On Tue, 2006-05-23 at 14:27 -0400, Tom Lane wrote:
> Martijn van Oosterhout writes:
> > - Test a way of storing tuples with less overhead than a HeapTuple
> > header. If you could do it for in-memory sorts, that'd mean you could
> > fit more tuples in memory before spilling to disk. Given the
> >
Martijn van Oosterhout writes:
> - Test a way of storing tuples with less overhead than a HeapTuple
> header. If you could do it for in-memory sorts, that'd mean you could
> fit more tuples in memory before spilling to disk. Given the
> "compression" in that case is extremely cheap, it'd be much m
Martijn van Oosterhout writes:
> I implemented a basic implementation using pg_lzcompress. It appears
> that pg_lzcompress is very, very slow. I was afraid that I'd made an
> infinite loop, but it was just really slow. Mind you, the overhead of
> each call might have been the problem, it was being
BTW, the test I ran this weekend ended up filling the disk, so I wasn't
able to get results. I hope to have results for a compressed sort that's
still larger than memory in the morning. Unfortunately I'm doing all
this on a machine I use for other things, so it's hard to do testing and
other things
I'm going to be offline for a few days but there are some things I've
tested in the meantime.
Once the compression level drops below 4-to-1 the overhead of zlib
becomes overwhelming compared to the savings. I'm not sure how common
that is, I basically filled a table for random data to get it that
