Subject: Re: More speedups for tuple deformation

From: David Rowley <[email-masked]>
Date: Fri, 6 Mar 2026 17:09:41 +1300

One of my goals for proactively populating
CompactAttribute.attcacheoff is to make it so we're able to support
deforming only a subset of columns. If we only need a small number of
columns from the tuple and all those columns have a known attcacheoff
and no NULLs come prior, then we can quite efficiently just go to
those cached offsets and fetch only the attributes that we need.  To
do this, we'll need an extra array to store which attnums we're
interested in, rather than deforming all attrs up to the highest
attnum that we need, as we do today.  I expect that looking at this
new array will slow things down a bit when we're accessing either most
or all columns in, say, a SELECT * query. So, IMO, it'd be bad to
*replace* the current deforming code with code which does this.
Instead, I propose we add an additional deform operator and have some
heuristic which decides which one is best to use. I expect
ExecPushExprSetupSteps() could make that choice fairly easily. Perhaps
something cheap like bms_num_members(scan_attrs) is less than half the
bms_prev_member(scan_attrs, -1) (the highest member).

There's going to be many cases where the attcacheoff isn't known in
the attributes being selected. So that we still get some gains when
that's the case, I've coded it up so that we start walking the tuple
at the last attribute that has an attcacheoff. In many cases, that'll
mean we don't need to walk the entire tuple. Often, leading columns
are fixed-width, so this means that there's likely some benefit to
most cases. There might need to be a bit more education or
documentation about best column ordering practises.

There are a few hurdles to make this work, and one is the physical
tlist optimization. If the planner replaces the targetlist with a
physical tlist, the executor is going to think we need all columns,
which would have it likely choose not to do the selective deforming.
To make this work, I've added some code in createplan.c to extract the
attnums we need from the qual and tlist before the physical tlist is
installed. That's recorded in a Bitmapset and passed down to the
executor and to the code which sets up the ExprStates. Currently,
mostly to exercise this code as much as possible, I've coded it to
always do the selective deforming when the Bitmapset isn't empty. So
far, I've only done this for Seq Scan, but I expect all the scans that
deform tuples could use this.

I've attached the code which does all this in the 0006 patch.
Ideally, I'd have had this at least to the current state about 2-3
months ago, so I don't intend that 0006 is v19 material, but I wanted
to share to show where I intend this work to go.

Performance:

Using the t_1_40 table from the deform_test_setup.sh script I sent in
[1], running "select a from t_1_40 where a = 0;" ("a" is the 43rd
column in that table), on my Zen2 machine, I get the following from
perf top and pgbench:

master:
  75.57%  postgres   [.] tts_buffer_heap_getsomeattrs
   4.70%  postgres   [.] ExecInterpExpr
   2.85%  postgres   [.] ExecSeqScanWithQualProject
   1.94%  postgres   [.] heapgettup_pagemode
   1.21%  postgres   [.] UnlockBuffer
   1.15%  postgres   [.] slot_getsomeattrs_int

$ for i in {1..3}; do pgbench -n -f bench.sql -M prepared -T 10
postgres | grep latency; done
latency average = 154.175 ms
latency average = 156.780 ms
latency average = 157.599 ms

0001-0005:
  64.24%  postgres   [.] tts_buffer_heap_getsomeattrs
  15.01%  postgres   [.] ExecInterpExpr
   3.22%  postgres   [.] ExecSeqScanWithQualProject
   3.01%  postgres   [.] heapgettup_pagemode
   1.57%  postgres   [.] ExecStoreBufferHeapTuple
   1.53%  postgres   [.] heap_prepare_pagescan

$ for i in {1..3}; do pgbench -n -f bench.sql -M prepared -T 10
postgres | grep latency; done
latency average = 130.981 ms
latency average = 134.700 ms
latency average = 134.898 ms

0001-0006:
  42.28%  postgres          [.] heapgettup_pagemode
  11.38%  postgres          [.] ExecInterpExpr
   7.13%  postgres          [.] ExecSeqScanWithQualProject
   5.92%  postgres          [.] tts_buffer_heap_selectattrs <-- it's down here.
   5.69%  postgres          [.] ExecStoreBufferHeapTuple
   5.11%  postgres          [.] heap_getnextslot
   3.87%  postgres          [.] heap_prepare_pagescan

$ for i in {1..3}; do pgbench -n -f bench.sql -M prepared -T 10
postgres | grep latency; done
latency average = 71.689 ms
latency average = 75.638 ms
latency average = 75.149 ms

Keep in mind that this is one of the best cases as t_1_40 has no NULLs
and only has fixed-width columns. The only slightly better case would
be to add more columns and fetch only the final one. 40 doesn't seem
excessively unrealistic, to get an idea of the gains that someone
*could* see.

You can see that perf top report that tts_buffer_heap_getsomeattrs
dropped from taking 75.57% down to 64.24% with 0001-0005.  Adding 0006
sees that replaced with tts_buffer_heap_selectattrs which takes less
than 6% of the CPU time. It also highlights the next most interesting
thing we should probably make faster, heapgettup_pagemode().

I've attached v12 of the patch. There are a few changes in 0001-0005
that should help make things a bit faster than v11. I've also attached
the new selective deforming code in 0006. There's no JIT support for
0006 yet, I don't need to be told about that :-)

I'm planning on starting to go through 0002-0005 in much more detail
from mid next week with my committer hat on. If anyone wants to relook
at any of the 0002-0005 patches, there's still time. I'm also happy to
receive feedback on 0006, but I will address concerns with that at a
lower priority. One thing that's still left todo in the 0004 patch is
enable the TTS_FLAG_OBEYS_NOT_NULL_CONSTRAINTS optimisation for a few
other scan types.

