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Re: LWLocks in DSM memory - Mailing list pgsql-hackers

From Mithun Cy
Subject Re: LWLocks in DSM memory
Date
Msg-id CAD__OujBo=E9MXt5GaJe9asb5xM0rL=K4xs83GyeZH=m1N0X8A@mail.gmail.com
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In response to Re: LWLocks in DSM memory  (Andres Freund <andres@anarazel.de>)
Responses Re: LWLocks in DSM memory  (Amit Kapila <amit.kapila16@gmail.com>)
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On Wed, Aug 17, 2016 at 9:12 PM, Andres Freund <andres@anarazel.de> wrote:
>Yes. I want a long wait list, modified in bulk - which should be the
>case with the above.

I ran some pgbench. And, I do not see much difference in performance, small variance in perf can be attributed to variance in probability of drawing the particular built-in script.

Server configuration:
                ./postgres -c shared_buffers=8GB -N 200 -c min_wal_size=15GB -c max_wal_size=20GB -c checkpoint_timeout=900 -c maintenance_work_mem=1GB -c checkpoint_completion_target=0.9 &

pgbench configuration: initialized with scale_factor 300
./pgbench -c $threads -j $threads -T 1800 -M prepared -b simple-update@1 -b  select-only@20 postgres


Simple-update : select-only = 5:95


cilents864128
Current Code38279.663784258196.067342283150.495921
After Patch revert37316.09022268285.506338280077.913954
% diff -2.51719442843.9076656356-1.0851409449




Simple-update : selec-only = 20:80


cilents864128
Current Code23169.021469134791.996882154057.101004
After Patch revert23892.91539135091.645551150402.80543
%diff3.12440437750.2223044958-2.3720396854


And this was done on our 8 socket  intel machine machine

--
Thanks and Regards
Mithun C Y

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