How to Repair & Optimize a MySQL Database

Over time a MySQL database can pick up small problems: a crashed table after an interrupted write, or wasted space that slows queries down. Two quick jobs keep it healthy – repair fixes damaged tables, and optimize reclaims space. This guide shows both in phpMyAdmin.

When you need this

Repair a database when your site shows a database error, or a table is marked as crashed. Optimize it now and then for busy sites – especially after deleting a lot of rows – to tidy up the table and keep queries fast. Both tools are available on every JetHost web hosting plan.

Repair a database

1. Log in to cPanel and open phpMyAdmin.
2. Select the database in the left sidebar to see its tables.
3. Tick the tables to fix, or click Check all.
4. From the With selected drop-down, choose Repair table.

phpMyAdmin runs the REPAIR TABLE command and reports the result for each table.

Optimize a database

The steps are identical – select the tables, then choose Optimize table from the With selected drop-down. This runs OPTIMIZE TABLE, which defragments the tables and updates their statistics.

Repair from cPanel (no phpMyAdmin)

You don’t always need phpMyAdmin to repair a database. In cPanel, open Manage My Databases and scroll to the Modify Databases section. There you’ll find two tools:

1. Under Check Database, pick your database from the drop-down and click Check Database to scan it for problems.
2. If it reports an issue, select the same database under Repair Database and click Repair Database.

Each tool runs on the whole database at once, so it’s the quickest way to check and fix without opening a single table. Note that cPanel only offers Check and Repair here – for Optimize, use the phpMyAdmin method above.

Why databases get corrupted

Most table corruption comes from an interrupted write – the server losing power mid-query, a process being killed, or a disk that briefly ran out of space. A crashed table usually shows up as a database error on your site, or a plugin that suddenly can’t save. Running a repair fixes the table structure so your data is readable again. Optimizing is different: it doesn’t fix errors, it tidies up. After you delete a lot of rows, the table still reserves that space until you optimize it, so a periodic optimize on busy tables keeps queries quick and files lean.

Need more help?

Repair not fixing the error? Open a ticket through Client Area → Support Tickets and our team will take a closer look at your database.