Remove WITH OIDS support, change oid catalog column visibility.

Previously tables declared WITH OIDS, including a significant fraction
of the catalog tables, stored the oid column not as a normal column,
but as part of the tuple header.

This special column was not shown by default, which was somewhat odd,
as it's often (consider e.g. pg_class.oid) one of the more important
parts of a row.  Neither pg_dump nor COPY included the contents of the
oid column by default.

The fact that the oid column was not an ordinary column necessitated a
significant amount of special case code to support oid columns. That
already was painful for the existing, but upcoming work aiming to make
table storage pluggable, would have required expanding and duplicating
that "specialness" significantly.

WITH OIDS has been deprecated since 2005 (commit ff02d0a05280e0).
Remove it.

Removing includes:
- CREATE TABLE and ALTER TABLE syntax for declaring the table to be
  WITH OIDS has been removed (WITH (oids[ = true]) will error out)
- pg_dump does not support dumping tables declared WITH OIDS and will
  issue a warning when dumping one (and ignore the oid column).
- restoring an pg_dump archive with pg_restore will warn when
  restoring a table with oid contents (and ignore the oid column)
- COPY will refuse to load binary dump that includes oids.
- pg_upgrade will error out when encountering tables declared WITH
  OIDS, they have to be altered to remove the oid column first.
- Functionality to access the oid of the last inserted row (like
  plpgsql's RESULT_OID, spi's SPI_lastoid, ...) has been removed.

The syntax for declaring a table WITHOUT OIDS (or WITH (oids = false)
for CREATE TABLE) is still supported. While that requires a bit of
support code, it seems unnecessary to break applications / dumps that
do not use oids, and are explicit about not using them.

The biggest user of WITH OID columns was postgres' catalog. This
commit changes all 'magic' oid columns to be columns that are normally
declared and stored. To reduce unnecessary query breakage all the
newly added columns are still named 'oid', even if a table's column
naming scheme would indicate 'reloid' or such.  This obviously
requires adapting a lot code, mostly replacing oid access via
HeapTupleGetOid() with access to the underlying Form_pg_*->oid column.

The bootstrap process now assigns oids for all oid columns in
genbki.pl that do not have an explicit value (starting at the largest
oid previously used), only oids assigned later by oids will be above
FirstBootstrapObjectId. As the oid column now is a normal column the
special bootstrap syntax for oids has been removed.

Oids are not automatically assigned during insertion anymore, all
backend code explicitly assigns oids with GetNewOidWithIndex(). For
the rare case that insertions into the catalog via SQL are called for
the new pg_nextoid() function can be used (which only works on catalog
tables).

The fact that oid columns on system tables are now normal columns
means that they will be included in the set of columns expanded
by * (i.e. SELECT * FROM pg_class will now include the table's oid,
previously it did not). It'd not technically be hard to hide oid
column by default, but that'd mean confusing behavior would either
have to be carried forward forever, or it'd cause breakage down the
line.

While it's not unlikely that further adjustments are needed, the
scope/invasiveness of the patch makes it worthwhile to get merge this
now. It's painful to maintain externally, too complicated to commit
after the code code freeze, and a dependency of a number of other
patches.

Catversion bump, for obvious reasons.

Author: Andres Freund, with contributions by John Naylor
Discussion: https://postgr.es/m/20180930034810.ywp2c7awz7opzcfr@alap3.anarazel.de

