Introduce CompactAttribute array in TupleDesc, take 2

The new compact_attrs array stores a few select fields from
FormData_pg_attribute in a more compact way, using only 16 bytes per
column instead of the 104 bytes that FormData_pg_attribute uses.  Using
CompactAttribute allows performance-critical operations such as tuple
deformation to be performed without looking at the FormData_pg_attribute
element in TupleDesc which means fewer cacheline accesses.

For some workloads, tuple deformation can be the most CPU intensive part
of processing the query.  Some testing with 16 columns on a table
where the first column is variable length showed around a 10% increase in
transactions per second for an OLAP type query performing aggregation on
the 16th column.  However, in certain cases, the increases were much
higher, up to ~25% on one AMD Zen4 machine.

This also makes pg_attribute.attcacheoff redundant.  A follow-on commit
will remove it, thus shrinking the FormData_pg_attribute struct by 4
bytes.

Author: David Rowley
Reviewed-by: Andres Freund, Victor Yegorov
Discussion: https://postgr.es/m/CAApHDvrBztXP3yx=NKNmo3xwFAFhEdyPnvrDg3=M0RhDs+4vYw@mail.gmail.com

35 files changed, 238 insertions, 128 deletions

diff --git a/src/backend/access/brin/brin_inclusion.c b/src/backend/access/brin/brin_inclusion.c
index 750276998c5..faec0a9da84 100644
--- a/src/backend/access/brin/brin_inclusion.c
+++ b/src/backend/access/brin/brin_inclusion.c
@@ -146,12 +146,12 @@ brin_inclusion_add_value(PG_FUNCTION_ARGS)
 	Datum		result;
 	bool		new = false;
 	AttrNumber	attno;
-	Form_pg_attribute attr;
+	CompactAttribute *attr;
 
 	Assert(!isnull);
 
 	attno = column->bv_attno;
-	attr = TupleDescAttr(bdesc->bd_tupdesc, attno - 1);
+	attr = TupleDescCompactAttr(bdesc->bd_tupdesc, attno - 1);
 
 	/*
 	 * If the recorded value is null, copy the new value (which we know to be
@@ -479,7 +479,7 @@ brin_inclusion_union(PG_FUNCTION_ARGS)
 	BrinValues *col_b = (BrinValues *) PG_GETARG_POINTER(2);
 	Oid			colloid = PG_GET_COLLATION();
 	AttrNumber	attno;
-	Form_pg_attribute attr;
+	CompactAttribute *attr;
 	FmgrInfo   *finfo;
 	Datum		result;
 
@@ -487,7 +487,7 @@ brin_inclusion_union(PG_FUNCTION_ARGS)
 	Assert(!col_a->bv_allnulls && !col_b->bv_allnulls);
 
 	attno = col_a->bv_attno;
-	attr = TupleDescAttr(bdesc->bd_tupdesc, attno - 1);
+	attr = TupleDescCompactAttr(bdesc->bd_tupdesc, attno - 1);
 
 	/* If B includes empty elements, mark A similarly, if needed. */
 	if (!DatumGetBool(col_a->bv_values[INCLUSION_CONTAINS_EMPTY]) &&
diff --git a/src/backend/access/brin/brin_tuple.c b/src/backend/access/brin/brin_tuple.c
index 997eb6d822c..aae646be5dd 100644
--- a/src/backend/access/brin/brin_tuple.c
+++ b/src/backend/access/brin/brin_tuple.c
@@ -699,7 +699,7 @@ brin_deconstruct_tuple(BrinDesc *brdesc,
 			 datumno < brdesc->bd_info[attnum]->oi_nstored;
 			 datumno++)
 		{
-			Form_pg_attribute thisatt = TupleDescAttr(diskdsc, stored);
+			CompactAttribute *thisatt = TupleDescCompactAttr(diskdsc, stored);
 
 			if (thisatt->attlen == -1)
 			{
diff --git a/src/backend/access/common/attmap.c b/src/backend/access/common/attmap.c
index b0fe27ef57d..0805c4121ee 100644
--- a/src/backend/access/common/attmap.c
+++ b/src/backend/access/common/attmap.c
@@ -135,7 +135,7 @@ build_attrmap_by_position(TupleDesc indesc,
 	/* Check for unused input columns */
 	for (; j < indesc->natts; j++)
 	{
-		if (TupleDescAttr(indesc, j)->attisdropped)
+		if (TupleDescCompactAttr(indesc, j)->attisdropped)
 			continue;
 		nincols++;
 		same = false;			/* we'll complain below */
@@ -299,8 +299,8 @@ check_attrmap_match(TupleDesc indesc,
 
 	for (i = 0; i < attrMap->maplen; i++)
 	{
-		Form_pg_attribute inatt = TupleDescAttr(indesc, i);
-		Form_pg_attribute outatt = TupleDescAttr(outdesc, i);
+		CompactAttribute *inatt = TupleDescCompactAttr(indesc, i);
+		CompactAttribute *outatt;
 
 		/*
 		 * If the input column has a missing attribute, we need a conversion.
@@ -311,6 +311,8 @@ check_attrmap_match(TupleDesc indesc,
 		if (attrMap->attnums[i] == (i + 1))
 			continue;
 
+		outatt = TupleDescCompactAttr(outdesc, i);
+
 		/*
 		 * If it's a dropped column and the corresponding input column is also
 		 * dropped, we don't need a conversion.  However, attlen and attalign
diff --git a/src/backend/access/common/heaptuple.c b/src/backend/access/common/heaptuple.c
index 9e3407bf987..982e7222c49 100644
--- a/src/backend/access/common/heaptuple.c
+++ b/src/backend/access/common/heaptuple.c
@@ -83,6 +83,10 @@
 #define VARLENA_ATT_IS_PACKABLE(att) \
 	((att)->attstorage != TYPSTORAGE_PLAIN)
 
+/* FormData_pg_attribute.attstorage != TYPSTORAGE_PLAIN and an attlen of -1 */
+#define COMPACT_ATTR_IS_PACKABLE(att) \
+	((att)->attlen == -1 && (att)->attispackable)
+
 /*
  * Setup for caching pass-by-ref missing attributes in a way that survives
  * tupleDesc destruction.
@@ -147,12 +151,12 @@ Datum
 getmissingattr(TupleDesc tupleDesc,
 			   int attnum, bool *isnull)
 {
-	Form_pg_attribute att;
+	CompactAttribute *att;
 
 	Assert(attnum <= tupleDesc->natts);
 	Assert(attnum > 0);
 
-	att = TupleDescAttr(tupleDesc, attnum - 1);
+	att = TupleDescCompactAttr(tupleDesc, attnum - 1);
 
 	if (att->atthasmissing)
 	{
@@ -223,15 +227,15 @@ heap_compute_data_size(TupleDesc tupleDesc,
 	for (i = 0; i < numberOfAttributes; i++)
 	{
 		Datum		val;
-		Form_pg_attribute atti;
+		CompactAttribute *atti;
 
 		if (isnull[i])
 			continue;
 
 		val = values[i];
-		atti = TupleDescAttr(tupleDesc, i);
+		atti = TupleDescCompactAttr(tupleDesc, i);
 
