基于代价的查询改写怎么和文档不一样呢

OceanBase 技术问题
#1

【 使用环境 】测试环境
【 OB or 其他组件 】
【 使用版本 】3.2.4
【问题描述】
https://www.oceanbase.com/docs/enterprise-oceanbase-database-cn-10000000000945967

image
image2150×1486 274 KB 

MySQL [test]> CREATE TABLE t1(a INT, b INT, c INT, d INT, e INT, INDEX IDX_a(a),
    ->          INDEX IDX_b(b));
Query OK, 0 rows affected (0.20 sec)

MySQL [test]> EXPLAIN SELECT/*+NO_REWRITE()*/ * FROM t1 WHERE t1.a = 1 OR t1.b = 1;
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Query Plan                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| ===================================================
|ID|OPERATOR            |NAME     |EST. ROWS|COST |
---------------------------------------------------
|0 |EXCHANGE IN REMOTE  |         |1485     |35144|
|1 | EXCHANGE OUT REMOTE|         |1485     |34868|
|2 |  UNION ALL         |         |1485     |34868|
|3 |   TABLE SCAN       |t1(IDX_a)|990      |17417|
|4 |   TABLE SCAN       |t1(IDX_b)|495      |17429|
===================================================

Outputs & filters:
-------------------------------------
  0 - output([UNION([1])], [UNION([2])], [UNION([3])], [UNION([4])], [UNION([5])]), filter(nil)
  1 - output([UNION([1])], [UNION([2])], [UNION([3])], [UNION([4])], [UNION([5])]), filter(nil)
  2 - output([UNION([1])], [UNION([2])], [UNION([3])], [UNION([4])], [UNION([5])]), filter(nil)
  3 - output([t1.a], [t1.b], [t1.c], [t1.d], [t1.e]), filter(nil),
      access([t1.a], [t1.b], [t1.c], [t1.d], [t1.e]), partitions(p0)
  4 - output([t1.a], [t1.b], [t1.c], [t1.d], [t1.e]), filter([lnnvl(cast(t1.a = 1, TINYINT(-1, 0)))]),
      access([t1.a], [t1.b], [t1.c], [t1.d], [t1.e]), partitions(p0)
 |
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.02 sec)

MySQL [test]> EXPLAIN SELECT * FROM t1 WHERE t1.a = 1 OR t1.b = 1;
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Query Plan                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| ===================================================
|ID|OPERATOR            |NAME     |EST. ROWS|COST |
---------------------------------------------------
|0 |EXCHANGE IN REMOTE  |         |1485     |35144|
|1 | EXCHANGE OUT REMOTE|         |1485     |34868|
|2 |  UNION ALL         |         |1485     |34868|
|3 |   TABLE SCAN       |t1(IDX_a)|990      |17417|
|4 |   TABLE SCAN       |t1(IDX_b)|495      |17429|
===================================================

Outputs & filters:
-------------------------------------
  0 - output([UNION([1])], [UNION([2])], [UNION([3])], [UNION([4])], [UNION([5])]), filter(nil)
  1 - output([UNION([1])], [UNION([2])], [UNION([3])], [UNION([4])], [UNION([5])]), filter(nil)
  2 - output([UNION([1])], [UNION([2])], [UNION([3])], [UNION([4])], [UNION([5])]), filter(nil)
  3 - output([t1.a], [t1.b], [t1.c], [t1.d], [t1.e]), filter(nil),
      access([t1.a], [t1.b], [t1.c], [t1.d], [t1.e]), partitions(p0)
  4 - output([t1.a], [t1.b], [t1.c], [t1.d], [t1.e]), filter([lnnvl(cast(t1.a = 1, TINYINT(-1, 0)))]),
      access([t1.a], [t1.b], [t1.c], [t1.d], [t1.e]), partitions(p0)
 |
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.02 sec)

【复现路径】问题出现前后相关操作
【附件及日志】推荐使用OceanBase敏捷诊断工具obdiag收集诊断信息,详情参见链接（右键跳转查看）：

【SOP系列 22 】——故障诊断第一步(自助诊断和诊断信息收集)

#3

你好，你提的这个技术问题牵涉到OceanBase企业版范围内的功能细节；针对此类问题，建议你通过以下方式寻求帮助：

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#4

mysql客户端登录的时候有没有加-c

#5

没加，确实是这个问题，加了后正常了

#6

没加默认会把/**/当成注释，就忽略掉了