Re: Postgres performance

From: PFC <lists(at)boutiquenumerique(dot)com>
To: "Mauro Bertoli" <bertolima(at)yahoo(dot)it>, "Richard Huxton" <dev(at)archonet(dot)com>
Cc: pgsql-sql(at)postgresql(dot)org
Subject: Re: Postgres performance
Date: 2005-03-04 23:20:54
Message-ID: opsm4y44r8th1vuj@musicbox
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> I don't require transaction because the query aren't
> complex and update a single tuple (in SELECT
> transactions are useless)

You mean, you have no foreign keys in your database ?
In SELECT they are definitely useful (think select for update, isolation
level serializable...)

> - start quote -
> You'll find inserts/updates with lots of users is
> where PostgreSQL works
> well compared to other systems.
> - end quote -
> Uhhmm.. this is interesting...

pg does not lock the whole table everytime anyone wants to write in it.
In MySQL when you run a big select, all write activity stops during that.
If you run a big update, all activity other than this update has to wait.

> - why postgres use a new process for every query ?
> (mySQL, if I'm not wrong, use threads... I think its
> faster)

Not for every query, for every CONNECTION.
You are using persistant connections are you. Are you ?

> - why connection time is slower? (compared to mySQL)?

This is of no importance as everyone uses persistent connections anyway.

> - why postgres require analyze? (mySQL, if I'm not
> wrong, don't require it)
> Yours answers will be very apreciated! Thx

So it has a planner which knows what it's doing ;) instead of just
guessing in the dark.

And MySQL requires analyze too (read the docs), optimize table which
looks like vacuum to me, and sometimes repair table...

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