Thanks for reading

David

[1] https://postgr.es/m/[email-masked]
From 27cf8d0007487d9dd22a7b6e0562e0399403dfef Mon Sep 17 00:00:00 2001
From: David Rowley <[email-masked]>
Date: Tue, 27 Jan 2026 15:08:09 +1300
Subject: [PATCH v12 1/6] Introduce deform_bench test module

For benchmarking tuple deformation.
---
 src/test/modules/deform_bench/.gitignore      |   4 +
 src/test/modules/deform_bench/Makefile        |  21 ++++
 .../deform_bench/deform_bench--1.0.sql        |   8 ++
 src/test/modules/deform_bench/deform_bench.c  | 107 ++++++++++++++++++
 .../modules/deform_bench/deform_bench.control |   4 +
 src/test/modules/deform_bench/meson.build     |  22 ++++
 src/test/modules/meson.build                  |   1 +
 7 files changed, 167 insertions(+)
 create mode 100644 src/test/modules/deform_bench/.gitignore
 create mode 100644 src/test/modules/deform_bench/Makefile
 create mode 100644 src/test/modules/deform_bench/deform_bench--1.0.sql
 create mode 100644 src/test/modules/deform_bench/deform_bench.c
 create mode 100644 src/test/modules/deform_bench/deform_bench.control
 create mode 100644 src/test/modules/deform_bench/meson.build

diff --git a/src/test/modules/deform_bench/.gitignore b/src/test/modules/deform_bench/.gitignore
new file mode 100644
index 00000000000..5dcb3ff9723
--- /dev/null
+++ b/src/test/modules/deform_bench/.gitignore
@@ -0,0 +1,4 @@
+# Generated subdirectories
+/log/
+/results/
+/tmp_check/
diff --git a/src/test/modules/deform_bench/Makefile b/src/test/modules/deform_bench/Makefile
new file mode 100644
index 00000000000..b5fc0f7a583
--- /dev/null
+++ b/src/test/modules/deform_bench/Makefile
@@ -0,0 +1,21 @@
+# src/test/modules/deform_bench/Makefile
+
+MODULE_big = deform_bench
+OBJS = deform_bench.o
+
+EXTENSION = deform_bench
+DATA = deform_bench--1.0.sql
+PGFILEDESC = "deform_bench - tuple deform benchmarking"
+
+REGRESS = deform_bench
+
+ifdef USE_PGXS
+PG_CONFIG = pg_config
+PGXS := $(shell $(PG_CONFIG) --pgxs)
+include $(PGXS)
+else
+subdir = src/test/modules/deform_bench
+top_builddir = ../..
+include $(top_builddir)/src/Makefile.global
+include $(top_srcdir)/contrib/contrib-global.mk
+endif
diff --git a/src/test/modules/deform_bench/deform_bench--1.0.sql b/src/test/modules/deform_bench/deform_bench--1.0.sql
new file mode 100644
index 00000000000..492b71dba3b
--- /dev/null
+++ b/src/test/modules/deform_bench/deform_bench--1.0.sql
@@ -0,0 +1,8 @@
+/* deform_bench--1.0.sql */
+
+-- complain if script is sourced in psql, rather than via CREATE EXTENSION
+\echo Use "CREATE EXTENSION deform_bench" to load this file. \quit
+
+CREATE FUNCTION deform_bench(tableoid Oid, attnum int[]) RETURNS FLOAT
+AS 'MODULE_PATHNAME', 'deform_bench'
+LANGUAGE C VOLATILE STRICT;
diff --git a/src/test/modules/deform_bench/deform_bench.c b/src/test/modules/deform_bench/deform_bench.c
new file mode 100644
index 00000000000..7838f639bef
--- /dev/null
+++ b/src/test/modules/deform_bench/deform_bench.c
@@ -0,0 +1,107 @@
+/*-------------------------------------------------------------------------
+ *
+ * deform_bench.c
+ *
+ * for benchmarking tuple deformation routines
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include <time.h>
+#include <sys/time.h>
+
+#include "access/heapam.h"
+#include "access/relscan.h"
+#include "catalog/pg_am_d.h"
+#include "catalog/pg_type_d.h"
+#include "funcapi.h"
+#include "miscadmin.h"
+#include "utils/array.h"
+#include "utils/arrayaccess.h"
+#include "utils/builtins.h"
+
+PG_MODULE_MAGIC;
+
+PG_FUNCTION_INFO_V1(deform_bench);
+
+Datum
+deform_bench(PG_FUNCTION_ARGS)
+{
+	Oid			tableoid = PG_GETARG_OID(0);
+	ArrayType  *array = PG_GETARG_ARRAYTYPE_P(1);
+	TableScanDesc scan;
+	Relation	rel;
+	TupleDesc	tupdesc;
+	TupleTableSlot *slot;
+	Datum	   *elem_datums = NULL;
+	bool	   *elem_nulls = NULL;
+	int			elem_count;
+	int		   *attnums;
+	clock_t		start,
+				end;
+
+	rel = relation_open(tableoid, AccessShareLock);
+
+	if (rel->rd_rel->relam != HEAP_TABLE_AM_OID)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("only heap AM is supported")));
+
+	tupdesc = RelationGetDescr(rel);
+	slot = MakeTupleTableSlot(tupdesc, &TTSOpsBufferHeapTuple);
+	scan = table_beginscan_strat(rel, GetActiveSnapshot(), 0, NULL, true, false);
+
+	/*
+	 * The array is used to allow callers to define how many atts to deform.
+	 * e.g: '{1,10}'::int[] would deform attnum=1, then in a 2nd pass deform
+	 * the remainder up to attnum=10.  Passing an element as NULL means all
+	 * attnums.  This allows simulation of incremental deformation.  Generally
+	 * if you're passing an array with more than 1 element, then the array
+	 * should be in ascending order.  Doing something like '{10,1}' would mean
+	 * we've already deformed 10 attributes and on the 2nd pass there's
+	 * nothing to do since attnum=1 was already deformed in the first pass.
+	 *
+	 * You'll get an ERROR if you pass a number higher than the number of
+	 * attributes in the table.
+	 */
+	deconstruct_array(array,
+					  INT4OID,
+					  sizeof(int32),
+					  true,
+					  'i',
+					  &elem_datums,
+					  &elem_nulls,
+					  &elem_count);
+
+	attnums = palloc_array(int, elem_count);
+
+	for (int i = 0; i < elem_count; i++)
+	{
+		/* Make a NULL element mean all attributes */
+		if (elem_nulls[i])
+			attnums[i] = tupdesc->natts;
+		else
+			attnums[i] = DatumGetInt32(elem_datums[i]);
+	}
+
+	start = clock();
+
+	while (heap_getnextslot(scan, ForwardScanDirection, slot))
+	{
+		CHECK_FOR_INTERRUPTS();
+
+		/* Deform in stages according to the attnums array */
+		for (int i = 0; i < elem_count; i++)
+			slot_getsomeattrs(slot, attnums[i]);
+	}
+
+	end = clock();
+
+	ExecDropSingleTupleTableSlot(slot);
+	table_endscan(scan);
+	relation_close(rel, AccessShareLock);
+
+
+	/* Returns the number of milliseconds to run the test */
+	PG_RETURN_FLOAT8((double) (end - start) / (CLOCKS_PER_SEC / 1000));
+}
diff --git a/src/test/modules/deform_bench/deform_bench.control b/src/test/modules/deform_bench/deform_bench.control
new file mode 100644
index 00000000000..a2023f9d738
--- /dev/null
+++ b/src/test/modules/deform_bench/deform_bench.control
@@ -0,0 +1,4 @@
+# deform_bench extension
+comment = 'functions for benchmarking tuple deformation'
+default_version = '1.0'
+module_pathname = '$libdir/deform_bench'
diff --git a/src/test/modules/deform_bench/meson.build b/src/test/modules/deform_bench/meson.build
new file mode 100644
index 00000000000..82049585244
--- /dev/null
+++ b/src/test/modules/deform_bench/meson.build
@@ -0,0 +1,22 @@
+# Copyright (c) 2026, PostgreSQL Global Development Group
+
+deform_bench_sources = files(
+  'deform_bench.c',
+)
+
+if host_system == 'windows'
+  deform_bench_sources += rc_lib_gen.process(win32ver_rc, extra_args: [
+    '--NAME', 'deform_bench',
+    '--FILEDESC', 'deform_bench - benchmarking tuple deformation',])
+endif
+
+deform_bench = shared_module('deform_bench',
+  deform_bench_sources,
+  kwargs: pg_test_mod_args,
+)
+test_install_libs += deform_bench
+
+test_install_data += files(
+  'deform_bench--1.0.sql',
+  'deform_bench.control',
+)
diff --git a/src/test/modules/meson.build b/src/test/modules/meson.build
index e2b3eef4136..1312f3b4d7b 100644
--- a/src/test/modules/meson.build
+++ b/src/test/modules/meson.build
@@ -2,6 +2,7 @@
 
