Rebuilding partitions: Rebuilds the partition; this has the same effect as dropping all records stored in the partition, then reinserting them. This can be useful for purposes of defragmentation.

Example:

ALTER TABLE t1 REBUILD PARTITION p0, p1;

Optimizing partitions: If you have deleted a large number of rows from a partition or if you have made many changes to a partitioned table with variable-length rows (that is, having VARCHAR, BLOB, or TEXT columns), you can use ALTER TABLE ... OPTIMIZE PARTITION to reclaim any unused space and to defragment the partition data file.

Example:

ALTER TABLE t1 OPTIMIZE PARTITION p0, p1;

Using OPTIMIZE PARTITION on a given partition is equivalent to running CHECK PARTITION, ANALYZE PARTITION, and REPAIR PARTITION on that partition.

Analyzing partitions: This reads and stores the key distributions for partitions.

Example:

ALTER TABLE t1 ANALYZE PARTITION p3;

Repairing partitions: This repairs corrupted partitions.

Example:

ALTER TABLE t1 REPAIR PARTITION p0,p1;

Checking partitions: You can check partitions for errors in much the same way that you can use CHECK TABLE with non-partitioned tables.

Example:

ALTER TABLE trb3 CHECK PARTITION p1;

This command will tell you if the data or indexes in partition p1 of table t1 are corrupted. If this is the case, use ALTER TABLE ... REPAIR PARTITION to repair the partition.