[08:57:41] <Remilia>	 this reminded me to check apc.shm_size for my php 8 installation and sure enough it was the default 32M instead of 1G that I had for 7.4
[13:17:02] <Remilia>	 …wow, shm_size affects load averages a whole lot, the values dropped from 1.2 to 0.4 even when I use a very agressively caching Varnish in front
[20:59:14] <Guest85>	 Hi, how can I start to investigate why users are getting 'session_fail_preview' msg?
[21:11:53] <bawolff>	 Guest85: typically this is an issue if things fall out of cache too quickly
[21:12:36] <bawolff>	 Guest85: you can try setting $wgSessionCacheType = CACHE_DB; to tell it to store user sessions in db rather than the more ephermal cache, which is slightly slower, but won't have the issue of things getting deleted too soon
[21:13:11] <bawolff>	 If using apcu (CACHE_ACCEL), check what apcu.shm_size is set to in php.ini
[21:13:13] <Guest85>	 Actually I'm with CACHE_DB option
[21:13:27] <bawolff>	 Ah ok. In that case its probably a different cause
[21:13:34] <Guest85>	 There is any way to check the log and identify why it happened?
[21:14:13] <bawolff>	 MediaWiki debug log might have some information about why the user session failed. It might not be the easiest to interpret
[21:14:39] <Guest85>	 This is part of 'happy flow' of the user or it's an exception?
[21:14:59] <bawolff>	 In theory its not supposed to happen, or at least if it does its supposed to be very rare
[21:17:10] <bawolff>	 Its basically saying that it looks like the save page came from a different user session than the one that started editing. Which really should only happen if the user logs in/logs out between starting the edit and finishing the edit
[21:17:50] <bawolff>	 Sometimes though, it can happen if the user deletes their cookie or if for some reason the user session was prematurely deleted
[21:18:30] <bawolff>	 If you have any authentication extensions they can potentially affect things
[21:21:07] <Guest85>	 Got you, thanks for help!