-		if (ATT_IS_PACKABLE(atti) &&
+		if (COMPACT_ATTR_IS_PACKABLE(atti) &&
 			VARATT_CAN_MAKE_SHORT(DatumGetPointer(val)))
 		{
 			/*
@@ -268,7 +272,7 @@ heap_compute_data_size(TupleDesc tupleDesc,
  * Fill in either a data value or a bit in the null bitmask
  */
 static inline void
-fill_val(Form_pg_attribute att,
+fill_val(CompactAttribute *att,
 		 bits8 **bit,
 		 int *bitmask,
 		 char **dataP,
@@ -349,8 +353,7 @@ fill_val(Form_pg_attribute att,
 			data_length = VARSIZE_SHORT(val);
 			memcpy(data, val, data_length);
 		}
-		else if (VARLENA_ATT_IS_PACKABLE(att) &&
-				 VARATT_CAN_MAKE_SHORT(val))
+		else if (att->attispackable && VARATT_CAN_MAKE_SHORT(val))
 		{
 			/* convert to short varlena -- no alignment */
 			data_length = VARATT_CONVERTED_SHORT_SIZE(val);
@@ -427,7 +430,7 @@ heap_fill_tuple(TupleDesc tupleDesc,
 
 	for (i = 0; i < numberOfAttributes; i++)
 	{
-		Form_pg_attribute attr = TupleDescAttr(tupleDesc, i);
+		CompactAttribute *attr = TupleDescCompactAttr(tupleDesc, i);
 
 		fill_val(attr,
 				 bitP ? &bitP : NULL,
@@ -461,7 +464,8 @@ heap_attisnull(HeapTuple tup, int attnum, TupleDesc tupleDesc)
 	Assert(!tupleDesc || attnum <= tupleDesc->natts);
 	if (attnum > (int) HeapTupleHeaderGetNatts(tup->t_data))
 	{
-		if (tupleDesc && TupleDescAttr(tupleDesc, attnum - 1)->atthasmissing)
+		if (tupleDesc &&
+			TupleDescCompactAttr(tupleDesc, attnum - 1)->atthasmissing)
 			return false;
 		else
 			return true;
@@ -570,13 +574,13 @@ nocachegetattr(HeapTuple tup,
 
 	if (!slow)
 	{
-		Form_pg_attribute att;
+		CompactAttribute *att;
 
 		/*
 		 * If we get here, there are no nulls up to and including the target
 		 * attribute.  If we have a cached offset, we can use it.
 		 */
-		att = TupleDescAttr(tupleDesc, attnum);
+		att = TupleDescCompactAttr(tupleDesc, attnum);
 		if (att->attcacheoff >= 0)
 			return fetchatt(att, tp + att->attcacheoff);
 
@@ -591,7 +595,7 @@ nocachegetattr(HeapTuple tup,
 
 			for (j = 0; j <= attnum; j++)
 			{
-				if (TupleDescAttr(tupleDesc, j)->attlen <= 0)
+				if (TupleDescCompactAttr(tupleDesc, j)->attlen <= 0)
 				{
 					slow = true;
 					break;
@@ -614,18 +618,18 @@ nocachegetattr(HeapTuple tup,
 		 * fixed-width columns, in hope of avoiding future visits to this
 		 * routine.
 		 */
-		TupleDescAttr(tupleDesc, 0)->attcacheoff = 0;
+		TupleDescCompactAttr(tupleDesc, 0)->attcacheoff = 0;
 
 		/* we might have set some offsets in the slow path previously */
-		while (j < natts && TupleDescAttr(tupleDesc, j)->attcacheoff > 0)
+		while (j < natts && TupleDescCompactAttr(tupleDesc, j)->attcacheoff > 0)
 			j++;
 
-		off = TupleDescAttr(tupleDesc, j - 1)->attcacheoff +
-			TupleDescAttr(tupleDesc, j - 1)->attlen;
+		off = TupleDescCompactAttr(tupleDesc, j - 1)->attcacheoff +
+			TupleDescCompactAttr(tupleDesc, j - 1)->attlen;
 
 		for (; j < natts; j++)
 		{
-			Form_pg_attribute att = TupleDescAttr(tupleDesc, j);
+			CompactAttribute *att = TupleDescCompactAttr(tupleDesc, j);
 
 			if (att->attlen <= 0)
 				break;
@@ -639,7 +643,7 @@ nocachegetattr(HeapTuple tup,
 
 		Assert(j > attnum);
 
-		off = TupleDescAttr(tupleDesc, attnum)->attcacheoff;
+		off = TupleDescCompactAttr(tupleDesc, attnum)->attcacheoff;
 	}
 	else
 	{
@@ -659,7 +663,7 @@ nocachegetattr(HeapTuple tup,
 		off = 0;
 		for (i = 0;; i++)		/* loop exit is at "break" */
 		{
-			Form_pg_attribute att = TupleDescAttr(tupleDesc, i);
+			CompactAttribute *att = TupleDescCompactAttr(tupleDesc, i);
 
 			if (HeapTupleHasNulls(tup) && att_isnull(i, bp))
 			{
@@ -707,7 +711,7 @@ nocachegetattr(HeapTuple tup,
 		}
 	}
 
-	return fetchatt(TupleDescAttr(tupleDesc, attnum), tp + off);
+	return fetchatt(TupleDescCompactAttr(tupleDesc, attnum), tp + off);
 }
 
 /* ----------------
@@ -892,7 +896,7 @@ expand_tuple(HeapTuple *targetHeapTuple,
 		{
 			if (attrmiss[attnum].am_present)
 			{
-				Form_pg_attribute att = TupleDescAttr(tupleDesc, attnum);
+				CompactAttribute *att = TupleDescCompactAttr(tupleDesc, attnum);
 
 				targetDataLen = att_align_datum(targetDataLen,
 												att->attalign,
@@ -1020,8 +1024,7 @@ expand_tuple(HeapTuple *targetHeapTuple,
 	/* Now fill in the missing values */
 	for (attnum = sourceNatts; attnum < natts; attnum++)
 	{
-
-		Form_pg_attribute attr = TupleDescAttr(tupleDesc, attnum);
+		CompactAttribute *attr = TupleDescCompactAttr(tupleDesc, attnum);
 
 		if (attrmiss && attrmiss[attnum].am_present)
 		{
@@ -1370,7 +1373,7 @@ heap_deform_tuple(HeapTuple tuple, TupleDesc tupleDesc,
 
 	for (attnum = 0; attnum < natts; attnum++)
 	{
-		Form_pg_attribute thisatt = TupleDescAttr(tupleDesc, attnum);
+		CompactAttribute *thisatt = TupleDescCompactAttr(tupleDesc, attnum);
 
 		if (hasnulls && att_isnull(attnum, bp))
 		{
diff --git a/src/backend/access/common/indextuple.c b/src/backend/access/common/indextuple.c
index bb2c6a2bcc1..38aeb230879 100644
--- a/src/backend/access/common/indextuple.c
+++ b/src/backend/access/common/indextuple.c
@@ -303,13 +303,13 @@ nocache_index_getattr(IndexTuple tup,
 
 	if (!slow)
 	{
-		Form_pg_attribute att;
+		CompactAttribute *att;
 
 		/*
 		 * If we get here, there are no nulls up to and including the target
 		 * attribute.  If we have a cached offset, we can use it.
 		 */
-		att = TupleDescAttr(tupleDesc, attnum);
+		att = TupleDescCompactAttr(tupleDesc, attnum);
 		if (att->attcacheoff >= 0)
 			return fetchatt(att, tp + att->attcacheoff);
 