1 files changed, 41 insertions, 278 deletions

diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index a15e6045075..a1137a3bf09 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -305,8 +305,7 @@ static void truncate_check_activity(Relation rel);
 static void RangeVarCallbackForTruncate(const RangeVar *relation,
 							Oid relId, Oid oldRelId, void *arg);
 static List *MergeAttributes(List *schema, List *supers, char relpersistence,
-				bool is_partition, List **supOids, List **supconstr,
-				int *supOidCount);
+				bool is_partition, List **supOids, List **supconstr);
 static bool MergeCheckConstraint(List *constraints, char *name, Node *expr);
 static void MergeAttributesIntoExisting(Relation child_rel, Relation parent_rel);
 static void MergeConstraintsIntoExisting(Relation child_rel, Relation parent_rel);
@@ -363,15 +362,13 @@ static List *find_typed_table_dependencies(Oid typeOid, const char *typeName,
 static void ATPrepAddColumn(List **wqueue, Relation rel, bool recurse, bool recursing,
 				bool is_view, AlterTableCmd *cmd, LOCKMODE lockmode);
 static ObjectAddress ATExecAddColumn(List **wqueue, AlteredTableInfo *tab,
-				Relation rel, ColumnDef *colDef, bool isOid,
+				Relation rel, ColumnDef *colDef,
 				bool recurse, bool recursing,
 				bool if_not_exists, LOCKMODE lockmode);
 static bool check_for_column_name_collision(Relation rel, const char *colname,
 								bool if_not_exists);
 static void add_column_datatype_dependency(Oid relid, int32 attnum, Oid typid);
 static void add_column_collation_dependency(Oid relid, int32 attnum, Oid collid);
-static void ATPrepAddOids(List **wqueue, Relation rel, bool recurse,
-			  AlterTableCmd *cmd, LOCKMODE lockmode);
 static void ATPrepDropNotNull(Relation rel, bool recurse, bool recursing);
 static ObjectAddress ATExecDropNotNull(Relation rel, const char *colName, LOCKMODE lockmode);
 static void ATPrepSetNotNull(Relation rel, bool recurse, bool recursing);
@@ -531,8 +528,6 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	TupleDesc	descriptor;
 	List	   *inheritOids;
 	List	   *old_constraints;
-	bool		localHasOids;
-	int			parentOidCount;
 	List	   *rawDefaults;
 	List	   *cookedDefaults;
 	Datum		reloptions;
@@ -654,7 +649,7 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 		MergeAttributes(stmt->tableElts, stmt->inhRelations,
 						stmt->relation->relpersistence,
 						stmt->partbound != NULL,
-						&inheritOids, &old_constraints, &parentOidCount);
+						&inheritOids, &old_constraints);
 
 	/*
 	 * Create a tuple descriptor from the relation schema.  Note that this
@@ -664,29 +659,6 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 	descriptor = BuildDescForRelation(stmt->tableElts);
 
 	/*
-	 * Notice that we allow OIDs here only for plain tables and partitioned
-	 * tables, even though some other relkinds can support them.  This is
-	 * necessary because the default_with_oids GUC must apply only to plain
-	 * tables and not any other relkind; doing otherwise would break existing
-	 * pg_dump files.  We could allow explicit "WITH OIDS" while not allowing
-	 * default_with_oids to affect other relkinds, but it would complicate
-	 * interpretOidsOption().
-	 */
-	localHasOids = interpretOidsOption(stmt->options,
-									   (relkind == RELKIND_RELATION ||
-										relkind == RELKIND_PARTITIONED_TABLE));
-	descriptor->tdhasoid = (localHasOids || parentOidCount > 0);
-
-	/*
-	 * If a partitioned table doesn't have the system OID column, then none of
-	 * its partitions should have it.
-	 */
-	if (stmt->partbound && parentOidCount == 0 && localHasOids)
-		ereport(ERROR,
-				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
-				 errmsg("cannot create table with OIDs as partition of table without OIDs")));
-
-	/*
 	 * Find columns with default values and prepare for insertion of the
 	 * defaults.  Pre-cooked (that is, inherited) defaults go into a list of
 	 * CookedConstraint structs that we'll pass to heap_create_with_catalog,
@@ -764,8 +736,6 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 										  stmt->relation->relpersistence,
 										  false,
 										  false,
-										  localHasOids,
-										  parentOidCount,
 										  stmt->oncommit,
 										  reloptions,
 										  true,
@@ -1816,7 +1786,6 @@ storage_name(char c)
  * 'supOids' receives a list of the OIDs of the parent relations.
  * 'supconstr' receives a list of constraints belonging to the parents,
  *		updated as necessary to be valid for the child.
- * 'supOidCount' is set to the number of parents that have OID columns.
  *
  * Return value:
  * Completed schema list.
@@ -1862,14 +1831,12 @@ storage_name(char c)
  */
 static List *
 MergeAttributes(List *schema, List *supers, char relpersistence,
-				bool is_partition, List **supOids, List **supconstr,
-				int *supOidCount)
+				bool is_partition, List **supOids, List **supconstr)
 {
 	ListCell   *entry;
 	List	   *inhSchema = NIL;
 	List	   *parentOids = NIL;
 	List	   *constraints = NIL;
-	int			parentsWithOids = 0;
 	bool		have_bogus_defaults = false;
 	int			child_attno;
 	static Node bogus_marker = {0}; /* marks conflicting defaults */
@@ -2077,9 +2044,6 @@ MergeAttributes(List *schema, List *supers, char relpersistence,
 
 		parentOids = lappend_oid(parentOids, RelationGetRelid(relation));
 
