\u7684\u7d22\u5f15\u8def\u5f84 range \u884c\u6570\u8f83\u5c0f\u3002<\/td><\/tr><tr><td>stats version<\/td><td><code>t1<\/code> \u8868\u7edf\u8ba1\u4fe1\u606f\u7248\u672c\u53f7\uff0c\u5982\u679c\u503c\u4e3a <code>0<\/code>\uff0c\u8868\u793a\u8be5\u8868\u6ca1\u6709\u6536\u96c6\u7edf\u8ba1\u4fe1\u606f\u3002\u4e3a\u4e86\u4fdd\u8bc1\u8ba1\u5212\u751f\u6210\u6b63\u786e\uff0c\u53ef\u4ee5\u81ea\u52a8\u6216\u8005\u624b\u52a8\u6536\u96c6\u5bf9\u5e94\u8868\u7684\u7edf\u8ba1\u4fe1\u606f\u3002<\/td><\/tr><tr><td>dynamic sampling level<\/td><td>\u52a8\u6001\u91c7\u6837\u7b49\u7ea7\uff0c\u5982\u679c\u503c\u4e3a <code>0<\/code>\uff0c\u8868\u793a\u8be5\u8868\u6ca1\u6709\u4f7f\u7528\u52a8\u6001\u91c7\u6837\u3002<br>\u52a8\u6001\u91c7\u6837\u662f\u4e00\u79cd\u4f18\u5316\u5668\u7684\u4f18\u5316\u5de5\u5177\uff0c\u8be6\u89c1\u5b98\u7f51\u300aOceanBase \u6570\u636e\u5e93\u300b\u6587\u6863 <a href=\"https:\/\/www.oceanbase.com\/docs\/common-oceanbase-database-cn-1000000000511118\">\u53c2\u8003\u6307\u5357\/\u6027\u80fd\u8c03\u4f18\/SQL \u8c03\u4f18\u6307\u5357\/SQL \u4f18\u5316\/\u4f18\u5316\u5668\u7edf\u8ba1\u4fe1\u606f\/\u7edf\u8ba1\u4fe1\u606f\u6536\u96c6\u65b9\u5f0f\/\u4f18\u5316\u5668\u52a8\u6001\u91c7\u6837<\/a>\u3002<\/td><\/tr><tr><td>estimation method<\/td><td><code>t1<\/code> \u8868\u884c\u6570\u4f30\u8ba1\u65b9\u5f0f\uff0c\u53ef\u4ee5\u662f DEFAULT\uff08\u4f7f\u7528\u7684\u9ed8\u8ba4\u7edf\u8ba1\u4fe1\u606f\uff0c\u8fd9\u79cd\u60c5\u51b5\u884c\u6570\u4f30\u8ba1\u53ef\u80fd\u4f1a\u4e0d\u51c6\uff0c\u9700\u8981 DBA \u4ecb\u5165\u4f18\u5316\uff09\u3001STORAGE\uff08\u4f7f\u7528\u5b58\u50a8\u5c42\u5b9e\u65f6\u4f30\u884c\uff09\u3001STATS\uff08\u4f7f\u7528\u7edf\u8ba1\u4fe1\u606f\u4f30\u884c\uff09\u3002<\/td><\/tr><tr><td>Plan Type<\/td><td>\u5f53\u524d\u8ba1\u5212\u7c7b\u578b\uff0c\u53ef\u4ee5\u662f LOCAL\u3001REMOTE\u3001DISTRIBUTED\u3002\u5177\u4f53\u542b\u4e49\u8be6\u89c1\u672c\u6559\u7a0b <a href=\"20.odp-sql-rout.md\">ODP SQL \u8def\u7531\u539f\u7406<\/a> \u4e2d\u7684 <strong>SQL \u7684\u8ba1\u5212\u7c7b\u578b<\/strong> \u90e8\u5206\u3002<\/td><\/tr><tr><td>Note<\/td><td>\u751f\u6210\u8be5\u8ba1\u5212\u7684\u4e00\u4e9b\u5907\u6ce8\u4fe1\u606f\u3002\u4f8b\u5982\u4e0a\u9762\u8fd9\u4e2a\u8ba1\u5212\u4e2d\u7684\uff1a<code>Degree of Parallelisim is 1 because of table property<\/code> \u8868\u793a\u7531\u4e8e\u5f53\u524d\u8868\u7684\u5e76\u884c\u5ea6\u8bbe\u7f6e\u4e3a <code>1<\/code>\uff0c\u6240\u4ee5\u5f53\u524d\u67e5\u8be2\u7684\u5e76\u884c\u5ea6\u88ab\u8bbe\u7f6e\u4e3a <code>1<\/code>\u3002<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<ul class=\"wp-block-list\">\n<li>EXPLAIN EXTENDED \u5728 EXPLAIN EXTENDED_NOADDR \u7684\u57fa\u7840\u4e0a\uff0c\u8fd8\u4f1a\u989d\u5916\u5c55\u793a\u5404\u4e2a\u7b97\u5b50\u4e2d\u6d89\u53ca\u5230\u7684\u5404\u4e2a\u8868\u8fbe\u5f0f\u7684\u6570\u636e\u6240\u5b58\u653e\u7684\u5730\u5740\u4fe1\u606f\u3002\u901a\u5e38\u6280\u672f\u652f\u6301\u540c\u5b66\u548c\u7814\u53d1\u540c\u5b66\u5728\u6392\u67e5 SQL \u6b63\u786e\u6027\u95ee\u9898\u65f6\uff0c\u4f1a\u4f7f\u7528\u5230\u8fd9\u79cd\u5c55\u793a\u6a21\u5f0f\u3002\u4e00\u822c\u7528\u6237\u4e0d\u9700\u8981\u5173\u5fc3\u5404\u4e2a\u8868\u8fbe\u5f0f\u540e\u9762\u5bf9\u5e94\u7684\u5730\u5740\u4fe1\u606f\uff0c\u53ef\u4ee5\u76f4\u63a5\u5ffd\u7565\u3002<\/li>\n<\/ul>\n\n\n\n<pre class=\"wp-block-code\"><code>  explain EXTENDED select * from t1 where c1 &gt; 10;<\/code><\/pre>\n\n\n\n<p>\u8f93\u51fa\u5982\u4e0b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>  +---------------------------------------------------------------------------------------------------------------------+\n  | Query Plan                                                                                                          |\n  +---------------------------------------------------------------------------------------------------------------------+\n  | ===================================================                                                                 |\n  | |ID|OPERATOR        |NAME   |EST.ROWS|EST.TIME(us)|                                                                 |\n  | ---------------------------------------------------                                                                 |\n  | |0 |TABLE RANGE SCAN|t1(idx)|1       |7           |                                                                 |\n  | ===================================================                                                                 |\n  | Outputs &amp; filters:                                                                                                  |\n  | -------------------------------------                                                                               |\n  |   0 - output(&#91;t1.c1(0x7fed4fe0df50)], &#91;t1.c2(0x7fed4fe0e4c0)]), filter(nil), rowset=16                              |\n  |       access(&#91;t1.__pk_increment(0x7fed4fe0e9d0)], &#91;t1.c1(0x7fed4fe0df50)], &#91;t1.c2(0x7fed4fe0e4c0)]), partitions(p0) |\n  |       is_index_back=true, is_global_index=false,                                                                    |\n  |       range_key(&#91;t1.c1(0x7fed4fe0df50)], &#91;t1.__pk_increment(0x7fed4fe0e9d0)]), range(10,MAX ; MAX,MAX),             |\n  |       range_cond(&#91;t1.c1(0x7fed4fe0df50) &gt; 10(0x7fed4fe0d800)])                                                      |\n  |                                                                                                                     |\n  |       ......                                                                                                        |\n  |                                                                                                                     |\n  +---------------------------------------------------------------------------------------------------------------------+<\/code><\/pre>\n\n\n\n<h2 class=\"wp-block-heading\">\u6267\u884c\u8ba1\u5212\u4e2d\u7684\u7b97\u5b50\u4ecb\u7ecd<\/h2>\n\n\n\n<p>\u5e38\u89c1\u7684\u7b97\u5b50\u8be6\u89c1\u5b98\u7f51\u300aOceanBase \u6570\u636e\u5e93\u300b\u6587\u6863 <a href=\"https:\/\/www.oceanbase.com\/docs\/common-oceanbase-database-cn-1000000000510550\">\u53c2\u8003\u6307\u5357\/\u6027\u80fd\u8c03\u4f18\/SQL \u8c03\u4f18\u6307\u5357\/SQL \u6267\u884c\u8ba1\u5212\/\u6267\u884c\u8ba1\u5212\u7b97\u5b50<\/a> \u7ae0\u8282\u3002\u56e0\u4e3a\u5b98\u7f51\u5185\u5bb9\u8db3\u591f\u8be6\u7ec6\uff0c\u6240\u4ee5\u672c\u6587\u6863\u4e0d\u518d\u5bf9\u5404\u4e2a\u7b97\u5b50\u9010\u4e00\u8fdb\u884c\u4ecb\u7ecd\u3002<\/p>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p><strong>\u8bf4\u660e<\/strong><\/p>\n\n\n\n<p>\u5f3a\u70c8\u63a8\u8350\u7528\u6237\u53bb\u4e86\u89e3\u4e00\u4e0b\u5176\u4e2d\u6700\u5e38\u89c1\u7684 <a href=\"https:\/\/www.oceanbase.com\/docs\/common-oceanbase-database-cn-1000000000510550\">TABLE SCAN \u7b97\u5b50<\/a> \u548c <a href=\"https:\/\/www.oceanbase.com\/docs\/common-oceanbase-database-cn-1000000000510551\">JOIN \u7b97\u5b50<\/a>\uff0c\u4ee5\u53ca TABLE SCAN \u4e2d\u7684 <a href=\"https:\/\/www.oceanbase.com\/knowledge-base\/oceanbase-database-1000000000217873\">DAS \u6267\u884c<\/a>\u3002<\/p>\n<\/blockquote>\n\n\n\n<p>\u672c\u6587\u53ea\u4f1a\u91cd\u70b9\u5bf9\u4e00\u4e2a\u88ab\u79f0\u4e3a EXCHANGE \u7684\u7b97\u5b50\u8fdb\u884c\u4ecb\u7ecd\u3002\u8fd9\u4e2a EXCHANGE \u7b97\u5b50\u5728 OceanBase \u6570\u636e\u5e93\u7684\u5206\u5e03\u5f0f\u8ba1\u5212\u4e2d\u5f88\u5e38\u89c1\uff0c\u4e14\u4f5c\u7528\u548c\u542b\u4e49\u4e0d\u50cf\u5176\u4ed6\u7b97\u5b50\u90a3\u4e48\u5bb9\u6613\u7406\u89e3\uff0c\u56e0\u6b64\u4f1a\u5728\u5b98\u7f51\u5185\u5bb9\u7684\u57fa\u7840\u4e0a\uff0c\u5bf9 EXCHANGE \u7b97\u5b50\u8fdb\u884c\u4e00\u4e9b\u8865\u5145\u3002<\/p>\n\n\n\n<p>EXCHANGE \u7b97\u5b50\u662f\u7528\u4e8e\u7ebf\u7a0b\u95f4\u8fdb\u884c\u6570\u636e\u4ea4\u4e92\u7684\u7b97\u5b50\uff0c\u4e00\u822c\u90fd\u662f\u6210\u5bf9\u51fa\u73b0\u7684\uff0c\u6570\u636e\u6e90\u7aef\u6709\u4e00\u4e2a OUT \u7b97\u5b50\uff0c\u76ee\u7684\u7aef\u4f1a\u6709\u4e00\u4e2a IN \u7b97\u5b50\u3002\u4f5c\u7528\u4e3b\u8981\u662f\uff1agather\uff08\u6570\u636e\u6c47\u805a\uff09\u3001transmit\uff08\u6570\u636e\u8f6c\u53d1\uff09\u3001re-partition\uff08\u6570\u636e\u91cd\u5206\u533a\uff09\uff0c\u4e0b\u9762\u4f1a\u5bf9\u8fd9\u4e09\u79cd\u4f5c\u7528\u9010\u4e00\u8fdb\u884c\u4ecb\u7ecd\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">EXCH-IN\/OUT<\/h3>\n\n\n\n<p>EXCHANGE IN\/EXCHANGE OUT \u88ab\u7528\u4e8e\u5c06\u591a\u4e2a\u5206\u533a\u4e0a\u7684\u6570\u636e\u6c47\u805a\u5230\u4e00\u8d77\uff0c\u53d1\u9001\u5230\u67e5\u8be2\u6240\u5728\u7684\u4e3b\u8282\u70b9\u4e0a\u3002<\/p>\n\n\n\n<p>\u4e0b\u9762\u7684\u67e5\u8be2\u4e2d\u8bbf\u95ee\u4e86 5 \u4e2a\u5206\u533a\uff08p0-p4\uff09\u7684\u6570\u636e\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>CREATE TABLE t3 (c1 INT, c2 INT) PARTITION BY HASH(c1) PARTITIONS 5;<\/code><\/pre>\n\n\n\n<p>\u6267\u884c explain \u547d\u4ee4\u67e5\u770b\u6267\u884c\u8ba1\u5212<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>explain select * from t3 where c1 &gt; 10;<\/code><\/pre>\n\n\n\n<p>\u8f93\u51fa\u5982\u4e0b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>+------------------------------------------------------------------------------------+\n| Query Plan                                                                         |\n+------------------------------------------------------------------------------------+\n| =============================================================                      |\n| |ID|OPERATOR                 |NAME    |EST.ROWS|EST.TIME(us)|                      |\n| -------------------------------------------------------------                      |\n| |0 |PX COORDINATOR           |        |1       |20          |                      |\n| |1 |\u2514\u2500EXCHANGE OUT DISTR     |:EX10000|1       |20          |                      |\n| |2 |  \u2514\u2500PX PARTITION ITERATOR|        |1       |19          |                      |\n| |3 |    \u2514\u2500TABLE FULL SCAN    |t3      |1       |19          |                      |\n| =============================================================                      |\n| Outputs &amp; filters:                                                                 |\n| -------------------------------------                                              |\n|   0 - output(&#91;INTERNAL_FUNCTION(t3.c1, t3.c2)]), filter(nil), rowset=16            |\n|   1 - output(&#91;INTERNAL_FUNCTION(t3.c1, t3.c2)]), filter(nil), rowset=16            |\n|       dop=1                                                                        |\n|   2 - output(&#91;t3.c1], &#91;t3.c2]), filter(nil), rowset=16                             |\n|       force partition granule                                                      |\n|   3 - output(&#91;t3.c1], &#91;t3.c2]), filter(&#91;t3.c1 &gt; 10]), rowset=16                    |\n|       access(&#91;t3.c1], &#91;t3.c2]), partitions(p&#91;0-4])                                 |\n|       is_index_back=false, is_global_index=false, filter_before_indexback&#91;false],  |\n|       range_key(&#91;t3.__pk_increment]), range(MIN ; MAX)always true                  |\n+------------------------------------------------------------------------------------+<\/code><\/pre>\n\n\n\n<p>\u5176\u4e2d\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>2 \u53f7\u7b97\u5b50 <code>PX PARTITION ITERATOR<\/code> \u8d1f\u8d23\u6309\u7167\u5206\u533a\u7c92\u5ea6\u8fed\u4ee3\u6570\u636e\u3002granule iterator \u7b97\u5b50\u7684\u4ecb\u7ecd\u8be6\u89c1\u5b98\u7f51\u300aOceanBase \u6570\u636e\u5e93\u300b\u6587\u6863 <a href=\"https:\/\/www.oceanbase.com\/docs\/common-oceanbase-database-cn-1000000000510540\">\u53c2\u8003\u6307\u5357\/\u6027\u80fd\u8c03\u4f18\/SQL \u8c03\u4f18\u6307\u5357\/SQL \u6267\u884c\u8ba1\u5212\/\u6267\u884c\u8ba1\u5212\u7b97\u5b50\/GI<\/a>\u3002<\/li>\n\n\n\n<li>1 \u53f7\u7b97\u5b50 <code>EXCHANGE OUT DISTR<\/code> \u63a5\u53d7 2 \u53f7\u7b97\u5b50 <code>PX PARTITION ITERATOR<\/code> \u4ea7\u751f\u7684\u8f93\u51fa\uff0c\u5e76\u5c06\u6570\u636e\u4f20\u51fa\u3002<\/li>\n\n\n\n<li>0 \u53f7\u7b97\u5b50 <code>PX COORDINATOR<\/code> \u63a5\u6536\u591a\u4e2a\u5206\u533a\u4e0a 1 \u53f7\u7b97\u5b50\u4ea7\u751f\u7684\u8f93\u51fa\uff0c\u5e76\u5c06\u7ed3\u679c\u6c47\u603b\u8f93\u51fa\u7ed9\u7528\u6237\u3002<code>PX COORDINATOR<\/code> \u662f\u4e00\u79cd\u7279\u6b8a\u7684 EXCHANGE IN \u7b97\u5b50\uff0c\u9664\u4e86\u80fd\u591f\u62c9\u56de\u8fdc\u7a0b\u7684\u6570\u636e\u5916\uff0c\u8fd8\u8d1f\u8d23\u8c03\u5ea6\u5b50\u8ba1\u5212\u7684\u6267\u884c\u3002<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">EXCH-IN\/OUT (REMOTE)<\/h3>\n\n\n\n<p>\u6211\u4eec\u5728 <a href=\"20.odp-sql-rout.md\">ODP SQL \u8def\u7531\u539f\u7406<\/a> \u4e2d\u4ecb\u7ecd\u4e86\u6267\u884c\u8ba1\u5212\u4e3b\u8981\u5206\u4e3a\u4e09\u79cd\u4e0d\u540c\u7684\u7c7b\u578b\uff0c\u5206\u522b\u662f\u672c\u5730\uff08Local\uff09 \u8ba1\u5212\u3001\u8fdc\u7a0b\uff08Remote\uff09\u8ba1\u5212\u548c\u5206\u5e03\u5f0f\uff08Distributed\uff09\u8ba1\u5212\u3002EXCHANGE IN REMOTE \u548c EXCHANGE OUT REMOTE \u7b97\u5b50\u5c31\u662f\u5728\u8fdc\u7a0b\u8ba1\u5212\u4e2d\u7528\u4e8e\u5c06\u8fdc\u7a0b\u7684\u6570\u636e\uff08\u5355\u4e2a\u5206\u533a\u7684\u6570\u636e\uff09\u62c9\u56de\u672c\u5730\u3002<\/p>\n\n\n\n<p>\u4f8b\u5982\u6211\u4eec\u521b\u5efa\u4e86\u4e00\u4e2a 1 &#8211; 1 &#8211; 1\uff083 Zone 3 \u8282\u70b9\uff09\u7684\u73af\u5883\uff0c\u4e09\u4e2a\u53ef\u7528\u533a\u5206\u522b\u662f\uff1a<code>zone1<\/code>\u3001<code>zone2<\/code>\u3001<code>zone3<\/code>\uff0c\u5bf9\u5e94\u7684\u4e09\u4e2a\u8282\u70b9\u5206\u522b\u53eb\u505a <code>A<\/code>\u3001<code>B<\/code>\u3001<code>C<\/code>\u3002\u67d0\u4e2a\u79df\u6237\u7684 primary_zone \u662f <code>zone1<\/code>\uff0c\u5373\u8fd9\u4e2a\u79df\u6237\u4e0b\u7684\u6240\u6709\u8868\u7684\u4e3b\u526f\u672c\u90fd\u4f1a\u5728 <code>zone1<\/code> \u7684 <code>A<\/code> \u8282\u70b9\u4e0a\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">\u672c\u5730\u8ba1\u5212<\/h4>\n\n\n\n<p>\u5982\u679c\u6211\u4eec\u76f4\u8fde <code>A<\/code> \u8282\u70b9\uff0c\u5bf9\u4e24\u5f20\u975e\u5206\u533a\u8868\u8fdb\u884c\u8ba1\u7b97\uff0c\u56e0\u4e3a\u4e24\u8868\u7684\u4e3b\u526f\u672c\u90fd\u5728\u672c\u673a\uff0c\u5c31\u4f1a\u751f\u6210\u5982\u4e0b\u7684\u672c\u5730\u8ba1\u5212\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>create table t1(c1 int, c2 int);\n\ncreate table t2(c1 int, c2 int);\n\nexplain select * from t1, t2 where t1.c1 = t2.c1 and t1.c1 &gt; 10;\n+------------------------------------------------------------------------------------+\n| Query Plan                                                                         |\n+------------------------------------------------------------------------------------+\n| =================================================                                  |\n| |ID|OPERATOR         |NAME|EST.ROWS|EST.TIME(us)|                                  |\n| -------------------------------------------------                                  |\n| |0 |HASH JOIN        |    |1       |9           |                                  |\n| |1 |\u251c\u2500TABLE FULL SCAN|t1  |1       |4           |                                  |\n| |2 |\u2514\u2500TABLE FULL SCAN|t2  |1       |4           |                                  |\n| =================================================                                  |\n| Outputs &amp; filters: \u7565                                                              |<\/code><\/pre>\n\n\n\n<h4 class=\"wp-block-heading\">\u8fdc\u7a0b\u8ba1\u5212<\/h4>\n\n\n\n<p>\u5982\u679c\u6211\u4eec\u76f4\u8fde <code>B<\/code> \u8282\u70b9\uff0c\u5bf9\u4e24\u5f20\u975e\u5206\u533a\u8868\u8fdb\u884c\u8ba1\u7b97\uff0c\u56e0\u4e3a\u4e24\u8868\u7684\u4e3b\u526f\u672c\u90fd\u4e0d\u5728\u672c\u673a\uff0c\u5c31\u4f1a\u751f\u6210\u5982\u4e0b\u7684\u8fdc\u7a0b\u8ba1\u5212\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>explain select * from t1, t2 where t1.c1 = t2.c1 and t1.c1 &gt; 10;<\/code><\/pre>\n\n\n\n<p>\u8f93\u51fa\u5982\u4e0b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>+------------------------------------------------------------------------------------+\n| Query Plan                                                                         |\n+------------------------------------------------------------------------------------+\n| =====================================================                              |\n| |ID|OPERATOR             |NAME|EST.ROWS|EST.TIME(us)|                              |\n| -----------------------------------------------------                              |\n| |0 |EXCHANGE IN REMOTE   |    |1       |11          |                              |\n| |1 |\u2514\u2500EXCHANGE OUT REMOTE|    |1       |10          |                              |\n| |2 |  \u2514\u2500HASH JOIN        |    |1       |9           |                              |\n| |3 |    \u251c\u2500TABLE FULL SCAN|t1  |1       |4           |                              |\n| |4 |    \u2514\u2500TABLE FULL SCAN|t2  |1       |4           |                              |\n| =====================================================                              |\n| Outputs &amp; filters:                                                                 |\n| -------------------------------------                                              |\n|   0 - output(&#91;t1.c1], &#91;t1.c2], &#91;t2.c1], &#91;t2.c2]), filter(nil)                      |\n|   1 - output(&#91;t1.c1], &#91;t1.c2], &#91;t2.c1], &#91;t2.c2]), filter(nil)                      |\n|   2 - output(&#91;t1.c1], &#91;t1.c2], &#91;t2.c1], &#91;t2.c2]), filter(nil), rowset=16           |\n|       equal_conds(&#91;t1.c1 = t2.c1]), other_conds(nil)                               |\n|   3 - output(&#91;t1.c1], &#91;t1.c2]), filter(&#91;t1.c1 &gt; 10]), rowset=16                    |\n|       access(&#91;t1.c1], &#91;t1.c2]), partitions(p0)                                     |\n|       is_index_back=false, is_global_index=false, filter_before_indexback&#91;false],  |\n|       range_key(&#91;t1.