Quoting Gunnar R|nning <gunnar@candleweb.no>:
> Barry Lind <barry@xythos.com> writes:
>
> > Gunner,
> >
> > Do your fixes address the concerns I raised on 12/21? (I have
> included
> > that email to the list below). To summarize the three major
> > concerns/bugs were:
> > 1) Code incorrectly deallocates when a new statement is executed,
> even
> > though the byte[]s are still being used.
> > 2) The cache isn't limited in size, resulting in essentially memory
> > leaks for long lived connections in a connection pool.
> > 3) The implementation is limited to a max 256 byte byte[], whereas my
> > queries have many values that exceed this size, and the current
> > implementation doesn't lend itself well (because of #2) to cache
> things
> > upto 8K in size.
>
> The original patch that I supplied was a proof of concept on what kind
> of
> performance improvements that could be made by reusing byte arrays.
> This
> was unfortunately committed before anybody but me had done any testing
> at
> all on it.
>
> The most serious problem with this code was your issue 1). Number 2) and
> 3)
> should be easy to handle has config parameters. The reason for
> hardcoding
> 3) to 256 was simply because I found this to be the most optimal value
> for
> the web application I was doing the testing on.
>
> Eventually, it should be configurable whether to use the byte[] caching
> implementation or not, as the perfomance of memory allocation may vary
> greatly depending on VM and OS implementations.
Now we use ANT this is extremely easy to do. Also, I have made some changes, in
that your supplied classes have moved to a new package org.postgresql.core, and
extend an interface ObjectPool. I did this so that it would be easier to change
the implementations without having to hack the main code too much.
Although your patch is in there, I've disabled the part that frees the arrays
(as that was the bit causing problems). Hopefully...
>
> If you go back to the October archives of pgsql-general you will find a
> pointer to my second shot at an implementation - this one fix your issue
> 1)
> but not the others.
>
> I would like to see what you have been working on as well, so we can
> come up with the best of breeds solution.
In cvs as of yesterday...
Peter
--
Peter Mount peter@retep.org.uk
PostgreSQL JDBC Driver: http://www.retep.org.uk/postgres/
RetepPDF PDF library for Java: http://www.retep.org.uk/pdf/
