Re: Unportable use of select for timeouts in PostgresNode.pm

Andrew Dunstan <andrew(dot)dunstan(at)2ndquadrant(dot)com> writes:
> I've been trying to get to the bottom of a nasty hang in buildfarm
> member jacana when running the pg_ctl TAP test. This test used to work,
> and was last known to work on June 22nd.

> My attention has become focussed on this change in commit de3de0afd:

> - # Wait a second before retrying.
> - sleep 1;
> + # Wait 0.1 second before retrying.
> + select undef, undef, undef, 0.1;

> This is a usage that is known not to work in Windows - IIRC we
> eliminated such calls from our C programs at the time of the Windows
> port - and it seems to me very likely to be the cause of the hang.

Ugh.

> Instead I think we should use the usleep() function from the standard
> (from 5.8) Perl module Time::HiRes, as recommended in the Perl docs for
> the sleep() function for situations where you need finer grained
> timeouts. I have verified that this works on jacana and friends.

> Unless I hear objections I'll prepare a patch along those lines.

WFM. Thanks for taking care of it.

regards, tom lane