Date: Wed, 11 Feb 2026 15:00:51 -0600
From: Nathan Bossart <nathandbossart@gmail.com>
To: Andres Freund <andres@anarazel.de>
Cc: Michael Paquier <michael@paquier.xyz>, Tom Lane <tgl@sss.pgh.pa.us>,
	Nitin Motiani <nitinmotiani@google.com>,
	Hannu Krosing <hannuk@google.com>,
	PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Subject: Re: pg_upgrade: transfer pg_largeobject_metadata's files when
 possible
Message-ID: <aYzuAz_ITUpd9ZvH@nathan>
References: <aYOnT5EqAqI3ooBO@nathan>
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On Sun, Feb 08, 2026 at 04:00:40PM -0600, Nathan Bossart wrote:
> On Sun, Feb 08, 2026 at 04:26:41PM -0500, Andres Freund wrote:
>> On 2026-02-05 15:29:55 -0600, Nathan Bossart wrote:
>>> +	 * commands.  We can only do this for upgrades from v12 and newer; in
>>> +	 * older versions, pg_largeobject_metadata was created WITH OIDS, so the
>>> +	 * OID column is hidden and won't be dumped.
>>>  	 */
>> 
>> It's not really related to this change, but what is that WITH OIDS bit about?
>> Sure, they aren't shown by default, but all it takes to change that is to
>> explicitly add the output column? I'm not saying we have to do that, I just
>> don't understand the reasoning as written here.
> 
> IIRC the issue is that getTableAttrs() won't pick up the OID column on
> older versions.  It might be easy to fix that by adjusting its query for
> binary upgrades from <v12.  That could be worth doing, if for no other
> reason than to simplify some of the pg_dump code.  I'll make a note of it.

This was a little more painful than I expected, but this seems to be what
is required to allow COPY-ing pg_largeobject_metadata during binary
upgrades from < v12.

-- 
nathan

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From 4d5041f6bf9a5e20b8257b98e7e0fab6edc40bd9 Mon Sep 17 00:00:00 2001
From: Nathan Bossart <nathan@postgresql.org>
Date: Wed, 11 Feb 2026 14:59:13 -0600
Subject: [PATCH v1 1/1] pg_upgrade: Remove version restriction on using COPY
 for pg_largeobject_metadata.

---
 src/bin/pg_dump/pg_backup_archiver.c |  7 +--
 src/bin/pg_dump/pg_dump.c            | 77 ++++++++++++++--------------
 2 files changed, 40 insertions(+), 44 deletions(-)

diff --git a/src/bin/pg_dump/pg_backup_archiver.c b/src/bin/pg_dump/pg_backup_archiver.c
index 35d3a07915d..dea26b8132a 100644
--- a/src/bin/pg_dump/pg_backup_archiver.c
+++ b/src/bin/pg_dump/pg_backup_archiver.c
@@ -2991,12 +2991,9 @@ _tocEntryRequired(TocEntry *te, teSection curSection, ArchiveHandle *AH)
 	/*
 	 * For binary upgrade mode, dump pg_largeobject_metadata and the
 	 * associated pg_shdepend rows. This is faster to restore than the
-	 * equivalent set of large object commands.  We can only do this for
-	 * upgrades from v12 and newer; in older versions, pg_largeobject_metadata
-	 * was created WITH OIDS, so the OID column is hidden and won't be dumped.
+	 * equivalent set of large object commands.
 	 */
-	if (ropt->binary_upgrade && AH->public.remoteVersion >= 120000 &&
-		strcmp(te->desc, "TABLE DATA") == 0 &&
+	if (ropt->binary_upgrade && strcmp(te->desc, "TABLE DATA") == 0 &&
 		(te->catalogId.oid == LargeObjectMetadataRelationId ||
 		 te->catalogId.oid == SharedDependRelationId))
 		return REQ_DATA;
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 2c3754d020f..ae57127e5dd 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -1118,11 +1118,9 @@ main(int argc, char **argv)
 	 * For binary upgrade mode, dump the pg_shdepend rows for large objects
 	 * and maybe even pg_largeobject_metadata (see comment below for details).
 	 * This is faster to restore than the equivalent set of large object
-	 * commands.  We can only do this for upgrades from v12 and newer; in
-	 * older versions, pg_largeobject_metadata was created WITH OIDS, so the
-	 * OID column is hidden and won't be dumped.
+	 * commands.
 	 */
-	if (dopt.binary_upgrade && fout->remoteVersion >= 120000)
+	if (dopt.binary_upgrade)
 	{
 		TableInfo  *shdepend;
 