__pk_increment]), range(MIN ; MAX)always true                  |\n|   4 - output(&#91;t2.c1], &#91;t2.c2]), filter(&#91;t2.c1 &gt; 10]), rowset=16                    |\n|       access(&#91;t2.c1], &#91;t2.c2]), partitions(p0)                                     |\n|       is_index_back=false, is_global_index=false, filter_before_indexback&#91;false],  |\n|       range_key(&#91;t2.__pk_increment]), range(MIN ; MAX)always true                  |\n+------------------------------------------------------------------------------------+\n23 rows in set<\/code><\/pre>\n\n\n\n<p>\u8fdc\u7a0b\u8ba1\u5212\u4e2d\u7684 <code>EXCHANGE IN REMOTE<\/code> \u548c <code>EXCHANGE OUT REMOTE<\/code> \u7b97\u5b50\u7528\u4e8e\u5c06\u8fdc\u7a0b\u7684\u6570\u636e\uff08\u5355\u4e2a\u5206\u533a\u7684\u6570\u636e\uff09\u62c9\u56de\u672c\u5730\u3002<\/p>\n\n\n\n<p>\u7531\u4e8e\u5f85\u8bfb\u53d6\u7684\u6570\u636e\u5728\u8fdc\u7a0b\uff0c\u6267\u884c\u8ba1\u5212\u4e2d\u5206\u914d\u4e86 0 \u53f7\u7b97\u5b50\u548c 1 \u53f7\u7b97\u5b50\u6765\u62c9\u53d6\u8fdc\u7a0b\u7684\u6570\u636e\u3002\u5176\u4e2d\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>2 \u53f7 &#8211; 4 \u53f7\u7b97\u5b50\u5728 A \u673a\u5668\u4e0a\u6267\u884c\uff0c\u8d1f\u8d23\u8bfb\u53d6\u5b58\u50a8\u5c42\u7684\u6570\u636e\uff0c\u5e76\u5b8c\u6210 HASH JOIN \u7684\u8ba1\u7b97\u3002<\/li>\n\n\n\n<li>1 \u53f7\u7b97\u5b50 <code>EXCHANGE OUT REMOTE<\/code> \u4e5f\u5728 <code>A<\/code> \u673a\u5668\u4e0a\u6267\u884c\uff0c\u8bfb\u53d6 2 \u53f7\u7b97\u5b50 HASH JOIN \u8ba1\u7b97\u7684\u7ed3\u679c\u6570\u636e\uff0c\u5e76\u5c06\u6570\u636e\u4f20\u51fa\u7ed9 0 \u53f7\u7b97\u5b50\u3002<\/li>\n\n\n\n<li>0 \u53f7\u7b97\u5b50 <code>EXCHANGE IN REMOTE<\/code> \u5728 <code>B<\/code> \u673a\u5668\u4e0a\u6267\u884c\uff0c\u63a5\u6536 1 \u53f7\u7b97\u5b50\u4ea7\u751f\u7684\u8f93\u51fa\u3002<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">EXCH-IN\/OUT (PKEY)<\/h3>\n\n\n\n<p>EXCH-IN\/OUT (PKEY) \u7b97\u5b50\u7528\u4e8e\u6570\u636e\u91cd\u5206\u533a\u3002\u5b83\u901a\u5e38\u7528\u4e8e\u4e8c\u5143\u7b97\u5b50\uff08\u4f8b\u5982 JOIN \u7b97\u5b50\uff09\u4e2d\uff0c\u5c06\u7b97\u5b50\u5176\u4e2d\u4e00\u4e2a\u5b69\u5b50\u8282\u70b9\uff08\u5de6\u652f\uff09\u7684\u6570\u636e\uff0c\u6309\u7167\u53e6\u5916\u4e00\u4e2a\u5b69\u5b50\u8282\u70b9\uff08\u53f3\u652f\uff09\u7684\u5206\u533a\u65b9\u5f0f\u8fdb\u884c\u91cd\u5206\u533a\uff0c\u7136\u540e\u5c06\u5de6\u652f\u91cd\u5206\u533a\u540e\u7684\u6570\u636e\u53d1\u9001\u7ed9\u53f3\u652f\u5bf9\u5e94\u5206\u533a\u6240\u5728\u7684\u8282\u70b9\uff0c\u6700\u7ec8\u5b8c\u6210\u76f8\u5e94\u7684\u8ba1\u7b97\u3002<\/p>\n\n\n\n<p>\u5982\u4e0b\u793a\u4f8b\u4e2d\uff0c\u8be5\u67e5\u8be2\u662f\u5bf9\u4e24\u4e2a\u5206\u533a\u8868\u7684\u6570\u636e\u8fdb\u884c\u8054\u63a5\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>CREATE TABLE t1 (c1 INT, c2 INT) PARTITION BY HASH(c1) PARTITIONS 5;\n\nCREATE TABLE t2 (c1 INT PRIMARY KEY, c2 INT) PARTITION BY HASH(c1) PARTITIONS 4;\n\nEXPLAIN SELECT * FROM t1, t2 WHERE t1.c1 = t2.c1;\n+---------------------------------------------------------------------------------------+\n| Query Plan                                                                            |\n+---------------------------------------------------------------------------------------+\n| =====================================================================                 |\n| |ID|OPERATOR                         |NAME    |EST.ROWS|EST.TIME(us)|                 |\n| ---------------------------------------------------------------------                 |\n| |0 |PX COORDINATOR                   |        |1       |38          |                 |\n| |1 |\u2514\u2500EXCHANGE OUT DISTR             |:EX10001|1       |37          |                 |\n| |2 |  \u2514\u2500HASH JOIN                    |        |1       |36          |                 |\n| |3 |    \u251c\u2500EXCHANGE IN DISTR          |        |1       |20          |                 |\n| |4 |    \u2502 \u2514\u2500EXCHANGE OUT DISTR (PKEY)|:EX10000|1       |20          |                 |\n| |5 |    \u2502   \u2514\u2500PX PARTITION ITERATOR  |        |1       |19          |                 |\n| |6 |    \u2502     \u2514\u2500TABLE FULL SCAN      |t1      |1       |19          |                 |\n| |7 |    \u2514\u2500PX PARTITION ITERATOR      |        |1       |16          |                 |\n| |8 |      \u2514\u2500TABLE FULL SCAN          |t2      |1       |16          |                 |\n| =====================================================================                 |\n| Outputs &amp; filters:                                                                    |\n| -------------------------------------                                                 |\n|   0 - output(&#91;INTERNAL_FUNCTION(t1.c1, t1.c2, t2.c1, t2.c2)]), filter(nil), rowset=16 |\n|   1 - output(&#91;INTERNAL_FUNCTION(t1.c1, t1.c2, t2.c1, t2.c2)]), filter(nil), rowset=16 |\n|       dop=1                                                                           |\n|   2 - output(&#91;t1.c1], &#91;t2.c1], &#91;t1.c2], &#91;t2.c2]), filter(nil), rowset=16              |\n|       equal_conds(&#91;t1.c1 = t2.c1]), other_conds(nil)                                  |\n|   3 - output(&#91;t1.c1], &#91;t1.c2]), filter(nil), rowset=16                                |\n|   4 - output(&#91;t1.c1], &#91;t1.c2]), filter(nil), rowset=16                                |\n|       (#keys=1, &#91;t1.c1]), dop=1                                                       |\n|   5 - output(&#91;t1.c1], &#91;t1.c2]), filter(nil), rowset=16                                |\n|       force partition granule                                                         |\n|   6 - output(&#91;t1.c1], &#91;t1.c2]), filter(nil), rowset=16                                |\n|       access(&#91;t1.c1], &#91;t1.c2]), partitions(p&#91;0-4])                                    |\n|       is_index_back=false, is_global_index=false,                                     |\n|       range_key(&#91;t1.__pk_increment]), range(MIN ; MAX)always true                     |\n|   7 - output(&#91;t2.c1], &#91;t2.c2]), filter(nil), rowset=16                                |\n|       affinitize, force partition granule                                             |\n|   8 - output(&#91;t2.c1], &#91;t2.c2]), filter(nil), rowset=16                                |\n|       access(&#91;t2.c1], &#91;t2.c2]), partitions(p&#91;0-3])                                    |\n|       is_index_back=false, is_global_index=false,                                     |\n|       range_key(&#91;t2.c1]), range(MIN ; MAX)always true                                 |\n+---------------------------------------------------------------------------------------+<\/code><\/pre>\n\n\n\n<p>\u6267\u884c\u8ba1\u5212\u5c06 <code>t1<\/code> \u8868\u7684\u6570\u636e\u6309\u7167 <code>t2<\/code> \u8868\u7684\u5206\u533a\u65b9\u5f0f\u8fdb\u884c\u91cd\u5206\u533a\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>4 \u53f7\u7b97\u5b50 <code>EXCHANGE OUT DISTR (PKEY)<\/code> \u8d1f\u8d23\u6839\u636e <code>t2<\/code> \u8868\u7684\u6570\u636e\u5206\u533a\u65b9\u5f0f\uff0c\u4ee5\u53ca\u67e5\u8be2\u7684\u8054\u63a5\u6761\u4ef6\uff0c\u786e\u5b9a <code>t1<\/code> \u8868\u4e2d\u7684\u6bcf\u4e00\u884c\u6570\u636e\u5e94\u8be5\u53d1\u9001\u5230\u54ea\u4e2a\u8282\u70b9\u624d\u80fd\u5b8c\u6210\u4e0e <code>t2<\/code> \u8868\u5bf9\u5e94\u5206\u533a\u7684\u8fde\u63a5\u64cd\u4f5c\uff0c\u5e76\u5c06 <code>t1<\/code> \u8868\u7684\u5404\u884c\u6570\u636e\u53d1\u9001\u5230\u76f8\u5e94\u7684\u8282\u70b9\u3002<\/li>\n\n\n\n<li>3 \u53f7\u7b97\u5b50 <code>EXCHANGE IN DISTR<\/code> \u8d1f\u8d23\u5728\u76f8\u5e94\u8282\u70b9\u5b8c\u6210 <code>t1<\/code> \u8868\u6570\u636e\u7684\u63a5\u6536\u3002<\/li>\n\n\n\n<li>2 \u53f7\u7b97\u5b50 HASH JOIN \u8d1f\u8d23\u5728\u5404\u4e2a\u8282\u70b9\uff0c\u5bf9 7 \u53f7\u7b97\u5b50\u8fed\u4ee3\u51fa\u7684 <code>t2<\/code> \u8868\u5404\u5206\u533a\u7684\u6570\u636e\uff0c\u548c 3 \u53f7\u7b97\u5b50\u63a5\u6536\u5230\u7684 <code>t1<\/code> \u8868\u4ee5 <code>t2<\/code> \u8868\u5206\u533a\u89c4\u5219\u91cd\u5206\u533a\u540e\u7684\u5bf9\u5e94\u5206\u533a\u6570\u636e\uff0c\u8fdb\u884c JOIN \u8ba1\u7b97\u3002<\/li>\n\n\n\n<li>1 \u53f7\u7b97\u5b50 <code>EXCHANGE OUT DISTR<\/code> \u8d1f\u8d23\u628a\u5404\u8282\u70b9\u3001\u5404\u5206\u533a JOIN \u4e4b\u540e\u7684\u7ed3\u679c\u53d1\u9001\u5230 0 \u53f7\u7b97\u5b50\u3002<\/li>\n\n\n\n<li>0 \u53f7\u7b97\u5b50 <code>PX COORDINATOR<\/code> \u8d1f\u8d23\u63a5\u6536\u5404\u4e2a\u8282\u70b9 JOIN \u7684\u7ed3\u679c\uff0c\u5e76\u5bf9\u7ed3\u679c\u8fdb\u884c\u6c47\u603b\u3002<\/li>\n<\/ul>\n\n\n\n<p>\u9664\u4e86\u4e0a\u8ff0\u7684 EXCH-IN\/OUT (PKEY) \u4ee5\u5916\uff0c\u4f18\u5316\u5668\u8fd8\u4f1a\u6839\u636e\u9002\u5408\u4e0d\u540c SQL \u7684\u4e0d\u540c\u91cd\u5206\u533a\u65b9\u5f0f\uff0c\u751f\u6210 EXCH-IN\/OUT (HASH)\u3001EXCH-IN\/OUT (BC2HOST) \u7b49\u7b97\u5b50\uff0c\u8fd9\u91cc\u4e0d\u518d\u4e00\u4e00\u8d58\u8ff0\u3002\u4e0d\u540c\u7684\u6570\u636e\u91cd\u5206\u5e03\u65b9\u5f0f\uff0c\u8be6\u89c1\u5b98\u7f51\u300aOceanBase \u6570\u636e\u5e93\u300b\u6587\u6863 <a href=\"https:\/\/www.oceanbase.com\/docs\/common-oceanbase-database-cn-1000000000508513\">\u53c2\u8003\u6307\u5357\/\u6027\u80fd\u8c03\u4f18\/SQL \u8c03\u4f18\u6307\u5357\/\u5e76\u884c\u6267\u884c\u8ba1\u5212\/\u5e76\u884c\u6267\u884c\u8ba1\u5212\u7b80\u4ecb<\/a> \u4e2d <strong>\u5e38\u89c1\u7684\u5e76\u884c\u6267\u884c\u4e2d\u7684\u6570\u636e\u5206\u53d1\u65b9\u5f0f<\/strong> \u90e8\u5206\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">\u901a\u8fc7 Hint \u751f\u6210\u6307\u5b9a\u8ba1\u5212<\/h2>\n\n\n\n<p>Hint \u673a\u5236\u53ef\u4ee5\u4f7f\u4f18\u5316\u5668\u751f\u6210\u6307\u5b9a\u7684\u6267\u884c\u8ba1\u5212\u3002\u4e00\u822c\u60c5\u51b5\u4e0b\uff0c\u4f18\u5316\u5668\u4f1a\u4e3a\u7528\u6237\u67e5\u8be2\u9009\u62e9\u6700\u4f73\u7684\u6267\u884c\u8ba1\u5212\uff0c\u4e0d\u9700\u8981\u7528\u6237\u4f7f\u7528 Hint \u6307\u5b9a\u3002\u4f46\u5728\u67d0\u4e9b\u573a\u666f\u4e0b\uff0c\u4f18\u5316\u5668\u751f\u6210\u7684\u6267\u884c\u8ba1\u5212\u53ef\u80fd\u4e0d\u6ee1\u8db3\u7528\u6237\u7684\u8981\u6c42\uff0c\u8fd9\u65f6\u5c31\u9700\u8981\u7528\u6237\u4f7f\u7528 Hint \u6765\u6307\u5b9a\u751f\u6210\u67d0\u79cd\u6267\u884c\u8ba1\u5212\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Hint \u8bed\u6cd5<\/h3>\n\n\n\n<pre class=\"wp-block-code\"><code>{ DELETE | INSERT | SELECT | UPDATE | REPLACE } \/*+ &#91;hint_text]&#91;,hint_text]... *\/<\/code><\/pre>\n\n\n\n<p>\u4f8b\u5982\u4e0b\u9762\u8fd9\u6761\u67e5\u8be2\u8bed\u53e5\uff0c\u901a\u8fc7 <code>\/*+ PARALLEL(3)*\/<\/code> \u6307\u5b9a SQL \u7684\u6267\u884c\u5e76\u884c\u5ea6\u4e3a <code>3<\/code>\uff0c\u901a\u8fc7 explain \u5c31\u53ef\u4ee5\u770b\u5230\u8ba1\u5212\u7684 <code>dop = 3<\/code>\uff0c\u901a\u8fc7 explain EXTENDED_NOADDR \u8fd8\u53ef\u4ee5\u770b\u5230\u8ba1\u5212\u4e2d\u4f1a\u5c55\u793a\u4e00\u4e2a <code>Note: Degree of Parallelism is 3 because of hint<\/code>\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>create t1 (c1 int, c2 int) PARTITION BY HASH(c1) PARTITIONS 5;\n\nexplain EXTENDED_NOADDR select \/*+ PARALLEL(3) *\/* from t1 where c1 &gt; 10;\n+--------------------------------------------------------------------------+\n| Query Plan                                                               |\n+--------------------------------------------------------------------------+\n| ==========================================================               |\n| |ID|OPERATOR              |NAME    |EST.ROWS|EST.TIME(us)|               |\n| ----------------------------------------------------------               |\n| |0 |PX COORDINATOR        |        |1       |3           |               |\n| |1 |\u2514\u2500EXCHANGE OUT DISTR  |:EX10000|1       |3           |               |\n| |2 |  \u2514\u2500PX BLOCK ITERATOR |        |1       |3           |               |\n| |3 |    \u2514\u2500TABLE RANGE SCAN|t1(idx) |1       |3           |               |\n| ==========================================================               |\n| Outputs &amp; filters:                                                       |\n| -------------------------------------                                    |\n|   0 - output(&#91;INTERNAL_FUNCTION(t1.c1, t1.c2)]), filter(nil), rowset=16  |\n|   1 - output(&#91;INTERNAL_FUNCTION(t1.c1, t1.c2)]), filter(nil), rowset=16  |\n|       dop=3                                                              |\n|   2 - output(&#91;t1.c1], &#91;t1.c2]), filter(nil), rowset=16                   |\n|   3 - output(&#91;t1.c1], &#91;t1.c2]), filter(nil), rowset=16                   |\n|       access(&#91;t1.__pk_increment], &#91;t1.c1], &#91;t1.c2]), partitions(p0)      |\n|       is_index_back=true, is_global_index=false,                         |\n|       range_key(&#91;t1.c1], &#91;t1.__pk_increment]), range(10,MAX ; MAX,MAX),  |\n|       range_cond(&#91;t1.c1 &gt; 10])                                           |\n| Used Hint:                                                               |\n| -------------------------------------                                    |\n|   \/*+                                                                    |\n|       PARALLEL(3)                                                        |\n|   *\/                                                                     |\n|                                                                          |\n|   ......                                                                 |\n|                                                                          |\n|   Note:                                                                  |\n|       Degree of Parallelism is 3 because of hint                         |\n+--------------------------------------------------------------------------+<\/code><\/pre>\n\n\n\n<p>Hint \u4ece\u8bed\u6cd5\u4e0a\u770b\u662f\u4e00\u79cd\u7279\u6b8a\u7684 SQL \u6ce8\u91ca\uff0c\u6240\u4e0d\u540c\u7684\u662f\u5728\u6ce8\u91ca\u7684\u5de6\u6807\u8bb0\u540e\uff08<code>\/*<\/code> \u7b26\u53f7\uff09\u589e\u52a0\u4e86\u4e00\u4e2a <code>+<\/code>\u3002 \u56e0\u4e3a Hint \u662f\u6ce8\u91ca\uff0c\u6240\u4ee5\u5982\u679c\u56e0\u4e3a\u8bed\u6cd5\u51fa\u9519\u7684\u539f\u56e0\uff0c\u5bfc\u81f4 OBServer \u670d\u52a1\u7aef\u65e0\u6cd5\u8bc6\u522b SQL \u8bed\u53e5\u4e2d\u7684 Hint\uff0c\u4f18\u5316\u5668\u4f1a\u9009\u62e9\u5ffd\u7565\u7528\u6237\u6307\u5b9a\u7684 Hint\uff0c\u53bb\u751f\u6210\u9ed8\u8ba4\u7684\u6267\u884c\u8ba1\u5212\u3002\u53e6\u5916\uff0cHint \u53ea\u5f71\u54cd\u4f18\u5316\u5668\u751f\u6210\u7684\u6267\u884c\u8ba1\u5212\uff0c\u4e0d\u4f1a\u5f71\u54cd SQL \u8bed\u53e5\u7684\u8bed\u4e49\u3002<\/p>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p><strong>\u8bf4\u660e<\/strong><\/p>\n\n\n\n<p>\u5982\u679c\u4f7f\u7528 MySQL \u7684 C \u5ba2\u6237\u7aef\u6267\u884c\u5e26 Hint \u7684 SQL \u8bed\u53e5\uff0c\u9700\u8981\u4f7f\u7528 <code>-c<\/code> \u9009\u9879\u767b\u5f55\uff0c\u5426\u5219 MySQL \u5ba2\u6237\u7aef\u4f1a\u5c06 Hint \u4f5c\u4e3a\u6ce8\u91ca\u4ece\u7528\u6237 SQL \u8bed\u53e5\u4e2d\u53bb\u9664\uff0c\u5bfc\u81f4\u7cfb\u7edf\u65e0\u6cd5\u6536\u5230\u7528\u6237 Hint\u3002<\/p>\n<\/blockquote>\n\n\n\n<h3 class=\"wp-block-heading\">Hint \u53c2\u6570<\/h3>\n\n\n\n<p>Hint \u76f8\u5173\u53c2\u6570\u540d\u79f0\u3001\u8bed\u4e49\u548c\u8bed\u6cd5\u5982\u4e0b\u8868\u6240\u793a\u3002<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th><strong>\u540d\u79f0<\/strong><\/th><th><strong>\u8bed\u6cd5<\/strong><\/th><th><strong>\u8bed\u4e49<\/strong><\/th><\/tr><\/thead><tbody><tr><td>NO_REWRITE<\/td><td>NO_REWRITE<\/td><td>\u7981\u6b62 SQL \u6539\u5199\u3002<\/td><\/tr><tr><td>READ_CONSISTENCY<\/td><td>READ_CONSISTENCY(WEAK [STRONG])<\/td><td>\u8bfb\u4e00\u81f4\u6027\u8bbe\u7f6e\uff08\u5f31\/\u5f3a\uff09\u3002<\/td><\/tr><tr><td>INDEX_HINT<\/td><td>INDEX(table_name index_name)<\/td><td>\u8bbe\u7f6e\u8868\u7d22\u5f15\u3002<\/td><\/tr><tr><td>QUERY_TIMEOUT<\/td><td>QUERY_TIMEOUT(INTNUM)<\/td><td>\u8bbe\u7f6e\u8bed\u53e5\u8d85\u65f6\u65f6\u95f4\u3002<\/td><\/tr><tr><td>LOG_LEVEL<\/td><td>LOG_LEVEL([&#8216;]log_level[&#8216;])<\/td><td>\u8bbe\u7f6e\u65e5\u5fd7\u7ea7\u522b\uff0c\u5f53\u8bbe\u7f6e\u6a21\u5757\u7ea7\u522b\u8bed\u53e5\u65f6\u5019\uff0c\u4ee5\u7b2c\u4e00\u4e2a\u5355\u5f15\u53f7\uff08<code>'<\/code>\uff09\u4f5c\u4e3a\u5f00\u59cb\uff0c\u7b2c\u4e8c\u4e2a\u5355\u5f15\u53f7\uff08<code>'<\/code>\uff09\u4f5c\u4e3a\u7ed3\u675f\uff1b\u4f8b\u5982 <code>'DEBUG'<\/code>\u3002<\/td><\/tr><tr><td>LEADING<\/td><td>LEADING([qb_name] TBL_NAME_LIST)<\/td><td>\u8bbe\u7f6e\u8054\u63a5\u987a\u5e8f\u3002<\/td><\/tr><tr><td>ORDERED<\/td><td>ORDERED<\/td><td>\u8bbe\u7f6e\u6309\u7167 SQL \u4e2d\u7684\u987a\u5e8f\u8fdb\u884c\u8054\u63a5\u3002<\/td><\/tr><tr><td>FULL<\/td><td>FULL([qb_name] TBL_NAME)<\/td><td>\u8bbe\u7f6e\u8868\u8bbf\u95ee\u8def\u5f84\u4e3a\u4e3b\u8868\u7b49\u4ef7\u4e8e <code>INDEX(TBL_NAME PRIMARY)<\/code>\u3002<\/td><\/tr><tr><td>USE_PLAN_CACHE<\/td><td>USE_PLAN_CACHE(NONE[DEFAULT])<\/td><td>\u8bbe\u7f6e\u662f\u5426\u4f7f\u7528\u8ba1\u5212\u7f13\u5b58\uff1a<code>NONE<\/code>\uff1a\u8868\u793a\u4e0d\u4f7f\u7528\u8ba1\u5212\u7f13\u5b58\u3002<code>DEFAULT<\/code>\uff1a\u8868\u793a\u6309\u7167\u670d\u52a1\u5668\u672c\u8eab\u7684\u8bbe\u7f6e\u6765\u51b3\u5b9a\u662f\u5426\u4f7f\u7528\u8ba1\u5212\u7f13\u5b58\u3002<\/td><\/tr><tr><td>USE_MERGE<\/td><td>USE_MERGE([qb_name] TBL_NAME_LIST)<\/td><td>\u8bbe\u7f6e\u6307\u5b9a\u8868\u5728\u4f5c\u4e3a\u53f3\u8868\u65f6\u4f7f\u7528 Merge Join\u3002<\/td><\/tr><tr><td>USE_HASH<\/td><td>USE_HASH([qb_name] TBL_NAME_LIST)<\/td><td>\u8bbe\u7f6e\u6307\u5b9a\u8868\u5728\u4f5c\u4e3a\u53f3\u8868\u65f6\u4f7f\u7528 Hash Join\u3002<\/td><\/tr><tr><td>NO_USE_HASH<\/td><td>NO_USE_HASH([qb_name] TBL_NAME_LIST)<\/td><td>\u8bbe\u7f6e\u6307\u5b9a\u8868\u5728\u4f5c\u4e3a\u53f3\u8868\u65f6\u4e0d\u4f7f\u7528 Hash Join\u3002<\/td><\/tr><tr><td>USE_NL<\/td><td>USE_NL([qb_name] TBL_NAME_LIST)<\/td><td>\u8bbe\u7f6e\u6307\u5b9a\u8868\u5728\u4f5c\u4e3a\u53f3\u8868\u65f6\u4f7f\u7528 Nested Loop Join\u3002<\/td><\/tr><tr><td>USE_BNL<\/td><td>USE_BNL([qb_name] TBL_NAME_LIST)<\/td><td>\u8bbe\u7f6e\u6307\u5b9a\u8868\u5728\u4f5c\u4e3a\u53f3\u8868\u65f6\u4f7f\u7528 Block Nested Loop Join<\/td><\/tr><tr><td>USE_HASH_AGGREGATION<\/td><td>USE_HASH_AGGREGATION([qb_name])<\/td><td>\u8bbe\u7f6e\u805a\u5408\u7b97\u6cd5\u4e3a Hash\u3002\u4f8b\u5982 Hash Group By \u6216\u8005 Hash Distinct\u3002<\/td><\/tr><tr><td>NO_USE_HASH_AGGREGATION<\/td><td>NO_USE_HASH_AGGREGATION([qb_name])<\/td><td>\u8bbe\u7f6e Aggregate \u65b9\u6cd5\u4e0d\u4f7f\u7528 Hash Aggregate\uff0c\u4f7f\u7528 Merge Group By \u6216\u8005 Merge Distinct\u3002<\/td><\/tr><tr><td>USE_LATE_MATERIALIZATION<\/td><td>USE_LATE_MATERIALIZATION<\/td><td>\u8bbe\u7f6e\u4f7f\u7528\u665a\u671f\u7269\u5316\u3002<\/td><\/tr><tr><td>NO_USE_LATE_MATERIALIZATION<\/td><td>NO_USE_LATE_MATERIALIZATION<\/td><td>\u8bbe\u7f6e\u4e0d\u4f7f\u7528\u665a\u671f\u7269\u5316\u3002<\/td><\/tr><tr><td>TRACE_LOG<\/td><td>TRACE_LOG<\/td><td>\u8bbe\u7f6e\u6536\u96c6 Trace \u8bb0\u5f55\u7528\u4e8e SHOW TRACE \u5c55\u793a\u3002<\/td><\/tr><tr><td>QB_NAME<\/td><td>QB_NAME( NAME )<\/td><td>\u8bbe\u7f6e Query Block \u7684\u540d\u79f0\u3002<\/td><\/tr><tr><td>PARALLEL<\/td><td>PARALLEL(INTNUM)<\/td><td>\u8bbe\u7f6e\u5206\u5e03\u5f0f\u6267\u884c\u5e76\u884c\u5ea6\u3002<\/td><\/tr><tr><td>TOPK<\/td><td>TOPK(PRECISION MINIMUM_ROWS)<\/td><td>\u8bbe\u7f6e\u6a21\u7cca\u67e5\u8be2\u7684\u7cbe\u5ea6\u548c\u6700\u5c0f\u884c\u6570\u3002 \u5176\u4e2d PRECSION \u4e3a\u6574\u578b\uff0c\u53d6\u503c\u8303\u56f4 [0\uff0c100]\uff0c\u8868\u793a\u6a21\u7cca\u67e5\u8be2\u7684\u884c\u6570\u767e\u5206\u6bd4\uff1bMINIMUM_ROWS \u4e3a\u6700\u5c0f\u8fd4\u56de\u884c\u6570\u3002<\/td><\/tr><tr><td>MAX_CONCURRENT|MAX_CONCURRENT(n)<\/td><td>\u9650\u5236\u8fd9\u4e2a SQL \u6587\u672c\u7684\u5e76\u53d1\u6570\u3002<\/td><td><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p><strong>\u8bf4\u660e<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>QB_NAME \u8bed\u6cd5\u662f: @NAME<\/li>\n\n\n\n<li>TBL_NAME \u8bed\u6cd5\u662f: [db_name.]relation_name [qb_name]<\/li>\n<\/ul>\n<\/blockquote>\n\n\n\n<h3 class=\"wp-block-heading\">QB_NAME \u53c2\u6570<\/h3>\n\n\n\n<p>\u5728 DML \u8bed\u53e5\u4e2d\uff0c\u6bcf\u4e00\u4e2a Query Block \u90fd\u4f1a\u6709\u4e00\u4e2a QB_NAME\uff08Query Block Name\uff09\uff0c\u53ef\u4ee5\u7531\u7528\u6237\u6307\u5b9a\uff0c\u4e5f\u53ef\u4ee5\u7531\u7cfb\u7edf\u81ea\u52a8\u751f\u6210\u3002\u6bcf\u4e00\u4e2a Query Block \u90fd\u662f\u4e00\u4e2a\u8bed\u4e49\u4e0a\u5b8c\u6574\u7684\u67e5\u8be2\u8bed\u53e5\uff0c\u7b80\u5355\u6765\u770b\u5c31\u662f\u628a SQL \u6309 select\u3001delete \u8fd9\u4e9b\u8bcd\u63d0\u53d6\u51fa\u6765\u5e76\u7ed3\u6784\u5316\u4e4b\u540e\uff0c\u6309\u4ece\u5de6\u5230\u53f3\u7684\u65b9\u5f0f\u6807\u53f7\u3002Query Block \u7684\u4ecb\u7ecd\u8be6\u89c1\u5b98\u7f51\u300aOceanBase \u6570\u636e\u5e93\u300b\u77e5\u8bc6\u5e93 <a href=\"https:\/\/www.oceanbase.com\/knowledge-base\/oceanbase-database-1000000000217859?back=kb\">\u6027\u80fd\u8bca\u65ad\u548c\u4f18\u5316\/SQL \u8bca\u65ad\u548c\u4f18\u5316\/Query Block \u4ecb\u7ecd<\/a>\u3002<\/p>\n\n\n\n<p>\u5728\u7528\u6237\u6ca1\u6709\u7528 Hint \u6307\u5b9a QB_NAME \u7684\u65f6\u5019\uff0c\u7cfb\u7edf\u4f1a\u6309\u7167 SEL$1\u3001SEL$2\u3001UPD$1\u3001DEL$1 \u65b9\u5f0f\u4ece\u5de6\u5230\u53f3\uff08\u5b9e\u9645\u4e5f\u662f Resolver \u7684\u89e3\u6790\u987a\u5e8f\uff09\u4f9d\u6b21\u751f\u6210\u3002<\/p>\n\n\n\n<p>\u901a\u8fc7 QB_NAME \u53ef\u4ee5\u7cbe\u786e\u5b9a\u4f4d\u5230\u6bcf\u4e00\u4e2a\u8868\uff0c\u4e5f\u53ef\u4ee5\u5728\u67d0\u5904\u6307\u5b9a\u4efb\u610f Query Block \u7684\u884c\u4e3a\u3002TBL_NAME \u4e2d\u7684 QB_NAME \u7528\u4e8e\u5b9a\u4f4d\u8868\uff0c\u5728 Hint \u4e2d\u6700\u524d\u9762\u7684 QB_NAME \u7528\u4e8e\u5b9a\u4f4d Hint \u4f5c\u7528\u4e8e\u54ea\u4e00\u4e2a Query Block\u3002<\/p>\n\n\n\n<p>\u5982\u4e0b\u4f8b\u6240\u793a\uff0c\u5bf9\u4e8e <code>SELECT *FROM t1, (SELECT* FROM t2 WHERE c2 = 1 LIMIT 5) WHERE t1.c1 = 1;<\/code> \u8fd9\u6761 SQL\uff0c\u6309\u7167\u9ed8\u8ba4\u89c4\u5219\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u7b2c\u4e00\u4e2a Query Block SEL$1 \u662f\u6700\u5916\u5c42\u7684\uff1a<code>SELECT * FROM t1, VIEW1 WHERE t1.c1 = 1<\/code>\u3002<\/li>\n\n\n\n<li>\u7b2c\u4e8c\u4e2a Query Block SEL$2 \u662f VIEW1\uff08\u5373\u8ba1\u5212\u91cc\u7684 ANONYMOUS_VIEW1\uff09\uff1a<code>SELECT * FROM t2 WHERE c2 = 1 LIMIT 5<\/code>\u3002<\/li>\n<\/ul>\n\n\n\n<p>\u4f18\u5316\u5668\u4e3a SEL$1 \u4e2d\u7684 <code>t1<\/code> \u8868\u9009\u62e9\u8d70\u7d22\u5f15 <code>t1_c1<\/code> \u8def\u5f84\uff0c\u800c\u4e3a SEL$2 \u4e2d\u7684 <code>t2<\/code> \u8868\u9009\u62e9\u4e3b\u8868\uff08Primary\uff09\u8bbf\u95ee\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>CREATE TABLE t1(c1 INT, c2 INT, KEY t1_c1(c1));\n\nCREATE TABLE t2(c1 INT, c2 INT, KEY t2_c1(c1));\n\nEXPLAIN EXTENDED_NOADDR SELECT * FROM t1, (SELECT * FROM t2 WHERE c2 = 1 LIMIT 5) WHERE t1.c1 = 1;\n+-----------------------------------------------------------------------------------------------------------+\n| Query Plan                                                                                                |\n+-----------------------------------------------------------------------------------------------------------+\n| ======================================================================                                    |\n| |ID|OPERATOR                   |NAME           |EST.ROWS|EST.TIME(us)|                                    |\n| ----------------------------------------------------------------------                                    |\n| |0 |NESTED-LOOP JOIN CARTESIAN |               |1       |11          |                                    |\n| |1 |\u251c\u2500TABLE RANGE SCAN         |t1(t1_c1)      |1       |7           |                                    |\n| |2 |\u2514\u2500MATERIAL                 |               |1       |4           |                                    |\n| |3 |  \u2514\u2500SUBPLAN SCAN           |ANONYMOUS_VIEW1|1       |4           |                                    |\n| |4 |    \u2514\u2500TABLE FULL SCAN      |t2             |1       |4           |                                    |\n| ======================================================================                                    |\n| Outputs &amp; filters:                                                                                        |\n| -------------------------------------                                                                     |\n|   0 - output(&#91;t1.c1], &#91;t1.c2], &#91;.c1], &#91;.c2]), filter(nil), rowset=16                                      |\n|       conds(nil), nl_params_(nil), use_batch=false                                                        |\n|   1 - output(&#91;t1.c1], &#91;t1.c2]), filter(nil), rowset=16                                                    |\n|       access(&#91;t1.__pk_increment], &#91;t1.c1], &#91;t1.c2]), partitions(p0)                                       |\n|       is_index_back=true, is_global_index=false,                                                          |\n|       range_key(&#91;t1.c1], &#91;t1.__pk_increment]), range(1,MIN ; 1,MAX),                                      |\n|       range_cond(&#91;t1.c1 = 1])                                                                             |\n|   2 - output(&#91;.c1], &#91;.c2]), filter(nil), rowset=16                                                        |\n|   3 - output(&#91;.c1], &#91;.c2]), filter(nil), rowset=16                                                        |\n|       access(&#91;.c1], &#91;.c2])                                                                                |\n|   4 - output(&#91;t2.c1], &#91;t2.c2]), filter(&#91;t2.c2 = 1]), rowset=16                                            |\n|       access(&#91;t2.c2], &#91;t2.c1]), partitions(p0)                                                            |\n|       limit(5), offset(nil), is_index_back=false, is_global_index=false, filter_before_indexback&#91;false],  |\n|       range_key(&#91;t2.__pk_increment]), range(MIN ; MAX)always true                                         |\n| Used Hint:                                                                                                |\n| -------------------------------------                                                                     |\n|   \/*+                                                                                                     |\n|                                                                                                           |\n|   *\/                                                                                                      |\n| Qb name trace:                                                                                            |\n| -------------------------------------                                                                     |\n|   stmt_id:0, stmt_type:T_EXPLAIN                                                                          |\n|   stmt_id:1, SEL$1                                                                                        |\n|   stmt_id:2, SEL$2                                                                                        |\n| Outline Data:                                                                                             |\n| -------------------------------------                                                                     |\n|   \/*+                                                                                                     |\n|       BEGIN_OUTLINE_DATA                                                                                  |\n|       LEADING(@\"SEL$1\" (\"test\".\"t1\"@\"SEL$1\" \"ANONYMOUS_VIEW1\"@\"SEL$1\"))                                   |\n|       USE_NL(@\"SEL$1\" \"ANONYMOUS_VIEW1\"@\"SEL$1\")                                                          |\n|       USE_NL_MATERIALIZATION(@\"SEL$1\" \"ANONYMOUS_VIEW1\"@\"SEL$1\")                                          |\n|       INDEX(@\"SEL$1\" \"test\".\"t1\"@\"SEL$1\" \"t1_c1\")                                                         |\n|       FULL(@\"SEL$2\" \"test\".\"t2\"@\"SEL$2\")                                                                  |\n|       OPTIMIZER_FEATURES_ENABLE('4.0.0.0')                                                                |\n|       END_OUTLINE_DATA                                                                                    |\n|   *\/                                                                                                      |\n|   ......                                                                                                  |\n+-----------------------------------------------------------------------------------------------------------+<\/code><\/pre>\n\n\n\n<p>\u5982\u679c SQL \u901a\u8fc7 Hint \u6765\u6307\u5b9a SEL$1 \u7684 <code>t1<\/code> \u8868\u8d70\u4e3b\u8868\uff0cSEL$2 \u7684 <code>t2<\/code> \u8868\u8d70\u7d22\u5f15\uff0c\u793a\u4f8b\u5982\u4e0b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>EXPLAIN EXTENDED_NOADDR\nSELECT \/*+ INDEX(@SEL$1 t1 PRIMARY) INDEX(@SEL$2 t2 t2_c1) *\/ *\nFROM t1 , (SELECT * FROM t2 WHERE c2 = 1 LIMIT 5) WHERE t1.c1 = 1;\n+----------------------------------------------------------------------------------------------------------+\n| Query Plan                                                                                               |\n+----------------------------------------------------------------------------------------------------------+\n| ======================================================================                                   |\n| |ID|OPERATOR                   |NAME           |EST.ROWS|EST.TIME(us)|                                   |\n| ----------------------------------------------------------------------                                   |\n| |0 |NESTED-LOOP JOIN CARTESIAN |               |1       |11          |                                   |\n| |1 |\u251c\u2500TABLE FULL SCAN          |t1             |1       |4           |                                   |\n| |2 |\u2514\u2500MATERIAL                 |               |1       |7           |                                   |\n| |3 |  \u2514\u2500SUBPLAN SCAN           |ANONYMOUS_VIEW1|1       |7           |                                   |\n| |4 |    \u2514\u2500TABLE FULL SCAN      |t2(t2_c1)      |1       |7           |                                   |\n| ======================================================================                                   |\n| Outputs &amp; filters:                                                                                       |\n| -------------------------------------                                                                    |\n|   0 - output(&#91;t1.c1], &#91;t1.c2], &#91;.c1], &#91;.c2]), filter(nil), rowset=16                                     |\n|       conds(nil), nl_params_(nil), use_batch=false                                                       |\n|   1 - output(&#91;t1.c1], &#91;t1.c2]), filter(&#91;t1.c1 = 1]), rowset=16                                           |\n|       access(&#91;t1.c1], &#91;t1.c2]), partitions(p0)                                                           |\n|       is_index_back=false, is_global_index=false, filter_before_indexback&#91;false],                        |\n|       range_key(&#91;t1.__pk_increment]), range(MIN ; MAX)always true                                        |\n|   2 - output(&#91;.c1], &#91;.c2]), filter(nil), rowset=16                                                       |\n|   3 - output(&#91;.c1], &#91;.c2]), filter(nil), rowset=16                                                       |\n|       access(&#91;.c1], &#91;.c2])                                                                               |\n|   4 - output(&#91;t2.c1], &#91;t2.c2]), filter(&#91;t2.c2 = 1]), rowset=16                                           |\n|       access(&#91;t2.__pk_increment], &#91;t2.c2], &#91;t2.c1]), partitions(p0)                                      |\n|       limit(5), offset(nil), is_index_back=true, is_global_index=false, filter_before_indexback&#91;false],  |\n|       range_key(&#91;t2.c1], &#91;t2.__pk_increment]), range(MIN,MIN ; MAX,MAX)always true                       |\n| Used Hint:                                                                                               |\n| -------------------------------------                                                                    |\n|   \/*+                                                                                                    |\n|                                                                                                          |\n|       INDEX(\"t1\" \"primary\")                                                                              |\n|       INDEX(@\"SEL$2\" \"t2\" \"t2_c1\")                                                                       |\n|   *\/                                                                                                     |\n| Qb name trace:                                                                                           |\n| -------------------------------------                                                                    |\n|   stmt_id:0, stmt_type:T_EXPLAIN                                                                         |\n|   stmt_id:1, SEL$1                                                                                       |\n|   stmt_id:2, SEL$2                                                                                       |\n| Outline Data:                                                                                            |\n| -------------------------------------                                                                    |\n|   \/*+                                                                                                    |\n|       BEGIN_OUTLINE_DATA                                                                                 |\n|       LEADING(@\"SEL$1\" (\"test\".\"t1\"@\"SEL$1\" \"ANONYMOUS_VIEW1\"@\"SEL$1\"))                                  |\n|       USE_NL(@\"SEL$1\" \"ANONYMOUS_VIEW1\"@\"SEL$1\")                                                         |\n|       USE_NL_MATERIALIZATION(@\"SEL$1\" \"ANONYMOUS_VIEW1\"@\"SEL$1\")                                         |\n|       FULL(@\"SEL$1\" \"test\".\"t1\"@\"SEL$1\")                                                                 |\n|       INDEX(@\"SEL$2\" \"test\".\"t2\"@\"SEL$2\" \"t2_c1\")                                                        |\n|       OPTIMIZER_FEATURES_ENABLE('4.0.0.0')                                                               |\n|       END_OUTLINE_DATA                                                                                   |\n|   *\/                                                                                                     |\n|   ......                                                                                                 |\n+----------------------------------------------------------------------------------------------------------+<\/code><\/pre>\n\n\n\n<p>\u8bfb\u8005\u53ef\u4ee5\u81ea\u884c\u7814\u7a76\u4e00\u4e0b\uff0c\u5728\u52a0\u8fd9\u4e2a <code>Hint \/*+ INDEX(t1 PRIMARY) INDEX(@SEL$2 t2 t2_c1)*\/<\/code> \u524d\u540e\uff0c\u8ba1\u5212 Query Plan \u90e8\u5206\u548c Outline Data \u90e8\u5206\u6709\u4ec0\u4e48\u53d8\u5316\uff0c\u4ee5\u53ca\u53d8\u5316\u662f\u5426\u662f\u7b26\u5408\u9884\u671f\u7684\uff1f<\/p>\n\n\n\n<p>\u4e0a\u8ff0\u793a\u4f8b\u4e2d\u7684 Hint \u4e5f\u53ef\u4ee5\u5199\u6210\u5982\u4e0b\u4e09\u79cd\u65b9\u5f0f\uff0c\u8fd9\u51e0\u79cd\u5199\u6cd5\u90fd\u662f\u7b49\u4ef7\u7684\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u65b9\u5f0f\u4e00\uff1a<\/li>\n<\/ul>\n\n\n\n<pre class=\"wp-block-code\"><code>  SELECT \/*+INDEX(@SEL$1 t1 PRIMARY) INDEX(@SEL$2 t2 t2_c1)*\/ * FROM t1 , (SELECT * FROM t2 WHERE c2 = 1 LIMIT 5) WHERE t1.c1 = 1;<\/code><\/pre>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u65b9\u5f0f\u4e8c\uff1a<\/li>\n<\/ul>\n\n\n\n<pre class=\"wp-block-code\"><code>  SELECT \/*+INDEX(t1 PRIMARY) INDEX(@SEL$2 t2@SEL$2 t2_c1)*\/ * FROM t1 , (SELECT * FROM t2 WHERE c2 = 1 LIMIT 5) WHERE t1.c1 = 1;<\/code><\/pre>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u65b9\u5f0f\u4e09\uff1a<\/li>\n<\/ul>\n\n\n\n<pre class=\"wp-block-code\"><code>  SELECT \/*+INDEX(t1 PRIMARY)*\/ * FROM t1 , (SELECT \/*+INDEX(t2 t2_c1)*\/ * FROM t2 WHERE c2 = 1 LIMIT 5) WHERE t1.c1 = 1;<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\">Hint \u4f7f\u7528\u89c4\u5219<\/h3>\n\n\n\n<p>Hint \u7684\u4e00\u822c\u4f7f\u7528\u89c4\u5219\u5982\u4e0b\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u5bf9\u4e8e\u6ca1\u6709\u6307\u5b9a Query Block \u7684 Hint\uff0c\u8868\u660e\u4f5c\u7528\u4e8e\u672c Query Block\u3002<\/li>\n\n\n\n<li>\u793a\u4f8b 1\uff1a\u7531\u4e8e Hint \u5199\u5728 Query Block 1\uff0c\u4f46 Hint \u4e2d\u7684 <code>t2<\/code> \u8868\u53ea\u51fa\u73b0\u5728 Query Block 2\uff0c\u4e14\u4f18\u5316\u5668\u65e0\u6cd5\u901a\u8fc7\u6539\u5199 SQL \u5c06 SEL$2 \u4e2d\u7684 <code>t2<\/code> \u8868\u63d0\u5347\u5230 SEL$1 \u4e2d\uff0c\u5219 Hint \u65e0\u6cd5\u751f\u6548\u3002 <code>EXPLAIN SELECT \/*+INDEX(t2 t2_c1)*\/ * FROM t1 , (SELECT * FROM t2 WHERE c2 = 1 LIMIT 5) WHERE t1.c1 = 1;<\/code> \u8f93\u51fa\u5982\u4e0b\uff1a <code>+-----------------------------------------------------------------------------------------------------------+ | Query Plan | +-----------------------------------------------------------------------------------------------------------+ | ====================================================================== | | |ID|OPERATOR |NAME |EST.ROWS|EST.TIME(us)| | | ---------------------------------------------------------------------- | | |0 |NESTED-LOOP JOIN CARTESIAN | |1 |11 | | | |1 |\u251c\u2500TABLE RANGE SCAN |t1(t1_c1) |1 |7 | | | |2 |\u2514\u2500MATERIAL | |1 |4 | | | |3 | \u2514\u2500SUBPLAN SCAN |ANONYMOUS_VIEW1|1 |4 | | | |4 | \u2514\u2500TABLE FULL SCAN |t2 |1 |4 | | | ====================================================================== | | ...... | +-----------------------------------------------------------------------------------------------------------+<\/code><\/li>\n\n\n\n<li>\u793a\u4f8b 2\uff1a\u5982\u679c SQL \u53ef\u4ee5\u901a\u8fc7\u4f18\u5316\u5668\u6539\u5199\u5c06 <code>t2<\/code> \u8868\u63d0\u5347\u5230 SEL$1\uff0c\u5219 Hint \u751f\u6548\u3002\u5982\u4e0b\u9762\u8fd9\u4e2a\u8ba1\u5212\u6240\u793a\uff0c\u539f\u672c\u7684 SQL \u660e\u663e\u662f\u88ab\u6539\u5199\u6210\u4e86\u4e00\u6761\u4e0d\u5b58\u5728\u533f\u540d\u89c6\u56fe\u7684 SQL\uff1a<code>SELECT \/*+INDEX(t2 t2_c1)*\/ * FROM t1, t2 WHERE t1.c1 = 1 and t2.c2 = 1;<\/code>\uff0c\u5728\u8fd9\u6761\u88ab\u6539\u5199\u4e4b\u540e\u7684 SQL \u4e2d\uff0ct2 \u8868\u88ab\u63d0\u5347\u5230\u4e86\u6700\u5916\u5c42\u7684 SEL$1 \u91cc\uff0c\u6240\u4ee5 Hint \u4f1a\u751f\u6548\u3002 <code>EXPLAIN SELECT \/*+ INDEX(t2 t2_c1) *\/ * FROM t1 , (SELECT * FROM t2 WHERE c2 = 1) WHERE t1.c1 = 1;<\/code> \u8f93\u51fa\u5982\u4e0b\uff1a <code>+------------------------------------------------------------------------------------+ | Query Plan | +------------------------------------------------------------------------------------+ | ================================================================ | | |ID|OPERATOR |NAME |EST.ROWS|EST.TIME(us)| | | ---------------------------------------------------------------- | | |0 |NESTED-LOOP JOIN CARTESIAN | |1 |13 | | | |1 |\u251c\u2500TABLE RANGE SCAN |t1(t1_c1)|1 |7 | | | |2 |\u2514\u2500MATERIAL | |1 |7 | | | |3 | \u2514\u2500TABLE FULL SCAN |t2(t2_c1)|1 |7 | | | ================================================================ | | Outputs &amp; filters: | | ------------------------------------- | | 0 - output([t1.c1], [t1.c2], [t2.c1], [t2.c2]), filter(nil), rowset=16 | | conds(nil), nl_params_(nil), use_batch=false | | 1 - output([t1.c1], [t1.c2]), filter(nil), rowset=16 | | access([t1.__pk_increment], [t1.c1], [t1.c2]), partitions(p0) | | is_index_back=true, is_global_index=false, | | range_key([t1.c1], [t1.__pk_increment]), range(1,MIN ; 1,MAX), | | range_cond([t1.c1 = 1]) | | 2 - output([t2.c1], [t2.c2]), filter(nil), rowset=16 | | 3 - output([t2.c2], [t2.c1]), filter([t2.c2 = 1]), rowset=16 | | access([t2.__pk_increment], [t2.c2], [t2.c1]), partitions(p0) | | is_index_back=true, is_global_index=false, filter_before_indexback[false], | | range_key([t2.c1], [t2.__pk_increment]), range(MIN,MIN ; MAX,MAX)always true | +------------------------------------------------------------------------------------+<\/code><\/li>\n\n\n\n<li>\u5982\u679c\u6307\u5b9a\u8868\u884c\u4e3a\uff0c\u4f46\u5728\u672c Query Block \u4e2d\u6ca1\u6709\u627e\u5230\u8be5\u8868\uff0c\u6216\u8005\u53d1\u751f\u51b2\u7a81\uff0c\u90a3\u4e48 Hint \u90fd\u5c06\u65e0\u6548\u3002<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">\u5e38\u7528 Hint<\/h3>\n\n\n\n<p>\u4e0e\u5176\u4ed6\u6570\u636e\u5e93\u7684\u884c\u4e3a\u76f8\u6bd4\uff0cOceanBase \u6570\u636e\u5e93\u4f18\u5316\u5668\u662f\u52a8\u6001\u89c4\u5212\u7684\uff0c\u5df2\u7ecf\u8003\u8651\u4e86\u6240\u6709\u53ef\u80fd\u7684\u6700\u4f18\u8def\u5f84\uff0cHint \u4e3b\u8981\u4f5c\u7528\u662f\u6307\u5b9a\u4f18\u5316\u5668\u7684\u884c\u4e3a\uff0c\u5e76\u6309\u7167 Hint \u6267\u884c SQL \u67e5\u8be2\u3002\u4e0b\u9762\u4f1a\u4ecb\u7ecd\u7528\u6237\u6700\u4e3a\u5e38\u7528\u7684\u4e00\u4e9b Hint\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">INDEX Hint<\/h4>\n\n\n\n<p>INDEX Hint \u7684\u8bed\u6cd5\u5982\u4e0b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>SELECT\/*+ INDEX(table_name index_name) *\/ * FROM table_name;<\/code><\/pre>\n\n\n\n<p>\u5728 SQL \u8bed\u53e5\u4e2d\uff0c\u8868\u540d\u5b58\u5728\u522b\u540d\u5373 <code>table_name [AS] alias<\/code>\uff0c\u5fc5\u987b\u5199\u8868\u522b\u540d\uff0c\u624d\u80fd\u4f7f INDEX \u751f\u6548\u3002\u793a\u4f8b\u5982\u4e0b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>create table t1(c1 int, c2 int, c3 int);\n\ncreate index idx1 on t1(c1);\n\ncreate index idx2 on t1(c2);\n\n-- \u63d2\u5165 1000 \u884c\u6d4b\u8bd5\u6570\u636e\ninsert into t1 with recursive cte(n) as (select 1 from dual union all select n + 1 from cte where n &lt; 1000) select n, mod(n, 3), n from cte;\n\n-- \u6536\u96c6\u6307\u5b9a\u8868 t1 \u7684\u7edf\u8ba1\u4fe1\u606f\nanalyze table t1 COMPUTE STATISTICS for all columns size 128;\n\n-- \u5bf9\u4e8e\u8fd9 1000 \u884c\u6d4b\u8bd5\u6570\u636e\u7684\u6570\u636e\u7279\u5f81\uff0cc1 = 1 \u8fc7\u6ee4\u6027\u4f18\u4e8e c2 = 1\n-- \u6240\u4ee5\u5728\u6ca1\u6709 index hint \u6216\u8005 hint \u4e0d\u751f\u6548\u65f6\uff0c\u4f18\u5316\u5668\u5728\u751f\u6210\u8ba1\u5212\u7684\u8fc7\u7a0b\u4e2d\uff0c\u9ed8\u8ba4\u4f1a\u4f18\u5148\u9009\u62e9\u4f7f\u7528 idx1 \u8fd9\u4e2a\u7d22\u5f15\nexplain select * from t1 where c1 = 1 and c2 = 1;\n+-----------------------------------------------------------------------------------+\n| Query Plan                                                                        |\n+-----------------------------------------------------------------------------------+\n| ====================================================                              |\n| |ID|OPERATOR        |NAME    |EST.ROWS|EST.TIME(us)|                              |\n| ----------------------------------------------------                              |\n| |0 |TABLE RANGE SCAN|t1(idx1)|1       |7           |                              |\n| ====================================================                              |\n| Outputs &amp; filters:                                                                |\n| -------------------------------------                                             |\n|   0 - output(&#91;t1.c1], &#91;t1.c2], &#91;t1.c3]), filter(&#91;t1.c2 = 1]), rowset=16           |\n|       access(&#91;t1.__pk_increment], &#91;t1.c1], &#91;t1.c2], &#91;t1.c3]), partitions(p0)      |\n|       is_index_back=true, is_global_index=false, filter_before_indexback&#91;false],  |\n|       range_key(&#91;t1.c1], &#91;t1.__pk_increment]), range(1,MIN ; 1,MAX),              |\n|       range_cond(&#91;t1.c1 = 1])                                                     |\n+-----------------------------------------------------------------------------------+\n\n-- \u751f\u6548\u7684 index hint\nexplain select \/*+index(t idx2)*\/ * from t1 as t where c1 = 1 and c2 = 1;\n+-----------------------------------------------------------------------------------+\n| Query Plan                                                                        |\n+-----------------------------------------------------------------------------------+\n| ===================================================                               |\n| |ID|OPERATOR        |NAME   |EST.ROWS|EST.TIME(us)|                               |\n| ---------------------------------------------------                               |\n| |0 |TABLE RANGE SCAN|t(idx2)|1       |871         |                               |\n| ===================================================                               |\n| Outputs &amp; filters:                                                                |\n| -------------------------------------                                             |\n|   0 - output(&#91;t.c1], &#91;t.c2], &#91;t.c3]), filter(&#91;t.c1 = 1]), rowset=16               |\n|       access(&#91;t.