Re: performance: use pread instead of lseek+read

Manfred Spraul <manfred@colorfullife.com> writes:
> Do you know that empty lseeks foul up readahead recognition on some OS?
> If yes, which OS? I've checked FreeBSD and Linux, they don't do it.

Who knows?  But it would be folly to extrapolate from those two
datapoints to all the platforms we support.

> - which benchmark would be interesting?

Something that measures the performance "in context", that is as part of
normal database activity, not just the syscall overhead.  pgbench is
notoriously hard to get reproducible numbers out of, but you could try
it if you like.

> - which OS did you use when you got 'no manpage for pread'?

HPUX 10.20.

            regards, tom lane