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From: Jacob Champion <[email protected]>
To: Thomas Munro <[email protected]>
Cc: PostgreSQL Hackers <[email protected]>
Cc: Daniel Gustafsson <[email protected]>
Cc: Peter Eisentraut <[email protected]>
Subject: Re: [PATCH] OAuth: fix performance bug with stuck multiplexer events
Date: Wed, 6 Aug 2025 09:13:32 -0700
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On Wed, Aug 6, 2025 at 8:04 AM Thomas Munro <[email protected]> wrote:
>  * If it returns 1, then it stopped on the first level-triggered event
> that it rechecked and found to be still true.  Who cares if there are
> more that didn't get rechecked?  poll(fd) will report POLLIN either
> way, and that's what you want.

I think the weaker guarantee might be sufficient. I was trying to get
a stronger primitive in place so that we wouldn't have to worry about
it down the line, but it is a lot of code to pay...

One sharp edge of that strategy is caught by the new tests, which is
that if you call drain_socket_events() and then unset the timer, your
multiplexer is still readable until you call drain_socket_events() yet
again. At the moment, our code only ever calls those two in the
opposite order (due to the race condition pointed out in 0002); we'd
just have to keep that in mind. Maybe "drain" would no longer be the
verb to use there.

--Jacob

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