@@ -324,7 +324,7 @@ nocache_index_getattr(IndexTuple tup,
 
 			for (j = 0; j <= attnum; j++)
 			{
-				if (TupleDescAttr(tupleDesc, j)->attlen <= 0)
+				if (TupleDescCompactAttr(tupleDesc, j)->attlen <= 0)
 				{
 					slow = true;
 					break;
@@ -347,18 +347,18 @@ nocache_index_getattr(IndexTuple tup,
 		 * fixed-width columns, in hope of avoiding future visits to this
 		 * routine.
 		 */
-		TupleDescAttr(tupleDesc, 0)->attcacheoff = 0;
+		TupleDescCompactAttr(tupleDesc, 0)->attcacheoff = 0;
 
 		/* we might have set some offsets in the slow path previously */
-		while (j < natts && TupleDescAttr(tupleDesc, j)->attcacheoff > 0)
+		while (j < natts && TupleDescCompactAttr(tupleDesc, j)->attcacheoff > 0)
 			j++;
 
-		off = TupleDescAttr(tupleDesc, j - 1)->attcacheoff +
-			TupleDescAttr(tupleDesc, j - 1)->attlen;
+		off = TupleDescCompactAttr(tupleDesc, j - 1)->attcacheoff +
+			TupleDescCompactAttr(tupleDesc, j - 1)->attlen;
 
 		for (; j < natts; j++)
 		{
-			Form_pg_attribute att = TupleDescAttr(tupleDesc, j);
+			CompactAttribute *att = TupleDescCompactAttr(tupleDesc, j);
 
 			if (att->attlen <= 0)
 				break;
@@ -372,7 +372,7 @@ nocache_index_getattr(IndexTuple tup,
 
 		Assert(j > attnum);
 
-		off = TupleDescAttr(tupleDesc, attnum)->attcacheoff;
+		off = TupleDescCompactAttr(tupleDesc, attnum)->attcacheoff;
 	}
 	else
 	{
@@ -392,7 +392,7 @@ nocache_index_getattr(IndexTuple tup,
 		off = 0;
 		for (i = 0;; i++)		/* loop exit is at "break" */
 		{
-			Form_pg_attribute att = TupleDescAttr(tupleDesc, i);
+			CompactAttribute *att = TupleDescCompactAttr(tupleDesc, i);
 
 			if (IndexTupleHasNulls(tup) && att_isnull(i, bp))
 			{
@@ -440,7 +440,7 @@ nocache_index_getattr(IndexTuple tup,
 		}
 	}
 
-	return fetchatt(TupleDescAttr(tupleDesc, attnum), tp + off);
+	return fetchatt(TupleDescCompactAttr(tupleDesc, attnum), tp + off);
 }
 
 /*
@@ -490,7 +490,7 @@ index_deform_tuple_internal(TupleDesc tupleDescriptor,
 
 	for (attnum = 0; attnum < natts; attnum++)
 	{
-		Form_pg_attribute thisatt = TupleDescAttr(tupleDescriptor, attnum);
+		CompactAttribute *thisatt = TupleDescCompactAttr(tupleDescriptor, attnum);
 
 		if (hasnulls && att_isnull(attnum, bp))
 		{
@@ -587,10 +587,8 @@ index_truncate_tuple(TupleDesc sourceDescriptor, IndexTuple source,
 	if (leavenatts == sourceDescriptor->natts)
 		return CopyIndexTuple(source);
 
-	/* Create temporary descriptor to scribble on */
-	truncdesc = palloc(TupleDescSize(sourceDescriptor));
-	TupleDescCopy(truncdesc, sourceDescriptor);
-	truncdesc->natts = leavenatts;
+	/* Create temporary truncated tuple descriptor */
+	truncdesc = CreateTupleDescTruncatedCopy(sourceDescriptor, leavenatts);
 
 	/* Deform, form copy of tuple with fewer attributes */
 	index_deform_tuple(source, truncdesc, values, isnull);
diff --git a/src/backend/access/common/tupdesc.c b/src/backend/access/common/tupdesc.c
index 47379fef220..4d89acbe5e2 100644
--- a/src/backend/access/common/tupdesc.c
+++ b/src/backend/access/common/tupdesc.c
@@ -57,6 +57,33 @@ ResourceOwnerForgetTupleDesc(ResourceOwner owner, TupleDesc tupdesc)
 }
 
 /*
+ * populate_compact_attribute
+ *		Fill in the corresponding CompactAttribute element from the
+ *		Form_pg_attribute for the given attribute number.  This must be called
+ *		whenever a change is made to a Form_pg_attribute in the TupleDesc.
+ */
+void
+populate_compact_attribute(TupleDesc tupdesc, int attnum)
+{
+	Form_pg_attribute src = TupleDescAttr(tupdesc, attnum);
+	CompactAttribute *dst = &tupdesc->compact_attrs[attnum];
+
+	memset(dst, 0, sizeof(CompactAttribute));
+
+	dst->attcacheoff = -1;
+	dst->attlen = src->attlen;
+
+	dst->attbyval = src->attbyval;
+	dst->attispackable = (src->attstorage != TYPSTORAGE_PLAIN);
+	dst->atthasmissing = src->atthasmissing;
+	dst->attisdropped = src->attisdropped;
+	dst->attgenerated = (src->attgenerated != '\0');
+	dst->attnotnull = src->attnotnull;
+
+	dst->attalign = src->attalign;
+}
+
+/*
  * CreateTemplateTupleDesc
  *		This function allocates an empty tuple descriptor structure.
  *
@@ -74,18 +101,20 @@ CreateTemplateTupleDesc(int natts)
 	Assert(natts >= 0);
 
 	/*
-	 * Allocate enough memory for the tuple descriptor, including the
-	 * attribute rows.
+	 * Allocate enough memory for the tuple descriptor, the CompactAttribute
+	 * array and also an array of FormData_pg_attribute.
 	 *
-	 * Note: the attribute array stride is sizeof(FormData_pg_attribute),
-	 * since we declare the array elements as FormData_pg_attribute for
-	 * notational convenience.  However, we only guarantee that the first
-	 * ATTRIBUTE_FIXED_PART_SIZE bytes of each entry are valid; most code that
-	 * copies tupdesc entries around copies just that much.  In principle that
-	 * could be less due to trailing padding, although with the current
-	 * definition of pg_attribute there probably isn't any padding.
+	 * Note: the FormData_pg_attribute array stride is
+	 * sizeof(FormData_pg_attribute), since we declare the array elements as
+	 * FormData_pg_attribute for notational convenience.  However, we only
+	 * guarantee that the first ATTRIBUTE_FIXED_PART_SIZE bytes of each entry
+	 * are valid; most code that copies tupdesc entries around copies just
+	 * that much.  In principle that could be less due to trailing padding,
+	 * although with the current definition of pg_attribute there probably
+	 * isn't any padding.
 	 */
-	desc = (TupleDesc) palloc(offsetof(struct TupleDescData, attrs) +
+	desc = (TupleDesc) palloc(offsetof(struct TupleDescData, compact_attrs) +
+							  natts * sizeof(CompactAttribute) +
 							  natts * sizeof(FormData_pg_attribute));
 
 	/*
@@ -117,8 +146,10 @@ CreateTupleDesc(int natts, Form_pg_attribute *attrs)
 	desc = CreateTemplateTupleDesc(natts);
 
 	for (i = 0; i < natts; ++i)
+	{
 		memcpy(TupleDescAttr(desc, i), attrs[i], ATTRIBUTE_FIXED_PART_SIZE);
-
+		populate_compact_attribute(desc, i);
+	}
 	return desc;
 }
 