 subdir('brin')
 subdir('commit_ts')
+subdir('deform_bench')
 subdir('delay_execution')
 subdir('dummy_index_am')
 subdir('dummy_seclabel')
-- 
2.51.0

From ceaf2c78facbc2e118152d419a2c7bcf72a63ad5 Mon Sep 17 00:00:00 2001
From: David Rowley <[email-masked]>
Date: Mon, 16 Feb 2026 14:20:19 +1300
Subject: [PATCH v12 2/6] Allow sibling call optimization in
 slot_getsomeattrs_int()

This changes the TupleTableSlotOps contract to make it so the
getsomeattrs() function is in charge of calling
slot_getmissingattrs().

Since this removes all code from slot_getsomeattrs_int() aside from the
getsomeattrs() call itself, we may as well adjust slot_getsomeattrs() so
that it calls getsomeattrs() directly.  We leave slot_getsomeattrs_int()
intact as this is still called from the JIT code.
---
 src/backend/executor/execTuples.c | 58 ++++++++++++++++---------------
 src/include/executor/tuptable.h   | 13 ++++---
 2 files changed, 38 insertions(+), 33 deletions(-)

diff --git a/src/backend/executor/execTuples.c b/src/backend/executor/execTuples.c
index b768eae9e53..7effe954286 100644
--- a/src/backend/executor/execTuples.c
+++ b/src/backend/executor/execTuples.c
@@ -73,7 +73,7 @@
 static TupleDesc ExecTypeFromTLInternal(List *targetList,
 										bool skipjunk);
 static pg_attribute_always_inline void slot_deform_heap_tuple(TupleTableSlot *slot, HeapTuple tuple, uint32 *offp,
-															  int natts);
+															  int reqnatts);
 static inline void tts_buffer_heap_store_tuple(TupleTableSlot *slot,
 											   HeapTuple tuple,
 											   Buffer buffer,
@@ -1108,7 +1108,10 @@ slot_deform_heap_tuple_internal(TupleTableSlot *slot, HeapTuple tuple,
  * slot_deform_heap_tuple
  *		Given a TupleTableSlot, extract data from the slot's physical tuple
  *		into its Datum/isnull arrays.  Data is extracted up through the
- *		natts'th column (caller must ensure this is a legal column number).
+ *		reqnatts'th column.  If there are insufficient attributes in the given
+ *		tuple, then slot_getmissingattrs() is called to populate the
+ *		remainder.  If reqnatts is above the number of attributes in the
+ *		slot's TupleDesc, an error is raised.
  *
  *		This is essentially an incremental version of heap_deform_tuple:
  *		on each call we extract attributes up to the one needed, without
@@ -1120,21 +1123,23 @@ slot_deform_heap_tuple_internal(TupleTableSlot *slot, HeapTuple tuple,
  */
 static pg_attribute_always_inline void
 slot_deform_heap_tuple(TupleTableSlot *slot, HeapTuple tuple, uint32 *offp,
-					   int natts)
+					   int reqnatts)
 {
 	bool		hasnulls = HeapTupleHasNulls(tuple);
 	int			attnum;
+	int			natts;
 	uint32		off;			/* offset in tuple data */
 	bool		slow;			/* can we use/set attcacheoff? */
 
