low wal_retrieve_retry_interval causes missed signals on Windows

From: Nathan Bossart <nathandbossart(at)gmail(dot)com>
To: pgsql-hackers(at)postgresql(dot)org
Subject: low wal_retrieve_retry_interval causes missed signals on Windows
Date: 2023-01-11 06:11:16
Message-ID: 20230111061116.GA1668254@nathanxps13
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I discussed this elsewhere [0], but I thought it deserved its own thread.

After setting wal_retrieve_retry_interval to 1ms in the tests, I noticed
that some of the archiving tests began consistently failing on Windows. I
believe the problem is that WaitForWALToBecomeAvailable() depends on the
call to WaitLatch() for wal_retrieve_retry_interval to ensure that signals
are dispatched (i.e., pgwin32_dispatch_queued_signals()). With a low retry
interval, WaitForWALToBecomeAvailable() might skip the call to WaitLatch(),
and the signals are never processed.

The attached patch fixes this by always calling WaitLatch(), even if
wal_retrieve_retry_interval milliseconds have already elapsed and the
timeout is 0.

[0] https://postgr.es/m/20221231235019.GA1223171%40nathanxps13

Nathan Bossart
Amazon Web Services: https://aws.amazon.com

Attachment Content-Type Size
v1-0001-ensure-signals-are-dispatched-in-startup-process-.patch text/x-diff 2.9 KB


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