Re: Need help with understanding the explain analyze query plan

From: David G Johnston <david(dot)g(dot)johnston(at)gmail(dot)com>
To: pgsql-novice(at)postgresql(dot)org
Subject: Re: Need help with understanding the explain analyze query plan
Date: 2014-10-29 21:21:58
Message-ID: 1414617718379-5824949.post@n5.nabble.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-novice

ssharma wrote
> "Total runtime: 76.051 ms"
> ======================
>
> I don't understand how to read the output.

I don't understand why you would want to...

There is considerable material on the internet about how to read plans,
including the documentation. You're not that likely to get someone to try
teaching you about EXPLAIN using the query you've shown but if you show
you've done some reading and ask somewhat more specific questions you will
find people willing to help fill in the gaps.

Typically you would start with a query that is performing poorly and at
first glance 76ms doesn't seem bad enough to warrant any effort trying to
understand how the planner is fulfilling your query.

Though, to make reading plans easier you should consider using this site:

http://explain.depesz.com/

I'd suggest copying your explain output there, taking some time to review it
and do some reading (on that site, in the documentation, and elsewhere), and
then come back and ask some specific questions.

David J.

--
View this message in context: http://postgresql.1045698.n5.nabble.com/Need-help-with-understanding-the-explain-analyze-query-plan-tp5824939p5824949.html
Sent from the PostgreSQL - novice mailing list archive at Nabble.com.

In response to

Browse pgsql-novice by date

  From Date Subject
Next Message sam pendleton 2014-11-04 21:53:18 ingesting a large xml file and formatting it
Previous Message Shubhra Sharma 2014-10-29 20:34:03 Need help with understanding the explain analyze query plan