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, 29 insertions, 96 deletions

diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index aecbd4a9437..c3071db1cdf 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -261,8 +261,7 @@ static void write_relcache_init_file(bool shared);
 static void write_item(const void *data, Size len, FILE *fp);
 
 static void formrdesc(const char *relationName, Oid relationReltype,
-		  bool isshared, bool hasoids,
-		  int natts, const FormData_pg_attribute *attrs);
+		  bool isshared, int natts, const FormData_pg_attribute *attrs);
 
 static HeapTuple ScanPgRelation(Oid targetRelId, bool indexOK, bool force_non_historic);
 static Relation AllocateRelationDesc(Form_pg_class relp);
@@ -328,7 +327,7 @@ ScanPgRelation(Oid targetRelId, bool indexOK, bool force_non_historic)
 	 * form a scan key
 	 */
 	ScanKeyInit(&key[0],
-				ObjectIdAttributeNumber,
+				Anum_pg_class_oid,
 				BTEqualStrategyNumber, F_OIDEQ,
 				ObjectIdGetDatum(targetRelId));
 
@@ -414,8 +413,7 @@ AllocateRelationDesc(Form_pg_class relp)
 	relation->rd_rel = relationForm;
 
 	/* and allocate attribute tuple form storage */
-	relation->rd_att = CreateTemplateTupleDesc(relationForm->relnatts,
-											   relationForm->relhasoids);
+	relation->rd_att = CreateTemplateTupleDesc(relationForm->relnatts);
 	/* which we mark as a reference-counted tupdesc */
 	relation->rd_att->tdrefcount = 1;
 
@@ -505,7 +503,6 @@ RelationBuildTupleDesc(Relation relation)
 	/* copy some fields from pg_class row to rd_att */
 	relation->rd_att->tdtypeid = relation->rd_rel->reltype;
 	relation->rd_att->tdtypmod = -1;	/* unnecessary, but... */
-	relation->rd_att->tdhasoid = relation->rd_rel->relhasoids;
 
 	constr = (TupleConstr *) MemoryContextAlloc(CacheMemoryContext,
 												sizeof(TupleConstr));
@@ -789,7 +786,7 @@ RelationBuildRuleLock(Relation relation)
 		rule = (RewriteRule *) MemoryContextAlloc(rulescxt,
 												  sizeof(RewriteRule));
 
-		rule->ruleId = HeapTupleGetOid(rewrite_tuple);
+		rule->ruleId = rewrite_form->oid;
 
 		rule->event = rewrite_form->ev_type - '0';
 		rule->enabled = rewrite_form->ev_enabled;
@@ -1090,8 +1087,8 @@ RelationBuildDesc(Oid targetRelId, bool insertIt)
 	/*
 	 * get information from the pg_class_tuple
 	 */
-	relid = HeapTupleGetOid(pg_class_tuple);
 	relp = (Form_pg_class) GETSTRUCT(pg_class_tuple);
+	relid = relp->oid;
 	Assert(relid == targetRelId);
 
 	/*
@@ -1641,7 +1638,7 @@ LookupOpclassInfo(Oid operatorClassOid,
 	 * work while bootstrapping.
 	 */
 	ScanKeyInit(&skey[0],
-				ObjectIdAttributeNumber,
+				Anum_pg_opclass_oid,
 				BTEqualStrategyNumber, F_OIDEQ,
 				ObjectIdGetDatum(operatorClassOid));
 	rel = heap_open(OperatorClassRelationId, AccessShareLock);
@@ -1725,7 +1722,7 @@ LookupOpclassInfo(Oid operatorClassOid,
  */
 static void
 formrdesc(const char *relationName, Oid relationReltype,
-		  bool isshared, bool hasoids,
+		  bool isshared,
 		  int natts, const FormData_pg_attribute *attrs)
 {
 	Relation	relation;
@@ -1789,7 +1786,6 @@ formrdesc(const char *relationName, Oid relationReltype,
 	relation->rd_rel->reltuples = 0;
 	relation->rd_rel->relallvisible = 0;
 	relation->rd_rel->relkind = RELKIND_RELATION;
-	relation->rd_rel->relhasoids = hasoids;
 	relation->rd_rel->relnatts = (int16) natts;
 
