Horton

Re: Unportable implementation of background worker start

Tom Lane <tgl@sss.pgh.pa.us>

View thread View on postgr.es
From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andres Freund <andres@anarazel.de>
Cc: cm@enterprisedb.com, remi_zara@mac.com, Alvaro Herrera <alvherre@2ndquadrant.com>, pgsql-hackers@postgresql.org
Date: 2017-04-24T22:20:44Z
Lists: pgsql-hackers 
Andres Freund <andres@anarazel.de> writes:
> On 2017-04-24 18:14:41 -0400, Tom Lane wrote:
>> A bit of googling establishes that NetBSD 5.1 has a broken pselect
>> implementation:
>> 
>> http://gnats.netbsd.org/cgi-bin/query-pr-single.pl?number=43625

> Yikes.  Do I understand correctly that they effectively just mapped
> pselect to select?

That's what it sounds like.  Probably not intentionally, but in effect.

>> What I'm inclined to do is to revert the pselect change but not the other,
>> to see if that fixes these two animals.  If it does, we could look into
>> blacklisting these particular platforms when choosing pselect.

> Seems sensible.

Will do.

			regards, tom lane

Commits

  1. Cope with glibc too old to have epoll_create1().

  2. Make latch.c more paranoid about child-process cases.

  3. Allow multiple bgworkers to be launched per postmaster iteration.

  4. Revert "Use pselect(2) not select(2), if available, to wait in postmaster's loop."

  5. Use pselect(2) not select(2), if available, to wait in postmaster's loop.

  6. Run the postmaster's signal handlers without SA_RESTART.

  7. Fix postmaster's handling of fork failure for a bgworker process.

  8. Partially revert commit 536d47bd9d5fce8d91929bee3128fa1d08dbcc57.

  9. Avoid depending on non-POSIX behavior of fcntl(2).

  10. Remove long-obsolete catering for platforms without F_SETFD/FD_CLOEXEC.