Re: [INTERFACES] Re: [PATCHES] Re: Fixes and enhancements to JDBC driver(take 2) - Mailing list pgsql-jdbc

Quoting Bruce Momjian <pgman@candle.pha.pa.us>:

> Can someone comment on this?
>
> ---------------------------------------------------------------------------
>
>
> Peter,
>
> What is the final resolution of this for 7.1?  I noticed that you have
> essentially commented out the byte array pooling code in current
> sources.  Given that 7.1 is rapidly coming to a close, is this
> something
> that is expected to get fixed and reenabled for 7.1, or is this going
> to wait for 7.2.

I commented it out to make sure that when 7.1 was released the driver would at
least work (with it enabled we would have one broken driver).

I've got a lot of work to do before 7.1 is released, and commenting out the
code was IMHO the best way to ensure that we had something that worked.

As for waiting for 7.2, I'd say 7.1.1. Unless it's something major (like the
change from postgresql.Driver to org.postgresql.Driver) JDBC doesn't
necessarily follow the postgresql versions. As it is, getting this feature is
now a bug fix anyhow...

> I don't like the way the code has been left at this moment.  Even
> though
> much of the code has been commented out, it still does stuff like
> allocate 512 SimpleObjectPool objects per PG_Stream (via the
> BytePoolDim1) that are then never used.

Yes, although all it takes is for me to comment out that bit as well before 7.1
is released.

> So if this is going to get fixed for 7.1, it needs to be done soon,
> preferably by beta4, otherwise I would recommend taking all of this
> code
> completely out of source control until it can be done correctly for 7.2
> (instead of commenting out certain pieces).  The reason I suggest this
> is that it is confusing for anyone looking at the source code seeing
> all
> of this stuff that isn't being used currently.

If it goes out of the source, it will be lost. Believe me it will. With the
ammount of commits made to JDBC recently, its easy for one copy of the source
to get out of sync.

The jdbc driver is under continual development. The CVS is meant to be dynamic,
not contain just the "working" copy. If it was, then no software project would
ever get completed.

> Finally, I will make a plug for my version of a fix to this overall
> problem that I sent out last weekend (Gunner did you finally get that
> attachment, and have you looked at that code?).  I can redo that fix
> against current sources and send a proper patch file if anyone thinks
> that is the best course of action.

I've not seen this...

Peter

>
> thanks,
> --Barry
>
>
> Bruce Momjian wrote:
> >
> > Gunnar, everyone, can people check the CVS or snapshot and make sure
> you
> > are happy.  This has been a confusing item for me, and I want to make
> > sure we have it working as intended.
> >
> > Thanks.
> >
> > [ Charset ISO-8859-1 unsupported, converting... ]
> > > 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/
> > >
> >
> > --
> >   Bruce Momjian                        |  http://candle.pha.pa.us
> >   pgman@candle.pha.pa.us               |  (610) 853-3000
> >   +  If your life is a hard drive,     |  830 Blythe Avenue
> >   +  Christ can be your backup.        |  Drexel Hill, Pennsylvania
> 19026
>
>
>
> --
>   Bruce Momjian                        |  http://candle.pha.pa.us
>   pgman@candle.pha.pa.us               |  (610) 853-3000
>   +  If your life is a hard drive,     |  830 Blythe Avenue
>   +  Christ can be your backup.        |  Drexel Hill, Pennsylvania
> 19026
>



--
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/