Thanks @ALone I think (but not 100% certain) that it’s a slightly different scenario. We’re using default queries for types of users as far I’m aware… but the issue is that if you look at the actual SQL being generated - it’s creating huge joins that take memory / CPU to process, when it doesn’t need to. In your case it was memory chewed up by Apache - in our case it’s memory being used by the database engine to try and process the joins.
Hmm… OK I thought I had looked at this previously… and I have:
SQL sorting issues with requestor in 5.0.2
But the “solution” I found at the time is what @knation identified as incorrect user configuration.
The behaviour of the component that generates the resulting DB SQL query actually changed from 4.x → 5.x. The exact same operation in 4.x generates different SQL vs 5.x.
Others have previously talked about similar issues in earlier versions Extremely slow SQL queries after RT3 to RT4 upgrade
So getting back to it - is this the right forum to ask this question? If not - please let me know where I should be posting the question & detail.