Re: PHP / MySQL Massively different speed differences between servers

[Jeremy James]

Data is exact same across the servers (replication)

however, after several hours of trying stuff, we have discovered that a group by query causes massive performance issues on the other servers compared to the ones that have no issues

removing it causes massive increase in performance

yet on two servers, having a group by has no issue at all

and we're talking about the exact same records being queried

very strange!! any ideas why a group by would behave so differently between exact same setups and same data sets?

potentially that means other statements might have similar impacts too which we have not discovered yet