Re: Consecutive Query Executions with Increasing Execution Time - Mailing list pgsql-performance

From Tom Lane
Subject Re: Consecutive Query Executions with Increasing Execution Time
Date
Msg-id 19575.1576529417@sss.pgh.pa.us
Whole thread Raw
In response to Re: Consecutive Query Executions with Increasing Execution Time  (Peter Geoghegan <pg@bowt.ie>)
Responses Re: Consecutive Query Executions with Increasing Execution Time  (Nicolas Charles <nicolas.charles@normation.com>)
Re: Consecutive Query Executions with Increasing Execution Time  (Laurenz Albe <laurenz.albe@cybertec.at>)
List pgsql-performance
Peter Geoghegan <pg@bowt.ie> writes:
> Why do the first and the twentieth executions of the query have almost
> identical "buffers shared/read" numbers? That seems odd.

It's repeat execution of the same query, so that doesn't seem odd to me.

This last set of numbers suggests that there's some issue with the
parallel execution infrastructure in particular, though I don't see what
it would be.  Doesn't execParallel wait for the workers to exit before
the leader finishes its query?  If so, how is there any persistent state
that would interfere with a later query?

            regards, tom lane



pgsql-performance by date:

Previous
From: Peter Geoghegan
Date:
Subject: Re: Consecutive Query Executions with Increasing Execution Time
Next
From: Nicolas Charles
Date:
Subject: Re: Consecutive Query Executions with Increasing Execution Time