Re: why is pg_upgrade's regression run so slow?

Andrew Dunstan <andrew(at)dunslane(dot)net> writes:
> As part of its 002_pgupgrade.pl, the pg_upgrade tests do a rerun of the
> normal regression tests. That in itself is sad, but what concerns me
> here is why it's so much slower than the regular run? This is apparent
> everywhere (e.g. on crake the standard run takes about 30 to 90 s, but
> pg_upgrade's run takes 5 minutes or more).

Just to add some more fuel to the fire: I do *not* observe such an
effect on my own animals. For instance, sifaka's last run shows
00:09 for install-check-C and the same (within rounding error)
for the regression test step in 002_pgupgrade; on the much slower
mamba, the last run took 07:33 for install-check-C and 07:40 for the
002_pgupgrade regression test step.

I'm still using the makefile-based build, and I'm not using
debug_parallel_query, but it doesn't make a lot of sense to me
that either of those things should affect this.

Looking at crake's last run, there are other oddities: why does
the "check" step take 00:24 while "install-check-en_US.utf8" (which
should be doing strictly less work) takes 01:00? Again, there are
not similar discrepancies on my animals. Are you sure there's not
background load on the machine?

regards, tom lane