Thread: tuning postgresql 9.3.5 and multiple cores
hi, recently i change the hardware of my database 32 cores up to 64 cores and 128GB Ram, but the performance is the same. Perhaps i have to change any parameter in the postgresql.conf?. Thanks by your help -- Atentamente, JEISON BEDOYA DELGADO . -- NOTA VERDE: No imprima este correo a menos que sea absolutamente necesario. Ahorre papel, ayude a salvar un arbol. -------------------------------------------------------------------- Este mensaje ha sido analizado por MailScanner en busca de virus y otros contenidos peligrosos, y se considera que esta limpio. -------------------------------------------------------------------- Este texto fue anadido por el servidor de correo de Audifarma S.A.: Las opiniones contenidas en este mensaje no necesariamente coinciden con las institucionales de Audifarma. La informacion y todos sus archivos Anexos, son confidenciales, privilegiados y solo pueden ser utilizados por sus destinatarios. Si por error usted recibe este mensaje, le ofrecemos disculpas, solicitamos eliminarlo de inmediato, notificarle de su error a la persona que lo envio y abstenerse de utilizar su contenido.
On Monday, August 25, 2014, Jeison Bedoya Delgado <jeisonb@audifarma.com.co> wrote:
hi, recently i change the hardware of my database 32 cores up to 64 cores and 128GB Ram, but the performance is the same. Perhaps i have to change any parameter in the postgresql.conf?.
PostgreSQL does not (yet) automatically parallelize queries.
Unless you have more than 32 queries trying to run at the same time, increasing the number of cores from 32 to 64 is unlikely to be useful.
Cheers,
Jeff
Changing to a higher rate CPU would be more helpful if you run less than 32 queries at a time.
On Tue, Aug 26, 2014 at 8:51 AM, Jeff Janes <jeff.janes@gmail.com> wrote:
On Monday, August 25, 2014, Jeison Bedoya Delgado <jeisonb@audifarma.com.co> wrote:hi, recently i change the hardware of my database 32 cores up to 64 cores and 128GB Ram, but the performance is the same. Perhaps i have to change any parameter in the postgresql.conf?.PostgreSQL does not (yet) automatically parallelize queries.Unless you have more than 32 queries trying to run at the same time, increasing the number of cores from 32 to 64 is unlikely to be useful.Cheers,Jeff
Regards,
On 26/08/14 06:47, Jeison Bedoya Delgado wrote: > hi, recently i change the hardware of my database 32 cores up to 64 > cores and 128GB Ram, but the performance is the same. Perhaps i have to > change any parameter in the postgresql.conf?. > In addition to the points that others have made, even if you do have > 32 active sessions it it not clear that 64 cores will automagically get you twice (or in fact any) better performance than 32. We are seeing exactly this effect with a (60 core) machine that gets pretty much the same performance as an older generation 32 core one. Interestingly while this is *likely* a software issue - it is not immediately obvious where it lies - we tested Postgres (9.3/9.4/9.5) and Mysql (5.5/5.6/5.7) *all* of which exhibited the the lack of improvement with more cores. Profiling suggested numa effects - but trying to eliminate these seemed to simply throw up new factors to inhibit performance. My *guess* (and it is a guess) is that we are seeing 2 (perhaps more) performance bottlenecks very close to each other: numa and spinlock contention at least. Regards Mark