@@ -155,6 +186,54 @@ CreateTupleDescCopy(TupleDesc tupdesc)
 		att->atthasmissing = false;
 		att->attidentity = '\0';
 		att->attgenerated = '\0';
+
+		populate_compact_attribute(desc, i);
+	}
+
+	/* We can copy the tuple type identification, too */
+	desc->tdtypeid = tupdesc->tdtypeid;
+	desc->tdtypmod = tupdesc->tdtypmod;
+
+	return desc;
+}
+
+/*
+ * CreateTupleDescTruncatedCopy
+ *		This function creates a new TupleDesc with only the first 'natts'
+ *		attributes from an existing TupleDesc
+ *
+ * !!! Constraints and defaults are not copied !!!
+ */
+TupleDesc
+CreateTupleDescTruncatedCopy(TupleDesc tupdesc, int natts)
+{
+	TupleDesc	desc;
+	int			i;
+
+	Assert(natts <= tupdesc->natts);
+
+	desc = CreateTemplateTupleDesc(natts);
+
+	/* Flat-copy the attribute array */
+	memcpy(TupleDescAttr(desc, 0),
+		   TupleDescAttr(tupdesc, 0),
+		   desc->natts * sizeof(FormData_pg_attribute));
+
+	/*
+	 * Since we're not copying constraints and defaults, clear fields
+	 * associated with them.
+	 */
+	for (i = 0; i < desc->natts; i++)
+	{
+		Form_pg_attribute att = TupleDescAttr(desc, i);
+
+		att->attnotnull = false;
+		att->atthasdef = false;
+		att->atthasmissing = false;
+		att->attidentity = '\0';
+		att->attgenerated = '\0';
+
+		populate_compact_attribute(desc, i);
 	}
 
 	/* We can copy the tuple type identification, too */
@@ -183,6 +262,9 @@ CreateTupleDescCopyConstr(TupleDesc tupdesc)
 		   TupleDescAttr(tupdesc, 0),
 		   desc->natts * sizeof(FormData_pg_attribute));
 
+	for (i = 0; i < desc->natts; i++)
+		populate_compact_attribute(desc, i);
+
 	/* Copy the TupleConstr data structure, if any */
 	if (constr)
 	{
@@ -207,7 +289,7 @@ CreateTupleDescCopyConstr(TupleDesc tupdesc)
 			{
 				if (constr->missing[i].am_present)
 				{
-					Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
+					CompactAttribute *attr = TupleDescCompactAttr(tupdesc, i);
 
 					cpy->missing[i].am_value = datumCopy(constr->missing[i].am_value,
 														 attr->attbyval,
@@ -252,7 +334,7 @@ TupleDescCopy(TupleDesc dst, TupleDesc src)
 {
 	int			i;
 
-	/* Flat-copy the header and attribute array */
+	/* Flat-copy the header and attribute arrays */
 	memcpy(dst, src, TupleDescSize(src));
 
 	/*
@@ -268,6 +350,8 @@ TupleDescCopy(TupleDesc dst, TupleDesc src)
 		att->atthasmissing = false;
 		att->attidentity = '\0';
 		att->attgenerated = '\0';
+
+		populate_compact_attribute(dst, i);
 	}
 	dst->constr = NULL;
 
@@ -322,6 +406,8 @@ TupleDescCopyEntry(TupleDesc dst, AttrNumber dstAttno,
 	dstAtt->atthasmissing = false;
 	dstAtt->attidentity = '\0';
 	dstAtt->attgenerated = '\0';
+
+	populate_compact_attribute(dst, dstAttno - 1);
 }
 
 /*
@@ -521,7 +607,7 @@ equalTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2)
 					return false;
 				if (missval1->am_present)
 				{
-					Form_pg_attribute missatt1 = TupleDescAttr(tupdesc1, i);
+					CompactAttribute *missatt1 = TupleDescCompactAttr(tupdesc1, i);
 
 					if (!datumIsEqual(missval1->am_value, missval2->am_value,
 									  missatt1->attbyval, missatt1->attlen))
@@ -714,6 +800,8 @@ TupleDescInitEntry(TupleDesc desc,
 	att->attcompression = InvalidCompressionMethod;
 	att->attcollation = typeForm->typcollation;
 
+	populate_compact_attribute(desc, attributeNumber - 1);
+
 	ReleaseSysCache(tuple);
 }
 
@@ -821,6 +909,8 @@ TupleDescInitBuiltinEntry(TupleDesc desc,
 		default:
 			elog(ERROR, "unsupported type %u", oidtypeid);
 	}
+
+	populate_compact_attribute(desc, attributeNumber - 1);
 }
 
 /*
diff --git a/src/backend/access/gin/ginbulk.c b/src/backend/access/gin/ginbulk.c
index f08b66ab791..d86b75bd639 100644
--- a/src/backend/access/gin/ginbulk.c
+++ b/src/backend/access/gin/ginbulk.c
@@ -127,10 +127,10 @@ ginInitBA(BuildAccumulator *accum)
 static Datum
 getDatumCopy(BuildAccumulator *accum, OffsetNumber attnum, Datum value)
 {
-	Form_pg_attribute att;
+	CompactAttribute *att;
 	Datum		res;
 
-	att = TupleDescAttr(accum->ginstate->origTupdesc, attnum - 1);
+	att = TupleDescCompactAttr(accum->ginstate->origTupdesc, attnum - 1);
 	if (att->attbyval)
 		res = value;
 	else
diff --git a/src/backend/access/gin/ginget.c b/src/backend/access/gin/ginget.c
index e8e0eab6552..c11ae0029c2 100644
--- a/src/backend/access/gin/ginget.c
+++ b/src/backend/access/gin/ginget.c
@@ -122,7 +122,7 @@ collectMatchBitmap(GinBtreeData *btree, GinBtreeStack *stack,
 				   GinScanEntry scanEntry, Snapshot snapshot)
 {
 	OffsetNumber attnum;
-	Form_pg_attribute attr;
+	CompactAttribute *attr;
 
 	/* Initialize empty bitmap result */
 	scanEntry->matchBitmap = tbm_create(work_mem * 1024L, NULL);
@@ -134,7 +134,7 @@ collectMatchBitmap(GinBtreeData *btree, GinBtreeStack *stack,
 
 	/* Locate tupdesc entry for key column (for attbyval/attlen data) */
 	attnum = scanEntry->attnum;
-	attr = TupleDescAttr(btree->ginstate->origTupdesc, attnum - 1);
+	attr = TupleDescCompactAttr(btree->ginstate->origTupdesc, attnum - 1);
 
