Re: Fun little performance IMPROVEMENT... - Mailing list pgsql-performance

From Tom Lane
Subject Re: Fun little performance IMPROVEMENT...
Date
Msg-id 17636.1295639447@sss.pgh.pa.us
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In response to Fun little performance IMPROVEMENT...  (grant@amadensor.com)
Responses Re: Fun little performance IMPROVEMENT...  (grant@amadensor.com)
List pgsql-performance
grant@amadensor.com writes:
> Here is the fun part.   When running 8 threads spinning calculating square
> roots (using the stress package), the full scan returned consistently 60%
> faster than the machine with no load.

Possibly the synchronized-seqscans logic kicking in, resulting in this
guy not having to do all his own I/Os.  It would be difficult to make
any trustworthy conclusions about performance in such cases from a view
of only one process's results --- you'd need to look at the aggregate
behavior to understand what's happening.

            regards, tom lane

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