Hi,
you are right Jonathan at the moment there's no real DB-Pool implementation
available like one knows it e.g. from Java.
a. Connection-Pool(Connection1, Connection2)
b. Apache-Child-1 "Request-Starts":
-> Connection1 = Pool->fetchConnection();
-> Connection1->executeQuery("SELECT * FROM bla")
-> Pool->returnConnection(Connection1);
c. Apache-Child-2 "Request-Starts":
-> Connection1 = Pool->fetchConnection();
-> Connection1->executeQuery("SELECT * FROM bla");
-> ... Start working
d. Apache-Child-1 "Request ends":
-> Connection2 = Pool->fetchConnection();
-> Connection2->executeQuery("SELECT * FROM bla");
-> Pool->returnConnection(Connection2);
e. Apache-Child-2 "Request ends":
-> Pool->returnConnection(Connection2);
I brought about a few days ago a discussion about mod_dbd (available with
Apache-2.2 ) which exactly acts like I think connection-pooling should work
in Apache.
I've now taken a closer look into the whole thing and at the moment
it seems to possible to use mod_dbd to provide the physical connection on
C-level to DBD::mysql. I've already contacted the maintainer of DBD::mysql
and I hope until next year i get something going.
Tom
> --- Ursprüngliche Nachricht ---
> Von: Jonathan Vanasco <[EMAIL PROTECTED]>
> An: Albert Vila <[EMAIL PROTECTED]>
> Kopie: modperl@perl.apache.org
> Betreff: Re: Persistent DB Connection problem
> Datum: Tue, 13 Dec 2005 13:26:18 -0500
>
>
> On Dec 13, 2005, at 12:59 PM, Albert Vila wrote:
>
> > I thought the persistent connection was only one for all childs.
> >
> > What happens then if I have 1000 childs each one with 1 db
> > connection? This means 1000 database connections. How do you setup
> > apache + mod_perl in this environment?
> >
> > Albert
>
> you want to set it up exactly like that - with 1000 db connections.
>
> if you have 1 db connection that everyone shares, then your
> connection ties up and each child has to wait for all the others to
> finish. not good.
>
> if you have 1000 children, i'd be amazed at your setup. maybe i'm
> just too green at this, but i've never had enough resources to go
> above 300 , even using a stripped down setup and preloading just
> about everything into shared space.
>
> anways:
> mysql and postgres, by default, support ~250 concurrent connections
> out of the config file just fine. you can tweak stuff in the
> settings to get more. there's a maxclient setting (or something like
> that).
>
> if you wanted to do something with 1000 children and 100 db handles,
> you could probably do some sort of pooling scheme with a singleton or
> something where a child 'checks out' a db connection for a request,
> then checks it back in after its done. i thought about that once.
> it gave me a headache. i brought it up here and with friends and
> everyone said "why?" - because you should be fine just adding more
> sql clients.
>
> if you're looking at 1000 children though, you would almost
> definitely want to look into a clustered db setup - probably
> something with reads from 2+ machines that are replicated from a
> master that handles writes.
>
> thats my .02¢
>
>
>
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