Re: Poor Performance running Django unit tests after upgrading from 10.6 - Mailing list pgsql-performance

From Tom Lane
Subject Re: Poor Performance running Django unit tests after upgrading from 10.6
Date
Msg-id 3678904.1602770172@sss.pgh.pa.us
Whole thread Raw
In response to Poor Performance running Django unit tests after upgrading from 10.6  (Roger Hunwicks <roger@tonic-solutions.com>)
List pgsql-performance
Roger Hunwicks <roger@tonic-solutions.com> writes:
> ...
> However, even though we have similar performance for 12.4 for most
> test runs, it remains very variable.
> ...
> I think we have narrowed down the problem to a single, very complex,
> materialized view using CTEs; the unit tests create the test data and
> then refresh the materialized view before executing the actual test
> code.

In addition to others' nearby comments, I'd suggest that running all this
under auto_explain would be informative.  You evidently are not getting a
stable plan for your troublesome query, so you need to see what the range
of plans is, not just probe it once with a manual EXPLAIN.

            regards, tom lane



pgsql-performance by date:

Previous
From: Andrew Dunstan
Date:
Subject: Re: Poor Performance running Django unit tests after upgrading from 10.6
Next
From: aditya desai
Date:
Subject: CPU Consuming query. Sequential scan despite indexing.