OPTIMIZE TABLE - MySQL

Overview

OPTIMIZE TABLE is a MySQL command used to optimize the performance of a table by rebuilding its internal structure and reorganizing its data for faster access. It is typically used on tables that have undergone frequent data modifications (inserts, updates, deletes), resulting in fragmentation and decreased performance.

Syntax

OPTIMIZE TABLE [modifier] table_name1, table_name2, ...
  • modifier (optional):
    • QUICK (default): Performs a quick optimization that only updates the table’s index statistics.
    • FULL: Performs a complete optimization that rebuilds the table’s data and index pages.

Options/Flags

  • NO_WRITE_TO_BINLOG: Prevents the optimization operation from being recorded in the binary log. This can improve optimization performance but is not recommended for tables used in replication.

Examples

Quick optimization:

OPTIMIZE TABLE QUICK my_table;

Full optimization:

OPTIMIZE TABLE FULL my_table;

Optimizing multiple tables:

OPTIMIZE TABLE my_table1, my_table2, my_table3;

Common Issues

  • Locking: OPTIMIZE TABLE can acquire an exclusive lock on the table being optimized. This can block other access to the table until the operation completes.
  • Large tables: Optimizing very large tables can be resource-intensive and may take a long time. Consider using OPTIMIZE PARTITION for partitioned tables to optimize individual partitions.
  • High workload: If the server is experiencing a high workload during optimization, performance may suffer. Schedule optimizations for off-peak hours or perform them on a replica.

Integration

ANALYZE TABLE: OPTIMIZE TABLE can be used in conjunction with ANALYZE TABLE to gather statistics about the table’s data distribution. This information is used to optimize the table’s index structure.

ALTER TABLE..REORGANIZE PARTITION: For partitioned tables, using ALTER TABLE..REORGANIZE PARTITION can move data between partitions to improve performance.

  • ANALYZE TABLE: Gathers statistics about a table’s data distribution for optimization purposes.
  • ALTER TABLE: Modifies the structure or constraints of a table.
  • REPAIR TABLE: Repairs corrupted or damaged tables, which may improve performance.