-		if (relation->rd_rel->relhasoids)
-			parentsWithOids++;
-
 		tupleDesc = RelationGetDescr(relation);
 		constr = tupleDesc->constr;
 
@@ -2498,7 +2462,6 @@ MergeAttributes(List *schema, List *supers, char relpersistence,
 
 	*supOids = parentOids;
 	*supconstr = constraints;
-	*supOidCount = parentsWithOids;
 	return schema;
 }
 
@@ -3424,7 +3387,6 @@ AlterTableGetLockLevel(List *cmds)
 								 * to SELECT */
 			case AT_SetTableSpace:	/* must rewrite heap */
 			case AT_AlterColumnType:	/* must rewrite heap */
-			case AT_AddOids:	/* must rewrite heap */
 				cmd_lockmode = AccessExclusiveLock;
 				break;
 
@@ -3453,7 +3415,7 @@ AlterTableGetLockLevel(List *cmds)
 				 */
 			case AT_DropColumn: /* change visible to SELECT */
 			case AT_AddColumnToView:	/* CREATE VIEW */
-			case AT_DropOids:	/* calls AT_DropColumn */
+			case AT_DropOids:	/* used to equiv to DropColumn */
 			case AT_EnableAlwaysRule:	/* may change SELECT rules */
 			case AT_EnableReplicaRule:	/* may change SELECT rules */
 			case AT_EnableRule: /* may change SELECT rules */
@@ -3862,25 +3824,8 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
 			}
 			pass = AT_PASS_MISC;
 			break;
-		case AT_AddOids:		/* SET WITH OIDS */
-			ATSimplePermissions(rel, ATT_TABLE | ATT_FOREIGN_TABLE);
-			if (!rel->rd_rel->relhasoids || recursing)
-				ATPrepAddOids(wqueue, rel, recurse, cmd, lockmode);
-			/* Recursion occurs during execution phase */
-			pass = AT_PASS_ADD_COL;
-			break;
 		case AT_DropOids:		/* SET WITHOUT OIDS */
 			ATSimplePermissions(rel, ATT_TABLE | ATT_FOREIGN_TABLE);
-			/* Performs own recursion */
-			if (rel->rd_rel->relhasoids)
-			{
-				AlterTableCmd *dropCmd = makeNode(AlterTableCmd);
-
-				dropCmd->subtype = AT_DropColumn;
-				dropCmd->name = pstrdup("oid");
-				dropCmd->behavior = cmd->behavior;
-				ATPrepCmd(wqueue, rel, dropCmd, recurse, false, lockmode);
-			}
 			pass = AT_PASS_DROP;
 			break;
 		case AT_SetTableSpace:	/* SET TABLESPACE */
@@ -4068,12 +4013,12 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
 		case AT_AddColumn:		/* ADD COLUMN */
 		case AT_AddColumnToView:	/* add column via CREATE OR REPLACE VIEW */
 			address = ATExecAddColumn(wqueue, tab, rel, (ColumnDef *) cmd->def,
-									  false, false, false,
+									  false, false,
 									  false, lockmode);
 			break;
 		case AT_AddColumnRecurse:
 			address = ATExecAddColumn(wqueue, tab, rel, (ColumnDef *) cmd->def,
-									  false, true, false,
+									  true, false,
 									  cmd->missing_ok, lockmode);
 			break;
 		case AT_ColumnDefault:	/* ALTER COLUMN DEFAULT */
@@ -4197,28 +4142,8 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
 		case AT_SetLogged:		/* SET LOGGED */
 		case AT_SetUnLogged:	/* SET UNLOGGED */
 			break;
-		case AT_AddOids:		/* SET WITH OIDS */
-			/* Use the ADD COLUMN code, unless prep decided to do nothing */
-			if (cmd->def != NULL)
-				address =
-					ATExecAddColumn(wqueue, tab, rel, (ColumnDef *) cmd->def,
-									true, false, false,
-									cmd->missing_ok, lockmode);
-			break;
-		case AT_AddOidsRecurse: /* SET WITH OIDS */
-			/* Use the ADD COLUMN code, unless prep decided to do nothing */
-			if (cmd->def != NULL)
-				address =
-					ATExecAddColumn(wqueue, tab, rel, (ColumnDef *) cmd->def,
-									true, true, false,
-									cmd->missing_ok, lockmode);
-			break;
 		case AT_DropOids:		/* SET WITHOUT OIDS */
-
-			/*
-			 * Nothing to do here; we'll have generated a DropColumn
-			 * subcommand to do the real work
-			 */
+			/* nothing to do here, oid columns don't exist anymore */
 			break;
 		case AT_SetTableSpace:	/* SET TABLESPACE */
 			/*
@@ -4774,12 +4699,8 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 		{
 			if (tab->rewrite > 0)
 			{
-				Oid			tupOid = InvalidOid;
-
 				/* Extract data from old tuple */
 				heap_deform_tuple(tuple, oldTupDesc, values, isnull);
-				if (oldTupDesc->tdhasoid)
-					tupOid = HeapTupleGetOid(tuple);
 
