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Percona Software for MySQL Documentation
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Updated supported features

The following is a list of the latest supported features:

  • Percona Server for MySQLsupports SELECT FOR UPDATE SKIP LOCKED/NOWAIT. The transaction isolation level must be READ COMMITTED.

  • Percona Server for MySQL adds the ability to cancel ongoing manual compactions. The cancel methods are the following:

    • Using either Control+C (from a session) or KILL (from another session) for client sessions running manual compactions by SET GLOBAL rocksdb_compact_cf (variable).

    • Using a global variable rocksdb_cancel_manual_compactions to cancel all ongoing manual compactions.

  • Percona Server for MySQL adds supported for Generated Columns and index are supported.

  • Percona Server for MySQL adds support for explicit DEFAULT value expressions .

Behavior changes in 8.4.12-13

Index statistics after crash recovery

As of Percona Server for MySQL 8.4.12-13, a compaction that runs before an index has been opened, for example during write-ahead log replay, leaves that index’s persisted cardinality statistics in place. Those compactions used to overwrite the statistics with zeros, and query plans regressed until the statistics were recalculated.

Missing unpack information

As of Percona Server for MySQL 8.4.12-13, missing unpack information in a secondary index record returns an error to the client instead of crashing the server.

Prepared XA transactions

As of Percona Server for MySQL 8.4.12-13, a prepared XA transaction that modified MyRocks tables is kept across a clean restart. XA RECOVER lists it, and XA COMMIT or XA ROLLBACK completes it. An XA transaction prepared while the session does not write to the binary log (sql_log_bin=0) is rolled back at restart. InnoDB rolls back that transaction at restart as well.

As of Percona Server for MySQL 8.4.12-13, the following issue was fixed. Recovering a prepared XA transaction after a crash no longer logs a false failure to prepare it.

XA PREPARE of a transaction that wrote to MyRocks with write batches is described under rocksdb_master_skip_tx_api and rocksdb_rpl_skip_tx_api.

Percona fixes in 8.4.12-13

As of Percona Server for MySQL 8.4.12-13, the following issues were fixed.

  • A read that fails inside RocksDB, for example with an I/O error during a scan, returns an error. The scan does not end early with partial results.

  • If repairing a table left by an interrupted ALTER TABLE fails at startup, the original table definition is kept, so the repair can be retried after a restart.

  • With rocksdb_enable_tmp_table=ON, committing an insert into a temporary table with an AUTO_INCREMENT column no longer aborts the server.

  • MyRocks messages longer than 1 KiB are no longer truncated in the error log and the RocksDB LOG file.