Date: Thu, 1 Sep 2022 00:52:07 -0500
From: Justin Pryzby <pryzby@telsasoft.com>
To: Thomas Munro <thomas.munro@gmail.com>
Cc: Kyotaro Horiguchi <horikyota.ntt@gmail.com>,
	"Shinoda, Noriyoshi (PN Japan FSIP)" <noriyoshi.shinoda@hpe.com>,
	Tomas Vondra <tomas.vondra@enterprisedb.com>,
	Stephen Frost <sfrost@snowman.net>,
	Andres Freund <andres@anarazel.de>,
	Jakub Wartak <Jakub.Wartak@tomtom.com>,
	Alvaro Herrera <alvherre@2ndquadrant.com>,
	Tomas Vondra <tomas.vondra@2ndquadrant.com>,
	Dmitry Dolgov <9erthalion6@gmail.com>,
	David Steele <david@pgmasters.net>, pgsql-hackers@postgresql.org
Subject: Re: pg15b3: recovery fails with wal prefetch enabled
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On Thu, Sep 01, 2022 at 05:35:23PM +1200, Thomas Munro wrote:
> So it *looks* like it finished early (and without the expected
> error?).  But it also looks like it replayed that record, according to
> the page LSN.  So which is it?  Could you recompile with WAL_DEBUG
> defined in pg_config_manual.h, and run recovery with wal_debug = on,
> and see if it replays 1CAF84B0?

This is with 6672d79139 un-reverted.

$ sudo -u postgres ./tmp_install/usr/local/pgsql/bin/postgres -D /mnt/tmp/15/data -c logging_collector=no -c port=5678 -c wal_debug=on 2>&1 |grep 1CAF84B0 || echo not found
not found

$ sudo -u postgres ./tmp_install/usr/local/pgsql/bin/postgres -D /mnt/tmp/15/data -c logging_collector=no -c port=5678 -c wal_debug=on -c recovery_prefetch=no 2>&1 |grep 1CAF84B0 || echo not found
< 2022-09-01 00:44:55.878 CDT  >LOG:  REDO @ 1201/1CAF8478; LSN 1201/1CAF84B0: prev 1201/1CAF8438; xid 0; len 2; blkref #0: rel 1663/16881/2840, blk 53 - Heap2/VACUUM: nunused 4
< 2022-09-01 00:44:55.878 CDT  >LOG:  REDO @ 1201/1CAF84B0; LSN 1201/1CAF84F0: prev 1201/1CAF8478; xid 0; len 5; blkref #0: rel 1663/16881/2840, fork 2, blk 0; blkref #1: rel 1663/16881/2840, blk 53 - Heap2/VISIBLE: cutoff xid 3678741092 flags 0x01
< 2022-09-01 00:44:55.878 CDT  >LOG:  REDO @ 1201/1CAF84F0; LSN 1201/1CAF8AC0: prev 1201/1CAF84B0; xid 0; len 2; blkref #0: rel 1663/16881/1259, blk 1 FPW, compression method: zstd - Heap/INPLACE: off 33

(Note that "compression method: zstd" is a local change to
xlog_block_info() which I just extracted from my original patch for
wal_compression, after forgetting to compile --with-zstd.  I'll mail
about that at a later time...).

-- 
Justin