Re: [REVIEW] Re: Compression of full-page-writes - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: [REVIEW] Re: Compression of full-page-writes
Date
Msg-id 20141211163459.GB19832@momjian.us
Whole thread Raw
In response to Re: [REVIEW] Re: Compression of full-page-writes  (Rahila Syed <rahilasyed90@gmail.com>)
Responses Re: [REVIEW] Re: Compression of full-page-writes  (Michael Paquier <michael.paquier@gmail.com>)
Re: [REVIEW] Re: Compression of full-page-writes  (Robert Haas <robertmhaas@gmail.com>)
List pgsql-hackers
On Thu, Dec 11, 2014 at 01:26:38PM +0530, Rahila Syed wrote:
> >I am sorry but I can't understand the above results due to wrapping.
> >Are you saying compression was twice as slow?
> 
> CPU usage at user level (in seconds)  for compression set 'on' is 562 secs
> while that for compression  set 'off' is 354 secs. As per the readings, it
> takes little less than double CPU time to compress.
> However , the total time  taken to run 250000 transactions for each of the
> scenario is as follows,
> 
> compression = 'on'  : 1838 secs
>             = 'off' : 1701 secs
> 
> 
> Different is around 140 secs.

OK, so the compression took 2x the cpu and was 8% slower.  The only
benefit is WAL files are 35% smaller?

--  Bruce Momjian  <bruce@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com
 + Everyone has their own god. +



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