 	/*
 	 * Predicate lock entry leaf page, following pages will be locked by
diff --git a/src/backend/access/gist/gist.c b/src/backend/access/gist/gist.c
index ebc65449c1b..272390ff67d 100644
--- a/src/backend/access/gist/gist.c
+++ b/src/backend/access/gist/gist.c
@@ -1557,9 +1557,8 @@ initGISTstate(Relation index)
 	 * tuples during page split.  Also, B-tree is not adjusting tuples on
 	 * internal pages the way GiST does.
 	 */
-	giststate->nonLeafTupdesc = CreateTupleDescCopyConstr(index->rd_att);
-	giststate->nonLeafTupdesc->natts =
-		IndexRelationGetNumberOfKeyAttributes(index);
+	giststate->nonLeafTupdesc = CreateTupleDescTruncatedCopy(index->rd_att,
+															 IndexRelationGetNumberOfKeyAttributes(index));
 
 	for (i = 0; i < IndexRelationGetNumberOfKeyAttributes(index); i++)
 	{
diff --git a/src/backend/access/gist/gistbuild.c b/src/backend/access/gist/gistbuild.c
index 63d1914b37f..3a2759b4468 100644
--- a/src/backend/access/gist/gistbuild.c
+++ b/src/backend/access/gist/gistbuild.c
@@ -657,10 +657,12 @@ gistInitBuffering(GISTBuildState *buildstate)
 	itupMinSize = (Size) MAXALIGN(sizeof(IndexTupleData));
 	for (i = 0; i < index->rd_att->natts; i++)
 	{
-		if (TupleDescAttr(index->rd_att, i)->attlen < 0)
+		CompactAttribute *attr = TupleDescCompactAttr(index->rd_att, i);
+
+		if (attr->attlen < 0)
 			itupMinSize += VARHDRSZ;
 		else
-			itupMinSize += TupleDescAttr(index->rd_att, i)->attlen;
+			itupMinSize += attr->attlen;
 	}
 
 	/* Calculate average and maximal number of index tuples which fit to page */
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index 6cdc68d981a..329e727f80d 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -4200,8 +4200,6 @@ static bool
 heap_attr_equals(TupleDesc tupdesc, int attrnum, Datum value1, Datum value2,
 				 bool isnull1, bool isnull2)
 {
-	Form_pg_attribute att;
-
 	/*
 	 * If one value is NULL and other is not, then they are certainly not
 	 * equal
@@ -4231,8 +4229,10 @@ heap_attr_equals(TupleDesc tupdesc, int attrnum, Datum value1, Datum value2,
 	}
 	else
 	{
+		CompactAttribute *att;
+
 		Assert(attrnum <= tupdesc->natts);
-		att = TupleDescAttr(tupdesc, attrnum - 1);
+		att = TupleDescCompactAttr(tupdesc, attrnum - 1);
 		return datumIsEqual(value1, value2, att->attbyval, att->attlen);
 	}
 }
@@ -4314,7 +4314,7 @@ HeapDetermineColumnsInfo(Relation relation,
 		 * that system attributes can't be stored externally.
 		 */
 		if (attrnum < 0 || isnull1 ||
-			TupleDescAttr(tupdesc, attrnum - 1)->attlen != -1)
+			TupleDescCompactAttr(tupdesc, attrnum - 1)->attlen != -1)
 			continue;
 
 		/*
diff --git a/src/backend/access/heap/heapam_handler.c b/src/backend/access/heap/heapam_handler.c
index 2da4e4da13e..9f17baea5d6 100644
--- a/src/backend/access/heap/heapam_handler.c
+++ b/src/backend/access/heap/heapam_handler.c
@@ -2550,7 +2550,7 @@ reform_and_rewrite_tuple(HeapTuple tuple,
 	/* Be sure to null out any dropped columns */
 	for (i = 0; i < newTupDesc->natts; i++)
 	{
-		if (TupleDescAttr(newTupDesc, i)->attisdropped)
+		if (TupleDescCompactAttr(newTupDesc, i)->attisdropped)
 			isnull[i] = true;
 	}
 
diff --git a/src/backend/access/heap/heaptoast.c b/src/backend/access/heap/heaptoast.c
index aae72bc2abf..eda81a35d50 100644
--- a/src/backend/access/heap/heaptoast.c
+++ b/src/backend/access/heap/heaptoast.c
@@ -369,7 +369,7 @@ toast_flatten_tuple(HeapTuple tup, TupleDesc tupleDesc)
 		/*
 		 * Look at non-null varlena attributes
 		 */
-		if (!toast_isnull[i] && TupleDescAttr(tupleDesc, i)->attlen == -1)
+		if (!toast_isnull[i] && TupleDescCompactAttr(tupleDesc, i)->attlen == -1)
 		{
 			struct varlena *new_value;
 
@@ -483,7 +483,7 @@ toast_flatten_tuple_to_datum(HeapTupleHeader tup,
 		 */
 		if (toast_isnull[i])
 			has_nulls = true;
-		else if (TupleDescAttr(tupleDesc, i)->attlen == -1)
+		else if (TupleDescCompactAttr(tupleDesc, i)->attlen == -1)
 		{
 			struct varlena *new_value;
 
@@ -584,7 +584,7 @@ toast_build_flattened_tuple(TupleDesc tupleDesc,
 		/*
 		 * Look at non-null varlena attributes
 		 */
-		if (!isnull[i] && TupleDescAttr(tupleDesc, i)->attlen == -1)
+		if (!isnull[i] && TupleDescCompactAttr(tupleDesc, i)->attlen == -1)
 		{
 			struct varlena *new_value;
 
diff --git a/src/backend/access/nbtree/nbtutils.c b/src/backend/access/nbtree/nbtutils.c
index afff7d63922..a531d37908a 100644
--- a/src/backend/access/nbtree/nbtutils.c
+++ b/src/backend/access/nbtree/nbtutils.c
@@ -4890,11 +4890,11 @@ _bt_keep_natts_fast(Relation rel, IndexTuple lastleft, IndexTuple firstright)
 					datum2;
 		bool		isNull1,
 					isNull2;
-		Form_pg_attribute att;
+		CompactAttribute *att;
 
 		datum1 = index_getattr(lastleft, attnum, itupdesc, &isNull1);
 		datum2 = index_getattr(firstright, attnum, itupdesc, &isNull2);
-		att = TupleDescAttr(itupdesc, attnum - 1);
+		att = TupleDescCompactAttr(itupdesc, attnum - 1);
 
 		if (isNull1 != isNull2)
 			break;
diff --git a/src/backend/access/spgist/spgdoinsert.c b/src/backend/access/spgist/spgdoinsert.c
index a4995c168b4..2cb7ce43ba1 100644
--- a/src/backend/access/spgist/spgdoinsert.c
+++ b/src/backend/access/spgist/spgdoinsert.c
@@ -1974,7 +1974,7 @@ spgdoinsert(Relation index, SpGistState *state,
 	{
 		if (!isnulls[i])
 		{
-			if (TupleDescAttr(leafDescriptor, i)->attlen == -1)
+			if (TupleDescCompactAttr(leafDescriptor, i)->attlen == -1)
 				leafDatums[i] = PointerGetDatum(PG_DETOAST_DATUM(datums[i]));
 			else
 				leafDatums[i] = datums[i];
diff --git a/src/backend/access/spgist/spgutils.c b/src/backend/access/spgist/spgutils.c
index e93d9869b27..da858182173 100644
--- a/src/backend/access/spgist/spgutils.c
+++ b/src/backend/access/spgist/spgutils.c
@@ -331,7 +331,9 @@ getSpGistTupleDesc(Relation index, SpGistTypeDesc *keyType)
 		att->attcollation = InvalidOid;
 		/* In case we changed typlen, we'd better reset following offsets */
 		for (int i = spgFirstIncludeColumn; i < outTupDesc->natts; i++)
-			TupleDescAttr(outTupDesc, i)->attcacheoff = -1;
+			TupleDescCompactAttr(outTupDesc, i)->attcacheoff = -1;
+
+		populate_compact_attribute(outTupDesc, spgKeyColumn);
 	}
 	return outTupDesc;
 }
diff --git a/src/backend/access/table/toast_helper.c b/src/backend/access/table/toast_helper.c
index 53224932f0d..b16fd21b8d0 100644
--- a/src/backend/access/table/toast_helper.c
+++ b/src/backend/access/table/toast_helper.c
@@ -324,7 +324,7 @@ toast_delete_external(Relation rel, const Datum *values, const bool *isnull,
 
 	for (i = 0; i < numAttrs; i++)
 	{
-		if (TupleDescAttr(tupleDesc, i)->attlen == -1)
+		if (TupleDescCompactAttr(tupleDesc, i)->attlen == -1)
 		{
 			Datum		value = values[i];
 
