Expected: report loads fast and does not use more than 256M of memory

That's a bit a random requirement. How much does it actually take? Can you increase to 1GB and see if it works and how much it actually uses?

I think it'd be better to check if we can find a memory leak or something but a 512MB memory usage might be valid

After changing memory limit to 1024M, the row evolution loads. It took 1 min to load the report (period month) which is quite slow.

Surprisingly

• it is only very slow for Period = Week or Month or Year
• It is very fast for period = day and period = range (takes 1 second)

This only affects the "User cities" report, other Row Evolution reports load very fast

It's also very slow in Pages report.

Row Evolution should be quite fast in general as long as reports are pre-processed by the cron, and that browser archiving is disabled. Will close the issue as we haven't had this issue recently.