__pk_increment], &#91;t.c1], &#91;t.c2], &#91;t.c3]), partitions(p0)          |\n|       is_index_back=true, is_global_index=false, filter_before_indexback&#91;false],  |\n|       range_key(&#91;t.c2], &#91;t.__pk_increment]), range(1,MIN ; 1,MAX),                |\n|       range_cond(&#91;t.c2 = 1])                                                      |\n+-----------------------------------------------------------------------------------+\n\n-- \u4e0d\u751f\u6548\u7684 index\uff0c\u56e0\u4e3a t1 \u5df2\u7ecf\u88ab\u8d4b\u4e88\u4e86\u4e00\u4e2a\u522b\u540d t\nexplain select \/*+index(t1 idx2)*\/ * from t1 t where c1 = 1 and c2 = 1;\n+-----------------------------------------------------------------------------------+\n| Query Plan                                                                        |\n+-----------------------------------------------------------------------------------+\n| ===================================================                               |\n| |ID|OPERATOR        |NAME   |EST.ROWS|EST.TIME(us)|                               |\n| ---------------------------------------------------                               |\n| |0 |TABLE RANGE SCAN|t(idx1)|1       |7           |                               |\n| ===================================================                               |\n| Outputs &amp; filters:                                                                |\n| -------------------------------------                                             |\n|   0 - output(&#91;t.c1], &#91;t.c2], &#91;t.c3]), filter(&#91;t.c2 = 1]), rowset=16               |\n|       access(&#91;t.__pk_increment], &#91;t.c1], &#91;t.c2], &#91;t.c3]), partitions(p0)          |\n|       is_index_back=true, is_global_index=false, filter_before_indexback&#91;false],  |\n|       range_key(&#91;t.c1], &#91;t.__pk_increment]), range(1,MIN ; 1,MAX),                |\n|       range_cond(&#91;t.c1 = 1])                                                      |\n+-----------------------------------------------------------------------------------+<\/code><\/pre>\n\n\n\n<h4 class=\"wp-block-heading\">FULL Hint<\/h4>\n\n\n\n<p>FULL Hint \u7684\u8bed\u6cd5\u662f\u7528\u4e8e\u6307\u5b9a\u8868\u4f7f\u7528\u4e3b\u8868\u626b\u63cf\uff0c\u7b49\u4ef7\u4e8e <code>INDEX Hint \/*+ INDEX(table_name PRIMARY)*\/<\/code>\u3002<\/p>\n\n\n\n<p>\u793a\u4f8b\u5982\u4e0b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>create table t1(c1 int, c2 int, c3 int);\n\ncreate index idx1 on t1(c1);\n\n-- c1 \u4e0a\u6709\u4e00\u4e2a\u7d22\u5f15 idx1\uff0c\u4e14\u8fc7\u6ee4\u6761\u4ef6\u4e2d\u7684\u5217\u548c\u7ed3\u679c\u5217\u90fd\u662f c1\uff0c\u6240\u4ee5\u4f18\u5316\u5668\u4f1a\u9ed8\u8ba4\u9009\u62e9\u4f7f\u7528 idx1\nexplain select c1 from t1 where c1 = 1;\n+-----------------------------------------------------------------------+\n| Query Plan                                                            |\n+-----------------------------------------------------------------------+\n| ====================================================                  |\n| |ID|OPERATOR        |NAME    |EST.ROWS|EST.TIME(us)|                  |\n| ----------------------------------------------------                  |\n| |0 |TABLE RANGE SCAN|t1(idx1)|1       |4           |                  |\n| ====================================================                  |\n| Outputs &amp; filters:                                                    |\n| -------------------------------------                                 |\n|   0 - output(&#91;t1.c1]), filter(nil), rowset=4                          |\n|       access(&#91;t1.c1]), partitions(p0)                                 |\n|       is_index_back=false, is_global_index=false,                     |\n|       range_key(&#91;t1.c1], &#91;t1.__pk_increment]), range(1,MIN ; 1,MAX),  |\n|       range_cond(&#91;t1.c1 = 1])                                         |\n+-----------------------------------------------------------------------+\n\n-- \u901a\u8fc7 hint \u8ba9\u8ba1\u5212\u4e0d\u8d70\u7d22\u5f15\uff0c\u53d8\u4e3a\u5168\u8868\u626b\u63cf\nexplain select \/*+ FULL(t1) *\/ c1 from t1 where c1 = 1;\n+------------------------------------------------------------------------------------+\n| Query Plan                                                                         |\n+------------------------------------------------------------------------------------+\n| ===============================================                                    |\n| |ID|OPERATOR       |NAME|EST.ROWS|EST.TIME(us)|                                    |\n| -----------------------------------------------                                    |\n| |0 |TABLE FULL SCAN|t1  |1       |4           |                                    |\n| ===============================================                                    |\n| Outputs &amp; filters:                                                                 |\n| -------------------------------------                                              |\n|   0 - output(&#91;t1.c1]), filter(&#91;t1.c1 = 1]), rowset=4                               |\n|       access(&#91;t1.c1]), partitions(p0)                                              |\n|       is_index_back=false, is_global_index=false, filter_before_indexback&#91;false],  |\n|       range_key(&#91;t1.__pk_increment]), range(MIN ; MAX)always true                  |\n+------------------------------------------------------------------------------------+\n\n-- \u901a\u8fc7 hint \u8ba9\u8ba1\u5212\u4e0d\u8d70\u7d22\u5f15\uff0c\u53d8\u4e3a\u5168\u8868\u626b\u63cf\uff0c\u548c\u4e0a\u9762\u90a3\u6761 SQL \u7b49\u4ef7\nexplain select \/*+ index(t1 PRIMARY) *\/ c1 from t1 where c1 = 1;\n+------------------------------------------------------------------------------------+\n| Query Plan                                                                         |\n+------------------------------------------------------------------------------------+\n| ===============================================                                    |\n| |ID|OPERATOR       |NAME|EST.ROWS|EST.TIME(us)|                                    |\n| -----------------------------------------------                                    |\n| |0 |TABLE FULL SCAN|t1  |1       |4           |                                    |\n| ===============================================                                    |\n| Outputs &amp; filters:                                                                 |\n| -------------------------------------                                              |\n|   0 - output(&#91;t1.c1]), filter(&#91;t1.c1 = 1]), rowset=4                               |\n|       access(&#91;t1.c1]), partitions(p0)                                              |\n|       is_index_back=false, is_global_index=false, filter_before_indexback&#91;false],  |\n|       range_key(&#91;t1.__pk_increment]), range(MIN ; MAX)always true                  |\n+------------------------------------------------------------------------------------+<\/code><\/pre>\n\n\n\n<h4 class=\"wp-block-heading\">LEADING Hint<\/h4>\n\n\n\n<p>LEADING Hint \u53ef\u4ee5\u6307\u5b9a\u8868\u7684\u8054\u63a5\u987a\u5e8f\u3002\u8bed\u6cd5\u662f\uff1a<code>\/*+ LEADING(table_name_list)*\/<\/code>\u3002\u5728 table_name_list \u4e2d\u53ef\u4ee5\u4f7f\u7528 <code>()<\/code> \u8868\u793a\u5185\u90e8\u5404\u8868\u7684\u8054\u63a5\u4f18\u5148\u7ea7\uff0c\u6307\u5b9a\u590d\u6742\u7684\u8054\u63a5\u987a\u5e8f\uff0c\u6bd4 ordered \u6709\u66f4\u5927\u7684\u7075\u6d3b\u6027\u3002\u793a\u4f8b\u5982\u4e0b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>EXPLAIN BASIC SELECT \/*+LEADING(d c b a)*\/ * FROM t1 a, t1 b, t1 c, t1 d;\n+------------------------------------------------------------------------------------------------------+\n| Query Plan                                                                                           |\n+------------------------------------------------------------------------------------------------------+\n| =========================================                                                            |\n| |ID|OPERATOR                       |NAME|                                                            |\n| -----------------------------------------                                                            |\n| |0 |NESTED-LOOP JOIN CARTESIAN     |    |                                                            |\n| |1 |\u251c\u2500NESTED-LOOP JOIN CARTESIAN   |    |                                                            |\n| |2 |\u2502 \u251c\u2500NESTED-LOOP JOIN CARTESIAN |    |                                                            |\n| |3 |\u2502 \u2502 \u251c\u2500TABLE FULL SCAN          |d   |                                                            |\n| |4 |\u2502 \u2502 \u2514\u2500MATERIAL                 |    |                                                            |\n| |5 |\u2502 \u2502   \u2514\u2500TABLE FULL SCAN        |c   |                                                            |\n| |6 |\u2502 \u2514\u2500MATERIAL                   |    |                                                            |\n| |7 |\u2502   \u2514\u2500TABLE FULL SCAN          |b   |                                                            |\n| |8 |\u2514\u2500MATERIAL                     |    |                                                            |\n| |9 |  \u2514\u2500TABLE FULL SCAN            |a   |                                                            |\n| =========================================                                                            |\n+------------------------------------------------------------------------------------------------------+\n\nEXPLAIN BASIC SELECT \/*+LEADING((d c) (b a))*\/ * FROM  t1 a, t1 b, t1 c, t1 d;\n+------------------------------------------------------------------------------------------------------+\n| Query Plan                                                                                           |\n+------------------------------------------------------------------------------------------------------+\n| =========================================                                                            |\n| |ID|OPERATOR                       |NAME|                                                            |\n| -----------------------------------------                                                            |\n| |0 |NESTED-LOOP JOIN CARTESIAN     |    |                                                            |\n| |1 |\u251c\u2500NESTED-LOOP JOIN CARTESIAN   |    |                                                            |\n| |2 |\u2502 \u251c\u2500TABLE FULL SCAN            |d   |                                                            |\n| |3 |\u2502 \u2514\u2500MATERIAL                   |    |                                                            |\n| |4 |\u2502   \u2514\u2500TABLE FULL SCAN          |c   |                                                            |\n| |5 |\u2514\u2500MATERIAL                     |    |                                                            |\n| |6 |  \u2514\u2500NESTED-LOOP JOIN CARTESIAN |    |                                                            |\n| |7 |    \u251c\u2500TABLE FULL SCAN          |b   |                                                            |\n| |8 |    \u2514\u2500MATERIAL                 |    |                                                            |\n| |9 |      \u2514\u2500TABLE FULL SCAN        |a   |                                                            |\n| =========================================                                                            |\n+------------------------------------------------------------------------------------------------------+\n\nEXPLAIN BASIC SELECT \/*+LEADING((d c b) a))*\/ * FROM t1 a, t1 b, t1 c, t1 d;\n+------------------------------------------------------------------------------------------------------+\n| Query Plan                                                                                           |\n+------------------------------------------------------------------------------------------------------+\n| =========================================                                                            |\n| |ID|OPERATOR                       |NAME|                                                            |\n| -----------------------------------------                                                            |\n| |0 |NESTED-LOOP JOIN CARTESIAN     |    |                                                            |\n| |1 |\u251c\u2500NESTED-LOOP JOIN CARTESIAN   |    |                                                            |\n| |2 |\u2502 \u251c\u2500NESTED-LOOP JOIN CARTESIAN |    |                                                            |\n| |3 |\u2502 \u2502 \u251c\u2500TABLE FULL SCAN          |d   |                                                            |\n| |4 |\u2502 \u2502 \u2514\u2500MATERIAL                 |    |                                                            |\n| |5 |\u2502 \u2502   \u2514\u2500TABLE FULL SCAN        |c   |                                                            |\n| |6 |\u2502 \u2514\u2500MATERIAL                   |    |                                                            |\n| |7 |\u2502   \u2514\u2500TABLE FULL SCAN          |b   |                                                            |\n| |8 |\u2514\u2500MATERIAL                     |    |                                                            |\n| |9 |  \u2514\u2500TABLE FULL SCAN            |a   |                                                            |\n| =========================================                                                            |\n+------------------------------------------------------------------------------------------------------+<\/code><\/pre>\n\n\n\n<p>\u4e3a\u786e\u4fdd\u6309\u7167\u7528\u6237\u6307\u5b9a\u7684\u987a\u5e8f\u8fdb\u884c\u8054\u63a5\uff0cLEADING Hint \u7684\u68c0\u67e5\u6bd4\u8f83\u4e25\u683c\uff0c\u5982\u679c\u53d1\u73b0 Hint \u6307\u5b9a\u7684 table_name \u4e0d\u5b58\u5728\uff0cLEADING Hint \u5931\u6548\uff1b\u5982\u679c\u53d1\u73b0 Hint \u4e2d\u5b58\u5728\u91cd\u590d\u8868\uff0cLEADING Hint \u5931\u6548\u3002\u5982\u679c\u5728 Optimizer \u8054\u63a5\u671f\u95f4\uff0c\u6309 table_id \u65e0\u6cd5\u5728 From Items \u4e2d\u627e\u5230\u5bf9\u5e94\u7684\u8868\uff0c\u5219\u53ef\u80fd\u53d1\u751f\u6539\u5199\uff0c\u90a3\u4e48\u8be5\u8868\u53ca\u540e\u9762\u7684\u8868\u6307\u5b9a\u7684 JOIN \u987a\u5e8f\u5931\u6548\uff0c\u8be5\u8868\u524d\u9762\u7684 JOIN \u987a\u5e8f\u4f9d\u7136\u6709\u6548\u3002<\/p>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p><strong>\u8bf4\u660e<\/strong><\/p>\n\n\n\n<p>\u5982\u679c\u540c\u65f6\u4f7f\u7528 ordered \u548c leading\uff0c\u5219\u4ec5 ordered \u751f\u6548\u3002<\/p>\n<\/blockquote>\n\n\n\n<h4 class=\"wp-block-heading\">USE_NL Hint<\/h4>\n\n\n\n<p>\u548c join \u76f8\u5173\u7684 Hint \u7684\u57fa\u672c\u7ed3\u6784\u5982\u4e0b\uff1a<code>join_hint_name ( @ qb_name table_name_list)<\/code>\uff0c\u57fa\u672c\u8bed\u4e49\u4e3a\uff0c\u5f53\u8054\u63a5\u7684\u53f3\u8868\u5339\u914d <code>table_name_list<\/code> \u65f6\uff0c\u6309\u7167 Hint \u8bed\u4e49\u751f\u6210\u8ba1\u5212\u3002\u4e00\u822c\u9700\u8981\u4f7f\u7528 LEADING Hint \u6307\u5b9a\u8054\u63a5\u987a\u5e8f\uff0c\u4f7f <code>table_name_list<\/code> \u4e2d\u7684\u8868\u4e3a\u53f3\u8868\uff0c\u5426\u5219 Hint \u4f1a\u968f\u7740\u8054\u63a5\u987a\u5e8f\u53d8\u5316\u800c\u5931\u6548\u3002<\/p>\n\n\n\n<p>\u5176\u4e2d <code>table_name_list<\/code> \u53ef\u6709\u4ee5\u4e0b\u5f62\u5f0f\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u5355\u8868 <code>use_nl ( t1 )<\/code>\uff1a\u4ee5 <code>t1<\/code> \u4e3a\u53f3\u8868\u65f6\u4f7f\u7528 Nested Loop Join\u3002<\/li>\n\n\n\n<li>\u591a\u4e2a\u5355\u8868 <code>use_nl ( t1 t2 ... )<\/code>\uff1a\u4ee5 <code>t1<\/code> \u6216 <code>t2<\/code> \u7b49\u4e3a\u53f3\u8868\u65f6\u4f7f\u7528 Nested Loop Join\u3002<\/li>\n\n\n\n<li>\u591a\u8868 <code>use_nl ((t1 t2))<\/code>\uff1a\u4ee5 <code>t1 join t2<\/code> \u4e3a\u53f3\u8868\u65f6\u4f7f\u7528 Nested Loop Join\uff0c\u5ffd\u7565 <code>t1<\/code>\/<code>t2<\/code> \u8fde\u63a5\u987a\u5e8f\u548c\u65b9\u6cd5\u3002<\/li>\n\n\n\n<li>\u591a\u7ec4\u8868 <code>use_nl (t1 (t2 t3) (t4 t5 t6) ... )<\/code>\uff1a\u4ee5 <code>t1<\/code>\/<code>t2 join t3<\/code>\/<code>t4 join t5 join t6<\/code> \u7b49\u8868\u4e3a\u53f3\u8868\u65f6\u4f7f\u7528 Nested Loop Join\u3002<\/li>\n<\/ul>\n\n\n\n<p>\u5728 USE_NL \u6307\u5b9a\u7684\u8868\u662f NLJ \u7684\u53f3\u8868\uff0c\u5728\u8054\u63a5\u7684\u65f6\u5019\u4f1a\u4f7f\u7528 Nested Loop Join \u7b97\u6cd5\uff0c\u8bed\u6cd5\u662f\uff1a<code>\/*+ USE_NL(table_name_list)*\/<\/code>\u3002\u793a\u4f8b\u5982\u4e0b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>CREATE TABLE t0(c1 INT, c2 INT, c3 INT);\n\nCREATE TABLE t1(c1 INT, c2 INT, c3 INT);\n\nCREATE TABLE t2(c1 INT, c2 INT, c3 INT);\n\n-- \u5982\u679c\u60f3\u8ba9 join \u7684\u987a\u5e8f\u662f t0 join t1\uff0cjoin \u4e3a nest loop join\uff0c\u5219\u5e94\u8be5\u8fd9\u6837\u5199 hint\uff1a\nEXPLAIN BASIC SELECT \/*+ LEADING(t0 t1) USE_NL(t1) *\/ * FROM t0, t1 WHERE t0.c1 = t1.c1;\n+--------------------------------------------------------------------------------------------+\n| Query Plan                                                                                 |\n+--------------------------------------------------------------------------------------------+\n| =============================                                                              |\n| |ID|OPERATOR           |NAME|                                                              |\n| -----------------------------                                                              |\n| |0 |NESTED-LOOP JOIN   |    |                                                              |\n| |1 |\u251c\u2500TABLE FULL SCAN  |t0  |                                                              |\n| |2 |\u2514\u2500MATERIAL         |    |                                                              |\n| |3 |  \u2514\u2500TABLE FULL SCAN|t1  |                                                              |\n| =============================                                                              |\n+--------------------------------------------------------------------------------------------+\n\n-- \u5982\u679c\u60f3\u8ba9 join \u7684\u987a\u5e8f\u662f t0 join (t1 join t2)\uff0c\u4e14\u60f3\u8ba9\u6700\u5916\u5c42\u7684 join \u4e3a nest loop join\uff0c\u5219\u5e94\u8be5\u8fd9\u6837\u5199 hint\uff1a\nEXPLAIN BASIC SELECT \/*+ LEADING(t0 (t1 t2)) USE_NL((t1 t2)) *\/ * FROM t0, t1, t2 WHERE t0.c1 = t1.c1 AND t0.c1 = t2.c1;\n+-----------------------------------------------------------------------------------------------------------------------+\n| Query Plan                                                                                                            |\n+-----------------------------------------------------------------------------------------------------------------------+\n| ===============================                                                                                       |\n| |ID|OPERATOR             |NAME|                                                                                       |\n| -------------------------------                                                                                       |\n| |0 |NESTED-LOOP JOIN     |    |                                                                                       |\n| |1 |\u251c\u2500TABLE FULL SCAN    |t0  |                                                                                       |\n| |2 |\u2514\u2500MATERIAL           |    |                                                                                       |\n| |3 |  \u2514\u2500HASH JOIN        |    |                                                                                       |\n| |4 |    \u251c\u2500TABLE FULL SCAN|t1  |                                                                                       |\n| |5 |    \u2514\u2500TABLE FULL SCAN|t2  |                                                                                       |\n| ===============================                                                                                       |\n+-----------------------------------------------------------------------------------------------------------------------+<\/code><\/pre>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p><strong>\u6ce8\u610f<\/strong><\/p>\n\n\n\n<p>USE_NL\u3001USE_HASH\u3001USE_MERGE \u8fd9\u4e09\u4e2a hint \u5f80\u5f80\u4f1a\u914d\u5408 LEADING \u8fd9\u4e2a hint \u4e00\u8d77\u4f7f\u7528\u3002\u56e0\u4e3a\u5f53 join \u7684\u53f3\u8868\u5339\u914d <code>table_name_list<\/code> \u65f6\uff0c\u624d\u4f1a\u6309\u7167 hint \u8bed\u4e49\u751f\u6210\u8ba1\u5212\u3002<\/p>\n\n\n\n<p>\u524d\u9762\u8fd9\u53e5\u8bdd\u7406\u89e3\u8d77\u6765\u53ef\u80fd\u4e0d\u662f\u90a3\u4e48\u76f4\u89c2\uff0c\u63a5\u4e0b\u6765\uff0c\u6211\u4eec\u6765\u4e3e\u4e00\u4e2a\u6700\u7b80\u5355\u7684\u5c0f\u4f8b\u5b50\u3002\u5047\u8bbe\u7528\u6237\u5e0c\u671b\u5bf9\u4e00\u6761 SQL\uff1a<code>SELECT * FROM t1, t2 WHERE t1.c1 = t2.c1;<\/code> \u4e2d <code>t1 join t2<\/code> \u5bf9\u5e94\u8ba1\u5212\u4e2d\u7684 join \u8ba1\u7b97\u65b9\u5f0f\u8fdb\u884c\u5e72\u9884\u3002<\/p>\n\n\n\n<p>\u539f\u672c\u7684\u8ba1\u5212\u7a7a\u95f4\u6709\u516d\u79cd\uff0c\u5206\u522b\u662f\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>t1 nest loop join t2<\/li>\n\n\n\n<li>t1 hash join t2<\/li>\n\n\n\n<li>t1 merge join t2<\/li>\n\n\n\n<li>t2 nest loop join t1<\/li>\n\n\n\n<li>t2 hash join t1<\/li>\n\n\n\n<li>t2 merge join t1<\/li>\n<\/ul>\n\n\n\n<p>\u5982\u679c\u52a0\u4e86 <code>hint\uff1a\/*+ USE_NL(t1)*\/<\/code>\uff0c\u5219\u8ba1\u5212\u7a7a\u95f4\u51cf\u5c11\u4e3a\u56db\u79cd\uff0c\u5206\u522b\u662f\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>t1 nest loop join t2<\/li>\n\n\n\n<li>t1 hash join t2<\/li>\n\n\n\n<li>t1 merge join t2<\/li>\n\n\n\n<li>t2 nest loop join t1<\/li>\n<\/ul>\n\n\n\n<p>\u56e0\u4e3a\u8ba1\u5212\u7a7a\u95f4\u4e2d\uff0c\u53ea\u6709\u5f53 <code>t1<\/code> \u4e3a join \u7684\u53f3\u8868\u65f6\uff0c\u624d\u4f1a\u6309\u7167 hint \u751f\u6210 <code>t2 nest loop join t1<\/code> \u7684\u8ba1\u5212\uff1b\u5f53 <code>t1<\/code> \u4e3a join \u7684\u5de6\u8868\u65f6\uff0c\u5219\u4e0d\u53d7\u8fd9\u4e2a hint \u7684\u5f71\u54cd\u3002<\/p>\n\n\n\n<p>\u5982\u679c\u52a0\u4e86 <code>hint\uff1a\/*+ LEADING(t2 t1) USE_NL(t1)*\/<\/code>\uff0c\u8ba1\u5212\u7a7a\u95f4\u5c31\u53ea\u6709\u786e\u5b9a\u7684\u4e00\u79cd\uff1at2 nest loop join t1<\/p>\n<\/blockquote>\n\n\n\n<h4 class=\"wp-block-heading\">USE_HASH Hint<\/h4>\n\n\n\n<p>\u548c USE_NL \u7c7b\u4f3c\uff0cUSE_HASH \u6307\u5b9a\u8868\u4f5c\u4e3a HJ \u7684\u53f3\u8868\uff0c\u5728\u8054\u63a5\u7684\u65f6\u5019\u4f7f\u7528 Hash Join \u7b97\u6cd5\uff0c\u8bed\u6cd5\u662f\uff1a<code>\/*+ USE_HASH(table_name_list)*\/<\/code>\u3002\u793a\u4f8b\u5982\u4e0b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>CREATE TABLE t0(c1 INT, c2 INT, c3 INT);\n\nCREATE TABLE t1(c1 INT, c2 INT, c3 INT);\n\nEXPLAIN BASIC SELECT \/*+LEADING(t0 t1) USE_HASH(t1)*\/ * FROM t0, t1 WHERE t0.c1 = t1.c1;\n+--------------------------------------------------------------------------------------------+\n| Query Plan                                                                                 |\n+--------------------------------------------------------------------------------------------+\n| ===========================                                                                |\n| |ID|OPERATOR         |NAME|                                                                |\n| ---------------------------                                                                |\n| |0 |HASH JOIN        |    |                                                                |\n| |1 |\u251c\u2500TABLE FULL SCAN|t0  |                                                                |\n| |2 |\u2514\u2500TABLE FULL SCAN|t1  |                                                                |\n| ===========================                                                                |\n+--------------------------------------------------------------------------------------------+<\/code><\/pre>\n\n\n\n<h4 class=\"wp-block-heading\">USE_MERGE Hint<\/h4>\n\n\n\n<p>\u548c USE_NL \u7c7b\u4f3c\uff0cUSE_MERGE \u6307\u5b9a\u8868\u4f5c\u4e3a MJ \u7684\u53f3\u8868\uff0c\u5728\u8054\u63a5\u7684\u65f6\u5019\u4f7f\u7528 Merge Join \u7b97\u6cd5\uff0c\u8bed\u6cd5\u662f\uff1a<code>\/*+ USE_MERGE(table_name_list)*\/<\/code>\u3002\u793a\u4f8b\u5982\u4e0b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>CREATE TABLE t0(c1 INT, c2 INT, c3 INT);\n\nCREATE TABLE t1(c1 INT, c2 INT, c3 INT);\n\nEXPLAIN BASIC SELECT \/*+LEADING(t0 t1) USE_MERGE(t1)*\/ * FROM t0, t1 WHERE t0.c1 = t1.c1;\n+--------------------------------------------------------------------------------------------+\n| Query Plan                                                                                 |\n+--------------------------------------------------------------------------------------------+\n| =============================                                                              |\n| |ID|OPERATOR           |NAME|                                                              |\n| -----------------------------                                                              |\n| |0 |MERGE JOIN         |    |                                                              |\n| |1 |\u251c\u2500SORT             |    |                                                              |\n| |2 |\u2502 \u2514\u2500TABLE FULL SCAN|t0  |                                                              |\n| |3 |\u2514\u2500SORT             |    |                                                              |\n| |4 |  \u2514\u2500TABLE FULL SCAN|t1  |                                                              |\n| =============================                                                              |\n+--------------------------------------------------------------------------------------------+<\/code><\/pre>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p><strong>\u8bf4\u660e<\/strong><\/p>\n\n\n\n<p>OceanBase \u6570\u636e\u5e93\u4e2d Merge Join \u5fc5\u987b\u6709\u7b49\u503c\u7684 join \u8054\u63a5\u6761\u4ef6\u3002\u5982\u679c\u65e0\u7b49\u503c\u6761\u4ef6\u7684\u4e24\u4e2a\u8868\u8054\u63a5\uff0c<code>USE_MERGE<\/code> \u4f1a\u5931\u6548\u3002<\/p>\n<\/blockquote>\n\n\n\n<h4 class=\"wp-block-heading\">PARALLEL Hint<\/h4>\n\n\n\n<p>PARALLEL \u6307\u5b9a\u8bed\u53e5\u7ea7\u522b\u7684\u5e76\u884c\u5ea6\u3002\u8bed\u6cd5\u662f\uff1a<code>\/*+ PARALLEL(n)*\/<\/code>\u3002\u5176\u4e2d <code>n<\/code> \u4e3a\u6574\u6570\uff0c\u8868\u793a SQL \u7684\u5168\u5c40\u5e76\u884c\u5ea6\u3002\u793a\u4f8b\u5982\u4e0b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>CREATE TABLE tbl1 (col1 INT) PARTITION BY HASH(col1) ;\n\nEXPLAIN BASIC SELECT \/*+ PARALLEL(5) *\/ * FROM tbl1;\n+----------------------------------------------------------------------+\n| Query Plan                                                           |\n+----------------------------------------------------------------------+\n| ===================================                                  |\n| |ID|OPERATOR             |NAME    |                                  |\n| -----------------------------------                                  |\n| |0 |PX COORDINATOR       |        |                                  |\n| |1 |\u2514\u2500EXCHANGE OUT DISTR |:EX10000|                                  |\n| |2 |  \u2514\u2500PX BLOCK ITERATOR|        |                                  |\n| |3 |    \u2514\u2500TABLE FULL SCAN|tbl1    |                                  |\n| ===================================                                  |\n| Outputs &amp; filters:                                                   |\n| -------------------------------------                                |\n|   0 - output(&#91;INTERNAL_FUNCTION(tbl1.col1)]), filter(nil), rowset=16 |\n|   1 - output(&#91;INTERNAL_FUNCTION(tbl1.col1)]), filter(nil), rowset=16 |\n|       dop=5                                                          |\n|   2 - output(&#91;tbl1.col1]), filter(nil), rowset=16                    |\n|   3 - output(&#91;tbl1.col1]), filter(nil), rowset=16                    |\n|       access(&#91;tbl1.col1]), partitions(p0)                            |\n|       is_index_back=false, is_global_index=false,                    |\n|       range_key(&#91;tbl1.__pk_increment]), range(MIN ; MAX)always true  |\n+----------------------------------------------------------------------+<\/code><\/pre>\n\n\n\n<p>\u8ba1\u5212\u4e2d\u663e\u793a\u7684 <code>dop=5<\/code> \u8868\u660e hint \u5df2\u7ecf\u751f\u6548\u3002<\/p>\n\n\n\n<p>OceanBase \u6570\u636e\u5e93\u540c\u65f6\u4e5f\u652f\u6301\u8868\u7ea7\u522b\u7684 PARALLEL Hint\uff0c\u8bed\u6cd5\u662f\uff1a<code>\/*+ PARALLEL(table_name n)*\/<\/code>\u3002\u793a\u4f8b\u5982\u4e0b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>CREATE TABLE t1 (c1 INT, c2 INT) PARTITION BY HASH(c1) PARTITIONS 5;\n\nCREATE TABLE t2 (c1 INT PRIMARY KEY, c2 INT) PARTITION BY HASH(c1) PARTITIONS 4;\n\nEXPLAIN SELECT \/*+ PARALLEL(3) PARALLEL(t2 5)*\/* FROM t1, t2 WHERE t1.c1 = t2.c1;\nEXPLAIN SELECT \/*+ PARALLEL(3) PARALLEL(t1 4) PARALLEL(t2 5)*\/* FROM t1, t2 WHERE t1.c1 = t2.c1;\n+---------------------------------------------------------------------------------------+\n| Query Plan                                                                            |\n+---------------------------------------------------------------------------------------+\n| =======================================================================               |\n| |ID|OPERATOR                           |NAME    |EST.ROWS|EST.TIME(us)|               |\n| -----------------------------------------------------------------------               |\n| |0 |PX COORDINATOR                     |        |1       |9           |               |\n| |1 |\u2514\u2500EXCHANGE OUT DISTR               |:EX10001|1       |9           |               |\n| |2 |  \u2514\u2500HASH JOIN                      |        |1       |9           |               |\n| |3 |    \u251c\u2500PART JOIN FILTER CREATE      |:RF0000 |1       |5           |               |\n| |4 |    \u2502 \u2514\u2500PX PARTITION ITERATOR      |        |1       |5           |               |\n| |5 |    \u2502   \u2514\u2500TABLE FULL SCAN          |t1      |1       |5           |               |\n| |6 |    \u2514\u2500EXCHANGE IN DISTR            |        |1       |4           |               |\n| |7 |      \u2514\u2500EXCHANGE OUT DISTR (PKEY)  |:EX10000|1       |4           |               |\n| |8 |        \u2514\u2500PX BLOCK HASH JOIN-FILTER|:RF0000 |1       |4           |               |\n| |9 |          \u2514\u2500TABLE FULL SCAN        |t2      |1       |4           |               |\n| =======================================================================               |\n| Outputs &amp; filters:                                                                    |\n| -------------------------------------                                                 |\n|   0 - output(&#91;INTERNAL_FUNCTION(t1.c1, t1.c2, t2.c1, t2.c2)]), filter(nil), rowset=16 |\n|   1 - output(&#91;INTERNAL_FUNCTION(t1.c1, t1.c2, t2.c1, t2.c2)]), filter(nil), rowset=16 |\n|       dop=4                                                                           |\n|   2 - output(&#91;t1.c1], &#91;t2.c1], &#91;t1.c2], &#91;t2.c2]), filter(nil), rowset=16              |\n|       equal_conds(&#91;t1.c1 = t2.c1]), other_conds(nil)                                  |\n|   3 - output(&#91;t1.c1], &#91;t1.c2]), filter(nil), rowset=16                                |\n|       RF_TYPE(bloom), RF_EXPR&#91;calc_tablet_id(t1.c1)]                                  |\n|   4 - output(&#91;t1.c1], &#91;t1.c2]), filter(nil), rowset=16                                |\n|       affinitize                                                                      |\n|   5 - output(&#91;t1.c1], &#91;t1.c2]), filter(nil), rowset=16                                |\n|       access(&#91;t1.c1], &#91;t1.c2]), partitions(p&#91;0-4])                                    |\n|       is_index_back=false, is_global_index=false,                                     |\n|       range_key(&#91;t1.