@@ -2406,11 +2404,14 @@ dumpTableData_copy(Archive *fout, const void *dcontext)
 	column_list = fmtCopyColumnList(tbinfo, clistBuf);
 
 	/*
-	 * Use COPY (SELECT ...) TO when dumping a foreign table's data, and when
-	 * a filter condition was specified.  For other cases a simple COPY
-	 * suffices.
+	 * Use COPY (SELECT ...) TO when dumping a foreign table's data, when a
+	 * filter condition was specified, and when in binary upgrade mode and
+	 * dumping an old pg_largeobject_metadata defined WITH OIDS.  For other
+	 * cases a simple COPY suffices.
 	 */
-	if (tdinfo->filtercond || tbinfo->relkind == RELKIND_FOREIGN_TABLE)
+	if (tdinfo->filtercond || tbinfo->relkind == RELKIND_FOREIGN_TABLE ||
+		(fout->dopt->binary_upgrade && fout->remoteVersion < 120000 &&
+		 tbinfo->dobj.catId.oid == LargeObjectMetadataRelationId))
 	{
 		/* Temporary allows to access to foreign tables to dump data */
 		if (tbinfo->relkind == RELKIND_FOREIGN_TABLE)
@@ -3967,14 +3968,13 @@ getLOs(Archive *fout)
 						 "FROM pg_largeobject_metadata ");
 
 	/*
-	 * For binary upgrades from v12 or newer, we transfer
-	 * pg_largeobject_metadata via COPY or by copying/linking its files from
-	 * the old cluster.  On such upgrades, we only need to consider large
-	 * objects that have comments or security labels, since we still restore
-	 * those objects via COMMENT/SECURITY LABEL commands.
+	 * For binary upgrades, we transfer pg_largeobject_metadata via COPY or by
+	 * copying/linking its files from the old cluster.  On such upgrades, we
+	 * only need to consider large objects that have comments or security
+	 * labels, since we still restore those objects via COMMENT/SECURITY LABEL
+	 * commands.
 	 */
-	if (dopt->binary_upgrade &&
-		fout->remoteVersion >= 120000)
+	if (dopt->binary_upgrade)
 		appendPQExpBufferStr(loQry,
 							 "WHERE oid IN "
 							 "(SELECT objoid FROM pg_description "
@@ -4063,25 +4063,13 @@ getLOs(Archive *fout)
 			loinfo->dobj.components |= DUMP_COMPONENT_ACL;
 
 		/*
-		 * In binary-upgrade mode for LOs, we do *not* dump out the LO data,
-		 * as it will be copied by pg_upgrade, which simply copies the
-		 * pg_largeobject table.
-		 *
-		 * The story for LO metadata is more complicated.  For upgrades from
-		 * versions older than v12, we use ordinary SQL commands to restore
-		 * both the content of pg_largeobject_metadata and any associated
-		 * pg_shdepend rows.  For upgrades from newer versions, we transfer
-		 * this information via COPY or by copying/linking the files from the
-		 * old cluster.  For such upgrades, we do not need to dump the data,
-		 * ACLs, or definitions of large objects.
+		 * In binary upgrade mode, pg_largeobject and pg_largeobject_metadata
+		 * are transferred via COPY or by copying/linking the files from the
+		 * old cluster.  Thus, we do not need to dump LO data, definitions, or
+		 * ACLs.
 		 */
 		if (dopt->binary_upgrade)
-		{
-			if (fout->remoteVersion >= 120000)
-				loinfo->dobj.dump &= ~(DUMP_COMPONENT_DATA | DUMP_COMPONENT_ACL | DUMP_COMPONENT_DEFINITION);
-			else
-				loinfo->dobj.dump &= ~DUMP_COMPONENT_DATA;
-		}
+			loinfo->dobj.dump &= ~(DUMP_COMPONENT_DATA | DUMP_COMPONENT_ACL | DUMP_COMPONENT_DEFINITION);
 
