bulk_insert_buffer_size

This page is original PmaControl documentation. It keeps a practical index structure for MySQL optimization work, without copying third-party content or depending on an external product.

Role

Memory used to speed up some large MyISAM inserts.

Diagnosis

SHOW VARIABLES LIKE 'bulk_insert_buffer_size';
SHOW GLOBAL STATUS LIKE '%bulk%';

The status counters do not always use the same name as the variable. Use this command as a starting point, then complete with performance_schema, SHOW ENGINE INNODB STATUS, or system metrics.

Tuning

Useful only for MyISAM workloads or specific imports. Do not increase it for InnoDB without a reason.

Risks

• A global value that is too high can increase memory consumed at startup.
• A per-connection value can explode with max_connections.
• A change must be tested with a before/after measurement and rollback.