 	/* We can only fetch as many attributes as the tuple has. */
-	natts = Min(HeapTupleHeaderGetNatts(tuple->t_data), natts);
+	natts = Min(HeapTupleHeaderGetNatts(tuple->t_data), reqnatts);
 
 	/*
 	 * Check whether the first call for this tuple, and initialize or restore
 	 * loop state.
 	 */
 	attnum = slot->tts_nvalid;
+	slot->tts_nvalid = reqnatts;
 	if (attnum == 0)
 	{
 		/* Start from the first attribute */
@@ -1199,12 +1204,15 @@ slot_deform_heap_tuple(TupleTableSlot *slot, HeapTuple tuple, uint32 *offp,
 	/*
 	 * Save state for next execution
 	 */
-	slot->tts_nvalid = attnum;
 	*offp = off;
 	if (slow)
 		slot->tts_flags |= TTS_FLAG_SLOW;
 	else
 		slot->tts_flags &= ~TTS_FLAG_SLOW;
+
+	/* Fetch any missing attrs and raise an error if reqnatts is invalid. */
+	if (unlikely(attnum < reqnatts))
+		slot_getmissingattrs(slot, attnum, reqnatts);
 }
 
 const TupleTableSlotOps TTSOpsVirtual = {
@@ -2058,34 +2066,36 @@ slot_getmissingattrs(TupleTableSlot *slot, int startAttNum, int lastAttNum)
 {
 	AttrMissing *attrmiss = NULL;
 
+	/* Check for invalid attnums */
+	if (unlikely(lastAttNum > slot->tts_tupleDescriptor->natts))
+		elog(ERROR, "invalid attribute number %d", lastAttNum);
+
 	if (slot->tts_tupleDescriptor->constr)
 		attrmiss = slot->tts_tupleDescriptor->constr->missing;
 
 	if (!attrmiss)
 	{
 		/* no missing values array at all, so just fill everything in as NULL */
-		memset(slot->tts_values + startAttNum, 0,
-			   (lastAttNum - startAttNum) * sizeof(Datum));
-		memset(slot->tts_isnull + startAttNum, 1,
-			   (lastAttNum - startAttNum) * sizeof(bool));
+		for (int attnum = startAttNum; attnum < lastAttNum; attnum++)
+		{
+			slot->tts_values[attnum] = (Datum) 0;
+			slot->tts_isnull[attnum] = true;
+		}
 	}
 	else
 	{
-		int			missattnum;
-
-		/* if there is a missing values array we must process them one by one */
-		for (missattnum = startAttNum;
-			 missattnum < lastAttNum;
-			 missattnum++)
+		/* use attrmiss to set the missing values */
+		for (int attnum = startAttNum; attnum < lastAttNum; attnum++)
 		{
-			slot->tts_values[missattnum] = attrmiss[missattnum].am_value;
-			slot->tts_isnull[missattnum] = !attrmiss[missattnum].am_present;
+			slot->tts_values[attnum] = attrmiss[attnum].am_value;
+			slot->tts_isnull[attnum] = !attrmiss[attnum].am_present;
 		}
 	}
 }
 
 /*
- * slot_getsomeattrs_int - workhorse for slot_getsomeattrs()
+ * slot_getsomeattrs_int
+ *		external function to call getsomeattrs() for use in JIT
  */
 void
 slot_getsomeattrs_int(TupleTableSlot *slot, int attnum)
@@ -2094,21 +2104,13 @@ slot_getsomeattrs_int(TupleTableSlot *slot, int attnum)
 	Assert(slot->tts_nvalid < attnum);	/* checked in slot_getsomeattrs */
 	Assert(attnum > 0);
 
-	if (unlikely(attnum > slot->tts_tupleDescriptor->natts))
-		elog(ERROR, "invalid attribute number %d", attnum);
-
 	/* Fetch as many attributes as possible from the underlying tuple. */
 	slot->tts_ops->getsomeattrs(slot, attnum);
 
 	/*
-	 * If the underlying tuple doesn't have enough attributes, tuple
-	 * descriptor must have the missing attributes.
+	 * Avoid putting new code here as that would prevent the compiler from
+	 * using the sibling call optimization for the above function.
 	 */
-	if (unlikely(slot->tts_nvalid < attnum))
-	{
-		slot_getmissingattrs(slot, slot->tts_nvalid, attnum);
-		slot->tts_nvalid = attnum;
-	}
 }
 
 /* ----------------------------------------------------------------
diff --git a/src/include/executor/tuptable.h b/src/include/executor/tuptable.h
index a2dfd707e78..3b09abbf99f 100644
--- a/src/include/executor/tuptable.h
+++ b/src/include/executor/tuptable.h
@@ -151,10 +151,12 @@ struct TupleTableSlotOps
 
