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

9 files changed, 21 insertions, 21 deletions

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])
 		{