Tatsuo Ishii <t-ishii(at)sra(dot)co(dot)jp> writes:
> It worked with 2GB+ table but was much slower than before.
> Before(with 8MB sort memory): 22 minutes
> After(with 8MB sort memory): 1 hour and 5 minutes
> After(with 80MB sort memory): 42 minutes.
I've committed some changes to tuplesort.c to try to improve
performance. Would you try your test case again with current
sources? Also, please see if you can record the CPU time
consumed by the backend while doing the sort.
regards, tom lane