 				/* Set dropped attributes to null in new tuple */
 				foreach(lc, dropped_attrs)
@@ -4807,10 +4728,6 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 				 */
 				tuple = heap_form_tuple(newTupDesc, values, isnull);
 
-				/* Preserve OID, if any */
-				if (newTupDesc->tdhasoid)
-					HeapTupleSetOid(tuple, tupOid);
-
 				/*
 				 * Constraints might reference the tableoid column, so
 				 * initialize t_tableOid before evaluating them.
@@ -5293,6 +5210,8 @@ find_typed_table_dependencies(Oid typeOid, const char *typeName, DropBehavior be
 
 	while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
 	{
+		Form_pg_class classform = (Form_pg_class) GETSTRUCT(tuple);
+
 		if (behavior == DROP_RESTRICT)
 			ereport(ERROR,
 					(errcode(ERRCODE_DEPENDENT_OBJECTS_STILL_EXIST),
@@ -5300,7 +5219,7 @@ find_typed_table_dependencies(Oid typeOid, const char *typeName, DropBehavior be
 							typeName),
 					 errhint("Use ALTER ... CASCADE to alter the typed tables too.")));
 		else
-			result = lappend_oid(result, HeapTupleGetOid(tuple));
+			result = lappend_oid(result, classform->oid);
 	}
 
 	heap_endscan(scan);
@@ -5345,7 +5264,7 @@ check_of_type(HeapTuple typetuple)
 		ereport(ERROR,
 				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
 				 errmsg("type %s is not a composite type",
-						format_type_be(HeapTupleGetOid(typetuple)))));
+						format_type_be(typ->oid))));
 }
 
 
@@ -5385,7 +5304,7 @@ ATPrepAddColumn(List **wqueue, Relation rel, bool recurse, bool recursing,
  */
 static ObjectAddress
 ATExecAddColumn(List **wqueue, AlteredTableInfo *tab, Relation rel,
-				ColumnDef *colDef, bool isOid,
+				ColumnDef *colDef,
 				bool recurse, bool recursing,
 				bool if_not_exists, LOCKMODE lockmode)
 {
@@ -5455,13 +5374,6 @@ ATExecAddColumn(List **wqueue, AlteredTableInfo *tab, Relation rel,
 								   get_collation_name(ccollid),
 								   get_collation_name(childatt->attcollation))));
 
-			/* If it's OID, child column must actually be OID */
-			if (isOid && childatt->attnum != ObjectIdAttributeNumber)
-				ereport(ERROR,
-						(errcode(ERRCODE_DATATYPE_MISMATCH),
-						 errmsg("child table \"%s\" has a conflicting \"%s\" column",
-								RelationGetRelationName(rel), colDef->colname)));
-
 			/* Bump the existing child att's inhcount */
 			childatt->attinhcount++;
 			CatalogTupleUpdate(attrdesc, &tuple->t_self, tuple);
@@ -5506,21 +5418,16 @@ ATExecAddColumn(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	}
 