__pk_increment]), range(MIN ; MAX)always true                     |\n|   6 - output(&#91;t2.c1], &#91;t2.c2]), filter(nil), rowset=16                                |\n|   7 - output(&#91;t2.c1], &#91;t2.c2]), filter(nil), rowset=16                                |\n|       (#keys=1, &#91;t2.c1]), dop=5                                                       |\n|   8 - output(&#91;t2.c1], &#91;t2.c2]), filter(nil), rowset=16                                |\n|   9 - output(&#91;t2.c1], &#91;t2.c2]), filter(nil), rowset=16                                |\n|       access(&#91;t2.c1], &#91;t2.c2]), partitions(p&#91;0-3])                                    |\n|       is_index_back=false, is_global_index=false,                                     |\n|       range_key(&#91;t2.c1]), range(MIN ; MAX)always true                                 |\n+---------------------------------------------------------------------------------------+<\/code><\/pre>\n\n\n\n<h4 class=\"wp-block-heading\">READ_CONSISTENCY(WEAK) Hint<\/h4>\n\n\n\n<p>READ_CONSISTENCY Hint \u7528\u4e8e\u6307\u5b9a SQL \u7684\u8bfb\u4e00\u81f4\u6027\u7ea7\u522b\u4e3a\u5f31\u4e00\u81f4\u6027\uff0c\u8bed\u6cd5\u662f\uff1a<code>\/*+ READ_CONSISTENCY(WEAK)*\/<\/code>\u3002\u793a\u4f8b\u5982\u4e0b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>-- \u8bfb\u53d6 t1 \u8868\u5907\u526f\u672c\u4e0a\u7684\u6570\u636e\nSELECT \/*+ READ_CONSISTENCY(WEAK) *\/ * FROM t1;<\/code><\/pre>\n\n\n\n<p>\u5bf9\u4e8e\u5b9e\u65f6\u6027\u8981\u6c42\u4e0d\u9ad8\u7684\u504f AP \u7c7b\u8bf7\u6c42\uff0c\u4e3a\u4e86\u5b9e\u73b0 AP \u4e1a\u52a1\u548c TP \u4e1a\u52a1\u7684\u8bfb\u5199\u5206\u79bb\uff0c\u51cf\u5c11 AP \u8bf7\u6c42\u5bf9\u4e3b\u526f\u672c\u7684\u5f71\u54cd\uff0c\u53ef\u4ee5\u8bbe\u7f6e\u5f31\u4e00\u81f4\u6027\u8bfb\u3002\u8bbe\u7f6e\u5f31\u4e00\u81f4\u6027\u8bfb\u7684 hint \u4e4b\u540e\uff0c\u8bfb\u64cd\u4f5c\u4f1a\u5230\u5907\u526f\u672c\u4e0a\u6267\u884c\u3002\u5f31\u4e00\u81f4\u6027\u8bfb\u7684\u6982\u5ff5\u8be6\u89c1\u5b98\u7f51\u300aOceanBase \u6570\u636e\u5e93\u300b\u6587\u6863 <a href=\"https:\/\/www.oceanbase.com\/docs\/common-oceanbase-database-cn-1000000000508629\">\u53c2\u8003\u6307\u5357\/\u7cfb\u7edf\u539f\u7406\/\u4e8b\u52a1\u7ba1\u7406\/\u4e8b\u52a1\u5e76\u53d1\u548c\u4e00\u81f4\u6027\/\u5f31\u4e00\u81f4\u6027\u8bfb<\/a>\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">QUERY_TIMEOUT Hint<\/h4>\n\n\n\n<p>QUERY_TIMEOUT Hint \u7528\u4e8e\u8bbe\u7f6e\u67e5\u8be2\u8bed\u53e5\u7684\u8d85\u65f6\u65f6\u95f4\uff0c\u8bed\u6cd5\u662f\uff1a<code>\/*+ query_timeout(n)*\/<\/code>\uff0c\u5176\u4e2d\u7684 <code>n<\/code> \u662f\u6574\u6570\uff0c\u5355\u4f4d\u662f\u5fae\u79d2\uff08us\uff09\u3002\u793a\u4f8b\u5982\u4e0b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>-- \u6307\u5b9a\u8fd9\u6761 SQL \u6267\u884c\u7684\u8d85\u65f6\u65f6\u95f4\u4e3a 100000000 \u5fae\u79d2\uff0c\u5373 100 \u79d2\u3002\nSELECT \/*+ query_timeout(100000000) *\/ * FROM t1;<\/code><\/pre>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p><strong>\u8bf4\u660e<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u7528\u6237\u53ef\u4ee5\u901a\u8fc7\u6267\u884c <code>SHOW VARIABLES LIKE 'ob_query_timeout';<\/code> \u67e5\u770b\u9ed8\u8ba4\u7684 SQL \u8d85\u65f6\u65f6\u95f4\u3002<\/li>\n\n\n\n<li>OceanBase \u6570\u636e\u5e93\u9664\u4e86\u652f\u6301\u901a\u8fc7 hint \u4fee\u6539 SQL \u7ea7\u522b\u7684 SQL \u8d85\u65f6\u65f6\u95f4\uff0c\u8fd8\u652f\u6301\u901a\u8fc7\u6267\u884c <code>SET SESSION ob_query_timeout = 100000000;<\/code> \u4fee\u6539\u4f1a\u8bdd\uff08session\uff09\u7ea7\u522b\u7684SQL \u8d85\u65f6\u65f6\u95f4\uff0c\u652f\u6301\u901a\u8fc7\u6267\u884c <code>SET GLOBAL ob_query_timeout = 100000000;<\/code> \u4fee\u6539\u79df\u6237\u7ea7\u522b\u7684 SQL \u8d85\u65f6\u65f6\u95f4\u3002<\/li>\n<\/ul>\n<\/blockquote>\n\n\n\n<h2 class=\"wp-block-heading\">\u901a\u8fc7 Outline \u8fdb\u884c\u8ba1\u5212\u7ed1\u5b9a<\/h2>\n\n\n\n<p>\u901a\u8fc7\u5bf9\u67d0\u6761 SQL \u521b\u5efa Outline \u53ef\u5b9e\u73b0\u8ba1\u5212\u7ed1\u5b9a\u3002<\/p>\n\n\n\n<p>\u5728\u751f\u4ea7\u7cfb\u7edf\u4e0a\u7ebf\u524d\uff0c\u53ef\u4ee5\u76f4\u63a5\u5728 SQL \u8bed\u53e5\u4e2d\u6dfb\u52a0 Hint\uff0c\u63a7\u5236\u4f18\u5316\u5668\u6309 Hint \u6307\u5b9a\u7684\u884c\u4e3a\u8fdb\u884c\u8ba1\u5212\u751f\u6210\u3002<\/p>\n\n\n\n<p>\u4f46\u5bf9\u4e8e\u5df2\u4e0a\u7ebf\u7684\u4e1a\u52a1\uff0c\u5982\u679c\u51fa\u73b0\u4f18\u5316\u5668\u9009\u62e9\u7684\u8ba1\u5212\u4e0d\u591f\u4f18\u65f6\uff0c\u5219\u9700\u8981\u5728\u7ebf\u8fdb\u884c\u8ba1\u5212\u7ed1\u5b9a\uff0c\u65e0\u9700\u4e1a\u52a1\u5bf9 SQL \u8fdb\u884c\u66f4\u6539\u3002\u800c\u662f\u901a\u8fc7 DDL \u64cd\u4f5c\u5c06\u4e00\u7ec4 Hint \u52a0\u5165\u5230\u7279\u5b9a\u7684 SQL \u4e2d\uff0c\u4ece\u800c\u4f7f\u4f18\u5316\u5668\u6839\u636e\u6307\u5b9a\u7684\u4e00\u7ec4 Hint\uff0c\u5bf9\u8be5 SQL \u751f\u6210\u66f4\u4f18\u8ba1\u5212\u3002\u8be5\u7ec4 Hint \u79f0\u4e3a Outline\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Outline \u76f8\u5173\u7684\u5b57\u5178\u89c6\u56fe<\/h3>\n\n\n\n<p>Outline \u89c6\u56fe\u4e3a <code>DBA_OB_OUTLINES<\/code>\uff0c\u5176\u5b57\u6bb5\u8bf4\u660e\u5982\u4e0b\u8868\u6240\u793a\u3002<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th><strong>\u5b57\u6bb5\u540d\u79f0<\/strong><\/th><th><strong>\u7c7b\u578b\uff08MySQL \u6a21\u5f0f\uff09<\/strong><\/th><th><strong>\u7c7b\u578b\uff08Oracle \u6a21\u5f0f\uff09<\/strong><\/th><th><strong>\u63cf\u8ff0<\/strong><\/th><\/tr><\/thead><tbody><tr><td>CREATE_TIME<\/td><td>TIMESTAMP(6)<\/td><td>TIMESTAMP(6)<\/td><td>\u521b\u5efa\u65f6\u95f4\u6233<\/td><\/tr><tr><td>MODIFY_TIME<\/td><td>TIMESTAMP(6)<\/td><td>TIMESTAMP(6)<\/td><td>\u4fee\u6539\u65f6\u95f4\u6233<\/td><\/tr><tr><td>TENANT_ID<\/td><td>BIGINT(20)<\/td><td>NUMBER(38)<\/td><td>\u79df\u6237 ID<\/td><\/tr><tr><td>DATABASE_ID<\/td><td>BIGINT(20)<\/td><td>NUMBER(38)<\/td><td>\u6570\u636e\u5e93 ID<\/td><\/tr><tr><td>OUTLINE_ID<\/td><td>BIGINT(20)<\/td><td>NUMBER(38)<\/td><td>Outline ID<\/td><\/tr><tr><td>DATABASE_NAME<\/td><td>VARCHAR2(128)<\/td><td>VARCHAR2(128)<\/td><td>\u6570\u636e\u5e93\u540d\u79f0<\/td><\/tr><tr><td>OUTLINE_NAME<\/td><td>VARCHAR2(128)<\/td><td>VARCHAR2(128)<\/td><td>Outline \u540d\u79f0<\/td><\/tr><tr><td>VISIBLE_SIGNATURE<\/td><td>LONGTEXT<\/td><td>CLOB<\/td><td>Signature \u7684\u53cd\u5e8f\u5217\u5316\u7ed3\u679c\uff0c\u4e3a\u4e86\u4fbf\u4e8e\u67e5\u770b Signature \u7684\u4fe1\u606f\u3002<\/td><\/tr><tr><td>SQL_TEXT<\/td><td>LONGTEXT<\/td><td>CLOB<\/td><td>\u521b\u5efa Outline \u65f6\uff0c\u5728 ON \u5b50\u53e5\u4e2d\u6307\u5b9a\u7684 SQL\u3002<\/td><\/tr><tr><td>OUTLINE_TARGET<\/td><td>LONGTEXT<\/td><td>CLOB<\/td><td>\u521b\u5efa Outline \u65f6\uff0c\u5728 TO \u5b50\u53e5\u4e2d\u6307\u5b9a\u7684 SQL\u3002<\/td><\/tr><tr><td>OUTLINE_SQL<\/td><td>LONGTEXT<\/td><td>CLOB<\/td><td>\u5177\u6709\u5b8c\u6574 Outline \u4fe1\u606f\u7684 SQL<\/td><\/tr><tr><td>SQL_ID<\/td><td>VARCHAR2(32)<\/td><td>VARCHAR2(32)<\/td><td>SQL \u6807\u8bc6\u7b26<\/td><\/tr><tr><td>OUTLINE_CONTENT<\/td><td>LONGTEXT<\/td><td>CLOB<\/td><td>\u5b8c\u6574\u7684\u6267\u884c\u8ba1\u5212 Outline \u4fe1\u606f<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\">\u521b\u5efa Outline<\/h3>\n\n\n\n<p>OceanBase \u6570\u636e\u5e93\u652f\u6301\u901a\u8fc7\u4e24\u79cd\u65b9\u5f0f\u521b\u5efa Outline\uff0c\u4e00\u79cd\u662f\u901a\u8fc7 SQL_TEXT (\u7528\u6237\u6267\u884c\u7684\u5e26\u53c2\u6570\u7684\u539f\u59cb\u8bed\u53e5)\uff0c\u53e6\u4e00\u79cd\u662f\u901a\u8fc7 SQL_ID\u3002<\/p>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p><strong>\u6ce8\u610f<\/strong><\/p>\n\n\n\n<p>\u521b\u5efa Outline \u9700\u8981\u8fdb\u5165\u5bf9\u5e94\u7684\u6570\u636e\u5e93\u4e0b\u6267\u884c\u3002<\/p>\n<\/blockquote>\n\n\n\n<h4 class=\"wp-block-heading\">\u4f7f\u7528 SQL_TEXT \u521b\u5efa Outline<\/h4>\n\n\n\n<p>\u4f7f\u7528 SQL_TEXT \u521b\u5efa Outline \u540e\uff0c\u4f1a\u751f\u6210\u4e00\u4e2a Key-Value \u5bf9\u5b58\u50a8\u5728 Map \u4e2d\uff0c\u5176\u4e2d Key \u4e3a\u7ed1\u5b9a\u7684 SQL \u53c2\u6570\u5316\u540e\u7684\u6587\u672c\uff0cValue \u4e3a\u7ed1\u5b9a\u7684 Hint\u3002\u5177\u4f53\u53c2\u6570\u5316\u539f\u5219\uff0c\u8be6\u89c1\u5b98\u7f51\u300aOceanBase \u6570\u636e\u5e93\u300b\u6587\u6863 <a href=\"https:\/\/www.oceanbase.com\/docs\/common-oceanbase-database-cn-1000000000508527\">\u53c2\u8003\u6307\u5357\/\u6027\u80fd\u8c03\u4f18\/SQL \u8c03\u4f18\u6307\u5357\/SQL \u6267\u884c\u8ba1\u5212\/\u5feb\u901f\u53c2\u6570\u5316<\/a>\u3002<\/p>\n\n\n\n<p>\u4f7f\u7528 SQL_TEXT \u521b\u5efa Outline \u7684\u8bed\u6cd5\u5982\u4e0b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>CREATE &#91;OR REPLACE] OUTLINE &lt;outline_name&gt; ON &lt;stmt&gt;;<\/code><\/pre>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u6307\u5b9a <code>OR REPLACE<\/code> \u540e\uff0c\u53ef\u4ee5\u5bf9\u5df2\u7ecf\u5b58\u5728\u6267\u884c\u8ba1\u5212\u8fdb\u884c\u66ff\u6362\u3002<\/li>\n\n\n\n<li>\u5176\u4e2d <code>stmt<\/code> \u4e00\u822c\u4e3a\u4e00\u4e2a\u5e26\u6709 Hint \u548c\u539f\u59cb\u53c2\u6570\u7684 DML \u8bed\u53e5\u3002\u793a\u4f8b\u5982\u4e0b\uff1a<\/li>\n<\/ul>\n\n\n\n<pre class=\"wp-block-code\"><code>  CREATE OUTLINE outline1 ON \n  SELECT \/*+NO_REWRITE*\/ * \n  FROM tbl1\n  WHERE col1 = 4 AND col2 = 6 ORDER BY 2 TO SELECT  * FROM tbl1 WHERE col1 = 4 AND col2 = 6 ORDER BY 2;<\/code><\/pre>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p><strong>\u6ce8\u610f<\/strong><\/p>\n\n\n\n<p>\u5728\u4f7f\u7528 <code>target_stmt<\/code> \u65f6\uff0c\u4e25\u683c\u8981\u6c42 <code>stmt<\/code> \u4e0e <code>target_stmt<\/code> \u5728\u53bb\u6389 Hint \u540e\u5b8c\u5168\u5339\u914d\u3002<\/p>\n<\/blockquote>\n\n\n\n<p>\u5982\u4e0b\u793a\u4f8b\u4e2d\uff0c\u4f18\u5316\u5668\u53ef\u80fd\u9ed8\u8ba4\u4f1a\u9009\u62e9\u8d70 <code>idx_c2<\/code> \u7d22\u5f15\u3002\u7d22\u5f15\u4e0a\u53ea\u6709\u7d22\u5f15\u5217 <code>c2<\/code> \u548c\u4e3b\u952e\u5217 <code>c1<\/code>\uff08\u7d22\u5f15\u4e0a\u7684\u4e3b\u952e\u5217\u5728\u7d22\u5f15\u4e2d\u662f\u9690\u85cf\u5217\uff0c\u4ec5\u7528\u4e8e\u7d22\u5f15\u56de\u8868\uff09\uff0c\u56e0\u4e3a\u7ed3\u679c\u4e2d\u8fd8\u9700\u8981\u8fd4\u56de <code>c3<\/code> \u5217\u7684\u503c\uff0c\u6240\u4ee5\u9700\u8981\u7d22\u5f15\u56de\u8868\u67e5\u51fa <code>c3<\/code> \u5217\u3002<\/p>\n\n\n\n<p>\u7d22\u5f15\u56de\u8868\u4e00\u884c\u7684\u4ee3\u4ef7\u8fdc\u8fdc\u5927\u4e8e\u5168\u8868\u626b\u63cf\u4e00\u884c\u7684\u4ee3\u4ef7\uff08\u5927\u6982\u662f\u5341\u500d\u5de6\u53f3\u7684\u4ee3\u4ef7\uff09\u3002\u5982\u679c\u7528\u6237\u5df2\u77e5 <code>c2<\/code> \u5217\u7684\u8fc7\u6ee4\u6027\u5f88\u5dee\uff0c\u6240\u4ee5\u628a\u8be5 SQL \u6539\u4e3a\u5f3a\u5236\u8d70\u5168\u8868\u626b\u63cf\uff0c\u6027\u80fd\u53cd\u5012\u4f1a\u66f4\u4f18\u3002\u6b64\u65f6\u53ef\u4ee5\u901a\u8fc7\u521b\u5efa Outline \u5c06\u8be5 SQL \u7ed1\u5b9a\u5168\u8868\u626b\u63cf\u7684\u8ba1\u5212\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>CREATE TABLE t1 (c1 INT PRIMARY KEY, c2 INT, c3 INT, INDEX idx_c2(c2));\n\nINSERT INTO t1 VALUES(1, 1, 1), (2, 1, 2), (3, 1, 3);\n\nEXPLAIN SELECT * FROM t1 WHERE c2 = 1;\n+-----------------------------------------------------------------+\n| Query Plan                                                      |\n+-----------------------------------------------------------------+\n| ======================================================          |\n| |ID|OPERATOR        |NAME      |EST.ROWS|EST.TIME(us)|          |\n| ------------------------------------------------------          |\n| |0 |TABLE RANGE SCAN|t1(idx_c2)|1       |7           |          |\n| ======================================================          |\n| Outputs &amp; filters:                                              |\n| -------------------------------------                           |\n|   0 - output(&#91;t1.c1], &#91;t1.c2], &#91;t1.c3]), filter(nil), rowset=16 |\n|       access(&#91;t1.c1], &#91;t1.c2], &#91;t1.c3]), partitions(p0)         |\n|       is_index_back=true, is_global_index=false,                |\n|       range_key(&#91;t1.c2], &#91;t1.c1]), range(1,MIN ; 1,MAX),        |\n|       range_cond(&#91;t1.c2 = 1])                                   |\n+-----------------------------------------------------------------+<\/code><\/pre>\n\n\n\n<p>\u6839\u636e\u5982\u4e0b SQL \u8bed\u53e5\u521b\u5efa Outline\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>CREATE OR REPLACE OUTLINE otl_t1_full ON SELECT \/*+ full(t1) *\/ * FROM t1 WHERE c2 = 1;<\/code><\/pre>\n\n\n\n<p>\u4e3a\u4e86\u786e\u8ba4\u67d0\u4e00\u6761 SQL \u5728\u6267\u884c\u65f6\u7684\u771f\u5b9e\u8ba1\u5212\uff0c\u4e0d\u5e94\u8be5\u76f4\u63a5\u6267\u884c explain \u8bed\u53e5\uff0c\u800c\u662f\u8981\u901a\u8fc7\u67e5\u8be2\u4e0a\u8ff0\u7684\u4e24\u4e2a\u8ba1\u5212\u76d1\u63a7\u89c6\u56fe <code>GV$OB_PLAN_CACHE_PLAN_STAT<\/code> \u548c <code>GV$OB_PLAN_CACHE_PLAN_EXPLAIN<\/code>\u3002\u8be6\u89c1\u4e0b\u6587 <a href=\"#\u786e\u5b9a%20Outline%20\u521b\u5efa\u751f\u6548\">\u786e\u5b9a Outline \u521b\u5efa\u751f\u6548<\/a> \u90e8\u5206\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">\u4f7f\u7528 SQL_ID \u521b\u5efa Outline<\/h4>\n\n\n\n<p>\u4f7f\u7528 SQL_ID \u521b\u5efa Outline \u7684\u8bed\u6cd5\u5982\u4e0b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>CREATE OUTLINE outline_name ON sql_id USING HINT hint_text;<\/code><\/pre>\n\n\n\n<p><code>SQL_ID<\/code> \u4e3a\u9700\u8981\u7ed1\u5b9a\u7684 SQL \u5bf9\u5e94\u7684 <code>SQL_ID<\/code>\uff0c\u53ef\u4ee5\u67e5\u8be2 <code>GV$OB_PLAN_CACHE_PLAN_STAT<\/code> \u83b7\u53d6\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>select\n  TENANT_ID,\n  SVR_IP,\n  SVR_PORT,\n  PLAN_ID,\n  LAST_ACTIVE_TIME,\n  QUERY_SQL,\n  SQL_ID\nfrom\n  oceanbase.GV$OB_PLAN_CACHE_PLAN_STAT\nwhere\n  QUERY_SQL = 'SELECT * FROM t1 WHERE c2 = 1';<\/code><\/pre>\n\n\n\n<p>\u8f93\u51fa\u5982\u4e0b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>+-----------+--------------+----------+---------+----------------------------+-------------------------------+----------------------------------+\n| TENANT_ID | SVR_IP       | SVR_PORT | PLAN_ID | LAST_ACTIVE_TIME           | QUERY_SQL                     | SQL_ID                           |\n+-----------+--------------+----------+---------+----------------------------+-------------------------------+----------------------------------+\n|      1002 | 10.10.10.1   |    22602 |   49820 | 2024-03-13 18:49:17.375906 | SELECT * FROM t1 WHERE c2 = 1 | ED570339F2C856BA96008A29EDF04C74 |\n+-----------+--------------+----------+---------+----------------------------+-------------------------------+----------------------------------+<\/code><\/pre>\n\n\n\n<p>\u4f7f\u7528 <code>SQL_ID<\/code> \u7ed1\u5b9a