Date: Tue, 2 Aug 2022 17:04:16 -0500
From: Justin Pryzby <pryzby@telsasoft.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Robert Haas <robertmhaas@gmail.com>,
	Dilip Kumar <dilipbalaut@gmail.com>,
	Andres Freund <andres@anarazel.de>,
	Ashutosh Sharma <ashu.coek88@gmail.com>,
	Maciek Sakrejda <m.sakrejda@gmail.com>,
	Bruce Momjian <bruce@momjian.us>,
	Alvaro Herrera <alvherre@alvh.no-ip.org>,
	Andrew Dunstan <andrew@dunslane.net>,
	Heikki Linnakangas <hlinnaka@iki.fi>,
	pgsql-hackers@lists.postgresql.org
Subject: Re: [Proposal] Fully WAL logged CREATE DATABASE - No Checkpoints
Message-ID: <20220802220416.GC13682@telsasoft.com>
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On Tue, Aug 02, 2022 at 05:46:34PM -0400, Tom Lane wrote:
> Robert Haas <robertmhaas@gmail.com> writes:
> > WARNING:  problem in alloc set PortalContext: req size > alloc size for chunk 0x7f99508911f0 in block 0x7f9950890800
> 
> This looks like nothing so much as the fallout from something scribbling
> past the end of an allocated palloc chunk, or perhaps writing on
> already-freed space.  Perhaps running the test case under valgrind
> would help to finger the culprit.

Yeah but my test case is so poor that it's a chore ...

(Sorry for that, but it took me 2 days to be able to reproduce the problem so I
sent it sooner rather than looking for a better way ... )

I got this interesting looking thing.

==11628== Invalid write of size 8
==11628==    at 0x1D12B3A: smgrsetowner (smgr.c:213)
==11628==    by 0x1C7C224: RelationGetSmgr (rel.h:572)
==11628==    by 0x1C7C224: RelationCopyStorageUsingBuffer (bufmgr.c:3725)
==11628==    by 0x1C7C7A6: CreateAndCopyRelationData (bufmgr.c:3817)
==11628==    by 0x14A4518: CreateDatabaseUsingWalLog (dbcommands.c:221)
==11628==    by 0x14AB009: createdb (dbcommands.c:1393)
==11628==    by 0x1D2B9AF: standard_ProcessUtility (utility.c:776)
==11628==    by 0x1D2C46A: ProcessUtility (utility.c:530)
==11628==    by 0x1D265F5: PortalRunUtility (pquery.c:1158)
==11628==    by 0x1D27089: PortalRunMulti (pquery.c:1315)
==11628==    by 0x1D27A7C: PortalRun (pquery.c:791)
==11628==    by 0x1D1E33D: exec_simple_query (postgres.c:1243)
==11628==    by 0x1D218BC: PostgresMain (postgres.c:4505)
==11628==  Address 0x1025bc18 is 2,712 bytes inside a block of size 8,192 free'd
==11628==    at 0x4033A3F: free (in /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so)
==11628==    by 0x217D7C2: AllocSetReset (aset.c:608)
==11628==    by 0x219B57A: MemoryContextResetOnly (mcxt.c:181)
==11628==    by 0x217DBD5: AllocSetDelete (aset.c:654)
==11628==    by 0x219C1EC: MemoryContextDelete (mcxt.c:252)
==11628==    by 0x21A109F: PortalDrop (portalmem.c:596)
==11628==    by 0x21A269C: AtCleanup_Portals (portalmem.c:907)
==11628==    by 0x11FEAB1: CleanupTransaction (xact.c:2890)
==11628==    by 0x120A74C: AbortCurrentTransaction (xact.c:3328)
==11628==    by 0x1D2158C: PostgresMain (postgres.c:4232)
==11628==    by 0x1B15DB5: BackendRun (postmaster.c:4490)
==11628==    by 0x1B1D799: BackendStartup (postmaster.c:4218)
==11628==  Block was alloc'd at
==11628==    at 0x40327F3: malloc (in /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so)
==11628==    by 0x217F0DC: AllocSetAlloc (aset.c:920)
==11628==    by 0x219E4D2: palloc (mcxt.c:1082)
==11628==    by 0x14A14BE: ScanSourceDatabasePgClassTuple (dbcommands.c:444)
==11628==    by 0x14A1CD8: ScanSourceDatabasePgClassPage (dbcommands.c:384)
==11628==    by 0x14A20BF: ScanSourceDatabasePgClass (dbcommands.c:322)
==11628==    by 0x14A4348: CreateDatabaseUsingWalLog (dbcommands.c:177)
==11628==    by 0x14AB009: createdb (dbcommands.c:1393)
==11628==    by 0x1D2B9AF: standard_ProcessUtility (utility.c:776)
==11628==    by 0x1D2C46A: ProcessUtility (utility.c:530)
==11628==    by 0x1D265F5: PortalRunUtility (pquery.c:1158)
==11628==    by 0x1D27089: PortalRunMulti (pquery.c:1315)

-- 
Justin