Re: [Sqlgrey-users] Solution to sqlgrey & postgresql memory leaks?

[Karl O. P. <ko...@me...>]

On 08/05/2007 12:22:12 PM, Lionel Bouton wrote:
> Karl O. Pinc wrote the following on 05.08.2007 18:26 :
> > Hi,
> >
> > So, I looked at the code.  I'm not a perl wiz,
> > but the problem appears to be obvious. Sqlgrey
> > seems to be repeatedly creating prepared queries,
> > each of which differs from the last.  The whole
> > point of prepared queries is to have _invariant_
> > queries, substituted parameters excepted.
> >
> >
> 
> Not exactly. It's only a problem when you cache the prepared
> statements.

Thanks for looking at this.

The DBI had also better be doing a "DEALLOCATE" when the
prepared query goes out of scope, or else (in PostgreSQL)
it won't get deallocated on the server side.

I don't see the point in using prepared queries that
are only executed once.  That would only introduce
extra overhead involved in the allocation and
deallocation of the prepared queries.  Which is, I suppose, what it
is that you're looking into.  :)

(To be persnickity about it, the queries won't be optimized
any better if you use prepared queries, but you eliminiate
at least some sql parsing overhead (perhaps all depending
on the api) and you eliminate the planner overhead --
which can amount to a lot.)

I see what you mean about using prepare and not prepare_cached.
You're right about my proposal not fixing memory leaks.  But
I've a gut feeling that it will work-around the memory
leaks, which I'm guessing have to do with preparing a
lot of unique statements.

Let me know if you need someone to test something.

Karl <ko...@me...>
Free Software:  "You don't pay back, you pay forward."
                  -- Robert A. Heinlein