Re: tuplestore potential performance problem

"Hitoshi Harada" <umi.tanuki@gmail.com> writes:
> 2009/1/15 Bruce Momjian <bruce@momjian.us>:
>> Has this been addressed?

> It is mentioned at
> http://archives.postgresql.org/pgsql-hackers/2008-12/msg01849.php
> but not solved yet. It seems to me that to solve this the tuplestore's
> inside design should be changed much. In-file state doesn't use memory
> any more but it should be re-used for writing buffer, whereas the
> current desgin uses BufFile to do it, which causes tell/seek overhead
> for repeated put/get operation. And this is not for 8.4, I guess.

I was thinking of something a lot simpler, like just allowing BufFile
to maintain separate buffers for read and write pointers.  But in any
case it's not likely to get done for 8.4.
        regards, tom lane