 	/*
 	 * Fill up first natts entries of tts_values and tts_isnull arrays with
-	 * values from the tuple contained in the slot. The function may be called
-	 * with natts more than the number of attributes available in the tuple,
-	 * in which case it should set tts_nvalid to the number of returned
-	 * columns.
+	 * values from the tuple contained in the slot and set the slot's
+	 * tts_nvalid to natts. The function may be called with an natts value
+	 * more than the number of attributes available in the tuple, in which
+	 * case the function must call slot_getmissingattrs() to populate the
+	 * remaining attributes.  The function must raise an ERROR if 'natts' is
+	 * higher than the number of attributes in the slot's TupleDesc.
 	 */
 	void		(*getsomeattrs) (TupleTableSlot *slot, int natts);
 
@@ -357,8 +359,9 @@ extern void slot_getsomeattrs_int(TupleTableSlot *slot, int attnum);
 static inline void
 slot_getsomeattrs(TupleTableSlot *slot, int attnum)
 {
+	/* Populate slot with attributes up to 'attnum', if it's not already */
 	if (slot->tts_nvalid < attnum)
-		slot_getsomeattrs_int(slot, attnum);
+		slot->tts_ops->getsomeattrs(slot, attnum);
 }
 
 /*
-- 
2.51.0

From 00bc3ecefc20daef125c766fa9ca1d5e5af4d250 Mon Sep 17 00:00:00 2001
From: David Rowley <[email-masked]>
Date: Wed, 21 Jan 2026 15:41:37 +1300
Subject: [PATCH v12 3/6] Add empty TupleDescFinalize() function

Currently does nothing, but will in a future commit.
---
 contrib/dblink/dblink.c                             |  4 ++++
 contrib/pg_buffercache/pg_buffercache_pages.c       |  2 ++
 contrib/pg_visibility/pg_visibility.c               |  2 ++
 src/backend/access/brin/brin_tuple.c                |  1 +
 src/backend/access/common/tupdesc.c                 | 13 +++++++++++++
 src/backend/access/gin/ginutil.c                    |  1 +
 src/backend/access/gist/gistscan.c                  |  1 +
 src/backend/access/spgist/spgutils.c                |  1 +
 src/backend/access/transam/twophase.c               |  1 +
 src/backend/access/transam/xlogfuncs.c              |  1 +
 src/backend/backup/basebackup_copy.c                |  3 +++
 src/backend/catalog/index.c                         |  2 ++
 src/backend/catalog/pg_publication.c                |  1 +
 src/backend/catalog/toasting.c                      |  6 ++++++
 src/backend/commands/explain.c                      |  1 +
 src/backend/commands/functioncmds.c                 |  1 +
 src/backend/commands/sequence.c                     |  1 +
 src/backend/commands/tablecmds.c                    |  4 ++++
 src/backend/commands/wait.c                         |  1 +
 src/backend/executor/execSRF.c                      |  2 ++
 src/backend/executor/execTuples.c                   |  4 ++++
 src/backend/executor/nodeFunctionscan.c             |  2 ++
 src/backend/parser/parse_relation.c                 |  4 +++-
 src/backend/parser/parse_target.c                   |  2 ++
 .../replication/libpqwalreceiver/libpqwalreceiver.c |  1 +
 src/backend/replication/walsender.c                 |  5 +++++
 src/backend/utils/adt/acl.c                         |  1 +
 src/backend/utils/adt/genfile.c                     |  1 +
 src/backend/utils/adt/lockfuncs.c                   |  1 +
 src/backend/utils/adt/orderedsetaggs.c              |  1 +
 src/backend/utils/adt/pgstatfuncs.c                 |  5 +++++
 src/backend/utils/adt/tsvector_op.c                 |  1 +
 src/backend/utils/cache/relcache.c                  |  8 ++++++++
 src/backend/utils/fmgr/funcapi.c                    |  6 ++++++
 src/backend/utils/misc/guc_funcs.c                  |  5 +++++
 src/include/access/tupdesc.h                        |  1 +
 src/pl/plpgsql/src/pl_comp.c                        |  2 ++
 .../test_custom_stats/test_custom_fixed_stats.c     |  1 +
 src/test/modules/test_predtest/test_predtest.c      |  1 +
 39 files changed, 100 insertions(+), 1 deletion(-)

diff --git a/contrib/dblink/dblink.c b/contrib/dblink/dblink.c
index 2498d80c8e7..4038950a6ef 100644
--- a/contrib/dblink/dblink.c
+++ b/contrib/dblink/dblink.c
@@ -881,6 +881,7 @@ materializeResult(FunctionCallInfo fcinfo, PGconn *conn, PGresult *res)
 		tupdesc = CreateTemplateTupleDesc(1);
 		TupleDescInitEntry(tupdesc, (AttrNumber) 1, "status",
 						   TEXTOID, -1, 0);
+		TupleDescFinalize(tupdesc);
 		ntuples = 1;
 		nfields = 1;
 	}
@@ -1044,6 +1045,7 @@ materializeQueryResult(FunctionCallInfo fcinfo,
 			tupdesc = CreateTemplateTupleDesc(1);
 			TupleDescInitEntry(tupdesc, (AttrNumber) 1, "status",
 							   TEXTOID, -1, 0);
+			TupleDescFinalize(tupdesc);
 			attinmeta = TupleDescGetAttInMetadata(tupdesc);
 
 			oldcontext = MemoryContextSwitchTo(rsinfo->econtext->ecxt_per_query_memory);
@@ -1529,6 +1531,8 @@ dblink_get_pkey(PG_FUNCTION_ARGS)
 		TupleDescInitEntry(tupdesc, (AttrNumber) 2, "colname",
 						   TEXTOID, -1, 0);
 
