Code review for HeapTupleHeader changes. Add version number to page headers

(overlaying low byte of page size) and add HEAP_HASOID bit to t_infomask,
per earlier discussion.  Simplify scheme for overlaying fields in tuple
header (no need for cmax to live in more than one place).  Don't try to
clear infomask status bits in tqual.c --- not safe to do it there.  Don't
try to force output table of a SELECT INTO to have OIDs, either.  Get rid
of unnecessarily complex three-state scheme for TupleDesc.tdhasoids, which
has already caused one recent failure.  Improve documentation.

2 files changed, 23 insertions, 28 deletions

diff --git a/src/backend/access/common/heaptuple.c b/src/backend/access/common/heaptuple.c
index 5735da26d46..884db0ad21f 100644
--- a/src/backend/access/common/heaptuple.c
+++ b/src/backend/access/common/heaptuple.c
@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/access/common/heaptuple.c,v 1.80 2002/08/25 17:20:00 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/access/common/heaptuple.c,v 1.81 2002/09/02 01:05:03 tgl Exp $
  *
  * NOTES
  *	  The old interface functions have been converted to macros
@@ -80,7 +80,7 @@ DataFill(char *data,
 		bitmask = CSIGNBIT;
 	}
 
-	*infomask &= HEAP_XACT_MASK;
+	*infomask &= ~(HEAP_HASNULL | HEAP_HASVARWIDTH | HEAP_HASEXTENDED);
 
 	for (i = 0; i < numberOfAttributes; i++)
 	{
@@ -584,8 +584,6 @@ heap_formtuple(TupleDesc tupleDescriptor,
 		elog(ERROR, "heap_formtuple: numberOfAttributes %d exceeds limit %d",
 			 numberOfAttributes, MaxTupleAttributeNumber);
 
-	AssertTupleDescHasOidIsValid(tupleDescriptor);
-
 	for (i = 0; i < numberOfAttributes; i++)
 	{
 		if (nulls[i] != ' ')
@@ -600,7 +598,7 @@ heap_formtuple(TupleDesc tupleDescriptor,
 	if (hasnull)
 		len += BITMAPLEN(numberOfAttributes);
 
-	if (tupleDescriptor->tdhasoid == WITHOID)
+	if (tupleDescriptor->tdhasoid)
 		len += sizeof(Oid);
 
 	hoff = len = MAXALIGN(len); /* align user data safely */
@@ -626,6 +624,9 @@ heap_formtuple(TupleDesc tupleDescriptor,
 			 &td->t_infomask,
 			 (hasnull ? td->t_bits : NULL));
 
+	if (tupleDescriptor->tdhasoid)
+		td->t_infomask |= HEAP_HASOID;
+
 	td->t_infomask |= HEAP_XMAX_INVALID;
 
 	return tuple;
@@ -651,7 +652,6 @@ heap_modifytuple(HeapTuple tuple,
 	char	   *nulls;
 	bool		isNull;
 	HeapTuple	newTuple;
-	uint8		infomask;
 
 	/*
 	 * sanity checks
@@ -702,18 +702,10 @@ heap_modifytuple(HeapTuple tuple,
 							  nulls);
 
 	/*
-	 * copy the header except for t_len, t_natts, t_hoff, t_bits,
-	 * t_infomask
+	 * copy the identification info of the old tuple: t_ctid, t_self,
+	 * and OID (if any)
 	 */
-	infomask = newTuple->t_data->t_infomask;
-	/*
-	 * copy t_xmin, t_cid, t_xmax, t_ctid, t_natts, t_infomask
-	 */
-	memmove((char *) newTuple->t_data,	/* XXX */
-			(char *) tuple->t_data,
-			offsetof(HeapTupleHeaderData, t_hoff));	/* XXX */
-	newTuple->t_data->t_infomask = infomask;
-	newTuple->t_data->t_natts = numberOfAttributes;
+	newTuple->t_data->t_ctid = tuple->t_data->t_ctid;
 	newTuple->t_self = tuple->t_self;
 	newTuple->t_tableOid = tuple->t_tableOid;
 	if (relation->rd_rel->relhasoids)
@@ -776,11 +768,11 @@ heap_addheader(int natts,		/* max domain index */
 	tuple->t_datamcxt = CurrentMemoryContext;
 	tuple->t_data = td = (HeapTupleHeader) ((char *) tuple + HEAPTUPLESIZE);
 
