From d2d0ed6ea1e3bbe87874a95b0630599a10d9118d Mon Sep 17 00:00:00 2001
From: Michael Paquier <michael@paquier.xyz>
Date: Thu, 14 Aug 2025 13:43:03 +0900
Subject: [PATCH v5 13/15] Add support for oid8 TOAST values

This commit adds the possibility to define TOAST tables with oid8 as
value ID, based on the reloption toast_value_type.  All the external
TOAST pointers still rely on varatt_external and a single vartag, with
all the values inserted in the bigint TOAST tables fed from the existing
OID value generator.  This will be changed in an upcoming patch that
adds more vartag_external types and its associated structures, with the
code being able to use a different external TOAST pointer depending on
the attribute type of chunk_id in TOAST relations.

All the changes done here are mechanical, with all the TOAST code able
to do chunk ID lookups based on the two types now supported.

XXX: Catalog version bump required.
---
 src/include/catalog/pg_opclass.dat          |  3 +-
 src/include/utils/rel.h                     |  1 +
 src/backend/access/common/reloptions.c      |  1 +
 src/backend/access/common/toast_internals.c | 94 +++++++++++++++------
 src/backend/access/heap/heaptoast.c         | 20 ++++-
 src/backend/catalog/toasting.c              | 24 +++++-
 doc/src/sgml/storage.sgml                   |  7 +-
 contrib/amcheck/verify_heapam.c             | 19 ++++-
 8 files changed, 129 insertions(+), 40 deletions(-)

diff --git a/src/include/catalog/pg_opclass.dat b/src/include/catalog/pg_opclass.dat
index c0de88fabc49..b8f2bc2d69c4 100644
--- a/src/include/catalog/pg_opclass.dat
+++ b/src/include/catalog/pg_opclass.dat
@@ -179,7 +179,8 @@
   opcintype => 'xid8' },
 { opcmethod => 'hash', opcname => 'oid8_ops', opcfamily => 'hash/oid8_ops',
   opcintype => 'oid8' },
-{ opcmethod => 'btree', opcname => 'oid8_ops', opcfamily => 'btree/oid8_ops',
+{ oid => '8285', oid_symbol => 'OID8_BTREE_OPS_OID',
+  opcmethod => 'btree', opcname => 'oid8_ops', opcfamily => 'btree/oid8_ops',
   opcintype => 'oid8' },
 { opcmethod => 'hash', opcname => 'cid_ops', opcfamily => 'hash/cid_ops',
   opcintype => 'cid' },
diff --git a/src/include/utils/rel.h b/src/include/utils/rel.h
index b846bd42103e..52646d43ebdc 100644
--- a/src/include/utils/rel.h
+++ b/src/include/utils/rel.h
@@ -342,6 +342,7 @@ typedef enum StdRdOptToastValueType
 {
 	STDRD_OPTION_TOAST_VALUE_TYPE_INVALID = 0,
 	STDRD_OPTION_TOAST_VALUE_TYPE_OID,
+	STDRD_OPTION_TOAST_VALUE_TYPE_OID8,
 } StdRdOptToastValueType;
 
 typedef struct StdRdOptions
diff --git a/src/backend/access/common/reloptions.c b/src/backend/access/common/reloptions.c
index b0447d9e39bb..f05eaacfa006 100644
--- a/src/backend/access/common/reloptions.c
+++ b/src/backend/access/common/reloptions.c
@@ -521,6 +521,7 @@ static relopt_enum_elt_def StdRdOptToastValueTypes[] =
 {
 	/* no value for INVALID */
 	{"oid", STDRD_OPTION_TOAST_VALUE_TYPE_OID},
+	{"oid8", STDRD_OPTION_TOAST_VALUE_TYPE_OID8},
 	{(const char *) NULL}		/* list terminator */
 };
 
diff --git a/src/backend/access/common/toast_internals.c b/src/backend/access/common/toast_internals.c
index 5d0aa664fc91..42a6a59d7536 100644
--- a/src/backend/access/common/toast_internals.c
+++ b/src/backend/access/common/toast_internals.c
@@ -26,6 +26,7 @@
 #include "utils/fmgroids.h"
 #include "utils/rel.h"
 #include "utils/snapmgr.h"
+#include "utils/lsyscache.h"
 
 static bool toastrel_valueid_exists(Relation toastrel, Oid8 valueid);
 static bool toastid_valueid_exists(Oid toastrelid, Oid8 valueid);
@@ -146,8 +147,10 @@ toast_save_datum(Relation rel, Datum value,
 	int			validIndex;
 	const toast_external_info *info;
 	uint8		tag = VARTAG_INDIRECT;	/* init value does not matter */
+	Oid			toast_typid = get_atttype(rel->rd_rel->reltoastrelid, 1);
 
