From 357adc84ff6cfc685df21e21c084abcd2d9cda96 Mon Sep 17 00:00:00 2001 From: Alina Derkach Date: Thu, 31 Jul 2025 17:19:40 +0200 Subject: [PATCH] PS-10085 MyRocks limitations section still showing the Online DDL limitation part modified: docs/limitations.md --- docs/limitations.md | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) diff --git a/docs/limitations.md b/docs/limitations.md index 4fad38c5e9f..99140331d77 100644 --- a/docs/limitations.md +++ b/docs/limitations.md @@ -2,12 +2,20 @@ The MyRocks storage engine lacks the following features compared to InnoDB: -* [Online DDL](https://dev.mysql.com/doc/refman/8.0/en/innodb-online-ddl.html) is not supported due to the lack of atomic DDL support. +* [Online DDL](https://dev.mysql.com/doc/refman/8.0/en/innodb-online-ddl.html) is generally **not supported** due to the lack of atomic DDL support. - * There is no `ALTER TABLE ... ALGORITHM=INSTANT` functionality + As of Percona Server for MySQL 8.0.42-33, RocksDB supports a limited set of Instant DDL operations through specific configuration variables: - * A partition management operation only supports the `COPY` algorithms, which rebuilds the partition table and moves the data based on the new `PARTITION ... VALUE` definition. In the case of `DROP PARTITION`, the data not moved to another partition is deleted. + * [`--rocksdb_enable_instant_ddl_for_append_column`](variables.md#rocksdb_enable_instant_ddl_for_append_column) + * [`--rocksdb_enable_instant_ddl_for_column_default_changes`](variables.md#rocksdb_enable_instant_ddl_for_column_default_changes) + * [`--rocksdb_enable_instant_ddl_for_drop_index_changes`](variables.md#rocksdb_enable_instant_ddl_for_drop_index_changes) + * [`--rocksdb_enable_instant_ddl_for_table_comment_changes`](variables.md#rocksdb_enable_instant_ddl_for_table_comment_changes) + However, RocksDB has important limitations compared to InnoDB's Instant DDL support. + + * The explicit `ALTER TABLE ... ALGORITHM=INSTANT` syntax is not supported for RocksDB tables. + + * Partition management operations only support the `COPY` algorithm. This algorithm rebuilds the partition table and moves data according to the new `PARTITION ... VALUE` definition. If you use `DROP PARTITION`, the system deletes any data not moved to another partition. * [ALTER TABLE .. EXCHANGE PARTITION](https://dev.mysql.com/doc/refman/8.0/en/partitioning-management-exchange.html).