Re: Comparing user attributes with bitwise operators

From: Josh Berkus <josh(at)agliodbs(dot)com>
To: pgsql-performance(at)postgresql(dot)org
Subject: Re: Comparing user attributes with bitwise operators
Date: 2004-10-05 16:32:38
Message-ID: 200410050932.38595.josh@agliodbs.com
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Patrick,

First off, thanks for posting this solution! I love to see a new demo of The
Power of Postgres(tm) and have been wondering about this particular problem
since it came up on IRC.

> The array method works quite nicely, especially for the
> columns like "languages" and "seeking" that are multiple choice. However,
> even though this method is fast, I still might opt for caching the results
> because the "real world" search query involves a lot more and will be
> executed non-stop. But to have it run this fast the first time certainly
> helps.

Now, for the bad news: you need to test having a large load of users updating
their data. The drawback to GiST indexes is that they are low-concurrency,
because the updating process needs to lock the whole index (this has been on
our TODO list for about a decade, but it's a hard problem).

--
Josh Berkus
Aglio Database Solutions
San Francisco

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