How the index works and how to keep it exact: the MySQL and SQLite storage engines, manual rebuilds for bulk changes, and scheduled rebuilds for sites that import on a rhythm.
Understanding the Indexer: MySQL vs SQLite
What the index is, how it maintains itself, and how the two storage engines differ.
How to Force Rebuild the Search Index
One button rebuilds everything; search keeps working while it runs.
Daily, weekly, or monthly rebuilds at a quiet hour, through WP-Cron.