+		TupleDescFinalize(tupdesc);
+
 		/*
 		 * Generate attribute metadata needed later to produce tuples from raw
 		 * C strings
diff --git a/contrib/pg_buffercache/pg_buffercache_pages.c b/contrib/pg_buffercache/pg_buffercache_pages.c
index 89b86855243..a6b4fb5252b 100644
--- a/contrib/pg_buffercache/pg_buffercache_pages.c
+++ b/contrib/pg_buffercache/pg_buffercache_pages.c
@@ -174,6 +174,7 @@ pg_buffercache_pages(PG_FUNCTION_ARGS)
 			TupleDescInitEntry(tupledesc, (AttrNumber) 9, "pinning_backends",
 							   INT4OID, -1, 0);
 
+		TupleDescFinalize(tupledesc);
 		fctx->tupdesc = BlessTupleDesc(tupledesc);
 
 		/* Allocate NBuffers worth of BufferCachePagesRec records. */
@@ -442,6 +443,7 @@ pg_buffercache_os_pages_internal(FunctionCallInfo fcinfo, bool include_numa)
 		TupleDescInitEntry(tupledesc, (AttrNumber) 3, "numa_node",
 						   INT4OID, -1, 0);
 
+		TupleDescFinalize(tupledesc);
 		fctx->tupdesc = BlessTupleDesc(tupledesc);
 		fctx->include_numa = include_numa;
 
diff --git a/contrib/pg_visibility/pg_visibility.c b/contrib/pg_visibility/pg_visibility.c
index 9bc3a784bf7..dfab0b64cf5 100644
--- a/contrib/pg_visibility/pg_visibility.c
+++ b/contrib/pg_visibility/pg_visibility.c
@@ -469,6 +469,8 @@ pg_visibility_tupdesc(bool include_blkno, bool include_pd)
 		TupleDescInitEntry(tupdesc, ++a, "pd_all_visible", BOOLOID, -1, 0);
 	Assert(a == maxattr);
 
+	TupleDescFinalize(tupdesc);
+
 	return BlessTupleDesc(tupdesc);
 }
 
diff --git a/src/backend/access/brin/brin_tuple.c b/src/backend/access/brin/brin_tuple.c
index 69c233c62eb..742ac089a28 100644
--- a/src/backend/access/brin/brin_tuple.c
+++ b/src/backend/access/brin/brin_tuple.c
@@ -84,6 +84,7 @@ brtuple_disk_tupdesc(BrinDesc *brdesc)
 
 		MemoryContextSwitchTo(oldcxt);
 
+		TupleDescFinalize(tupdesc);
 		brdesc->bd_disktdesc = tupdesc;
 	}
 
diff --git a/src/backend/access/common/tupdesc.c b/src/backend/access/common/tupdesc.c
index b69d10f0a45..2137385a833 100644
--- a/src/backend/access/common/tupdesc.c
+++ b/src/backend/access/common/tupdesc.c
@@ -221,6 +221,9 @@ CreateTupleDesc(int natts, Form_pg_attribute *attrs)
 		memcpy(TupleDescAttr(desc, i), attrs[i], ATTRIBUTE_FIXED_PART_SIZE);
 		populate_compact_attribute(desc, i);
 	}
+
+	TupleDescFinalize(desc);
+
 	return desc;
 }
 
@@ -265,6 +268,8 @@ CreateTupleDescCopy(TupleDesc tupdesc)
 	desc->tdtypeid = tupdesc->tdtypeid;
 	desc->tdtypmod = tupdesc->tdtypmod;
 
+	TupleDescFinalize(desc);
+
 	return desc;
 }
 
@@ -311,6 +316,8 @@ CreateTupleDescTruncatedCopy(TupleDesc tupdesc, int natts)
 	desc->tdtypeid = tupdesc->tdtypeid;
 	desc->tdtypmod = tupdesc->tdtypmod;
 
+	TupleDescFinalize(desc);
+
 	return desc;
 }
 
@@ -396,6 +403,8 @@ CreateTupleDescCopyConstr(TupleDesc tupdesc)
 	desc->tdtypeid = tupdesc->tdtypeid;
 	desc->tdtypmod = tupdesc->tdtypmod;
 
+	TupleDescFinalize(desc);
+
 	return desc;
 }
 
@@ -438,6 +447,8 @@ TupleDescCopy(TupleDesc dst, TupleDesc src)
 	 * source's refcount would be wrong in any case.)
 	 */
 	dst->tdrefcount = -1;
+
+	TupleDescFinalize(dst);
 }
 
 /*
@@ -1065,6 +1076,8 @@ BuildDescFromLists(const List *names, const List *types, const List *typmods, co
 		TupleDescInitEntryCollation(desc, attnum, attcollation);
 	}
 
+	TupleDescFinalize(desc);
+
 	return desc;
 }
 
diff --git a/src/backend/access/gin/ginutil.c b/src/backend/access/gin/ginutil.c
index ff927279cc3..fe7b984ff32 100644
--- a/src/backend/access/gin/ginutil.c
+++ b/src/backend/access/gin/ginutil.c
@@ -129,6 +129,7 @@ initGinState(GinState *state, Relation index)
 							   attr->attndims);
 			TupleDescInitEntryCollation(state->tupdesc[i], (AttrNumber) 2,
 										attr->attcollation);
+			TupleDescFinalize(state->tupdesc[i]);
 		}
 
