Re: [PERFORM] Sudden drop in DBb performance

2011-09-06 Thread Tomas Vondra
On 6 Září 2011, 10:26, Gerhard Wohlgenannt wrote: Thanks a lot to everybody for their helpful hints!!! I am running all these benchmarks while the VMs are up .. with the system under something like typical loads .. The RAID is hardware based. On of my colleagues will check if there is any

Re: [PERFORM] Sudden drop in DBb performance

2011-09-06 Thread Gerhard Wohlgenannt
Thanks a lot to everybody for their helpful hints!!! I am running all these benchmarks while the VMs are up .. with the system under something like typical loads .. The RAID is hardware based. On of my colleagues will check if there is any hardware problem on the RAID (the disks) today, but

Re: [PERFORM] Sudden drop in DBb performance

2011-09-06 Thread Gerhard Wohlgenannt
hi, What does a normal load mean? Does that mean a time when the queries are slow? yes, we are have slow queries (according to postgresql.log) with such load Are you sure the machine really has 48GB of RAM? Because from the vmstat output it seems like there's just 32GB. procs

Re: [PERFORM] Sudden drop in DBb performance

2011-09-06 Thread Gerhard Wohlgenannt
That's why I love dstat, just do this $ dstat -C 0,1,2,3,4,5,6,7 and you know all you need. dstat looks like a very nice tool, results below .. (now the system load seems a bit lower then before when generating results for vmstat and iostat) Good catch, thanks Scott. Yes, good catch.

Re: [PERFORM] Sudden drop in DBb performance

2011-09-06 Thread Gerhard Wohlgenannt
That's a good thought, maybe the stats are old and you have bad plans? It could also be major updates to the data too (as opposed to growth). we have made checks for number of dead tuples etc recently, but looks ok. and as everything in the database seems to be very slow atm, I guess the

Re: [PERFORM] Sudden drop in DBb performance

2011-09-06 Thread Tomas Vondra
On 6 Září 2011, 10:55, Gerhard Wohlgenannt wrote: That's why I love dstat, just do this $ dstat -C 0,1,2,3,4,5,6,7 and you know all you need. dstat looks like a very nice tool, results below .. (now the system load seems a bit lower then before when generating results for vmstat and

Re: [PERFORM] Sudden drop in DBb performance

2011-09-05 Thread pasman pasmański
Hi. Autoexplain module allow to log plans and statistics of live queries. Try it. 2011/9/3, Gerhard Wohlgenannt wo...@ai.wu.ac.at: Dear list, we are encountering serious performance problems with our database. Queries which took around 100ms or less last week now take several seconds. The

Re: [PERFORM] Sudden drop in DBb performance

2011-09-05 Thread Tomas Vondra
On 3 Září 2011, 9:26, Gerhard Wohlgenannt wrote: Dear list, we are encountering serious performance problems with our database. Queries which took around 100ms or less last week now take several seconds. The database runs on Ubuntu Server 10.4.3 (kernel: 2.6.32-33) on hardware as follows:

Re: [PERFORM] Sudden drop in DBb performance

2011-09-05 Thread Andy Colson
On 09/05/2011 02:48 AM, Tomas Vondra wrote: On 3 Září 2011, 9:26, Gerhard Wohlgenannt wrote: Dear list, we are encountering serious performance problems with our database. Queries which took around 100ms or less last week now take several seconds. Results of Bonnie++ Version 1.96

Re: [PERFORM] Sudden drop in DBb performance

2011-09-05 Thread Tomas Vondra
On 5 Září 2011, 15:51, Andy Colson wrote: On 09/05/2011 02:48 AM, Tomas Vondra wrote: That seems a bit slow ... 27MB/s for writes and 41MB/s forreads is ait slow with 8 drives. Tomas Agreed, that's really slow. A single SATA drive will get 60 MB/s. Did you run Bonnie while the VM's

Re: [PERFORM] Sudden drop in DBb performance

2011-09-05 Thread Tomas Vondra
On 5 Září 2011, 16:08, Gerhard Wohlgenannt wrote: Below please find the results of vmstat 2 over some periode of time .. with normal database / system load. What does a normal load mean? Does that mean a time when the queries are slow? Are you sure the machine really has 48GB of RAM? Because

Re: [PERFORM] Sudden drop in DBb performance

2011-09-05 Thread Andy Colson
On 09/05/2011 09:39 AM, Tomas Vondra wrote: On 5 Září 2011, 16:08, Gerhard Wohlgenannt wrote: Below please find the results of vmstat 2 over some periode of time .. with normal database / system load. What does a normal load mean? Does that mean a time when the queries are slow? Are you sure

Re: [PERFORM] Sudden drop in DBb performance

2011-09-05 Thread Gerhard Wohlgenannt
On 09/05/2011 03:51 PM, Andy Colson wrote: On 09/05/2011 02:48 AM, Tomas Vondra wrote: On 3 Září 2011, 9:26, Gerhard Wohlgenannt wrote: Dear list, we are encountering serious performance problems with our database. Queries which took around 100ms or less last week now take several seconds.

Re: [PERFORM] Sudden drop in DBb performance

2011-09-05 Thread Gerhard Wohlgenannt
hi, thanks a lot for your help! Dear list, we are encountering serious performance problems with our database. Queries which took around 100ms or less last week now take several seconds. The database runs on Ubuntu Server 10.4.3 (kernel: 2.6.32-33) on hardware as follows: 8-core Intel Xeon

Re: [PERFORM] Sudden drop in DBb performance

2011-09-05 Thread Gerhard Wohlgenannt
hi, thanks a lot for your help! Dear list, we are encountering serious performance problems with our database. Queries which took around 100ms or less last week now take several seconds. The database runs on Ubuntu Server 10.4.3 (kernel: 2.6.32-33) on hardware as follows: 8-core Intel Xeon

Re: [PERFORM] Sudden drop in DBb performance

2011-09-05 Thread Scott Marlowe
On Mon, Sep 5, 2011 at 8:08 AM, Gerhard Wohlgenannt wo...@ai.wu.ac.at wrote: Below please find the results of vmstat 2 over some periode of time .. with normal database / system load.  0  0 1344332 237196 104140 31468412    0    0   330   102 4322 7130  4  2 90  4  1  1 1344332 236708 104144

Re: [PERFORM] Sudden drop in DBb performance

2011-09-05 Thread Andy Colson
On 09/05/2011 01:45 PM, Scott Marlowe wrote: On Mon, Sep 5, 2011 at 8:08 AM, Gerhard Wohlgenanntwo...@ai.wu.ac.at wrote: Below please find the results of vmstat 2 over some periode of time .. with normal database / system load. 2 1 1344204 240924 104156 31462484 3500 1906 234 3687

Re: [PERFORM] Sudden drop in DBb performance

2011-09-05 Thread Tomas Vondra
On 5 Září 2011, 21:07, Andy Colson wrote: On 09/05/2011 01:45 PM, Scott Marlowe wrote: On Mon, Sep 5, 2011 at 8:08 AM, Gerhard Wohlgenanntwo...@ai.wu.ac.at wrote: Below please find the results of vmstat 2 over some periode of time .. with normal database / system load. 2 1 1344204 240924