Re: PG 9.1 much slower than 8.2 ?

From: Thomas Kellerer <spam_eater(at)gmx(dot)net>
To: pgsql-novice(at)postgresql(dot)org
Subject: Re: PG 9.1 much slower than 8.2 ?
Date: 2014-09-04 11:35:32
Message-ID: lu9iq5$t5i$1@ger.gmane.org
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> After this, I ran "ANALYSE;" while connected to the DB "db" without any further arguments, as Keith suggested.
> It echoed nothing but "ANALYZE" after a few seconds on both psql shells.
> After this, I ran the "SELECT *" again, identically with to what is described above.

This statement:

> The result is still the same: 9.3 needs twice the time of 8.2 to return the results.

doesn't match the results of explain analyze:

> "EXPLAIN ANALYSE" output for 8.2:
> Total runtime: 114.922 ms

vs.

> ... followed by 9.3 output for "EXPLAIN ANALYSE":
> Total runtime: 128.252 ms

So it took 114ms on 8.2 and 128ms on 9.3. That's hardly "twice as long".

My naive interpretation of that (not really knowing Linux) would be that the "time" command adds additional overhead that .

One thing I also noticed:

the 8.2 psql seems to be in an english environment (because of the "(2 rows)" feedback), whereas 9.3 seems to be a german environment (because of the "(2 Zeilen)" psql feedback). I wonder if different locales can make a difference - although I there is no string comparison involved in your query.

Thomas

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