Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

Migrate contributor PRs with pending CLA #4771

Merged
merged 1 commit into from
Nov 2, 2020
Merged

Migrate contributor PRs with pending CLA #4771

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
2 changes: 1 addition & 1 deletion sql-logical-optimization.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -5,7 +5,7 @@ aliases: ['/docs-cn/dev/sql-logical-optimization/']

# 逻辑优化

本章节将对一些比较关键的逻辑改写进行说明，帮助大家理解 TiDB 如何生成最终的查询计划。比如在 TiDB 输入 `select * from t where t.a in (select * from t1 where t1.b=t.b)` 这个查询时，在最终的执行计划中将看不到这个 `t.a in (select t1.a from t1 where t1.b=t.b` 这个 `IN` 子查询的存在，这便是因为 TiDB 对这里进行了一些改写。
本章节将对一些比较关键的逻辑改写进行说明，帮助大家理解 TiDB 如何生成最终的查询计划。比如在 TiDB 输入 `select * from t where t.a in (select t1.a from t1 where t1.b=t.b)` 这个查询时，在最终的执行计划中将看不到这个 `t.a in (select t1.a from t1 where t1.b=t.b)` 这个 `IN` 子查询的存在，这便是因为 TiDB 对这里进行了一些改写。

本章节会介绍如下几个关键改写：

Expand Down
2 changes: 1 addition & 1 deletion system-variables.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -722,7 +722,7 @@ set tidb_query_log_max_len = 20;

### `tidb_skip_isolation_level_check`

- 作用域：SESSION
- 作用域：SESSION | GLOBAL

- 默认值：0

Expand Down