Date: Mon, 29 Jan 2024 12:21:30 -0600
From: Nathan Bossart <nathandbossart@gmail.com>
To: Alexander Lakhin <exclusion@gmail.com>
Cc: Robert Haas <robertmhaas@gmail.com>,
	Matthias van de Meent <boekewurm+postgres@gmail.com>,
	PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Subject: Re: cleanup patches for incremental backup
Message-ID: <20240129182130.GA3670200@nathanxps13>
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On Sat, Jan 27, 2024 at 10:31:09AM -0600, Nathan Bossart wrote:
> On Sat, Jan 27, 2024 at 11:00:01AM +0300, Alexander Lakhin wrote:
>> I'm discouraged by "\n1" in the file name and in the
>> "examining summary..." message.
>> regress_log_002_blocks from the following successful test run on the same
>> sungazer node contains:
>> [15:21:58.924](0.106s) # examining summary for TLI 1 from 0/155BAE0 to 0/155E750
>> [15:21:58.925](0.001s) ok 1 - WAL summary file exists
> 
> Ah, I think this query:
> 
> 	SELECT tli, start_lsn, end_lsn from pg_available_wal_summaries()
> 		WHERE tli = $summarized_tli AND end_lsn > '$summarized_lsn'
> 
> is returning more than one row in some cases.  I attached a quick sketch of
> an easy way to reproduce the issue as well as one way to fix it.

The buildfarm just caught a failure with the new logging in place:

	https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=calliphoridae&dt=2024-01-29%2018%3A09%3A10

I'm not totally sure my "fix" is correct, but I think this does confirm the
theory.

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