 		/*
diff --git a/src/backend/access/gist/gistscan.c b/src/backend/access/gist/gistscan.c
index f23bc4a6757..c65f93abdae 100644
--- a/src/backend/access/gist/gistscan.c
+++ b/src/backend/access/gist/gistscan.c
@@ -201,6 +201,7 @@ gistrescan(IndexScanDesc scan, ScanKey key, int nkeys,
 											 attno - 1)->atttypid,
 							   -1, 0);
 		}
+		TupleDescFinalize(so->giststate->fetchTupdesc);
 		scan->xs_hitupdesc = so->giststate->fetchTupdesc;
 
 		/* Also create a memory context that will hold the returned tuples */
diff --git a/src/backend/access/spgist/spgutils.c b/src/backend/access/spgist/spgutils.c
index 9f5379b87ac..b246e8127db 100644
--- a/src/backend/access/spgist/spgutils.c
+++ b/src/backend/access/spgist/spgutils.c
@@ -340,6 +340,7 @@ getSpGistTupleDesc(Relation index, SpGistTypeDesc *keyType)
 			TupleDescCompactAttr(outTupDesc, i)->attcacheoff = -1;
 
 		populate_compact_attribute(outTupDesc, spgKeyColumn);
+		TupleDescFinalize(outTupDesc);
 	}
 	return outTupDesc;
 }
diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c
index 5f65fa7b80f..0281b58f40c 100644
--- a/src/backend/access/transam/twophase.c
+++ b/src/backend/access/transam/twophase.c
@@ -744,6 +744,7 @@ pg_prepared_xact(PG_FUNCTION_ARGS)
 		TupleDescInitEntry(tupdesc, (AttrNumber) 5, "dbid",
 						   OIDOID, -1, 0);
 
+		TupleDescFinalize(tupdesc);
 		funcctx->tuple_desc = BlessTupleDesc(tupdesc);
 
 		/*
diff --git a/src/backend/access/transam/xlogfuncs.c b/src/backend/access/transam/xlogfuncs.c
index 78543055895..be4cc24f1db 100644
--- a/src/backend/access/transam/xlogfuncs.c
+++ b/src/backend/access/transam/xlogfuncs.c
@@ -427,6 +427,7 @@ pg_walfile_name_offset(PG_FUNCTION_ARGS)
 	TupleDescInitEntry(resultTupleDesc, (AttrNumber) 2, "file_offset",
 					   INT4OID, -1, 0);
 
+	TupleDescFinalize(resultTupleDesc);
 	resultTupleDesc = BlessTupleDesc(resultTupleDesc);
 
 	/*
diff --git a/src/backend/backup/basebackup_copy.c b/src/backend/backup/basebackup_copy.c
index 07f58b39d8c..6c3453efd80 100644
--- a/src/backend/backup/basebackup_copy.c
+++ b/src/backend/backup/basebackup_copy.c
@@ -357,6 +357,8 @@ SendXlogRecPtrResult(XLogRecPtr ptr, TimeLineID tli)
 	 */
 	TupleDescInitBuiltinEntry(tupdesc, (AttrNumber) 2, "tli", INT8OID, -1, 0);
 
+	TupleDescFinalize(tupdesc);
+
 	/* send RowDescription */
 	tstate = begin_tup_output_tupdesc(dest, tupdesc, &TTSOpsVirtual);
 
@@ -388,6 +390,7 @@ SendTablespaceList(List *tablespaces)
 	TupleDescInitBuiltinEntry(tupdesc, (AttrNumber) 1, "spcoid", OIDOID, -1, 0);
 	TupleDescInitBuiltinEntry(tupdesc, (AttrNumber) 2, "spclocation", TEXTOID, -1, 0);
 	TupleDescInitBuiltinEntry(tupdesc, (AttrNumber) 3, "size", INT8OID, -1, 0);
+	TupleDescFinalize(tupdesc);
 
 	/* send RowDescription */
 	tstate = begin_tup_output_tupdesc(dest, tupdesc, &TTSOpsVirtual);
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 43de42ce39e..75e97fb394a 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -481,6 +481,8 @@ ConstructTupleDescriptor(Relation heapRelation,
 		populate_compact_attribute(indexTupDesc, i);
 	}
 
+	TupleDescFinalize(indexTupDesc);
+
 	return indexTupDesc;
 }
 
diff --git a/src/backend/catalog/pg_publication.c b/src/backend/catalog/pg_publication.c
index aadc7c202c6..a79157c43bf 100644
--- a/src/backend/catalog/pg_publication.c
+++ b/src/backend/catalog/pg_publication.c
@@ -1322,6 +1322,7 @@ pg_get_publication_tables(PG_FUNCTION_ARGS)
 		TupleDescInitEntry(tupdesc, (AttrNumber) 4, "qual",
 						   PG_NODE_TREEOID, -1, 0);
 
+		TupleDescFinalize(tupdesc);
 		funcctx->tuple_desc = BlessTupleDesc(tupdesc);
 		funcctx->user_fctx = table_infos;
 
diff --git a/src/backend/catalog/toasting.c b/src/backend/catalog/toasting.c
index c78dcea98c1..078a1cf5127 100644
--- a/src/backend/catalog/toasting.c
+++ b/src/backend/catalog/toasting.c
@@ -229,6 +229,12 @@ create_toast_table(Relation rel, Oid toastOid, Oid toastIndexOid,
 	TupleDescAttr(tupdesc, 1)->attcompression = InvalidCompressionMethod;
 	TupleDescAttr(tupdesc, 2)->attcompression = InvalidCompressionMethod;
 