 	Assert(!VARATT_IS_EXTERNAL(dval));
+	Assert(OidIsValid(toast_typid));
 
 	/*
 	 * Open the toast relation and its indexes.  We can use the index to check
@@ -228,24 +231,32 @@ toast_save_datum(Relation rel, Datum value,
 		toast_pointer.toastrelid = RelationGetRelid(toastrel);
 
 	/*
-	 * Choose an OID to use as the value ID for this toast value.
+	 * Choose a new value to use as the value ID for this toast value, be it
+	 * for OID or int8-based TOAST relations.
 	 *
-	 * Normally we just choose an unused OID within the toast table.  But
+	 * Normally we just choose an unused value within the toast table.  But
 	 * during table-rewriting operations where we are preserving an existing
-	 * toast table OID, we want to preserve toast value OIDs too.  So, if
+	 * toast table OID, we want to preserve toast value IDs too.  So, if
 	 * rd_toastoid is set and we had a prior external value from that same
 	 * toast table, re-use its value ID.  If we didn't have a prior external
 	 * value (which is a corner case, but possible if the table's attstorage
 	 * options have been changed), we have to pick a value ID that doesn't
-	 * conflict with either new or existing toast value OIDs.
+	 * conflict with either new or existing toast value IDs.  If the TOAST
+	 * table uses 8-byte value IDs, we should not really care much about
+	 * that.
 	 */
 	if (!OidIsValid(rel->rd_toastoid))
 	{
 		/* normal case: just choose an unused OID */
-		toast_pointer.valueid =
-			GetNewOidWithIndex(toastrel,
-							   RelationGetRelid(toastidxs[validIndex]),
-							   (AttrNumber) 1);
+		if (toast_typid == OIDOID)
+			toast_pointer.valueid =
+				GetNewOidWithIndex(toastrel,
+								   RelationGetRelid(toastidxs[validIndex]),
+								   (AttrNumber) 1);
+		else if (toast_typid == OID8OID)
+			toast_pointer.valueid = GetNewObjectId8();
+		else
+			Assert(false);
 	}
 	else
 	{
@@ -291,24 +302,32 @@ toast_save_datum(Relation rel, Datum value,
 		if (toast_pointer.valueid == InvalidOid8)
 		{
 			/*
-			 * new value; must choose an OID that doesn't conflict in either
-			 * old or new toast table
+			 * new value; must choose a value that doesn't conflict in either
+			 * old or new toast table.
 			 */
-			do
+			if (toast_typid == OIDOID)
 			{
-				toast_pointer.valueid =
-					GetNewOidWithIndex(toastrel,
-									   RelationGetRelid(toastidxs[validIndex]),
-									   (AttrNumber) 1);
-			} while (toastid_valueid_exists(rel->rd_toastoid,
-											toast_pointer.valueid));
+				do
+				{
+					toast_pointer.valueid =
+						GetNewOidWithIndex(toastrel,
+										   RelationGetRelid(toastidxs[validIndex]),
+										   (AttrNumber) 1);
+				} while (toastid_valueid_exists(rel->rd_toastoid,
+												toast_pointer.valueid));
+			}
+			else if (toast_typid == OID8OID)
+				toast_pointer.valueid = GetNewObjectId8();
 		}
 	}
 
