I'm running a 3.8.5 site with a fair bit of traffic. Because of some recent problems I noticed that the
__session table is not being automatically tidied up.
The session lifetime is set to 1 hour (60 minutes), but when I realised there was a problem, there were sessions in the database which were over a month old. I've truncated the
__session table four hours ago and it contains sessions which four hours old, so the garbage collections doesn't seem to be working correctly.
I can't be certain of the exact time-stamp of the the oldest session before I truncated the
__session table, but I think it was 30th/31st of January 2018. This may be a coincidence, but it would correlate with the release of 3.8.4, which includes this pull request that modifies how sessions are cleaned up.
How can I make sure that database sessions older than 'session lifetime' are correctly deleted.