Tom,
have you seen contrib/intarray ?
Oleg
On Fri, 6 Apr 2007, tom wrote:
I'm wondering where the differences are in running two different types of SQL
statements.
Given ~300 tokens/words I can either run 1 sql statement with a large list in
a "WHERE foo IN (...300 tokens...)"
or I can run ~300 statements, one for each token.
In the first case, the SQL is not prepared, but just executed.
In the second case, the SQL is prepared and run as a cached execution plan (I
think).
Now. It would seem that the second approach would be painfully slow. But
I'm not sure that I'm seeing this.
Currently I have <5 users. As always, this might change...
Before I start going about coding and testing lots of stuff I thought I would
ask for some historical experiences someone might have had when comparing
these two approaches and if there are inflection points between the
performance in terms of the number of tokens or simultaneous users.
I should add that the tokens are either indexed or primary indexed but in
both cases, unique, and not guaranteed to exist in every case.
Initially it seems that the WHERE IN (...) approach takes a turn for the
worse when the list gets very large.
It also seems to do comparatively worse when the number of tokens is very
small.
But I can't claim any scientifically sound basis for making this distinction.
Any experiences someone would like to share?
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Regards,
Oleg
_____________________________________________________________
Oleg Bartunov, Research Scientist, Head of AstroNet (www.astronet.ru),
Sternberg Astronomical Institute, Moscow University, Russia
Internet: oleg@xxxxxxxxxx, http://www.sai.msu.su/~megera/
phone: +007(495)939-16-83, +007(495)939-23-83