 	/*
@@ -1799,7 +1795,7 @@ formrdesc(const char *relationName, Oid relationReltype,
 	 * because it will never be replaced.  The data comes from
 	 * src/include/catalog/ headers via genbki.pl.
 	 */
-	relation->rd_att = CreateTemplateTupleDesc(natts, hasoids);
+	relation->rd_att = CreateTemplateTupleDesc(natts);
 	relation->rd_att->tdrefcount = 1;	/* mark as refcounted */
 
 	relation->rd_att->tdtypeid = relationReltype;
@@ -2964,7 +2960,6 @@ AtEOXact_cleanup(Relation relation, bool isCommit)
 	{
 		list_free(relation->rd_indexlist);
 		relation->rd_indexlist = NIL;
-		relation->rd_oidindex = InvalidOid;
 		relation->rd_pkindex = InvalidOid;
 		relation->rd_replidindex = InvalidOid;
 		relation->rd_indexvalid = 0;
@@ -3077,7 +3072,6 @@ AtEOSubXact_cleanup(Relation relation, bool isCommit,
 	{
 		list_free(relation->rd_indexlist);
 		relation->rd_indexlist = NIL;
-		relation->rd_oidindex = InvalidOid;
 		relation->rd_pkindex = InvalidOid;
 		relation->rd_replidindex = InvalidOid;
 		relation->rd_indexvalid = 0;
@@ -3208,7 +3202,6 @@ RelationBuildLocalRelation(const char *relname,
 	rel->rd_rel->relnamespace = relnamespace;
 
 	rel->rd_rel->relkind = relkind;
-	rel->rd_rel->relhasoids = rel->rd_att->tdhasoid;
 	rel->rd_rel->relnatts = natts;
 	rel->rd_rel->reltype = InvalidOid;
 	/* needed when bootstrapping: */
@@ -3508,15 +3501,15 @@ RelationCacheInitializePhase2(void)
 	if (!load_relcache_init_file(true))
 	{
 		formrdesc("pg_database", DatabaseRelation_Rowtype_Id, true,
-				  true, Natts_pg_database, Desc_pg_database);
+				  Natts_pg_database, Desc_pg_database);
 		formrdesc("pg_authid", AuthIdRelation_Rowtype_Id, true,
-				  true, Natts_pg_authid, Desc_pg_authid);
+				  Natts_pg_authid, Desc_pg_authid);
 		formrdesc("pg_auth_members", AuthMemRelation_Rowtype_Id, true,
-				  false, Natts_pg_auth_members, Desc_pg_auth_members);
+				  Natts_pg_auth_members, Desc_pg_auth_members);
 		formrdesc("pg_shseclabel", SharedSecLabelRelation_Rowtype_Id, true,
-				  false, Natts_pg_shseclabel, Desc_pg_shseclabel);
+				  Natts_pg_shseclabel, Desc_pg_shseclabel);
 		formrdesc("pg_subscription", SubscriptionRelation_Rowtype_Id, true,
-				  true, Natts_pg_subscription, Desc_pg_subscription);
+				  Natts_pg_subscription, Desc_pg_subscription);
 
 #define NUM_CRITICAL_SHARED_RELS	5	/* fix if you change list above */
 	}
@@ -3567,13 +3560,13 @@ RelationCacheInitializePhase3(void)
 		needNewCacheFile = true;
 
 		formrdesc("pg_class", RelationRelation_Rowtype_Id, false,
-				  true, Natts_pg_class, Desc_pg_class);
+				  Natts_pg_class, Desc_pg_class);
 		formrdesc("pg_attribute", AttributeRelation_Rowtype_Id, false,
-				  false, Natts_pg_attribute, Desc_pg_attribute);
+				  Natts_pg_attribute, Desc_pg_attribute);
 		formrdesc("pg_proc", ProcedureRelation_Rowtype_Id, false,
-				  true, Natts_pg_proc, Desc_pg_proc);
+				  Natts_pg_proc, Desc_pg_proc);
 		formrdesc("pg_type", TypeRelation_Rowtype_Id, false,
-				  true, Natts_pg_type, Desc_pg_type);
+				  Natts_pg_type, Desc_pg_type);
 
 #define NUM_CRITICAL_LOCAL_RELS 4	/* fix if you change list above */
 	}
@@ -3725,7 +3718,6 @@ RelationCacheInitializePhase3(void)
 			 */
 			Assert(relation->rd_att->tdtypeid == relp->reltype);
 			Assert(relation->rd_att->tdtypmod == -1);
-			Assert(relation->rd_att->tdhasoid == relp->relhasoids);
 
 			ReleaseSysCache(htup);
 
