Re: Performance problems testing with Spamassassin 3.1.0

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От Matthew Schumacher
Тема Re: Performance problems testing with Spamassassin 3.1.0
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Msg-id 42F23FB6.5010405@aptalaska.net
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Ответ на Re: Performance problems testing with Spamassassin 3.1.0  (Tom Lane <tgl@sss.pgh.pa.us>)
Ответы Re: Performance problems testing with Spamassassin 3.1.0  (Matthew Schumacher <matt.s@aptalaska.net>)
Список pgsql-performance
Tom Lane wrote:

> I don't really see why you think that this path is going to lead to
> better performance than where you were before.  Manipulation of the
> temp table is never going to be free, and IN (sub-select) is always
> inherently not fast, and NOT IN (sub-select) is always inherently
> awful.  Throwing a pile of simple queries at the problem is not
> necessarily the wrong way ... especially when you are doing it in
> plpgsql, because you've already eliminated the overhead of network
> round trips and repeated planning of the queries.
>
>             regards, tom lane

The reason why I think this may be faster is because I would avoid
running an update on data that needs to be inserted which saves
searching though the table for a matching token.

Perhaps I should do the insert first, then drop those tokens from the
temp table, then do my updates in a loop.

I'll have to do some benchmarking...

schu

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