 	/*
 	 * Initialize constant parts of the tuple data
 	 */
-	t_values[0] = ObjectIdGetDatum(toast_pointer.valueid);
+	if (toast_typid == OIDOID)
+		t_values[0] = ObjectIdGetDatum(toast_pointer.valueid);
+	else if (toast_typid == OID8OID)
+		t_values[0] = ObjectId8GetDatum(toast_pointer.valueid);
 	t_values[2] = PointerGetDatum(&chunk_data);
 	t_isnull[0] = false;
 	t_isnull[1] = false;
@@ -415,6 +434,7 @@ toast_delete_datum(Relation rel, Datum value, bool is_speculative)
 	HeapTuple	toasttup;
 	int			num_indexes;
 	int			validIndex;
+	Oid			toast_typid;
 
 	if (!VARATT_IS_EXTERNAL_ONDISK(attr))
 		return;
@@ -426,6 +446,8 @@ toast_delete_datum(Relation rel, Datum value, bool is_speculative)
 	 * Open the toast relation and its indexes
 	 */
 	toastrel = table_open(toast_pointer.toastrelid, RowExclusiveLock);
+	toast_typid = TupleDescAttr(toastrel->rd_att, 0)->atttypid;
+	Assert(toast_typid == OIDOID || toast_typid == OID8OID);
 
 	/* Fetch valid relation used for process */
 	validIndex = toast_open_indexes(toastrel,
@@ -436,10 +458,18 @@ toast_delete_datum(Relation rel, Datum value, bool is_speculative)
 	/*
 	 * Setup a scan key to find chunks with matching va_valueid
 	 */
-	ScanKeyInit(&toastkey,
-				(AttrNumber) 1,
-				BTEqualStrategyNumber, F_OIDEQ,
-				ObjectIdGetDatum(toast_pointer.valueid));
+	if (toast_typid == OIDOID)
+		ScanKeyInit(&toastkey,
+					(AttrNumber) 1,
+					BTEqualStrategyNumber, F_OIDEQ,
+					ObjectIdGetDatum(toast_pointer.valueid));
+	else if (toast_typid == OID8OID)
+		ScanKeyInit(&toastkey,
+					(AttrNumber) 1,
+					BTEqualStrategyNumber, F_OID8EQ,
+					ObjectId8GetDatum(toast_pointer.valueid));
+	else
+		Assert(false);
 
 	/*
 	 * Find all the chunks.  (We don't actually care whether we see them in
@@ -486,6 +516,7 @@ toastrel_valueid_exists(Relation toastrel, Oid8 valueid)
 	int			num_indexes;
 	int			validIndex;
 	Relation   *toastidxs;
+	Oid			toast_typid;
 
 	/* Fetch a valid index relation */
 	validIndex = toast_open_indexes(toastrel,
@@ -493,13 +524,24 @@ toastrel_valueid_exists(Relation toastrel, Oid8 valueid)
 									&toastidxs,
 									&num_indexes);
 
+	toast_typid = TupleDescAttr(toastrel->rd_att, 0)->atttypid;
+	Assert(toast_typid == OIDOID || toast_typid == OID8OID);
+
 	/*
 	 * Setup a scan key to find chunks with matching va_valueid
 	 */
-	ScanKeyInit(&toastkey,
-				(AttrNumber) 1,
-				BTEqualStrategyNumber, F_OIDEQ,
-				ObjectIdGetDatum(valueid));
+	if (toast_typid == OIDOID)
+		ScanKeyInit(&toastkey,
+					(AttrNumber) 1,
+					BTEqualStrategyNumber, F_OIDEQ,
+					ObjectIdGetDatum(valueid));
+	else if (toast_typid == OID8OID)
+		ScanKeyInit(&toastkey,
+					(AttrNumber) 1,
+					BTEqualStrategyNumber, F_OID8EQ,
+					ObjectId8GetDatum(valueid));
+	else
+		Assert(false);
 
 	/*
 	 * Is there any such chunk?
diff --git a/src/backend/access/heap/heaptoast.c b/src/backend/access/heap/heaptoast.c
index 230f2a6f35eb..50e9bf9047f9 100644
--- a/src/backend/access/heap/heaptoast.c
+++ b/src/backend/access/heap/heaptoast.c
@@ -654,6 +654,7 @@ heap_fetch_toast_slice(Relation toastrel, Oid8 valueid, int32 attrsize,
 	int32		max_chunk_size;
 	const toast_external_info *info;
 	uint8		tag = VARTAG_INDIRECT;	/* init value does not matter */
+	Oid			toast_typid;
 