@@ -3868,8 +3860,7 @@ load_critical_index(Oid indexoid, Oid heapoid)
  * extracting fields.
  */
 static TupleDesc
-BuildHardcodedDescriptor(int natts, const FormData_pg_attribute *attrs,
-						 bool hasoids)
+BuildHardcodedDescriptor(int natts, const FormData_pg_attribute *attrs)
 {
 	TupleDesc	result;
 	MemoryContext oldcxt;
@@ -3877,7 +3868,7 @@ BuildHardcodedDescriptor(int natts, const FormData_pg_attribute *attrs,
 
 	oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
 
-	result = CreateTemplateTupleDesc(natts, hasoids);
+	result = CreateTemplateTupleDesc(natts);
 	result->tdtypeid = RECORDOID;	/* not right, but we don't care */
 	result->tdtypmod = -1;
 
@@ -3906,8 +3897,7 @@ GetPgClassDescriptor(void)
 	/* Already done? */
 	if (pgclassdesc == NULL)
 		pgclassdesc = BuildHardcodedDescriptor(Natts_pg_class,
-											   Desc_pg_class,
-											   true);
+											   Desc_pg_class);
 
 	return pgclassdesc;
 }
@@ -3920,8 +3910,7 @@ GetPgIndexDescriptor(void)
 	/* Already done? */
 	if (pgindexdesc == NULL)
 		pgindexdesc = BuildHardcodedDescriptor(Natts_pg_index,
-											   Desc_pg_index,
-											   false);
+											   Desc_pg_index);
 
 	return pgindexdesc;
 }
@@ -4145,7 +4134,7 @@ RelationGetFKeyList(Relation relation)
 			continue;
 
 		info = makeNode(ForeignKeyCacheInfo);
-		info->conoid = HeapTupleGetOid(htup);
+		info->conoid = constraint->oid;
 		info->conrelid = constraint->conrelid;
 		info->confrelid = constraint->confrelid;
 
@@ -4248,11 +4237,6 @@ RelationGetFKeyList(Relation relation)
  * since the caller will typically be doing syscache lookups on the relevant
  * indexes, and syscache lookup could cause SI messages to be processed!
  *
- * We also update rd_oidindex, which this module treats as effectively part
- * of the index list.  rd_oidindex is valid when rd_indexvalid isn't zero;
- * it is the pg_class OID of a unique index on OID when the relation has one,
- * and InvalidOid if there is no such index.
- *
  * In exactly the same way, we update rd_pkindex, which is the OID of the
  * relation's primary key index if any, else InvalidOid; and rd_replidindex,
  * which is the pg_class OID of an index to be used as the relation's
@@ -4268,7 +4252,6 @@ RelationGetIndexList(Relation relation)
 	List	   *result;
 	List	   *oldlist;
 	char		replident = relation->rd_rel->relreplident;
-	Oid			oidIndex = InvalidOid;
 	Oid			pkeyIndex = InvalidOid;
 	Oid			candidateIndex = InvalidOid;
 	MemoryContext oldcxt;
@@ -4284,7 +4267,6 @@ RelationGetIndexList(Relation relation)
 	 * if we get some sort of error partway through.
 	 */
 	result = NIL;
-	oidIndex = InvalidOid;
 
 	/* Prepare to scan pg_index for entries having indrelid = this rel. */
 	ScanKeyInit(&skey,
@@ -4299,9 +4281,6 @@ RelationGetIndexList(Relation relation)
 	while (HeapTupleIsValid(htup = systable_getnext(indscan)))
 	{
 		Form_pg_index index = (Form_pg_index) GETSTRUCT(htup);
-		Datum		indclassDatum;
-		oidvector  *indclass;
-		bool		isnull;
 
 		/*
 		 * Ignore any indexes that are currently being dropped.  This will
@@ -4316,18 +4295,6 @@ RelationGetIndexList(Relation relation)
 		result = insert_ordered_oid(result, index->indexrelid);
 
 		/*
-		 * indclass cannot be referenced directly through the C struct,
-		 * because it comes after the variable-width indkey field.  Must
-		 * extract the datum the hard way...
-		 */
-		indclassDatum = heap_getattr(htup,
-									 Anum_pg_index_indclass,
-									 GetPgIndexDescriptor(),
-									 &isnull);
-		Assert(!isnull);
-		indclass = (oidvector *) DatumGetPointer(indclassDatum);
-
-		/*
 		 * Invalid, non-unique, non-immediate or predicate indexes aren't
 		 * interesting for either oid indexes or replication identity indexes,
 		 * so don't check them.
@@ -4337,12 +4304,6 @@ RelationGetIndexList(Relation relation)
 			!heap_attisnull(htup, Anum_pg_index_indpred, NULL))
 			continue;
 