Outline\uff0c\u5982\u4e0b\u4f8b\u6240\u793a\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>DROP OUTLINE otl_t1_full;\n\nCREATE OUTLINE otl_t1_idx_c2 ON \"ED570339F2C856BA96008A29EDF04C74\" USING HINT \/*+ INDEX(t1 idx_c2)*\/ ;<\/code><\/pre>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p><strong>\u6ce8\u610f<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Hint \u683c\u5f0f\u4e3a <code>\/*+ xxx*\/<\/code>\u3002<\/li>\n\n\n\n<li>\u4f7f\u7528 SQL_TEXT \u65b9\u5f0f\u521b\u5efa\u7684 Outline \u4f1a\u8986\u76d6 SQL_ID \u65b9\u5f0f\u521b\u5efa\u7684 Outline\u3002SQL_TEXT \u65b9\u5f0f\u521b\u5efa\u7684\u4f18\u5148\u7ea7\u66f4\u9ad8\u3002<\/li>\n\n\n\n<li>\u5982\u679c SQL_ID \u5bf9\u5e94\u7684 SQL \u8bed\u53e5\u5df2\u7ecf\u6709 Hint\uff0c\u5219\u521b\u5efa Outline \u6307\u5b9a\u7684 Hint \u4f1a\u8986\u76d6\u539f\u59cb\u8bed\u53e5\u4e2d\u6240\u6709 Hint\u3002<\/li>\n<\/ul>\n<\/blockquote>\n\n\n\n<p>Outline Data \u662f\u4f18\u5316\u5668\u4e3a\u4e86\u5b8c\u5168\u590d\u73b0\u67d0\u4e00\u8ba1\u5212\u800c\u751f\u6210\u7684\u4e00\u7ec4 Hint \u4fe1\u606f\uff0c\u4ee5 <code>BEGIN_OUTLINE_DATA<\/code> \u5f00\u59cb\uff0c\u5e76\u4ee5 <code>END_OUTLINE_DATA<\/code> \u7ed3\u675f\u3002Outline Data \u4fe1\u606f\u53ef\u4ee5\u901a\u8fc7 EXPLAIN outline \u547d\u4ee4\u83b7\u5f97\uff0c\u5982\u4e0b\u4f8b\u6240\u793a\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>EXPLAIN outline SELECT\/*+ index(t1 idx_c2)*\/ * FROM t1 WHERE c2 = 1;<\/code><\/pre>\n\n\n\n<p>\u8f93\u51fa\u5982\u4e0b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>-----------------------------------------------------------------+\n| Query Plan                                                      |\n+-----------------------------------------------------------------+\n| ======================================================          |\n| |ID|OPERATOR        |NAME      |EST.ROWS|EST.TIME(us)|          |\n| ------------------------------------------------------          |\n| |0 |TABLE RANGE SCAN|t1(idx_c2)|3       |12          |          |\n| ======================================================          |\n| Outputs &amp; filters:                                              |\n| -------------------------------------                           |\n|   0 - output(&#91;t1.c1], &#91;t1.c2], &#91;t1.c3]), filter(nil), rowset=16 |\n|       access(&#91;t1.c1], &#91;t1.c2], &#91;t1.c3]), partitions(p0)         |\n|       is_index_back=true, is_global_index=false,                |\n|       range_key(&#91;t1.c2], &#91;t1.c1]), range(1,MIN ; 1,MAX),        |\n|       range_cond(&#91;t1.c2 = 1])                                   |\n| Outline Data:                                                   |\n| -------------------------------------                           |\n|   \/*+                                                           |\n|       BEGIN_OUTLINE_DATA                                        |\n|       INDEX(@\"SEL$1\" \"test\".\"t1\"@\"SEL$1\" \"idx_c2\")              |\n|       OPTIMIZER_FEATURES_ENABLE('4.0.0.0')                      |\n|       END_OUTLINE_DATA                                          |\n|   *\/                                                            |\n+-----------------------------------------------------------------+<\/code><\/pre>\n\n\n\n<p>\u5176\u4e2d Outline Data \u4fe1\u606f\u5982\u4e0b\u6240\u793a\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>Outline Data:\n-------------------------------------\n\/*+\n    BEGIN_OUTLINE_DATA\n    INDEX(@\"SEL$1\" \"test\".\"t1\"@\"SEL$1\" \"idx_c2\")\n    OPTIMIZER_FEATURES_ENABLE('4.0.0.0')\n    END_OUTLINE_DATA\n*\/<\/code><\/pre>\n\n\n\n<p>Outline Data \u4e5f\u5c5e\u4e8e Hint\uff0c\u56e0\u6b64\u53ef\u4ee5\u7528\u5728\u8ba1\u5212\u7ed1\u5b9a\u7684\u8fc7\u7a0b\u4e2d\uff0c\u5982\u4e0b\u4f8b\u6240\u793a\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>DROP OUTLINE otl_t1_idx_c2;\n\nCREATE OUTLINE otl_t1_idx_c2\n     ON \"ED570339F2C856BA96008A29EDF04C74\" USING HINT\n\/*+\n    BEGIN_OUTLINE_DATA\n    INDEX(@\"SEL$1\" \"test\".\"t1\"@\"SEL$1\" \"idx_c2\")\n    OPTIMIZER_FEATURES_ENABLE('4.0.0.0')\n    END_OUTLINE_DATA\n*\/;<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\">\u786e\u5b9a Outline \u521b\u5efa\u751f\u6548<\/h3>\n\n\n\n<p>\u786e\u5b9a\u521b\u5efa\u7684 Outline \u662f\u5426\u6210\u529f\u4e14\u7b26\u5408\u9884\u671f\uff0c\u9700\u8981\u8fdb\u884c\u5982\u4e0b\u4e09\u6b65\u7684\u9a8c\u8bc1\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u786e\u5b9a Outline \u521b\u5efa\u6210\u529f\u3002\u901a\u8fc7\u67e5\u770b <code>DBA_OB_OUTLINES<\/code> \u89c6\u56fe\uff0c\u786e\u8ba4\u662f\u5426\u6210\u529f\u521b\u5efa\u5bf9\u5e94\u540d\u79f0\u7684 Outline\u3002<\/li>\n<\/ol>\n\n\n\n<pre class=\"wp-block-code\"><code>   SELECT * FROM oceanbase.DBA_OB_OUTLINES WHERE OUTLINE_NAME = 'otl_t1_full'\\G<\/code><\/pre>\n\n\n\n<p>\u8f93\u51fa\u5982\u4e0b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>   *************************** 1. row ***************************\n         CREATE_TIME: 2024-03-13 18:38:18.807692\n         MODIFY_TIME: 2024-03-13 18:39:57.210761\n           TENANT_ID: 1002\n         DATABASE_ID: 500001\n          OUTLINE_ID: 500133\n       DATABASE_NAME: test\n        OUTLINE_NAME: otl_t1_full\n   VISIBLE_SIGNATURE: SELECT * FROM t1 WHERE c2 = ?\n            SQL_TEXT: SELECT\/*+ full(t1) *\/ * FROM t1 WHERE c2 = 1\n      OUTLINE_TARGET:\n         OUTLINE_SQL: SELECT \/*+BEGIN_OUTLINE_DATA FULL(@\"SEL$1\" \"test\".\"t1\"@\"SEL$1\") OPTIMIZER_FEATURES_ENABLE('4.0.0.0') END_OUTLINE_DATA*\/* FROM t1 WHERE c2 = 1\n              SQL_ID:\n     OUTLINE_CONTENT: \/*+BEGIN_OUTLINE_DATA FULL(@\"SEL$1\" \"test\".\"t1\"@\"SEL$1\") OPTIMIZER_FEATURES_ENABLE('4.0.0.0') END_OUTLINE_DATA*\/<\/code><\/pre>\n\n\n\n<ol start=\"2\" class=\"wp-block-list\">\n<li>\u786e\u5b9a\u65b0\u7684 SQL \u662f\u5426\u901a\u8fc7\u7ed1\u5b9a\u7684 Outline \u751f\u6210\u4e86\u65b0\u6267\u884c\u8ba1\u5212\u3002\u5f53\u7ed1\u5b9a Outline \u7684 SQL \u6267\u884c\u65b0\u7684\u67e5\u8be2\u540e\uff0c\u67e5\u8be2 <code>GV$OB_PLAN_CACHE_PLAN_STAT<\/code> \u8868\u4e2d\u8be5 SQL \u5bf9\u5e94\u7684\u8ba1\u5212\u4fe1\u606f\u4e2d\u7684 <code>outline_id<\/code>\u3002\u5982\u679c <code>outline_id<\/code> \u4e0e\u5728 <code>DBA_OB_OUTLINES<\/code> \u4e2d\u67e5\u5230\u7684 <code>outline_id<\/code> \u76f8\u540c\uff0c\u5219\u8868\u793a\u662f\u6309\u7ed1\u5b9a\u7684 Outline \u751f\u6210\u7684\u6267\u884c\u8ba1\u5212\uff0c\u5426\u5219\u4e0d\u662f\u3002<\/li>\n<\/ol>\n\n\n\n<pre class=\"wp-block-code\"><code>   SELECT SQL_ID, PLAN_ID, STATEMENT, OUTLINE_ID, OUTLINE_DATA\n   FROM oceanbase.GV$OB_PLAN_CACHE_PLAN_STAT\n   WHERE STATEMENT LIKE '%SELECT * FROM t1 WHERE c2 =%'\\G<\/code><\/pre>\n\n\n\n<p>\u8f93\u51fa\u5982\u4e0b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>   *************************** 1. row ***************************\n         SQL_ID: ED570339F2C856BA96008A29EDF04C74\n        PLAN_ID: 49820\n      STATEMENT: SELECT * FROM t1 WHERE c2 = ?\n     OUTLINE_ID: 500133\n   OUTLINE_DATA: \/*+BEGIN_OUTLINE_DATA FULL(@\"SEL$1\" \"test\".\"t1\"@\"SEL$1\") OPTIMIZER_FEATURES_ENABLE('4.0.0.0') END_OUTLINE_DATA*\/<\/code><\/pre>\n\n\n\n<ol start=\"3\" class=\"wp-block-list\">\n<li>\u786e\u5b9a\u751f\u6210\u7684\u6267\u884c\u8ba1\u5212\u662f\u5426\u7b26\u5408\u9884\u671f\u3002\u786e\u5b9a\u662f\u901a\u8fc7\u7ed1\u5b9a\u7684 Outline \u751f\u6210\u7684\u8ba1\u5212\u540e\uff0c\u9700\u8981\u786e\u5b9a\u751f\u6210\u7684\u8ba1\u5212\u662f\u5426\u7b26\u5408\u9884\u671f\uff0c\u53ef\u4ee5\u901a\u8fc7\u67e5\u8be2 <code>GV$OB_PLAN_CACHE_PLAN_EXPLAIN<\/code> \u8868\u67e5\u770b plan_cache \u4e2d\u7f13\u5b58\u7684\u6267\u884c\u8ba1\u5212\u5f62\u72b6\uff0c\u5177\u4f53\u67e5\u770b\u65b9\u5f0f\u53ef\u53c2\u89c1\u5b98\u7f51\u300aOceanBase \u6570\u636e\u5e93\u300b\u6587\u6863 <a href=\"https:\/\/www.oceanbase.com\/docs\/common-oceanbase-database-cn-1000000000508528\">\u53c2\u8003\u6307\u5357\/\u6027\u80fd\u8c03\u4f18\/SQL \u8c03\u4f18\u6307\u5357\/SQL \u6267\u884c\u8ba1\u5212\/\u5b9e\u65f6\u6267\u884c\u8ba1\u5212\u5c55\u793a<\/a>\u3002<\/li>\n\n\n\n<li>\u901a\u8fc7 <code>GV$OB_PLAN_CACHE_PLAN_STAT<\/code> \u67e5\u8be2\u4e0a\u8ff0 SQL \u5bf9\u5e94\u7684 <code>TENANT_ID<\/code>\u3001<code>SVR_IP<\/code>\u3001<code>SVR_PORT<\/code>\u3001<code>PLAN_ID<\/code> \u5b57\u6bb5\u3002 <code>select TENANT_ID, SVR_IP, SVR_PORT, PLAN_ID, LAST_ACTIVE_TIME, QUERY_SQL from oceanbase.GV$OB_PLAN_CACHE_PLAN_STAT where QUERY_SQL = 'SELECT * FROM t1 WHERE c2 = 1';<\/code> \u8f93\u51fa\u5982\u4e0b\uff1a <code>+-----------+--------------+----------+---------+----------------------------+-------------------------------+ | TENANT_ID | SVR_IP | SVR_PORT | PLAN_ID | LAST_ACTIVE_TIME | QUERY_SQL | +-----------+--------------+----------+---------+----------------------------+-------------------------------+ | 1002 | 10.10.10.1 | 22602 | 49820 | 2024-03-13 18:49:17.375906 | SELECT * FROM t1 WHERE c2 = 1 | +-----------+--------------+----------+---------+----------------------------+-------------------------------+<\/code><\/li>\n\n\n\n<li>\u6839\u636e\u8f93\u51fa\uff0c\u901a\u8fc7 <code>oceanbase.GV$OB_PLAN_CACHE_PLAN_EXPLAIN<\/code> \u6765\u770b SQL \u5bf9\u5e94\u7684\u771f\u5b9e\u8ba1\u5212\uff0c<code>GV$OB_PLAN_CACHE_PLAN_EXPLAIN<\/code> \u89c6\u56fe\u5404\u5b57\u6bb5\u542b\u4e49\u8be6\u89c1\u5b98\u7f51\u300aOceanBase \u6570\u636e\u5e93\u300b\u6587\u6863 <a href=\"https:\/\/www.oceanbase.com\/docs\/common-oceanbase-database-cn-1000000000219855\">\u53c2\u8003\u6307\u5357\/\u7cfb\u7edf\u89c6\u56fe\/MySQL \u79df\u6237\u7cfb\u7edf\u89c6\u56fe\/\u6027\u80fd\u89c6\u56fe\/GV$OB_PLAN_CACHE_PLAN_EXPLAIN<\/a>\u3002 <code>SELECT * FROM oceanbase.GV$OB_PLAN_CACHE_PLAN_EXPLAIN WHERE tenant_id = 1002 AND SVR_IP = '10.10.10.1' AND SVR_PORT = 22602 AND PLAN_ID = 49820;<\/code> \u8f93\u51fa\u5982\u4e0b\uff1a <code>+-----------+--------------+----------+---------+------------+--------------+----------------+------+------+------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | TENANT_ID | SVR_IP | SVR_PORT | PLAN_ID | PLAN_DEPTH | PLAN_LINE_ID | OPERATOR | NAME | ROWS | COST | PROPERTY | +-----------+--------------+----------+---------+------------+--------------+----------------+------+------+------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | 1002 | 10.10.10.1 | 22602 | 49820 | 0 | 0 | PHY_TABLE_SCAN | t1 | 1 | 3 | table_rows:3, physical_range_rows:3, logical_range_rows:3, index_back_rows:0, output_rows:1, avaiable_index_name[idx_c2,t1], pruned_index_name[idx_c2], estimation info[table_id:500131, (table_type:0, version:-1--1--1, logical_rc:3, physical_rc:3)] | +-----------+--------------+----------+---------+------------+--------------+----------------+------+------+------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+<\/code> \u60a8\u4e5f\u53ef\u4ee5\u901a\u8fc7 <code>DBMS_XPLAN.DISPLAY_CURSOR<\/code> \u6765\u770b SQL \u5bf9\u5e94\u7684\u771f\u5b9e\u8ba1\u5212\uff0c\u5c55\u793a\u51fa\u6765\u7684\u4fe1\u606f\u6bd4 <code>oceanbase.GV$OB_PLAN_CACHE_PLAN_EXPLAIN<\/code> \u66f4\u50cf explain \u5c55\u793a\u51fa\u6765\u7684\u4fe1\u606f\uff0c\u8be6\u89c1\u5b98\u7f51\u300aOceanBase \u6570\u636e\u5e93\u300b\u6587\u6863 <a href=\"https:\/\/www.oceanbase.com\/docs\/common-oceanbase-database-cn-1000000000511256\">\u53c2\u8003\u6307\u5357\/SQL \u53c2\u8003\/PL \u53c2\u8003\/PL \u53c2\u8003\uff08MySQL \u6a21\u5f0f\uff09\/PL \u7cfb\u7edf\u5305\/DBMS_XPLAN\/DISPLAY_CURSOR<\/a>\u3002 <code>SELECT DBMS_XPLAN.DISPLAY_CURSOR( 49820, 'typical', '10.10.10.1', 22602, 1002 ) FROM DUAL;<\/code> \u8f93\u51fa\u5982\u4e0b\uff1a <code>================================================================================================ |ID|OPERATOR |NAME|EST.ROWS|EST.TIME(us)|REAL.ROWS|REAL.TIME(us)|IO TIME(us)|CPU TIME(us)| ------------------------------------------------------------------------------------------------ |0 |TABLE FULL SCAN|t1 |1 |4 |3 |0 |0 |0 | ================================================================================================ Outputs &amp; filters: ------------------------------------- 0 - output([t1.c1], [t1.c2], [t1.c3]), filter([t1.c2 = :0]), rowset=16 access([t1.c1], [t1.c2], [t1.c3]), partitions(p0) is_index_back=false, is_global_index=false, filter_before_indexback[false], range_key([t1.c1]), range(MIN ; MAX)always true<\/code><\/li>\n<\/ol>\n\n\n\n<h3 class=\"wp-block-heading\">\u5220\u9664 Outline<\/h3>\n\n\n\n<p>\u5220\u9664 Outline \u540e\uff0c\u5bf9\u5e94 SQL \u5c06\u4e0d\u518d\u4f9d\u636e\u6240\u7ed1\u5b9a\u7684 Outline \u91cd\u65b0\u751f\u6210\u6267\u884c\u8ba1\u5212\u3002\u5220\u9664 Outline \u7684\u8bed\u6cd5\u5982\u4e0b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>DROP OUTLINE outline_name;<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\">\u8ba1\u5212\u7ed1\u5b9a\u4e0e\u6267\u884c\u8ba1\u5212\u7f13\u5b58\u5173\u7cfb<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u4f7f\u7528 SQL_TEXT \u521b\u5efa Outline \u540e\uff0cSQL \u8bf7\u6c42\u751f\u6210\u65b0\u8ba1\u5212\u67e5\u627e Outline \u4f7f\u7528\u7684 Key \u4e0e\u8ba1\u5212\u7f13\u5b58\u4f7f\u7528\u7684 Key \u662f\u76f8\u540c\u7684\uff0c\u5373\u5747\u662f SQL \u53c2\u6570\u5316\u540e\u7684\u6587\u672c\u4e32\u3002<\/li>\n\n\n\n<li>\u5f53\u521b\u5efa\u548c\u5220\u9664 Outline \u540e\uff0c\u5bf9\u5e94 SQL \u6709\u65b0\u7684\u8bf7\u6c42\u65f6\uff0c\u4f1a\u89e6\u53d1\u6267\u884c\u8ba1\u5212\u7f13\u5b58\u4e2d\u5bf9\u5e94\u6267\u884c\u8ba1\u5212\u5931\u6548\uff0c\u66f4\u65b0\u4e3a\u6839\u636e\u7ed1\u5b9a\u7684 Outline \u6240\u751f\u6210\u7684\u6267\u884c\u8ba1\u5212\u3002<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">\u8ba1\u5212\u7ed1\u5b9a\u4e0e\u9650\u6d41\u89c4\u5219\u7684\u5173\u7cfb<\/h3>\n\n\n\n<p>\u4ece OceanBase \u6570\u636e\u5e93 4.2.2 \u7248\u672c\u5f00\u59cb\uff0c\u6570\u636e\u5e93\u7684 <code>CREATE OUTLINE<\/code> \u548c <code>ALTER OUTLINE<\/code> \u547d\u4ee4\u6269\u5c55\u4e86\u529f\u80fd\u3002\u9664\u4e86\u539f\u6709\u7684\u7ed1\u5b9a\u7279\u5b9a\u67e5\u8be2\u7684\u6267\u884c\u8ba1\u5212\u5916\uff0c\u8fd8\u5141\u8bb8\u7528\u6237\u4e3a\u67e5\u8be2\u8bbe\u7f6e\u6700\u5927\u5e76\u53d1\u6267\u884c\u6b21\u6570\u7684\u9650\u5236\u3002\u9650\u6d41\u529f\u80fd\u80fd\u591f\u5e2e\u52a9\u5927\u5bb6\u66f4\u6709\u6548\u5730\u7ba1\u7406\u6570\u636e\u5e93\u8d1f\u8f7d\uff0c\u9632\u6b62\u56e0\u9ad8\u5e76\u53d1\u67e5\u8be2\u800c\u5bfc\u81f4\u7684\u6027\u80fd\u95ee\u9898\u3002<\/p>\n\n\n\n<p>\u4f8b\u5982\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u4f7f\u7528 <code>CREATE OUTLINE<\/code> \u521b\u5efa\u4e86\u4e00\u4e2a OUTLINE\uff0c\u5176\u4e2d\u5305\u542b\u4e86 <code>USE_NL(tbl2)<\/code> \u63d0\u793a\uff0c\u8fd9\u544a\u8bc9\u4f18\u5316\u5668\u5bf9\u4e8e\u8868 <code>tbl2<\/code> \u4f7f\u7528 nest loop join\uff0c\u540c\u65f6 <code>MAX_CONCURRENT(1)<\/code> \u8fd9\u4e2a Hint \u5728\u4e0b\u9762\u8fd9\u4e2a\u793a\u4f8b\u4e2d\u8868\u793a\u540c\u4e00\u65f6\u523b\uff0c\u53ea\u5141\u8bb8\u4e00\u4e2a\u7ebf\u7a0b\u6267\u884c\u67e5\u8be2\uff1a<\/li>\n<\/ul>\n\n\n\n<pre class=\"wp-block-code\"><code>  CREATE OUTLINE otl2 ON SELECT \/*+ USE_NL(tbl2) MAX_CONCURRENT(1) *\/ * FROM t WHERE c1 = ?;<\/code><\/pre>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u540c\u6837\u5730\uff0c\u4f7f\u7528 <code>ALTER OUTLINE<\/code> \u4fee\u6539\u73b0\u6709 OUTLINE\uff0c\u540c\u6837\u53ef\u4ee5\u8fbe\u5230\u4e0a\u8ff0\u6548\u679c\u3002<\/li>\n<\/ul>\n\n\n\n<pre class=\"wp-block-code\"><code>  ALTER OUTLINE otl2 ON SELECT \/*+ USE_NL(tbl2) MAX_CONCURRENT(1) *\/ * FROM t WHERE c1 = ?;<\/code><\/pre>\n\n\n\n<p><\/p>\n\n\n\n<p><\/p>\n","protected":false},"excerpt":{"rendered":"<p>from \uff1ahttps:\/\/www.oceanbase.com\/docs\/community-tutorial &hellip; <a href=\"https:\/\/www.shoubashou.com\/?p=1\" class=\"more-link\">\u7ee7\u7eed\u9605\u8bfb<span class=\"screen-reader-text\">\u5b66\u4e60\u9605\u8bfb\u548c\u7ba1\u7406 OceanBase \u6570\u636e\u5e93 SQL 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