Horton

Re: connection establishment versus parallel workers

Nathan Bossart <nathandbossart@gmail.com>

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From: Nathan Bossart <nathandbossart@gmail.com>
To: Thomas Munro <thomas.munro@gmail.com>
Cc: pgsql-hackers@postgresql.org
Date: 2024-12-19T16:09:35Z
Lists: pgsql-hackers 
Sorry for the delay, and thanks again for digging into this.

On Fri, Dec 13, 2024 at 03:56:00PM +1300, Thomas Munro wrote:
> 0001 patch is unchanged, 0002 patch sketches out a response to the
> observation a couple of paragraphs above.

Both of these patches seem to improve matters quite a bit.  I haven't yet
thought too deeply about it all, but upon a skim, your patches seem
entirely reasonable to me.

However, while this makes the test numbers for >= v16 look more like those
for v15, we're also seeing a big jump from v13 to v14.  This bisects pretty
cleanly to commit d872510.  I haven't figured out _why_ this commit is
impacting this particular test, but I figured I'd at least update the
thread with what we know so far.

-- 
nathan

Commits

  1. Fix latch event policy that hid socket events.

  2. Teach WaitEventSetWait() to report multiple events on Windows.

  3. Process pending postmaster work before connections.

  4. Use WaitEventSet API for postmaster's event loop.

  5. Replace buffer I/O locks with condition variables.