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 05dc6add7eb..6200a0da501 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -477,6 +477,8 @@ ConstructTupleDescriptor(Relation heapRelation,
 
 			ReleaseSysCache(tuple);
 		}
+
+		populate_compact_attribute(indexTupDesc, i);
 	}
 
 	pfree(amroutine);
diff --git a/src/backend/commands/copy.c b/src/backend/commands/copy.c
index 2d98ecf3f4e..edcdb7c2d40 100644
--- a/src/backend/commands/copy.c
+++ b/src/backend/commands/copy.c
@@ -954,9 +954,9 @@ CopyGetAttnums(TupleDesc tupDesc, Relation rel, List *attnamelist)
 
 		for (i = 0; i < attr_count; i++)
 		{
-			if (TupleDescAttr(tupDesc, i)->attisdropped)
-				continue;
-			if (TupleDescAttr(tupDesc, i)->attgenerated)
+			CompactAttribute *attr = TupleDescCompactAttr(tupDesc, i);
+
+			if (attr->attisdropped || attr->attgenerated)
 				continue;
 			attnums = lappend_int(attnums, i + 1);
 		}
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 6ccae4cb4a8..49374782625 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -980,6 +980,8 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 			cookedDefaults = lappend(cookedDefaults, cooked);
 			attr->atthasdef = true;
 		}
+
+		populate_compact_attribute(descriptor, attnum - 1);
 	}
 
 	/*
@@ -1396,6 +1398,8 @@ BuildDescForRelation(const List *columns)
 			att->attstorage = entry->storage;
 		else if (entry->storage_name)
 			att->attstorage = GetAttributeStorage(att->atttypid, entry->storage_name);
+
+		populate_compact_attribute(desc, attnum - 1);
 	}
 
 	return desc;
diff --git a/src/backend/executor/execExpr.c b/src/backend/executor/execExpr.c
index 81714341f07..3d01a90bd64 100644
--- a/src/backend/executor/execExpr.c
+++ b/src/backend/executor/execExpr.c
@@ -598,7 +598,7 @@ ExecBuildUpdateProjection(List *targetList,
 	 */
 	for (int attnum = relDesc->natts; attnum > 0; attnum--)
 	{
-		Form_pg_attribute attr = TupleDescAttr(relDesc, attnum - 1);
+		CompactAttribute *attr = TupleDescCompactAttr(relDesc, attnum - 1);
 
 		if (attr->attisdropped)
 			continue;
@@ -694,7 +694,7 @@ ExecBuildUpdateProjection(List *targetList,
 	 */
 	for (int attnum = 1; attnum <= relDesc->natts; attnum++)
 	{
-		Form_pg_attribute attr = TupleDescAttr(relDesc, attnum - 1);
+		CompactAttribute *attr = TupleDescCompactAttr(relDesc, attnum - 1);
 
 		if (attr->attisdropped)
 		{
diff --git a/src/backend/executor/execExprInterp.c b/src/backend/executor/execExprInterp.c
index 60dcbcbe596..56e13d20a87 100644
--- a/src/backend/executor/execExprInterp.c
+++ b/src/backend/executor/execExprInterp.c
@@ -3152,7 +3152,7 @@ ExecEvalRowNullInt(ExprState *state, ExprEvalStep *op,
 	for (int att = 1; att <= tupDesc->natts; att++)
 	{
 		/* ignore dropped columns */
-		if (TupleDescAttr(tupDesc, att - 1)->attisdropped)
+		if (TupleDescCompactAttr(tupDesc, att - 1)->attisdropped)
 			continue;
 		if (heap_attisnull(&tmptup, att, tupDesc))
 		{
@@ -5296,8 +5296,8 @@ ExecEvalWholeRowVar(ExprState *state, ExprEvalStep *op, ExprContext *econtext)
 
 		for (int i = 0; i < var_tupdesc->natts; i++)
 		{
-			Form_pg_attribute vattr = TupleDescAttr(var_tupdesc, i);
-			Form_pg_attribute sattr = TupleDescAttr(tupleDesc, i);
+			CompactAttribute *vattr = TupleDescCompactAttr(var_tupdesc, i);
+			CompactAttribute *sattr = TupleDescCompactAttr(tupleDesc, i);
 
 			if (!vattr->attisdropped)
 				continue;		/* already checked non-dropped cols */
diff --git a/src/backend/executor/execJunk.c b/src/backend/executor/execJunk.c
index b962c313834..7d0afca4181 100644
--- a/src/backend/executor/execJunk.c
+++ b/src/backend/executor/execJunk.c
@@ -169,7 +169,7 @@ ExecInitJunkFilterConversion(List *targetList,
 		t = list_head(targetList);
 		for (i = 0; i < cleanLength; i++)
 		{
-			if (TupleDescAttr(cleanTupType, i)->attisdropped)
+			if (TupleDescCompactAttr(cleanTupType, i)->attisdropped)
 				continue;		/* map entry is already zero */
 			for (;;)
 			{
diff --git a/src/backend/executor/execTuples.c b/src/backend/executor/execTuples.c
index 00dc3396156..875515777b6 100644
--- a/src/backend/executor/execTuples.c
+++ b/src/backend/executor/execTuples.c
@@ -187,7 +187,7 @@ tts_virtual_materialize(TupleTableSlot *slot)
 	/* compute size of memory required */
 	for (int natt = 0; natt < desc->natts; natt++)
 	{
-		Form_pg_attribute att = TupleDescAttr(desc, natt);
+		CompactAttribute *att = TupleDescCompactAttr(desc, natt);
 		Datum		val;
 
 		if (att->attbyval || slot->tts_isnull[natt])
@@ -223,7 +223,7 @@ tts_virtual_materialize(TupleTableSlot *slot)
 	/* and copy all attributes into the pre-allocated space */
 	for (int natt = 0; natt < desc->natts; natt++)
 	{
-		Form_pg_attribute att = TupleDescAttr(desc, natt);
+		CompactAttribute *att = TupleDescCompactAttr(desc, natt);
 		Datum		val;
 
 		if (att->attbyval || slot->tts_isnull[natt])
@@ -1044,7 +1044,7 @@ slot_deform_heap_tuple(TupleTableSlot *slot, HeapTuple tuple, uint32 *offp,
 
 	for (; attnum < natts; attnum++)
 	{
-		Form_pg_attribute thisatt = TupleDescAttr(tupleDesc, attnum);
+		CompactAttribute *thisatt = TupleDescCompactAttr(tupleDesc, attnum);
 
