# Percona Distribution for MySQL 8.0.31 using Percona Server for MySQL (2023-02-09)

| Release date         | February 9, 2023 |
| :--------------      | :--------------- |
| Install instructions | [Installing Percona Distribution for MySQL](installing.md)|

Percona Distribution for MySQL is the most stable, scalable and secure open-source MySQL distribution, with two download options: one based on Percona Server for MySQL and one based on Percona XtraDB Cluster.

This release is focused on the Percona Server for MySQL-based deployment variation. It is based on [Percona Server for MySQL 8.0.31-23](https://www.percona.com/doc/percona-server/8.0/release-notes/8.0.31-23.html).

## Release highlights

Improvements and bug fixes introduced by Oracle for MySQL 8.0.31 and included in Percona Server for MySQL are the following:

* A replica can add a Generated Invisible Primary Keys(GIPK) to any InnoDB table. To achieve this behavior, the `GENERATE` value is added as a possible value for the `CHANGE REPLICATION SOURCE TO` statement's `REQUIRE_TABLE_PRIMARY_KEY_CHECK` option.

    `REQUIRE_TABLE_PRIMARY_KEY_CHECK = GENERATE` option can be used on a per-channel basis.

    Setting `sql_generate_invisible_primary_key` on the source is ignored by a replica because this variable is not replicated. This behavior is inherited from the previous releases.

* MySQL adds support for the SQL standard [`INTERSECT`](https://dev.mysql.com/doc/refman/8.0/en/intersect.html) and [`EXCEPT`](https://dev.mysql.com/doc/refman/8.0/en/except.html) table operators.

* InnoDB supports parallel index builds. This improves index build performance. The sorted index entries are loaded into a B-tree in a multithread. In previous releases, this action was performed by a single thread.

* The Performance and sys schemas show metrics for the global and session memory limits introduced in MySQL 8.0.28.

    The following columns have been added to the Performance Schema tables:

    | Performance Schema tables                                                            | Columns                                                   |
    | ------------------------------------------------------------------------------------ | --------------------------------------------------------- |
    | SETUP_INSTRUMENTS                                                                    | FLAGS                                                     |
    | THREADS                                                                              | CONTROLLED_MEMORY, MAX_CONTROLLED_MEMORY, TOTAL_MEMORY, MAX_TOTAL_MEMORY |
    | EVENTS_STATEMENTS_CURRENT, EVENTS_STATEMENTS_HISTORY, EVENTS_STATEMENTS_HISTORY_LONG | MAX_CONTROLLED_MEMORY, MAX_TOTAL_MEMORY                   |
    | Statement Summary Tables                                                             | MAX_CONTROLLED_MEMORY, MAX_TOTAL_MEMORY                   |
    | Performance Schema Connection Tables                                                 | MAX_SESSION_CONTROLLED_MEMORY, MAX_SESSION_TOTAL_MEMORY   |
    | PREPARED_STATEMENTS_INSTANCES                                                        | MAX_CONTROLLED_MEMORY, MAX_TOTAL_MEMORY                   |

    The following columns have been added to the sys schema `STATEMENT_ANALYSIS` and `X$STATEMENT_ANALYSIS` views:

    * MAX_CONTROLLED_MEMORY

    * MAX_TOTAL_MEMORY

    The `controlled_by_default` flag has been added to the `PROPERTIES` column of the `SETUP_INSTRUMENTS` table.

    Now, you can add and remove non-global memory instruments to the set of controlled-memory instruments. To do this, set the value of the `FLAGS` column of `SETUP_INSTRUMENTS`.

    ```sql
    SQL> UPDATE PERFORMANCE_SCHEMA.SETUP_INTRUMENTS SET FLAGS="controlled" 
    WHERE NAME='memory/sql/NET::buff';
    ```

* The `audit_log_flush` variable has been deprecated and will be removed in future releases.

Find the full list of bug fixes and changes in the [MySQL 8.0.31 Release Notes](https://dev.mysql.com/doc/relnotes/mysql/8.0/en/news-8-0-31.html).

## Supplied components

Review each component’s release notes for What’s new, improvements, or bug fixes. The following is a list of the components supplied with the Percona Server for MySQL-based variation of the Percona Distribution for MySQL:

| Component           | Version   | Description                                |
| ------------------- | --------- | -------------------------------------------|
| Orchestrator        | [3.2.6-7](https://github.com/percona/orchestrator/releases/tag/v3.2.6-7)     | The replication topology manager for Percona Server for MySQL|
| ProxySQL            | [2.4.4-1.2](https://docs.percona.com/proxysql/2.4.4-1.2.html)     | A high performance, high-availability, protocol-aware proxy for MySQL|
| Percona XtraBackup  | [8.0.31-24](https://docs.percona.com/percona-xtrabackup/8.0/release-notes/8.0/8.0.31-24.0.html)| An open-source hot backup utility for MySQL-based servers|
| Percona Toolkit     | [3.5.1](https://www.percona.com/doc/percona-toolkit/LATEST/release_notes.html#v3-5-1-released-2022-11-28)     | The set of scripts to simplify and optimize database operation|
| MySQL Shell         | [8.0.31](https://dev.mysql.com/doc/relnotes/mysql-shell/8.0/en/news-8-0-31.html)    | An advanced client and code editor for MySQL Server|
| MySQL Router        | [8.0.31](https://dev.mysql.com/doc/relnotes/mysql-router/en/news-8-0-31.html)    | Lightweight middleware that provides transparent routing between your application and back-end MySQL servers|