 	/* Look for the valid index of toast relation */
 	validIndex = toast_open_indexes(toastrel,
@@ -667,16 +668,27 @@ heap_fetch_toast_slice(Relation toastrel, Oid8 valueid, int32 attrsize,
 
 	max_chunk_size = info->maximum_chunk_size;
 
+	toast_typid = TupleDescAttr(toastrel->rd_att, 0)->atttypid;
+	Assert(toast_typid == OIDOID || toast_typid == OID8OID);
+
 	totalchunks = ((attrsize - 1) / max_chunk_size) + 1;
 	startchunk = sliceoffset / max_chunk_size;
 	endchunk = (sliceoffset + slicelength - 1) / max_chunk_size;
 	Assert(endchunk <= totalchunks);
 
 	/* Set up a scan key to fetch from the index. */
-	ScanKeyInit(&toastkey[0],
-				(AttrNumber) 1,
-				BTEqualStrategyNumber, F_OIDEQ,
-				ObjectIdGetDatum(valueid));
+	if (toast_typid == OIDOID)
+		ScanKeyInit(&toastkey[0],
+					(AttrNumber) 1,
+					BTEqualStrategyNumber, F_OIDEQ,
+					ObjectIdGetDatum(valueid));
+	else if (toast_typid == OID8OID)
+		ScanKeyInit(&toastkey[0],
+					(AttrNumber) 1,
+					BTEqualStrategyNumber, F_OID8EQ,
+					ObjectId8GetDatum(valueid));
+	else
+		Assert(false);
 
 	/*
 	 * No additional condition if fetching all chunks. Otherwise, use an
diff --git a/src/backend/catalog/toasting.c b/src/backend/catalog/toasting.c
index 545983b5be9d..2288311b22a4 100644
--- a/src/backend/catalog/toasting.c
+++ b/src/backend/catalog/toasting.c
@@ -31,6 +31,7 @@
 #include "nodes/makefuncs.h"
 #include "utils/fmgroids.h"
 #include "utils/rel.h"
+#include "utils/lsyscache.h"
 #include "utils/syscache.h"
 
 static void CheckAndCreateToastTable(Oid relOid, Datum reloptions,
@@ -167,6 +168,8 @@ create_toast_table(Relation rel, Oid toastOid, Oid toastIndexOid,
 		value_type = RelationGetToastValueType(rel, STDRD_OPTION_TOAST_VALUE_TYPE_OID);
 		if (value_type == STDRD_OPTION_TOAST_VALUE_TYPE_OID)
 			toast_chunkid_typid = OIDOID;
+		else if (value_type == STDRD_OPTION_TOAST_VALUE_TYPE_OID8)
+			toast_chunkid_typid = OID8OID;
 	}
 	else
 	{
@@ -199,7 +202,8 @@ create_toast_table(Relation rel, Oid toastOid, Oid toastIndexOid,
 			ereport(ERROR,
 					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 					 errmsg("toast chunk_id type not set while in binary upgrade mode")));
-		if (binary_upgrade_next_toast_chunk_id_typoid != OIDOID)
+		if (binary_upgrade_next_toast_chunk_id_typoid != OIDOID &&
+			binary_upgrade_next_toast_chunk_id_typoid != OID8OID)
 			ereport(ERROR,
 					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 					 errmsg("cannot support toast chunk_id type %u in binary upgrade mode",
@@ -224,6 +228,19 @@ create_toast_table(Relation rel, Oid toastOid, Oid toastIndexOid,
 	snprintf(toast_idxname, sizeof(toast_idxname),
 			 "pg_toast_%u_index", relOid);
 
+	/*
+	 * Special case here.  If OIDOldToast is defined, we need to rely on the
+	 * existing table for the job because we do not want to create an
+	 * inconsistent relation that would conflict with the parent and break
+	 * the world.
+	 */
+	if (OidIsValid(OIDOldToast))
+	{
+		toast_chunkid_typid = get_atttype(OIDOldToast, 1);
+		if (!OidIsValid(toast_chunkid_typid))
+			elog(ERROR, "cache lookup failed for relation %u", OIDOldToast);
+	}
+
 	/* this is pretty painful...  need a tuple descriptor */
 	tupdesc = CreateTemplateTupleDesc(3);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 1,
@@ -336,7 +353,10 @@ create_toast_table(Relation rel, Oid toastOid, Oid toastIndexOid,
 	collationIds[0] = InvalidOid;
 	collationIds[1] = InvalidOid;
 