 		/*
 		 * Create a "BLOBS" data item for the group, too. This is just a
@@ -9296,12 +9284,10 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		 * pg_shdepend so that the columns names are collected for the
 		 * corresponding COPY commands.  Restoring the data for those catalogs
 		 * is faster than restoring the equivalent set of large object
-		 * commands.  We can only do this for upgrades from v12 and newer; in
-		 * older versions, pg_largeobject_metadata was created WITH OIDS, so
-		 * the OID column is hidden and won't be dumped.
+		 * commands.
 		 */
 		if (!tbinfo->interesting &&
-			!(fout->dopt->binary_upgrade && fout->remoteVersion >= 120000 &&
+			!(fout->dopt->binary_upgrade &&
 			  (tbinfo->dobj.catId.oid == LargeObjectMetadataRelationId ||
 			   tbinfo->dobj.catId.oid == SharedDependRelationId)))
 			continue;
@@ -9442,7 +9428,18 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 							 "(pt.classoid = co.tableoid AND pt.objoid = co.oid)\n");
 
 	appendPQExpBufferStr(q,
-						 "WHERE a.attnum > 0::pg_catalog.int2\n"
+						 "WHERE a.attnum > 0::pg_catalog.int2\n");
+
+	/*
+	 * For binary upgrades from <v12, be sure to pick up
+	 * pg_largeobject_metadata's oid column.
+	 */
+	if (fout->dopt->binary_upgrade && fout->remoteVersion < 120000)
+		appendPQExpBufferStr(q,
+							 "OR (a.attnum = -2::pg_catalog.int2 AND src.tbloid = "
+							 CppAsString2(LargeObjectMetadataRelationId) ")\n");
+
+	appendPQExpBufferStr(q,
 						 "ORDER BY a.attrelid, a.attnum");
 
 	res = ExecuteSqlQuery(fout, q->data, PGRES_TUPLES_OK);
@@ -9510,7 +9507,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		/* cross-check that we only got requested tables */
 		if (tbinfo->relkind == RELKIND_SEQUENCE ||
 			(!tbinfo->interesting &&
-			 !(fout->dopt->binary_upgrade && fout->remoteVersion >= 120000 &&
+			 !(fout->dopt->binary_upgrade &&
 			   (tbinfo->dobj.catId.oid == LargeObjectMetadataRelationId ||
 				tbinfo->dobj.catId.oid == SharedDependRelationId))))
 			pg_fatal("unexpected column data for table \"%s\"",
@@ -9544,7 +9541,9 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 
 		for (int j = 0; j < numatts; j++, r++)
 		{
-			if (j + 1 != atoi(PQgetvalue(res, r, i_attnum)))
+			if (j + 1 != atoi(PQgetvalue(res, r, i_attnum)) &&
+				!(fout->dopt->binary_upgrade && fout->remoteVersion < 120000 &&
+				  tbinfo->dobj.catId.oid == LargeObjectMetadataRelationId))
 				pg_fatal("invalid column numbering in table \"%s\"",
 						 tbinfo->dobj.name);
 			tbinfo->attnames[j] = pg_strdup(PQgetvalue(res, r, i_attname));
-- 
2.50.1 (Apple Git-155)


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