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PS-10085 MyRocks limitations section still showing the Online DDL limitation part (8.0) #557

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PS-10085 MyRocks limitations section still showing the Online DDL limitation part (8.0) #557

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14 changes: 11 additions & 3 deletions docs/limitations.md
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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).

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