 		if (hasnulls && att_isnull(attnum, bp))
 		{
@@ -2237,7 +2237,7 @@ BuildTupleFromCStrings(AttInMetadata *attinmeta, char **values)
 	 */
 	for (i = 0; i < natts; i++)
 	{
-		if (!TupleDescAttr(tupdesc, i)->attisdropped)
+		if (!TupleDescCompactAttr(tupdesc, i)->attisdropped)
 		{
 			/* Non-dropped attributes */
 			dvalues[i] = InputFunctionCall(&attinmeta->attinfuncs[i],
diff --git a/src/backend/executor/functions.c b/src/backend/executor/functions.c
index 3b2f78b2197..3a2d51c5ad0 100644
--- a/src/backend/executor/functions.c
+++ b/src/backend/executor/functions.c
@@ -1886,7 +1886,7 @@ check_sql_fn_retval(List *queryTreeLists,
 		/* remaining columns in rettupdesc had better all be dropped */
 		for (colindex++; colindex <= tupnatts; colindex++)
 		{
-			if (!TupleDescAttr(rettupdesc, colindex - 1)->attisdropped)
+			if (!TupleDescCompactAttr(rettupdesc, colindex - 1)->attisdropped)
 				ereport(ERROR,
 						(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
 						 errmsg("return type mismatch in function declared to return %s",
diff --git a/src/backend/executor/nodeMemoize.c b/src/backend/executor/nodeMemoize.c
index df8e3fff082..aff3d9d921d 100644
--- a/src/backend/executor/nodeMemoize.c
+++ b/src/backend/executor/nodeMemoize.c
@@ -175,10 +175,10 @@ MemoizeHash_hash(struct memoize_hash *tb, const MemoizeKey *key)
 
 			if (!pslot->tts_isnull[i])	/* treat nulls as having hash key 0 */
 			{
-				Form_pg_attribute attr;
+				CompactAttribute *attr;
 				uint32		hkey;
 
-				attr = TupleDescAttr(pslot->tts_tupleDescriptor, i);
+				attr = TupleDescCompactAttr(pslot->tts_tupleDescriptor, i);
 
 				hkey = datum_image_hash(pslot->tts_values[i], attr->attbyval, attr->attlen);
 
@@ -242,7 +242,7 @@ MemoizeHash_equal(struct memoize_hash *tb, const MemoizeKey *key1,
 
 		for (int i = 0; i < numkeys; i++)
 		{
-			Form_pg_attribute attr;
+			CompactAttribute *attr;
 
 			if (tslot->tts_isnull[i] != pslot->tts_isnull[i])
 			{
@@ -255,7 +255,7 @@ MemoizeHash_equal(struct memoize_hash *tb, const MemoizeKey *key1,
 				continue;
 
 			/* perform binary comparison on the two datums */
-			attr = TupleDescAttr(tslot->tts_tupleDescriptor, i);
+			attr = TupleDescCompactAttr(tslot->tts_tupleDescriptor, i);
 			if (!datum_image_eq(tslot->tts_values[i], pslot->tts_values[i],
 								attr->attbyval, attr->attlen))
 			{
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index 1161520f76b..c445c433df4 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -496,14 +496,14 @@ ExecComputeStoredGenerated(ResultRelInfo *resultRelInfo,
 
 	for (int i = 0; i < natts; i++)
 	{
-		Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
+		CompactAttribute *attr = TupleDescCompactAttr(tupdesc, i);
 
 		if (ri_GeneratedExprs[i])
 		{
 			Datum		val;
 			bool		isnull;
 
-			Assert(attr->attgenerated == ATTRIBUTE_GENERATED_STORED);
+			Assert(TupleDescAttr(tupdesc, i)->attgenerated == ATTRIBUTE_GENERATED_STORED);
 
 			econtext->ecxt_scantuple = slot;
 
diff --git a/src/backend/executor/nodeValuesscan.c b/src/backend/executor/nodeValuesscan.c
index 92948917a08..9838977f08a 100644
--- a/src/backend/executor/nodeValuesscan.c
+++ b/src/backend/executor/nodeValuesscan.c
@@ -142,8 +142,8 @@ ValuesNext(ValuesScanState *node)
 		foreach(lc, exprstatelist)
 		{
 			ExprState  *estate = (ExprState *) lfirst(lc);
-			Form_pg_attribute attr = TupleDescAttr(slot->tts_tupleDescriptor,
-												   resind);
+			CompactAttribute *attr = TupleDescCompactAttr(slot->tts_tupleDescriptor,
+														  resind);
 
 			values[resind] = ExecEvalExpr(estate,
 										  econtext,
diff --git a/src/backend/executor/tstoreReceiver.c b/src/backend/executor/tstoreReceiver.c
index de4646b5c26..658d1724c83 100644
--- a/src/backend/executor/tstoreReceiver.c
+++ b/src/backend/executor/tstoreReceiver.c
@@ -65,7 +65,7 @@ tstoreStartupReceiver(DestReceiver *self, int operation, TupleDesc typeinfo)
 	{
 		for (i = 0; i < natts; i++)
 		{
-			Form_pg_attribute attr = TupleDescAttr(typeinfo, i);
+			CompactAttribute *attr = TupleDescCompactAttr(typeinfo, i);
 
 			if (attr->attisdropped)
 				continue;
@@ -154,7 +154,7 @@ tstoreReceiveSlot_detoast(TupleTableSlot *slot, DestReceiver *self)
 	for (i = 0; i < natts; i++)
 	{
 		Datum		val = slot->tts_values[i];
-		Form_pg_attribute attr = TupleDescAttr(typeinfo, i);
+		CompactAttribute *attr = TupleDescCompactAttr(typeinfo, i);
 
 		if (!attr->attisdropped && attr->attlen == -1 && !slot->tts_isnull[i])
 		{
diff --git a/src/backend/jit/llvm/llvmjit_deform.c b/src/backend/jit/llvm/llvmjit_deform.c
index b07f8e7f756..f49e7bce7d0 100644
--- a/src/backend/jit/llvm/llvmjit_deform.c
+++ b/src/backend/jit/llvm/llvmjit_deform.c
@@ -110,7 +110,7 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 	 */
 	for (attnum = 0; attnum < desc->natts; attnum++)
 	{
-		Form_pg_attribute att = TupleDescAttr(desc, attnum);
+		CompactAttribute *att = TupleDescCompactAttr(desc, attnum);
 
 		/*
 		 * If the column is declared NOT NULL then it must be present in every
@@ -393,7 +393,7 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 	 */
 	for (attnum = 0; attnum < natts; attnum++)
 	{
-		Form_pg_attribute att = TupleDescAttr(desc, attnum);
+		CompactAttribute *att = TupleDescCompactAttr(desc, attnum);
 		LLVMValueRef v_incby;
 		int			alignto;
 		LLVMValueRef l_attno = l_int16_const(lc, attnum);
diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c
index 153390f2dc9..c31cc3ee69f 100644
--- a/src/backend/optimizer/util/plancat.c
+++ b/src/backend/optimizer/util/plancat.c
@@ -175,12 +175,12 @@ get_relation_info(PlannerInfo *root, Oid relationObjectId, bool inhparent,
 	{
 		for (int i = 0; i < relation->rd_att->natts; i++)
 		{
-			Form_pg_attribute attr = TupleDescAttr(relation->rd_att, i);
+			CompactAttribute *attr = TupleDescCompactAttr(relation->rd_att, i);
 
 			if (attr->attnotnull)
 			{
 				rel->notnullattnums = bms_add_member(rel->notnullattnums,
-													 attr->attnum);
+													 i + 1);
 
 				/*
 				 * Per RemoveAttributeById(), dropped columns will have their
diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
index b50b3d62e3d..6db780d733c 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -1344,7 +1344,7 @@ pgoutput_row_filter(Relation relation, TupleTableSlot *old_slot,
 	 */
 	for (i = 0; i < desc->natts; i++)
 	{
-		Form_pg_attribute att = TupleDescAttr(desc, i);
+		CompactAttribute *att = TupleDescCompactAttr(desc, i);
 