 	/* Determine the new attribute's number */
-	if (isOid)
-		newattnum = ObjectIdAttributeNumber;
-	else
-	{
-		newattnum = ((Form_pg_class) GETSTRUCT(reltup))->relnatts + 1;
-		if (newattnum > MaxHeapAttributeNumber)
-			ereport(ERROR,
-					(errcode(ERRCODE_TOO_MANY_COLUMNS),
-					 errmsg("tables can have at most %d columns",
-							MaxHeapAttributeNumber)));
-	}
+	newattnum = ((Form_pg_class) GETSTRUCT(reltup))->relnatts + 1;
+	if (newattnum > MaxHeapAttributeNumber)
+		ereport(ERROR,
+				(errcode(ERRCODE_TOO_MANY_COLUMNS),
+				 errmsg("tables can have at most %d columns",
+						MaxHeapAttributeNumber)));
 
 	typeTuple = typenameType(NULL, colDef->typeName, &typmod);
 	tform = (Form_pg_type) GETSTRUCT(typeTuple);
-	typeOid = HeapTupleGetOid(typeTuple);
+	typeOid = tform->oid;
 
 	aclresult = pg_type_aclcheck(typeOid, GetUserId(), ACL_USAGE);
 	if (aclresult != ACLCHECK_OK)
@@ -5564,10 +5471,7 @@ ATExecAddColumn(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	/*
 	 * Update pg_class tuple as appropriate
 	 */
-	if (isOid)
-		((Form_pg_class) GETSTRUCT(reltup))->relhasoids = true;
-	else
-		((Form_pg_class) GETSTRUCT(reltup))->relnatts = newattnum;
+	((Form_pg_class) GETSTRUCT(reltup))->relnatts = newattnum;
 
 	CatalogTupleUpdate(pgclass, &reltup->t_self, reltup);
 
@@ -5716,13 +5620,6 @@ ATExecAddColumn(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	}
 
 	/*
-	 * If we are adding an OID column, we have to tell Phase 3 to rewrite the
-	 * table to fix that.
-	 */
-	if (isOid)
-		tab->rewrite |= AT_REWRITE_ALTER_OID;
-
-	/*
 	 * Add needed dependency entries for the new column.
 	 */
 	add_column_datatype_dependency(myrelid, newattnum, attribute.atttypid);
@@ -5767,7 +5664,7 @@ ATExecAddColumn(List **wqueue, AlteredTableInfo *tab, Relation rel,
 
 		/* Recurse to child; return value is ignored */
 		ATExecAddColumn(wqueue, childtab, childrel,
-						colDef, isOid, recurse, true,
+						colDef, recurse, true,
 						if_not_exists, lockmode);
 
 		heap_close(childrel, NoLock);
@@ -5872,35 +5769,6 @@ add_column_collation_dependency(Oid relid, int32 attnum, Oid collid)
 }
 
 /*
- * ALTER TABLE SET WITH OIDS
- *
- * Basically this is an ADD COLUMN for the special OID column.  We have
- * to cons up a ColumnDef node because the ADD COLUMN code needs one.
- */
-static void
-ATPrepAddOids(List **wqueue, Relation rel, bool recurse, AlterTableCmd *cmd, LOCKMODE lockmode)
-{
-	/* If we're recursing to a child table, the ColumnDef is already set up */
-	if (cmd->def == NULL)
-	{
-		ColumnDef  *cdef = makeNode(ColumnDef);
-
-		cdef->colname = pstrdup("oid");
-		cdef->typeName = makeTypeNameFromOid(OIDOID, -1);
-		cdef->inhcount = 0;
-		cdef->is_local = true;
-		cdef->is_not_null = true;
-		cdef->storage = 0;
-		cdef->location = -1;
-		cmd->def = (Node *) cdef;
-	}
-	ATPrepAddColumn(wqueue, rel, recurse, false, false, cmd, lockmode);
-
-	if (recurse)
-		cmd->subtype = AT_AddOidsRecurse;
-}
-
-/*
  * ALTER TABLE ALTER COLUMN DROP NOT NULL
  *
  * Return the address of the modified column.  If the column was already
@@ -6801,8 +6669,8 @@ ATExecDropColumn(List **wqueue, Relation rel, const char *colName,
 
 	attnum = targetatt->attnum;
 
-	/* Can't drop a system attribute, except OID */
-	if (attnum <= 0 && attnum != ObjectIdAttributeNumber)
+	/* Can't drop a system attribute */
+	if (attnum <= 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 				 errmsg("cannot drop system column \"%s\"",
@@ -6932,39 +6800,6 @@ ATExecDropColumn(List **wqueue, Relation rel, const char *colName,
 
 	performDeletion(&object, behavior, 0);
 
