Date: Wed, 25 Jan 2023 16:33:19 -0800
From: Nathan Bossart <nathandbossart@gmail.com>
To: Thomas Munro <thomas.munro@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>,
	"Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com>,
	"pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Subject: Re: suppressing useless wakeups in logical/worker.c
Message-ID: <20230126003319.GA1507251@nathanxps13>
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On Thu, Jan 26, 2023 at 01:23:41PM +1300, Thomas Munro wrote:
> Can we also use TimestampDifferenceMilliseconds()?  It knows about
> rounding up for WaitLatch().

I think we might risk overflowing "long" when all the wakeup times are
DT_NOEND:

	 * This is typically used to calculate a wait timeout for WaitLatch()
	 * or a related function.  The choice of "long" as the result type
	 * is to harmonize with that.  It is caller's responsibility that the
	 * input timestamps not be so far apart as to risk overflow of "long"
	 * (which'd happen at about 25 days on machines with 32-bit "long").

Maybe we can adjust that function or create a new one to deal with this.

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