Skip to content

master: correct stats variable defaults #21731

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

Open
qiancai wants to merge 4 commits into
base: master
Choose a base branch
from
Open

master: correct stats variable defaults #21731

Show file tree
Hide file tree
Changes from 3 commits
Commits
Show all changes
4 commits
Select commit Hold shift + click to select a range
e030368
Create empty translation PR
qiancai Jun 24, 2026
8e60855
Auto-sync: Update Chinese docs from English PR
github-actions[bot] Jun 24, 2026
a2fa2d8
Apply suggestions from code review
qiancai Jun 24, 2026
9a87c61
Apply suggestions from code review
qiancai Jun 24, 2026
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 statistics.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -22,7 +22,7 @@ TiDB 根据表的变更次数自动调度 [`ANALYZE`](/sql-statements/sql-statem

| 系统变量名 | 默认值 | 功能描述 |
| --------- | ----- | --------- |
| [`tidb_auto_analyze_concurrency`](/system-variables.md#tidb_auto_analyze_concurrency-从-v840-版本开始引入) | `1` | TiDB 集群中自动更新统计信息操作的并发度 |
| [`tidb_auto_analyze_concurrency`](/system-variables.md#tidb_auto_analyze_concurrency-从-v840-版本开始引入) | `3` | TiDB 集群中自动更新统计信息操作的并发度 |
| [`tidb_auto_analyze_end_time`](/system-variables.md#tidb_auto_analyze_end_time) | `23:59 +0000` | 一天中允许统计信息自动更新的结束时间 |
| [`tidb_auto_analyze_partition_batch_size`](/system-variables.md#tidb_auto_analyze_partition_batch_size-从-v640-版本开始引入) | `8192` | TiDB 自动 ANALYZE 分区表（即自动更新分区表的统计信息）时，每次同时 ANALYZE 分区的个数 |
| [`tidb_auto_analyze_ratio`](/system-variables.md#tidb_auto_analyze_ratio) | `0.5` | 自动更新阈值 |
Expand Down
12 changes: 8 additions & 4 deletions system-variables.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1124,9 +1124,11 @@ mysql> SELECT job_info FROM mysql.analyze_jobs ORDER BY end_time DESC LIMIT 1;
- 是否持久化到集群：是
- 是否受 Hint [SET_VAR](/optimizer-hints.md#set_varvar_namevar_value) 控制：否
- 类型：整数型
- 默认值：`1`
- 默认值：`3`
- 范围：`[1, 2147483647]`
- 这个变量用来设置 TiDB 集群中自动更新统计信息操作的并发度。在 v8.4.0 之前的版本中，该并发度固定为 `1`。你可以根据集群资源情况提高该并发度，从而加快统计信息收集任务的执行速度。
- 这个变量用来设置 TiDB 集群中自动更新统计信息操作的并发度。你可以根据集群资源情况提高该并发度，从而加快统计信息收集任务的执行速度。
- 在 v8.4.0 之前的版本中，该并发度固定为 `1`。
- 从 v8.5.7 开始，该变量的默认值从 `1` 变更为 `3`。如果你的集群是从之前的版本升级而来的，升级后该变量的值保持不变。
Comment thread
qiancai marked this conversation as resolved.
Outdated

### `tidb_auto_analyze_end_time`

Expand Down Expand Up @@ -1187,9 +1189,10 @@ mysql> SELECT job_info FROM mysql.analyze_jobs ORDER BY end_time DESC LIMIT 1;
- 是否持久化到集群：是
- 是否受 Hint [SET_VAR](/optimizer-hints.md#set_varvar_namevar_value) 控制：否
- 类型：整数型
- 默认值：`1`
- 默认值：`2`
- 范围：`[1, 256]`
- 这个变量用来设置执行统计信息自动更新的并发度。
- 从 v8.5.7 开始，该变量的默认值从 `1` 变更为 `2`。如果你的集群是从之前的版本升级而来的，升级后该变量的值保持不变。
Comment thread
qiancai marked this conversation as resolved.
Outdated

### `tidb_backoff_lock_fast`

Expand Down Expand Up @@ -5637,8 +5640,9 @@ Query OK, 0 rows affected, 1 warning (0.00 sec)
- 是否持久化到集群：是
- 是否受 Hint [SET_VAR](/optimizer-hints.md#set_varvar_namevar_value) 控制：否
- 类型：整数型
- 默认值：`1`
- 默认值：`4`
- 范围：`[0, 4294967295]`，在 v7.5.0 及之前版本中最大值为 `256`。在 v8.2.0 之前版本中，最小值为 `1`。当设置为 `0` 时，TiDB 会根据集群规模自适应调整并发度。
- 从 v8.5.7 开始，该变量的默认值从 `1` 变更为 `4`。如果你的集群是从之前的版本升级而来的，升级后该变量的值保持不变。
Comment thread
qiancai marked this conversation as resolved.
Outdated
- 这个变量用来设置 TiDB 执行内部 SQL 语句（例如统计信息自动更新）时 scan 操作的并发度。

### `tidb_table_cache_lease` <span class="version-mark">从 v6.0.0 版本开始引入</span>
Expand Down
Loading