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 -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
