Thread: How to practice on EXPLAIN/optimizing queries/constructing indices

So I found https://wiki.postgresql.org/wiki/Using_EXPLAIN but still I
feel there should be more to it.
What methods can I use to actually get better at spotting issues with a
query? How can I go from looking at a fancy EXPLAIN graph produced by
PgAdmin and realize what the problem is (if there is one)?

On Wed, Jul 9, 2014 at 1:24 PM, Magnus Persson
<magnus.e.persson@gmail.com> wrote:
> So I found https://wiki.postgresql.org/wiki/Using_EXPLAIN but still I feel
> there should be more to it.
> What methods can I use to actually get better at spotting issues with a
> query? How can I go from looking at a fancy EXPLAIN graph produced by
> PgAdmin and realize what the problem is (if there is one)?

There is a good set of articles by depesz that will give you some understanding:

http://www.depesz.com/2013/04/16/explaining-the-unexplainable/
http://www.depesz.com/2013/04/27/explaining-the-unexplainable-part-2/
http://www.depesz.com/2013/04/27/explaining-the-unexplainable-part-3/
http://www.depesz.com/2013/04/27/explaining-the-unexplainable-part-4/
http://www.depesz.com/2013/04/27/explaining-the-unexplainable-part-5/

--
Kind regards,
Sergey Konoplev
PostgreSQL Consultant and DBA

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