Sounds like a tmp drive issue to me. Maybe you had reiserfs on your old tmp partition and now you have ext3 or something like that.
Donny > -----Original Message----- > From: Charles, Tony (Exchange) [mailto:[EMAIL PROTECTED] > Sent: Friday, May 21, 2004 12:47 PM > To: [EMAIL PROTECTED] > Subject: upgraded hardware: new server is faster, but "GROUP BY" > operations are slower??? > > > Hi all, > > Just bought a new server, which was supposed to improve the performance of > our app. > > The new machine has the same OS (Redhat 8), same MySQL (4.0.18), and same > my.cnf. > > The problem is that this (frequently run) query, actually runs 41% slower! > > select * from LEG L, LEG_DETAIL D, DEAL_LEGS G > where L.latest_id = D.latest_id and D.latest_id = G.latest_id > group by L.dealid limit 750000; > > If I remove the "GROUP BY", then the new box returns the results 14% > faster than the old server. > > (So what's so special about "GROUP BY"?) > > I ran the benchmark scripts on both boxes, and it seems the following > operations are slower on the new server, for some reason? > > count_distinct (1000) > count_distinct_2 (1000) > count_distinct_group (1000) > count_distinct_group_on_key (1000) > count_distinct_group_on_key_parts (1 > count_distinct_key_prefix (1000) > count_group_on_key_parts (1000) > count_on_key (50100) > select_distinct (800) > select_group (2911) > > Can anyone suggest why the new machine might be slower, ONLY IN THE ABOVE > areas? > > Just in case these numbers help, here are lines from the RUN file, for two > of the slow operations above.... > > Operation seconds usr sys cpu > tests > count_distinct_group 19.00 1.17 0.08 1.25 > 1000 > count_distinct_group (new box) 26.00 0.39 0.26 0.65 > 1000 > count_distinct 12.00 0.51 0.02 0.53 > 1000 > count_distinct (new box) 15.00 0.10 0.01 0.11 > 1000 > > Any advice at all, would be very much appreciated! > > Thanks, > > Tony > > > > > > > > > *********************************************************************** > Bear Stearns is not responsible for any recommendation, solicitation, > offer or agreement or any information about any transaction, customer > account or account activity contained in this communication. > *********************************************************************** > > > -- > MySQL General Mailing List > For list archives: http://lists.mysql.com/mysql > To unsubscribe: > http://lists.mysql.com/[EMAIL PROTECTED] -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