-	/*
-	 * If we dropped the OID column, must adjust pg_class.relhasoids and tell
-	 * Phase 3 to physically get rid of the column.  We formerly left the
-	 * column in place physically, but this caused subtle problems.  See
-	 * http://archives.postgresql.org/pgsql-hackers/2009-02/msg00363.php
-	 */
-	if (attnum == ObjectIdAttributeNumber)
-	{
-		Relation	class_rel;
-		Form_pg_class tuple_class;
-		AlteredTableInfo *tab;
-
-		class_rel = heap_open(RelationRelationId, RowExclusiveLock);
-
-		tuple = SearchSysCacheCopy1(RELOID,
-									ObjectIdGetDatum(RelationGetRelid(rel)));
-		if (!HeapTupleIsValid(tuple))
-			elog(ERROR, "cache lookup failed for relation %u",
-				 RelationGetRelid(rel));
-		tuple_class = (Form_pg_class) GETSTRUCT(tuple);
-
-		tuple_class->relhasoids = false;
-		CatalogTupleUpdate(class_rel, &tuple->t_self, tuple);
-
-		heap_close(class_rel, RowExclusiveLock);
-
-		/* Find or create work queue entry for this table */
-		tab = ATGetQueueEntry(wqueue, rel);
-
-		/* Tell Phase 3 to physically remove the OID column */
-		tab->rewrite |= AT_REWRITE_ALTER_OID;
-	}
-
 	return object;
 }
 
@@ -7878,7 +7713,7 @@ ATExecAlterConstraint(Relation rel, AlterTableCmd *cmd,
 		CatalogTupleUpdate(conrel, &copyTuple->t_self, copyTuple);
 
 		InvokeObjectPostAlterHook(ConstraintRelationId,
-								  HeapTupleGetOid(contuple), 0);
+								  currcon->oid, 0);
 
 		heap_freetuple(copyTuple);
 
@@ -7891,7 +7726,7 @@ ATExecAlterConstraint(Relation rel, AlterTableCmd *cmd,
 		ScanKeyInit(&tgkey,
 					Anum_pg_trigger_tgconstraint,
 					BTEqualStrategyNumber, F_OIDEQ,
-					ObjectIdGetDatum(HeapTupleGetOid(contuple)));
+					ObjectIdGetDatum(currcon->oid));
 
 		tgscan = systable_beginscan(tgrel, TriggerConstraintIndexId, true,
 									NULL, 1, &tgkey);
@@ -7930,8 +7765,7 @@ ATExecAlterConstraint(Relation rel, AlterTableCmd *cmd,
 			copy_tg->tginitdeferred = cmdcon->initdeferred;
 			CatalogTupleUpdate(tgrel, &copyTuple->t_self, copyTuple);
 
-			InvokeObjectPostAlterHook(TriggerRelationId,
-									  HeapTupleGetOid(tgtuple), 0);
+			InvokeObjectPostAlterHook(TriggerRelationId, currcon->oid, 0);
 
 			heap_freetuple(copyTuple);
 		}
@@ -7952,8 +7786,7 @@ ATExecAlterConstraint(Relation rel, AlterTableCmd *cmd,
 			CacheInvalidateRelcacheByRelid(lfirst_oid(lc));
 		}
 
-		ObjectAddressSet(address, ConstraintRelationId,
-						 HeapTupleGetOid(contuple));
+		ObjectAddressSet(address, ConstraintRelationId, currcon->oid);
 	}
 	else
 		address = InvalidObjectAddress;
@@ -8043,7 +7876,7 @@ ATExecValidateConstraint(Relation rel, char *constrName, bool recurse,
 
 			validateForeignKeyConstraint(constrName, rel, refrel,
 										 con->conindid,
-										 HeapTupleGetOid(tuple));
+										 con->oid);
 			heap_close(refrel, NoLock);
 
 			/*
@@ -8116,13 +7949,11 @@ ATExecValidateConstraint(Relation rel, char *constrName, bool recurse,
 		copy_con->convalidated = true;
 		CatalogTupleUpdate(conrel, &copyTuple->t_self, copyTuple);
 
-		InvokeObjectPostAlterHook(ConstraintRelationId,
-								  HeapTupleGetOid(tuple), 0);
+		InvokeObjectPostAlterHook(ConstraintRelationId, con->oid, 0);
 
 		heap_freetuple(copyTuple);
 
