Databases grow, and growth causes problems.
WHAT GROWS
Log and audit tables Revisions, in content systems Expired sessions and transient data Spam comments Orders and their metadata, in shops Analytics and tracking tables added by plugins
FINDING THE LARGE TABLES
Query the information schema for table sizes, sorted largest first. That identifies the problem immediately.
REDUCING IT
Delete genuinely obsolete data, with a backup taken first Limit revisions Clear expired transients and sessions Remove tables belonging to plugins you no longer use, which are frequently left behind Archive old records to a separate table or export them
OPTIMISING
After large deletions, optimising the table reclaims the space. Deleted rows do not release space automatically.
WHY IT MATTERS
Every query on a large table is slower Backups take longer and consume more space Imports and migrations become difficult You may approach plan limits
A ROUTINE
Check table sizes quarterly. Growth is gradual until it is a problem.