-	MemSet((char *) td, 0, len);
+	MemSet((char *) td, 0, hoff);
 
 	td->t_hoff = hoff;
 	td->t_natts = natts;
-	td->t_infomask = HEAP_XMAX_INVALID; /* XXX sufficient? */
+	td->t_infomask = withoid ? (HEAP_XMAX_INVALID | HEAP_HASOID) : HEAP_XMAX_INVALID;
 
 	memcpy((char *) td + hoff, structure, structlen);
 
diff --git a/src/backend/access/common/tupdesc.c b/src/backend/access/common/tupdesc.c
index f90717aa12a..6d6cdf38ce8 100644
--- a/src/backend/access/common/tupdesc.c
+++ b/src/backend/access/common/tupdesc.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/access/common/tupdesc.c,v 1.87 2002/08/30 19:23:18 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/access/common/tupdesc.c,v 1.88 2002/09/02 01:05:03 tgl Exp $
  *
  * NOTES
  *	  some of the executor utility code such as "ExecTypeFromTL" should be
@@ -37,7 +37,7 @@
  * ----------------------------------------------------------------
  */
 TupleDesc
-CreateTemplateTupleDesc(int natts, hasoid_t withoid)
+CreateTemplateTupleDesc(int natts, bool hasoid)
 {
 	uint32		size;
 	TupleDesc	desc;
@@ -59,7 +59,7 @@ CreateTemplateTupleDesc(int natts, hasoid_t withoid)
 	MemSet(desc->attrs, 0, size);
 
 	desc->natts = natts;
-	desc->tdhasoid = withoid;
+	desc->tdhasoid = hasoid;
 
 	return desc;
 }
@@ -67,11 +67,12 @@ CreateTemplateTupleDesc(int natts, hasoid_t withoid)
 /* ----------------------------------------------------------------
  *		CreateTupleDesc
  *
- *		This function allocates a new TupleDesc from Form_pg_attribute array
+ *		This function allocates a new TupleDesc pointing to a given
+ *		Form_pg_attribute array
  * ----------------------------------------------------------------
  */
 TupleDesc
-CreateTupleDesc(int natts, Form_pg_attribute *attrs)
+CreateTupleDesc(int natts, bool hasoid, Form_pg_attribute *attrs)
 {
 	TupleDesc	desc;
 
@@ -84,7 +85,7 @@ CreateTupleDesc(int natts, Form_pg_attribute *attrs)
 	desc->attrs = attrs;
 	desc->natts = natts;
 	desc->constr = NULL;
-	desc->tdhasoid = UNDEFOID;
+	desc->tdhasoid = hasoid;
 
 	return desc;
 }
@@ -129,7 +130,6 @@ CreateTupleDescCopy(TupleDesc tupdesc)
  *
  *		This function creates a new TupleDesc by copying from an existing
  *		TupleDesc (with Constraints)
- *
  * ----------------------------------------------------------------
  */
 TupleDesc
@@ -477,6 +477,9 @@ TupleDescInitEntry(TupleDesc desc,
  * BuildDescForRelation
  *
  * Given a relation schema (list of ColumnDef nodes), build a TupleDesc.
+ *
+ * Note: the default assumption is no OIDs; caller may modify the returned
+ * TupleDesc if it wants OIDs.
  */
 TupleDesc
 BuildDescForRelation(List *schema)
@@ -497,7 +500,7 @@ BuildDescForRelation(List *schema)
 	 * allocate a new tuple descriptor
 	 */
 	natts = length(schema);
-	desc = CreateTemplateTupleDesc(natts, UNDEFOID);
+	desc = CreateTemplateTupleDesc(natts, false);
 	constr->has_not_null = false;
 
 	attnum = 0;
@@ -667,7 +670,7 @@ TypeGetTupleDesc(Oid typeoid, List *colaliases)
 		/* OK, get the column alias */
 		attname = strVal(lfirst(colaliases));
 
-		tupdesc = CreateTemplateTupleDesc(1, WITHOUTOID);
+		tupdesc = CreateTemplateTupleDesc(1, false);
 		TupleDescInitEntry(tupdesc,
 						   (AttrNumber) 1,
 						   attname,