-		ObjectAddressSet(address, ConstraintRelationId,
-						 HeapTupleGetOid(tuple));
+		ObjectAddressSet(address, ConstraintRelationId, con->oid);
 	}
 	else
 		address = InvalidObjectAddress; /* already validated */
@@ -8520,7 +8351,7 @@ validateCheckConstraint(Relation rel, HeapTuple constrtup)
 						  &isnull);
 	if (isnull)
 		elog(ERROR, "null conbin for constraint %u",
-			 HeapTupleGetOid(constrtup));
+			 constrForm->oid);
 	conbin = TextDatumGetCString(val);
 	origexpr = (Expr *) stringToNode(conbin);
 	exprstate = ExecPrepareExpr(origexpr, estate);
@@ -8944,7 +8775,7 @@ ATExecDropConstraint(Relation rel, const char *constrName,
 		 * Perform the actual constraint deletion
 		 */
 		conobj.classId = ConstraintRelationId;
-		conobj.objectId = HeapTupleGetOid(tuple);
+		conobj.objectId = con->oid;
 		conobj.objectSubId = 0;
 
 		performDeletion(&conobj, behavior, 0);
@@ -9419,7 +9250,7 @@ ATExecAlterColumnType(AlteredTableInfo *tab, Relation rel,
 	/* Look up the target type (should not fail, since prep found it) */
 	typeTuple = typenameType(NULL, typeName, &targettypmod);
 	tform = (Form_pg_type) GETSTRUCT(typeTuple);
-	targettype = HeapTupleGetOid(typeTuple);
+	targettype = tform->oid;
 	/* And the collation */
 	targetcollid = GetColumnDefCollation(NULL, def, targettype);
 
@@ -11229,10 +11060,8 @@ AlterTableMoveAll(AlterTableMoveAllStmt *stmt)
 	scan = heap_beginscan_catalog(rel, 1, key);
 	while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
 	{
-		Oid			relOid = HeapTupleGetOid(tuple);
-		Form_pg_class relForm;
-
-		relForm = (Form_pg_class) GETSTRUCT(tuple);
+		Form_pg_class relForm = (Form_pg_class) GETSTRUCT(tuple);
+		Oid			relOid = relForm->oid;
 
 		/*
 		 * Do not move objects in pg_catalog as part of this, if an admin
@@ -11536,14 +11365,6 @@ ATExecAddInherit(Relation child_rel, RangeVar *parent, LOCKMODE lockmode)
 						   parent->relname,
 						   RelationGetRelationName(child_rel))));
 
-	/* If parent has OIDs then child must have OIDs */
-	if (parent_rel->rd_rel->relhasoids && !child_rel->rd_rel->relhasoids)
-		ereport(ERROR,
-				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
-				 errmsg("table \"%s\" without OIDs cannot inherit from table \"%s\" with OIDs",
-						RelationGetRelationName(child_rel),
-						RelationGetRelationName(parent_rel))));
-
 	/*
 	 * If child_rel has row-level triggers with transition tables, we
 	 * currently don't allow it to become an inheritance child.  See also
@@ -11656,7 +11477,7 @@ decompile_conbin(HeapTuple contup, TupleDesc tupdesc)
 	con = (Form_pg_constraint) GETSTRUCT(contup);
 	attr = heap_getattr(contup, Anum_pg_constraint_conbin, tupdesc, &isnull);
 	if (isnull)
-		elog(ERROR, "null conbin for constraint %u", HeapTupleGetOid(contup));
+		elog(ERROR, "null conbin for constraint %u", con->oid);
 
 	expr = DirectFunctionCall2(pg_get_expr, attr,
 							   ObjectIdGetDatum(con->conrelid));
@@ -11790,45 +11611,6 @@ MergeAttributesIntoExisting(Relation child_rel, Relation parent_rel)
 		}
 	}
 
-	/*
-	 * If the parent has an OID column, so must the child, and we'd better
-	 * update the child's attinhcount and attislocal the same as for normal
-	 * columns.  We needn't check data type or not-nullness though.
-	 */
-	if (tupleDesc->tdhasoid)
-	{
-		/*
-		 * Here we match by column number not name; the match *must* be the
-		 * system column, not some random column named "oid".
-		 */
-		tuple = SearchSysCacheCopy2(ATTNUM,
-									ObjectIdGetDatum(RelationGetRelid(child_rel)),
-									Int16GetDatum(ObjectIdAttributeNumber));
-		if (HeapTupleIsValid(tuple))
-		{
-			Form_pg_attribute childatt = (Form_pg_attribute) GETSTRUCT(tuple);
-
-			/* See comments above; these changes should be the same */
-			childatt->attinhcount++;
-
-			if (child_is_partition)
-			{
-				Assert(childatt->attinhcount == 1);
-				childatt->attislocal = false;
-			}
-
-			CatalogTupleUpdate(attrrel, &tuple->t_self, tuple);
-			heap_freetuple(tuple);
-		}
-		else
-		{
-			ereport(ERROR,
-					(errcode(ERRCODE_DATATYPE_MISMATCH),
-					 errmsg("child table is missing column \"%s\"",
-							"oid")));
-		}
-	}
-
 	heap_close(attrrel, RowExclusiveLock);
 }
 
