Re: Better way of dealing with pgstat wait timeout during buildfarm runs?

Tomas Vondra <tv@fuzzy.cz> writes:
> The strange thing is that the split happened ~2 years ago, which is
> inconsistent with the sudden increase of this kind of issues. So maybe
> something changed on that particular animal (a failing SD card causing
> I/O stalls, perhaps)?

I think that hamster has basically got a tin can and string for an I/O
subsystem.  It's not real clear to me whether there's actually been an
increase in "wait timeout" failures recently; somebody would have to
go through and count them before I'd have much faith in that thesis.
However, I notice that at least the last few occurrences on "hamster"
all seem to have been in this parallel block:

test: brin gin gist spgist privileges security_label collate matview lock replica_identity rowsecurity object_address

which as recently as 9.4 contained just these tests:

test: privileges security_label collate matview lock replica_identity

I'm fairly sure that the index-related tests in this batch are I/O
intensive, and since they were not there at all six months ago, it's not
hard to believe that this block of tests has far greater I/O demands than
used to exist.  Draw your own conclusions ...
        regards, tom lane