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

stats: clarify configuration persistence of analyze statement #13840

Merged
merged 2 commits into from
Dec 20, 2023
Merged

stats: clarify configuration persistence of analyze statement #13840

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
f0932bb
stats: clarify configuration persistence of analyze statement
jackysp Jun 12, 2023
fb3c43a
Apply suggestions from code review
ran-huang Dec 20, 2023
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
8 changes: 7 additions & 1 deletion statistics.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -470,7 +470,13 @@ The `ANALYZE` configuration persistence feature is disabled by default. To enabl

You can use this feature to record the persistence configurations specified in the `ANALYZE` statement when executing the statement manually. Once recorded, the next time TiDB automatically updates statistics or you manually collect statistics without specifying these configuration, TiDB will collect statistics according to the recorded configurations.

When you manually execute the `ANALYZE` statement multiple times with persistence configurations specified, TiDB overwrites the previously recorded persistent configuration using the new configurations specified by the latest `ANALYZE` statement.
To query the configuration persisted on a specific table used for auto analyze operations, you can use the following SQL statement:

```sql
SELECT sample_num, sample_rate, buckets, topn, column_choice, column_ids FROM mysql.analyze_options opt JOIN information_schema.tables tbl ON opt.table_id = tbl.tidb_table_id WHERE tbl.table_schema = '{db_name}' AND tbl.table_name = '{table_name}';
```

TiDB will overwrite the previously recorded persistent configuration using the new configurations specified by the latest `ANALYZE` statement. For example, if you run `ANALYZE TABLE t WITH 200 TOPN;`, it will set the top 200 values in the `ANALYZE` statement. Subsequently, executing `ANALYZE TABLE t WITH 0.1 SAMPLERATE;` will set both the top 200 values and a sampling rate of 0.1 for auto `ANALYZE` statements, similar to `ANALYZE TABLE t WITH 200 TOPN, 0.1 SAMPLERATE;`.

#### Disable ANALYZE configuration persistence

Expand Down
Loading