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MySQL 5.7 Reference Manual  /  ...  /  Partitioning Limitations Relating to Storage Engines

22.6.2 Partitioning Limitations Relating to Storage Engines

The following limitations apply to the use of storage engines with user-defined partitioning of tables.

MERGE storage engine.  User-defined partitioning and the MERGE storage engine are not compatible. Tables using the MERGE storage engine cannot be partitioned. Partitioned tables cannot be merged.

FEDERATED storage engine.  Partitioning of FEDERATED tables is not supported; it is not possible to create partitioned FEDERATED tables.

CSV storage engine.  Partitioned tables using the CSV storage engine are not supported; it is not possible to create partitioned CSV tables.

InnoDB storage engine.  InnoDB foreign keys and MySQL partitioning are not compatible. Partitioned InnoDB tables cannot have foreign key references, nor can they have columns referenced by foreign keys. InnoDB tables which have or which are referenced by foreign keys cannot be partitioned.

InnoDB does not support the use of multiple disks for subpartitions. (This is currently supported only by MyISAM.)

In addition, ALTER TABLE ... OPTIMIZE PARTITION does not work correctly with partitioned tables that use the InnoDB storage engine. Use ALTER TABLE ... REBUILD PARTITION and ALTER TABLE ... ANALYZE PARTITION, instead, for such tables. For more information, see Section, “ALTER TABLE Partition Operations”.

User-defined partitioning and the NDB storage engine (NDB Cluster).  Partitioning by KEY (including LINEAR KEY) is the only type of partitioning supported for the NDB storage engine. It is not possible under normal circumstances in NDB Cluster to create an NDB Cluster table using any partitioning type other than [LINEAR] KEY, and attempting to do so fails with an error.

Exception (not for production): It is possible to override this restriction by setting the new system variable on NDB Cluster SQL nodes to ON. If you choose to do this, you should be aware that tables using partitioning types other than [LINEAR] KEY are not supported in production. In such cases, you can create and use tables with partitioning types other than KEY or LINEAR KEY, but you do this entirely at your own risk. You should also be aware that this functionality is now deprecated and subject to removal without further notice in a future release of NDB Cluster.

The maximum number of partitions that can be defined for an NDB table depends on the number of data nodes and node groups in the cluster, the version of the NDB Cluster software in use, and other factors. See NDB and user-defined partitioning, for more information.

As of MySQL NDB Cluster 7.5.2, the maximum amount of fixed-size data that can be stored per partition in an NDB table is 128 TB. Previously, this was 16 GB.

CREATE TABLE and ALTER TABLE statements that would cause a user-partitioned NDB table not to meet either or both of the following two requirements are not permitted, and fail with an error:

  1. The table must have an explicit primary key.

  2. All columns listed in the table's partitioning expression must be part of the primary key.

Exception.  If a user-partitioned NDB table is created using an empty column-list (that is, using PARTITION BY KEY() or PARTITION BY LINEAR KEY()), then no explicit primary key is required.

Partition selection.  Partition selection is not supported for NDB tables. See Section 22.5, “Partition Selection”, for more information.

Upgrading partitioned tables.  When performing an upgrade, tables which are partitioned by KEY and which use any storage engine other than NDB must be dumped and reloaded.

Same storage engine for all partitions.  All partitions of a partitioned table must use the same storage engine and it must be the same storage engine used by the table as a whole. In addition, if one does not specify an engine on the table level, then one must do either of the following when creating or altering a partitioned table:

  • Do not specify any engine for any partition or subpartition

  • Specify the engine for all partitions or subpartitions