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Re: Select performance vs. mssql

From: Christopher Kings-Lynne <chriskl(at)familyhealth(dot)com(dot)au>
To: mark durrant <markd89(at)yahoo(dot)com>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Select performance vs. mssql
Date: 2005-05-25 01:29:36
Message-ID: 4293D500.8010908@familyhealth.com.au (view raw or flat)
Thread:
Lists: pgsql-performance
> --As Chris pointed out, how real-world is this test?
> His point is valid. The database we're planning will
> have a lot of rows and require a lot of summarization
> (hence my attempt at a "test"), but we shouldn't be
> pulling a million rows at a time.

If you want to do lots of aggregate analysis, I suggest you create a 
sepearate summary table, and create triggers on the main table to 
maintain your summaries in the other table...

> --MSSQL's ability to hit the index only and not having
> to go to the table itself results in a _big_
> performance/efficiency gain. If someone who's in
> development wants to pass this along, it would be a
> nice addition to PostgreSQL sometime in the future.
> I'd suspect that as well as making one query faster,
> it would make everything else faster/more scalable as
> the server load is so much less.

This is well-known and many databases do it.  However, due to MVCC 
considerations in PostgreSQL, it's not feasible for us to implement it...

Chris

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