Re: Compression and on-disk sorting

"Jim C. Nasby" <jnasby@pervasive.com> writes:
> A recent post Tom made in -bugs about how bad performance would be if we
> spilled after-commit triggers to disk got me thinking... There are
> several operations the database performs that potentially spill to disk.
> Given that any time that happens we end up caring much less about CPU
> usage and much more about disk IO, for any of these cases that use
> non-random access, compressing the data before sending it to disk would
> potentially be a sizeable win.

Note however that what the code thinks is a spill to disk and what
actually involves disk I/O are two different things.  If you think
of it as a spill to kernel disk cache then the attraction is a lot
weaker...
        regards, tom lane