Ok, the problem was mysql5.1, as many of you suggested. I've dumped the dbmail db, downgraded to 5.0.67 and imported back again. The explain statement now yields the same result both with the "order by" and without. The system seems to work ok, I hope I'll get no more slow queries in the next days...
Thanks everybody for your help. _______________________________________________ DBmail mailing list [email protected] https://mailman.fastxs.nl/mailman/listinfo/dbmail