-	opclassIds[0] = OID_BTREE_OPS_OID;
+	if (toast_chunkid_typid == OIDOID)
+		opclassIds[0] = OID_BTREE_OPS_OID;
+	else if (toast_chunkid_typid == OID8OID)
+		opclassIds[0] = OID8_BTREE_OPS_OID;
 	opclassIds[1] = INT4_BTREE_OPS_OID;
 
 	coloptions[0] = 0;
diff --git a/doc/src/sgml/storage.sgml b/doc/src/sgml/storage.sgml
index 67600fd974d7..afddf663fec5 100644
--- a/doc/src/sgml/storage.sgml
+++ b/doc/src/sgml/storage.sgml
@@ -421,14 +421,15 @@ most <symbol>TOAST_OID_MAX_CHUNK_SIZE</symbol> bytes (by default this value is c
 so that four chunk rows will fit on a page, making it about 2000 bytes).
 Each chunk is stored as a separate row in the <acronym>TOAST</acronym> table
 belonging to the owning table.  Every
-<acronym>TOAST</acronym> table has the columns <structfield>chunk_id</structfield> (an OID
-identifying the particular <acronym>TOAST</acronym>ed value),
+<acronym>TOAST</acronym> table has the columns
+<structfield>chunk_id</structfield> (an OID or an 8-byte integer identifying
+the particular <acronym>TOAST</acronym>ed value),
 <structfield>chunk_seq</structfield> (a sequence number for the chunk within its value),
 and <structfield>chunk_data</structfield> (the actual data of the chunk).  A unique index
 on <structfield>chunk_id</structfield> and <structfield>chunk_seq</structfield> provides fast
 retrieval of the values.  A pointer datum representing an out-of-line on-disk
 <acronym>TOAST</acronym>ed value therefore needs to store the OID of the
-<acronym>TOAST</acronym> table in which to look and the OID of the specific value
+<acronym>TOAST</acronym> table in which to look and the specific value
 (its <structfield>chunk_id</structfield>).  For convenience, pointer datums also store the
 logical datum size (original uncompressed data length), physical stored size
 (different if compression was applied), and the compression method used, if
diff --git a/contrib/amcheck/verify_heapam.c b/contrib/amcheck/verify_heapam.c
index 9cf3c081bf01..143e6baa35cf 100644
--- a/contrib/amcheck/verify_heapam.c
+++ b/contrib/amcheck/verify_heapam.c
@@ -1880,6 +1880,9 @@ check_toasted_attribute(HeapCheckContext *ctx, ToastedAttribute *ta)
 	int32		last_chunk_seq;
 	Oid8		toast_valueid;
 	int32		max_chunk_size;
+	Oid			toast_typid;
+
+	toast_typid = TupleDescAttr(ctx->toast_rel->rd_att, 0)->atttypid;
 
 	extsize = ta->toast_pointer.extsize;
 
@@ -1889,10 +1892,18 @@ check_toasted_attribute(HeapCheckContext *ctx, ToastedAttribute *ta)
 	/*
 	 * Setup a scan key to find chunks in toast table with matching va_valueid
 	 */
-	ScanKeyInit(&toastkey,
-				(AttrNumber) 1,
-				BTEqualStrategyNumber, F_OIDEQ,
-				ObjectIdGetDatum(ta->toast_pointer.valueid));
+	if (toast_typid == OIDOID)
+		ScanKeyInit(&toastkey,
+					(AttrNumber) 1,
+					BTEqualStrategyNumber, F_OIDEQ,
+					ObjectIdGetDatum(ta->toast_pointer.valueid));
+	else if (toast_typid == OID8OID)
+		ScanKeyInit(&toastkey,
+					(AttrNumber) 1,
+					BTEqualStrategyNumber, F_OID8EQ,
+					ObjectId8GetDatum(ta->toast_pointer.valueid));
+	else
+		Assert(false);
 
 	/*
 	 * Check if any chunks for this toasted object exist in the toast table,
-- 
2.50.0