 		/*
 		 * if the column in the new tuple or old tuple is null, nothing to do
diff --git a/src/backend/utils/adt/expandedrecord.c b/src/backend/utils/adt/expandedrecord.c
index d2842495b57..913c08b06e0 100644
--- a/src/backend/utils/adt/expandedrecord.c
+++ b/src/backend/utils/adt/expandedrecord.c
@@ -699,7 +699,7 @@ ER_get_flat_size(ExpandedObjectHeader *eohptr)
 	{
 		for (i = 0; i < erh->nfields; i++)
 		{
-			Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
+			CompactAttribute *attr = TupleDescCompactAttr(tupdesc, i);
 
 			if (!erh->dnulls[i] &&
 				!attr->attbyval && attr->attlen == -1 &&
@@ -1115,7 +1115,7 @@ expanded_record_set_field_internal(ExpandedRecordHeader *erh, int fnumber,
 								   bool check_constraints)
 {
 	TupleDesc	tupdesc;
-	Form_pg_attribute attr;
+	CompactAttribute *attr;
 	Datum	   *dvalues;
 	bool	   *dnulls;
 	char	   *oldValue;
@@ -1146,7 +1146,7 @@ expanded_record_set_field_internal(ExpandedRecordHeader *erh, int fnumber,
 	 * Copy new field value into record's context, and deal with detoasting,
 	 * if needed.
 	 */
-	attr = TupleDescAttr(tupdesc, fnumber - 1);
+	attr = TupleDescCompactAttr(tupdesc, fnumber - 1);
 	if (!isnull && !attr->attbyval)
 	{
 		MemoryContext oldcxt;
@@ -1279,7 +1279,7 @@ expanded_record_set_fields(ExpandedRecordHeader *erh,
 
 	for (fnumber = 0; fnumber < erh->nfields; fnumber++)
 	{
-		Form_pg_attribute attr = TupleDescAttr(tupdesc, fnumber);
+		CompactAttribute *attr = TupleDescCompactAttr(tupdesc, fnumber);
 		Datum		newValue;
 		bool		isnull;
 
@@ -1541,7 +1541,7 @@ check_domain_for_new_field(ExpandedRecordHeader *erh, int fnumber,
 	 */
 	if (!isnull)
 	{
-		Form_pg_attribute attr = TupleDescAttr(erh->er_tupdesc, fnumber - 1);
+		CompactAttribute *attr = TupleDescCompactAttr(erh->er_tupdesc, fnumber - 1);
 
 		if (!attr->attbyval && attr->attlen == -1 &&
 			VARATT_IS_EXTERNAL(DatumGetPointer(newValue)))
diff --git a/src/backend/utils/adt/ri_triggers.c b/src/backend/utils/adt/ri_triggers.c
index 3185f48afa6..093a3f1b66b 100644
--- a/src/backend/utils/adt/ri_triggers.c
+++ b/src/backend/utils/adt/ri_triggers.c
@@ -2932,7 +2932,7 @@ ri_KeysEqual(Relation rel, TupleTableSlot *oldslot, TupleTableSlot *newslot,
 			 * difference for ON UPDATE CASCADE, but for consistency we treat
 			 * all changes to the PK the same.
 			 */
-			Form_pg_attribute att = TupleDescAttr(oldslot->tts_tupleDescriptor, attnums[i] - 1);
+			CompactAttribute *att = TupleDescCompactAttr(oldslot->tts_tupleDescriptor, attnums[i] - 1);
 
 			if (!datum_image_eq(oldvalue, newvalue, att->attbyval, att->attlen))
 				return false;
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index 422509f18d7..5658e4accbd 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -585,6 +585,8 @@ RelationBuildTupleDesc(Relation relation)
 			   attp,
 			   ATTRIBUTE_FIXED_PART_SIZE);
 
+		populate_compact_attribute(relation->rd_att, attnum - 1);
+
 		/* Update constraint/default info */
 		if (attp->attnotnull)
 			constr->has_not_null = true;
@@ -661,8 +663,7 @@ RelationBuildTupleDesc(Relation relation)
 
 	/*
 	 * The attcacheoff values we read from pg_attribute should all be -1
-	 * ("unknown").  Verify this if assert checking is on.  They will be
-	 * computed when and if needed during tuple access.
+	 * ("unknown").  Verify this if assert checking is on.
 	 */
 #ifdef USE_ASSERT_CHECKING
 	{
@@ -674,12 +675,12 @@ RelationBuildTupleDesc(Relation relation)
 #endif
 
 	/*
-	 * However, we can easily set the attcacheoff value for the first
-	 * attribute: it must be zero.  This eliminates the need for special cases
-	 * for attnum=1 that used to exist in fastgetattr() and index_getattr().
+	 * We can easily set the attcacheoff value for the first attribute: it
+	 * must be zero.  This eliminates the need for special cases for attnum=1
+	 * that used to exist in fastgetattr() and index_getattr().
 	 */
 	if (RelationGetNumberOfAttributes(relation) > 0)
-		TupleDescAttr(relation->rd_att, 0)->attcacheoff = 0;
+		TupleDescCompactAttr(relation->rd_att, 0)->attcacheoff = 0;
 
 	/*
 	 * Set up constraint/default info
@@ -1965,10 +1966,12 @@ formrdesc(const char *relationName, Oid relationReltype,
 		has_not_null |= attrs[i].attnotnull;
 		/* make sure attcacheoff is valid */
 		TupleDescAttr(relation->rd_att, i)->attcacheoff = -1;
+
+		populate_compact_attribute(relation->rd_att, i);
 	}
 
 	/* initialize first attribute's attcacheoff, cf RelationBuildTupleDesc */
-	TupleDescAttr(relation->rd_att, 0)->attcacheoff = 0;
+	TupleDescCompactAttr(relation->rd_att, 0)->attcacheoff = 0;
 
 	/* mark not-null status */
 	if (has_not_null)
@@ -3579,6 +3582,7 @@ RelationBuildLocalRelation(const char *relname,
 		datt->attgenerated = satt->attgenerated;
 		datt->attnotnull = satt->attnotnull;
 		has_not_null |= satt->attnotnull;
+		populate_compact_attribute(rel->rd_att, i);
 	}
 
 	if (has_not_null)
@@ -4399,10 +4403,12 @@ BuildHardcodedDescriptor(int natts, const FormData_pg_attribute *attrs)
 		memcpy(TupleDescAttr(result, i), &attrs[i], ATTRIBUTE_FIXED_PART_SIZE);
 		/* make sure attcacheoff is valid */
 		TupleDescAttr(result, i)->attcacheoff = -1;
+
+		populate_compact_attribute(result, i);
 	}
 
 	/* initialize first attribute's attcacheoff, cf RelationBuildTupleDesc */
-	TupleDescAttr(result, 0)->attcacheoff = 0;
+	TupleDescCompactAttr(result, 0)->attcacheoff = 0;
 
 	/* Note: we don't bother to set up a TupleConstr entry */
 
@@ -6199,6 +6205,8 @@ load_relcache_init_file(bool shared)
 				goto read_failed;
 
 			has_not_null |= attr->attnotnull;
+
+			populate_compact_attribute(rel->rd_att, i);
 		}
 
 		/* next read the access method specific field */