Last week I started getting "out of memory" errors in my 2009.6 mediawiki (MW) VM. After doing an apt-get upgrade, things would work fine for a while until the console would be soiled with error such as (see screenshot):
Out of memory: kill process 5023 (apache2) score 225331 or a child
Killed process 5023 (apache2)
Out of memory: kill process 4497 (mysqld) scrore 32182 or a child
Killed process 4497 (mysqld)
Firefox just shows a blank page, Chrome reports an error:
Error 324 (net::ERR_EMPTY_RESPONSE): Unknown error.
So i started comparing this MW to another very similar MW installation based off of the same 2009.6 ISO. I didn't have any problems there, but I also hadn't run the Linux upgrade yet. I compared LocalSettings, AdminSettings, made dumpbackups and mysqldump exports, just in case. But nothing I'd find would pinpoint the problem. So I upgraded the second MW as well. And this also led to failures on that VM. Clearly, something is not right in both installation when doing an upgrade. Apt-get must forget to correct something.
Both php5 and mysql5 were upgraded, as can be seen from the update log. Nothing was changed (by me) in any config files right before/after the update. Both VMs have 512MB but I bumped the first one up to 1GB to see if that helped. Same difference.
Even though the console shows the Out of memory error, both mysql.err and mysql.log in /var/log are empty.