Re: [phplib] MySQL or PostgreSQL? From: Matthias Mohr (m.mohr <email protected>)
Date: 04/10/01

Hello,

On Tue, 10 Apr 2001, Alex Black wrote:

> >> I heard that Postgres isn't quite suitable for some web applications,
> >> because it doesn't do UPDATEs in-place. Instead, it creates new records,
> >> and the garbage collection with VACUUM would require an exclusive lock.
> >>
> >> Is that right -- should I rather use MySQL for storing session data
> >> and other fast-changing information?
>
> It should be mentioned: Postgres is much more load-capable, i.e. it will
> continue to function in extreme situations where mySQL would fail, and most
> importantly, includes transaction support.
>
> Those reasons are enough to select Postgres over mySQL for any "larger
> scale" web application - but for smaller stuff mySQL really whips the
> llama's ass! (go download winamp if that makes no sense)
>
> _alex

I agree 100%. And I don't know what are the drawbacks of such an exclusive
lock. postgres ist quite aware of concurrend access, and vacuum is just one of
them. i just ran

#!/usr/bin/tcsh
while ( 1 )
    echo "vacuum;"|psql messju
end

and i did not mention any problems to connect and query the database while
running the "endless vacuum". of course the second to nth vacuum is done very
fast and this is not a representive environment, but when it comes to
concurrend (the one you mentionend is "vacuum" against access from the
weberver), i cannot imagine anything that makes mysql superior to postgres.

please correct me, if im totally wrong with my assumptions. i know quite some
hosts running medium-to-xmedium-loaded postgres-driven websites which all have
a vacuum-daily job in their crontab, but never heard of any complaints, due to
this maintainace thing at night.

just me
messju

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