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performance_schema -> information_schema (#7147) #7172

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Sep 26, 2021
Merged

performance_schema -> information_schema (#7147) #7172

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performance_schema -> information_schema
shichun-0415 Sep 17, 2021
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Update statement-summary-tables.md
TomShawn Sep 24, 2021
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4 changes: 2 additions & 2 deletions statement-summary-tables.md
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Expand Up @@ -6,7 +6,7 @@ title: Statement Summary Tables

针对 SQL 性能相关的问题，MySQL 在 `performance_schema` 提供了 [statement summary tables](https://dev.mysql.com/doc/refman/5.6/en/statement-summary-tables.html)，用来监控和统计 SQL。例如其中的一张表 `events_statements_summary_by_digest`，提供了丰富的字段，包括延迟、执行次数、扫描行数、全表扫描次数等，有助于用户定位 SQL 问题。

为此，从 4.0.0-rc.1 版本开始，TiDB 在 `information_schema` 中提供与 `events_statements_summary_by_digest` 功能相似的系统表：
为此，从 4.0.0-rc.1 版本开始，TiDB 在 `information_schema`（_而不是_ `performance_schema`）中提供与 `events_statements_summary_by_digest` 功能相似的系统表：

- `statements_summary`
- `statements_summary_history`
Expand All @@ -28,7 +28,7 @@ SELECT * FROM employee WHERE id IN (1, 2, 3) AND salary BETWEEN 1000 AND 2000;
select * from EMPLOYEE where ID in (4, 5) and SALARY between 3000 and 4000;
```

规一化后都是：
归一化后都是：

```sql
select * from employee where id in (...) and salary between ? and ?;
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