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Date: Sun, 21 Nov 2010 16:42:07 +0100
Subject: Re: Query Performance SQL Server vs. Postgresql
From: tv@fuzzy.cz
To: "Humair Mohammed" <humairm@hotmail.com>
Cc: pgsql-performance@postgresql.org
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>> 4) INDEXESI can certainly add an index but given the table sizes I am
>> not
>> sure if that is a factor. This by no means is a large dataset less than
>> 350,000 rows in total and 3 columns. Also this was just a quick dump of
>> data for comparison purpose. When I saw the poor performance on the
>> COALESCE, I pointed the data load to SQL Server and ran the same query
>> except with the TSQL specific ISNULL function.
>
> 350000 rows definitely is a lot of rows, although with 3 INT column it's
> just about 13MB of data (including overhead). But indexes can be quite
> handy when doing joins, as in this case.

OK, I've just realized the tables have 3 character columns, not integers.
In that case the tables are probably much bigger (and there are things
like TOAST). In that case indexes may be even more important.

Tomas