Why does WordPress keep asking me to update the database?

WordPress compares the database revision in its files with the db_version setting in the database. A loop means the new number is never written (no database rights, a timeout, mixed core files) or never read back (a persistent object cache such as Redis still serves the old value).

How do I fix the Database Update Required loop caused by Redis or Memcached?

Flush the object cache from the cache plugin, the host panel, or with wp cache flush. If you cannot reach those, rename wp-content/object-cache.php, load the dashboard once, rename it back and flush.

Can I run the WordPress database update without the browser?

Yes. With WP-CLI, wp core update-db runs it with no web time limit, which helps on large sites. On multisite, wp core update-db --network updates every site.

Should I change db_version in phpMyAdmin to stop the loop?

No. That hides the screen but skips the table changes the release needs. Fix the cache, the database rights or the core files, then let the update run once.

More fixes

WordPress keeps asking for a "Database Update" that never sticks

After an update, WordPress shows "Database Update Required". You click Update WordPress Database, it says Update Complete, you click Continue, and the same screen is back. You cannot reach the dashboard at all. The visitors' side of the site usually still works, which is why this can go unnoticed until someone needs to edit a page. Below is a rebuilt example (not a real client), the one-minute check, and the fix for each cause.

What the owner sees at /wp-admin

What the check found

Why WordPress asks at all

Every WordPress release carries a database revision number in its files. The database keeps the number of the last update it ran, in the db_version setting. When you open the dashboard, WordPress compares the two. If they differ it sends you to the update screen, runs the changes, and writes the new number. A loop means that new number is either never written or never read back: WordPress keeps seeing the old one.

The one-minute check

Take a backup first (database and files), from your host's panel if you cannot get into the dashboard. Everything below is safe, but a backup makes it reversible.
Look for an object cache. Over FTP or the host's file manager, open wp-content. A file called object-cache.php means Redis, Memcached or a cache plugin is storing settings outside the database. This is the most common cause of the loop.
Read the number in the database. In phpMyAdmin, open the wp_options table (your prefix may differ) and find db_version. Click the update button, then look again. If the number changed, the update worked and something is serving an old copy (row 1). If it did not change, the update could not write (rows 2-4).
If your host gives you WP-CLI, wp core version --extra shows the revision the files expect, and wp option get db_version shows what the database holds.

What causes it and the fix

What you see	Why it happens	The fix
"Update Complete", then the screen comes straight back. The number in the database did change	A persistent object cache (Redis, Memcached, or the host's own) still holds the old `db_version` and hands it to WordPress on every page load	Flush the object cache: the Redis or cache plugin's Flush button, the host panel's purge, or `wp cache flush`. If you cannot reach any of those, rename `wp-content/object-cache.php` to `object-cache.php.off`, load the dashboard once, then rename it back and flush
The number in the database never changes, no error shown	The database user in `wp-config.php` may read but not change tables (no ALTER, CREATE or INDEX rights). Common after a host move where the new user was given limited rights	In the host's MySQL users page, give that user all privileges on the site's database, then run the update again. Your host's support can do this in a minute if the page is hidden
The update screen spins, then a blank page or 500, and it starts again next time	A large site (big shop, years of posts) runs out of time or memory before the update finishes, or the host's disk or database quota is full so nothing can be written	Run it from the command line: `wp core update-db`, which has no web time limit. Check the host's disk and database usage; free space or raise the quota first. See memory exhausted if the log names memory
Started after an update that failed half way or was copied by FTP	Some core files are from the new release and some from the old one, so the files keep announcing a revision the update code does not finish	Download the same WordPress version fresh from wordpress.org and upload `wp-admin`, `wp-includes` and the root files over the old ones. Never overwrite `wp-content` or `wp-config.php`. Then run the update once
Multisite: the main site is fine, but each sub-site asks for the update	Every site in a network has its own tables and its own `db_version`. The network upgrade was never run, or stopped part way	As a Super Admin, go to Network Admin > Updates > Upgrade Network and let it finish all sites. On a large network, `wp core update-db --network`
It appeared after restoring a backup or moving the site	The database came from an older or newer WordPress than the files it now sits under	If the database is older, running the update once is correct. If it came from a newer WordPress, update the files to that version (or newer) instead of running the update against older files

What not to do

Do not edit db_version by hand to "match". The screen goes away, but the table changes the release needs never run, and things break later in quieter ways.
Do not delete object-cache.php and forget about it. Rename it, fix the loop, and put it back, or the site loses the speed the cache was giving it.
Do not restore an old backup over and over. Each restore can bring back a different mismatch.

Flushing a cache takes a minute. Finding which cache layer holds the old number, fixing database rights at a host you did not set up, or untangling a half-finished update on a live shop is where most owners would rather have someone do it. If that is you, the box below is for that. Related: a plugin won't install or update, stuck in maintenance mode and error establishing a database connection.