@@ -12258,6 +12040,7 @@ ATExecAddOf(Relation rel, const TypeName *ofTypename, LOCKMODE lockmode)
 {
 	Oid			relid = RelationGetRelid(rel);
 	Type		typetuple;
+	Form_pg_type typeform;
 	Oid			typeid;
 	Relation	inheritsRelation,
 				relationRelation;
@@ -12274,7 +12057,8 @@ ATExecAddOf(Relation rel, const TypeName *ofTypename, LOCKMODE lockmode)
 	/* Validate the type. */
 	typetuple = typenameType(NULL, ofTypename, NULL);
 	check_of_type(typetuple);
-	typeid = HeapTupleGetOid(typetuple);
+	typeform = (Form_pg_type) GETSTRUCT(typetuple);
+	typeid = typeform->oid;
 
 	/* Fail if the table has any inheritance parents. */
 	inheritsRelation = heap_open(InheritsRelationId, AccessShareLock);
@@ -12294,7 +12078,6 @@ ATExecAddOf(Relation rel, const TypeName *ofTypename, LOCKMODE lockmode)
 	/*
 	 * Check the tuple descriptors for compatibility.  Unlike inheritance, we
 	 * require that the order also match.  However, attnotnull need not match.
-	 * Also unlike inheritance, we do not require matching relhasoids.
 	 */
 	typeTupleDesc = lookup_rowtype_tupdesc(typeid, -1);
 	tableTupleDesc = RelationGetDescr(rel);
@@ -12619,10 +12402,6 @@ ATExecReplicaIdentity(Relation rel, ReplicaIdentityStmt *stmt, LOCKMODE lockmode
 		int16		attno = indexRel->rd_index->indkey.values[key];
 		Form_pg_attribute attr;
 
-		/* Allow OID column to be indexed; it's certainly not nullable */
-		if (attno == ObjectIdAttributeNumber)
-			continue;
-
 		/*
 		 * Reject any other system columns.  (Going forward, we'll disallow
 		 * indexes containing such columns in the first place, but they might
@@ -14292,22 +14071,6 @@ ATExecAttachPartition(List **wqueue, Relation rel, PartitionCmd *cmd)
 				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
 				 errmsg("cannot attach temporary relation of another session as partition")));
 
-	/* If parent has OIDs then child must have OIDs */
-	if (rel->rd_rel->relhasoids && !attachrel->rd_rel->relhasoids)
-		ereport(ERROR,
-				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
-				 errmsg("cannot attach table \"%s\" without OIDs as partition of"
-						" table \"%s\" with OIDs", RelationGetRelationName(attachrel),
-						RelationGetRelationName(rel))));
-
-	/* OTOH, if parent doesn't have them, do not allow in attachrel either */
-	if (attachrel->rd_rel->relhasoids && !rel->rd_rel->relhasoids)
-		ereport(ERROR,
-				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
-				 errmsg("cannot attach table \"%s\" with OIDs as partition of table"
-						" \"%s\" without OIDs", RelationGetRelationName(attachrel),
-						RelationGetRelationName(rel))));
-
 	/* Check if there are any columns in attachrel that aren't in the parent */
 	tupleDesc = RelationGetDescr(attachrel);
 	natts = tupleDesc->natts;
@@ -14728,7 +14491,7 @@ CloneRowTriggersToPartition(Relation parent, Relation partition)
 
 		CreateTrigger(trigStmt, NULL, RelationGetRelid(partition),
 					  trigForm->tgconstrrelid, InvalidOid, InvalidOid,
-					  trigForm->tgfoid, HeapTupleGetOid(tuple), qual,
+					  trigForm->tgfoid, trigForm->oid, qual,
 					  false, true);
 
 		MemoryContextReset(perTupCxt);