On Sat, Apr 23, 2016 at 11:21 AM, Sameer Kumar <sameer.ku...@ashnik.com> wrote:
> > > On Fri, Apr 22, 2016 at 5:21 PM raghu vineel <raghuvin...@gmail.com> > wrote: > >> >> Hi, >> >> I have a 4 core CPU for postgres and I have submitted 6 queries parallely >> in 6 different sessions. But I am seeing only 1 query per CPU and the >> remainig queries are queued. I am not sure why is it happening. Do you have >> any special scheduler for postgres? I can see that CPU has been shared with >> other non postgres processes but postgres processes are not sharing any CPU >> within a core. The following is the process states. >> >> >> *lms 2868 2209 98 07:20 ? 00:02:30 postgres: lms controller >> [local] SELECTlms 2869 2209 98 07:20 ? 00:02:30 postgres: lms >> controller [local] SELECT* >> lms 2870 2209 0 07:20 ? 00:00:00 postgres: lms controller >> [local] SELECT >> lms 2871 2209 0 07:20 ? 00:00:00 postgres: lms controller >> [local] SELECT >> lms 2872 2209 0 07:20 ? 00:00:00 postgres: lms controller >> [local] SELECT >> *lms 2873 2209 98 07:20 ? 00:02:30 postgres: lms controller >> [local] SELECT* >> >> If you see above, three Select queries have been queued. They are >> acquiring CPU only when there is a core without any postgres query running >> on it. >> >> I know the postgres limitation of one query using only one core. But is >> there any limitation of one CPU running only one query at a time? >> >> > Are all the queries related to the same table(s)? > Which version of PostgreSQL? What's the version of OS? > > Check out the locks which are not granted yet - pg_locks.granted > > >> Your help is appreciated. >> >> Thanks and regards, >> Vineel. >> >> -- > -- > Best Regards > Sameer Kumar | DB Solution Architect > *ASHNIK PTE. LTD.* > > 101 Cecil Street, #11-11 Tong Eng Building, Singapore 069 533 > > T: +65 6438 3504 | M: +65 8110 0350 | www.ashnik.com > Yes, they query the same table. But all queries are *select* only. Postgres is 8.3 and OS is *LINUX 2.6.32-431.el6.x86_64. * Also I could see that pg_locks.granted is true for the queries I have submitted and lock mode is * AccessShareLock.*
