Date: Wed, 15 Feb 2023 16:06:59 -0800
From: Nathan Bossart <nathandbossart@gmail.com>
To: "Ryo Matsumura (Fujitsu)" <matsumura.ryo@fujitsu.com>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Subject: Re: DDL result is lost by CREATE DATABASE with WAL_LOG strategy
Message-ID: <20230216000659.GA1932550@nathanxps13>
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On Wed, Feb 15, 2023 at 04:49:38AM +0000, Ryo Matsumura (Fujitsu) wrote:
> The above is occured by the following call.
> The argument 'permanent' of ReadBufferWithoutRelcache() is passed to
> BufferAlloc() as 'relpersistence'.
> 
> [src/backend/commands/]
>  298         buf = ReadBufferWithoutRelcache(rnode, MAIN_FORKNUM, blkno,
>  299                                         RBM_NORMAL, bstrategy, false);

Indeed, setting that to true (as per the attached patch) seems to fix this.
I don't see any reason this _shouldn't_ be true from what I've read so far.
We're reading pg_class, which will probably never be UNLOGGED.

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

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diff --git a/src/backend/commands/dbcommands.c b/src/backend/commands/dbcommands.c
index ef05633bb0..a0259cc593 100644
--- a/src/backend/commands/dbcommands.c
+++ b/src/backend/commands/dbcommands.c
@@ -296,7 +296,7 @@ ScanSourceDatabasePgClass(Oid tbid, Oid dbid, char *srcpath)
 		CHECK_FOR_INTERRUPTS();
 
 		buf = ReadBufferWithoutRelcache(rlocator, MAIN_FORKNUM, blkno,
-										RBM_NORMAL, bstrategy, false);
+										RBM_NORMAL, bstrategy, true);
 
 		LockBuffer(buf, BUFFER_LOCK_SHARE);
 		page = BufferGetPage(buf);

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