-		/* Check to see if is a usable btree index on OID */
-		if (index->indnatts == 1 &&
-			index->indkey.values[0] == ObjectIdAttributeNumber &&
-			indclass->values[0] == OID_BTREE_OPS_OID)
-			oidIndex = index->indexrelid;
-
 		/* remember primary key index if any */
 		if (index->indisprimary)
 			pkeyIndex = index->indexrelid;
@@ -4360,7 +4321,6 @@ RelationGetIndexList(Relation relation)
 	oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
 	oldlist = relation->rd_indexlist;
 	relation->rd_indexlist = list_copy(result);
-	relation->rd_oidindex = oidIndex;
 	relation->rd_pkindex = pkeyIndex;
 	if (replident == REPLICA_IDENTITY_DEFAULT && OidIsValid(pkeyIndex))
 		relation->rd_replidindex = pkeyIndex;
@@ -4435,7 +4395,11 @@ RelationGetStatExtList(Relation relation)
 								 NULL, 1, &skey);
 
 	while (HeapTupleIsValid(htup = systable_getnext(indscan)))
-		result = insert_ordered_oid(result, HeapTupleGetOid(htup));
+	{
+		Oid oid = ((Form_pg_statistic_ext) GETSTRUCT(htup))->oid;
+
+		result = insert_ordered_oid(result, oid);
+	}
 
 	systable_endscan(indscan);
 
@@ -4510,7 +4474,7 @@ insert_ordered_oid(List *list, Oid datum)
  * touch rd_keyattr, rd_pkattr or rd_idattr.
  */
 void
-RelationSetIndexList(Relation relation, List *indexIds, Oid oidIndex)
+RelationSetIndexList(Relation relation, List *indexIds)
 {
 	MemoryContext oldcxt;
 
@@ -4522,7 +4486,6 @@ RelationSetIndexList(Relation relation, List *indexIds, Oid oidIndex)
 	/* Okay to replace old list */
 	list_free(relation->rd_indexlist);
 	relation->rd_indexlist = indexIds;
-	relation->rd_oidindex = oidIndex;
 
 	/*
 	 * For the moment, assume the target rel hasn't got a pk or replica index.
@@ -4536,34 +4499,6 @@ RelationSetIndexList(Relation relation, List *indexIds, Oid oidIndex)
 }
 
 /*
- * RelationGetOidIndex -- get the pg_class OID of the relation's OID index
- *
- * Returns InvalidOid if there is no such index.
- */
-Oid
-RelationGetOidIndex(Relation relation)
-{
-	List	   *ilist;
-
-	/*
-	 * If relation doesn't have OIDs at all, caller is probably confused. (We
-	 * could just silently return InvalidOid, but it seems better to throw an
-	 * assertion.)
-	 */
-	Assert(relation->rd_rel->relhasoids);
-
-	if (relation->rd_indexvalid == 0)
-	{
-		/* RelationGetIndexList does the heavy lifting. */
-		ilist = RelationGetIndexList(relation);
-		list_free(ilist);
-		Assert(relation->rd_indexvalid != 0);
-	}
-
-	return relation->rd_oidindex;
-}
-
-/*
  * RelationGetPrimaryKeyIndex -- get OID of the relation's primary key index
  *
  * Returns InvalidOid if there is no such index.
@@ -5472,8 +5407,7 @@ load_relcache_init_file(bool shared)
 		rel->rd_rel = relform;
 
 		/* initialize attribute tuple forms */
-		rel->rd_att = CreateTemplateTupleDesc(relform->relnatts,
-											  relform->relhasoids);
+		rel->rd_att = CreateTemplateTupleDesc(relform->relnatts);
 		rel->rd_att->tdrefcount = 1;	/* mark as refcounted */
 
 		rel->rd_att->tdtypeid = relform->reltype;
@@ -5677,7 +5611,6 @@ load_relcache_init_file(bool shared)
 		rel->rd_fkeylist = NIL;
 		rel->rd_fkeyvalid = false;
 		rel->rd_indexlist = NIL;
-		rel->rd_oidindex = InvalidOid;
 		rel->rd_pkindex = InvalidOid;
 		rel->rd_replidindex = InvalidOid;
 		rel->rd_indexattr = NULL;