+	populate_compact_attribute(tupdesc, 0);
+	populate_compact_attribute(tupdesc, 1);
+	populate_compact_attribute(tupdesc, 2);
+
+	TupleDescFinalize(tupdesc);
+
 	/*
 	 * Toast tables for regular relations go in pg_toast; those for temp
 	 * relations go into the per-backend temp-toast-table namespace.
diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index 93918a223b8..5f922c3f5c2 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -281,6 +281,7 @@ ExplainResultDesc(ExplainStmt *stmt)
 	tupdesc = CreateTemplateTupleDesc(1);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 1, "QUERY PLAN",
 					   result_type, -1, 0);
+	TupleDescFinalize(tupdesc);
 	return tupdesc;
 }
 
diff --git a/src/backend/commands/functioncmds.c b/src/backend/commands/functioncmds.c
index 242372b1e68..3afd762e9dc 100644
--- a/src/backend/commands/functioncmds.c
+++ b/src/backend/commands/functioncmds.c
@@ -2424,6 +2424,7 @@ CallStmtResultDesc(CallStmt *stmt)
 							   -1,
 							   0);
 		}
+		TupleDescFinalize(tupdesc);
 	}
 
 	return tupdesc;
diff --git a/src/backend/commands/sequence.c b/src/backend/commands/sequence.c
index e1b808bbb60..551667650ba 100644
--- a/src/backend/commands/sequence.c
+++ b/src/backend/commands/sequence.c
@@ -1808,6 +1808,7 @@ pg_get_sequence_data(PG_FUNCTION_ARGS)
 					   BOOLOID, -1, 0);
 	TupleDescInitEntry(resultTupleDesc, (AttrNumber) 3, "page_lsn",
 					   LSNOID, -1, 0);
+	TupleDescFinalize(resultTupleDesc);
 	resultTupleDesc = BlessTupleDesc(resultTupleDesc);
 
 	seqrel = try_relation_open(relid, AccessShareLock);
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 85242dcc245..80922974970 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -1030,6 +1030,8 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 		}
 	}
 
+	TupleDescFinalize(descriptor);
+
 	/*
 	 * For relations with table AM and partitioned tables, select access
 	 * method to use: an explicitly indicated one, or (in the case of a
@@ -1458,6 +1460,8 @@ BuildDescForRelation(const List *columns)
 		populate_compact_attribute(desc, attnum - 1);
 	}
 
+	TupleDescFinalize(desc);
+
 	return desc;
 }
 
diff --git a/src/backend/commands/wait.c b/src/backend/commands/wait.c
index 1290df10c6f..8e920a72372 100644
--- a/src/backend/commands/wait.c
+++ b/src/backend/commands/wait.c
@@ -338,5 +338,6 @@ WaitStmtResultDesc(WaitStmt *stmt)
 	tupdesc = CreateTemplateTupleDesc(1);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 1, "status",
 					   TEXTOID, -1, 0);
+	TupleDescFinalize(tupdesc);
 	return tupdesc;
 }
diff --git a/src/backend/executor/execSRF.c b/src/backend/executor/execSRF.c
index a0b111dc0e4..b481e50acfb 100644
--- a/src/backend/executor/execSRF.c
+++ b/src/backend/executor/execSRF.c
@@ -272,6 +272,7 @@ ExecMakeTableFunctionResult(SetExprState *setexpr,
 									   funcrettype,
 									   -1,
 									   0);
+					TupleDescFinalize(tupdesc);
 					rsinfo.setDesc = tupdesc;
 				}
 				MemoryContextSwitchTo(oldcontext);
@@ -776,6 +777,7 @@ init_sexpr(Oid foid, Oid input_collation, Expr *node,
 							   funcrettype,
 							   -1,
 							   0);
+			TupleDescFinalize(tupdesc);
 			sexpr->funcResultDesc = tupdesc;
 			sexpr->funcReturnsTuple = false;
 		}
diff --git a/src/backend/executor/execTuples.c b/src/backend/executor/execTuples.c
index 7effe954286..07b248aa5f3 100644
--- a/src/backend/executor/execTuples.c
+++ b/src/backend/executor/execTuples.c
@@ -2175,6 +2175,8 @@ ExecTypeFromTLInternal(List *targetList, bool skipjunk)
 		cur_resno++;
 	}
 
+	TupleDescFinalize(typeInfo);
+
 	return typeInfo;
 }
 
@@ -2209,6 +2211,8 @@ ExecTypeFromExprList(List *exprList)
 		cur_resno++;
 	}
 
+	TupleDescFinalize(typeInfo);
+
 	return typeInfo;
 }
 
diff --git a/src/backend/executor/nodeFunctionscan.c b/src/backend/executor/nodeFunctionscan.c
index 63e605e1f81..feb82d64967 100644
--- a/src/backend/executor/nodeFunctionscan.c
+++ b/src/backend/executor/nodeFunctionscan.c
@@ -414,6 +414,7 @@ ExecInitFunctionScan(FunctionScan *node, EState *estate, int eflags)
 				TupleDescInitEntryCollation(tupdesc,
 											(AttrNumber) 1,
 											exprCollation(funcexpr));
+				TupleDescFinalize(tupdesc);
 			}
 			else
 			{
@@ -485,6 +486,7 @@ ExecInitFunctionScan(FunctionScan *node, EState *estate, int eflags)
 							   0);
 		}
 
+		TupleDescFinalize(scan_tupdesc);
 		Assert(attno == natts);
 	}
 
diff --git a/src/backend/parser/parse_relation.c b/src/backend/parser/parse_relation.c
index e003db520de..9c415e166ee 100644
--- a/src/backend/parser/parse_relation.c
+++ b/src/backend/parser/parse_relation.c
@@ -1883,6 +1883,7 @@ addRangeTableEntryForFunction(ParseState *pstate,
 			TupleDescInitEntryCollation(tupdesc,
 										(AttrNumber) 1,
 										exprCollation(funcexpr));
+			TupleDescFinalize(tupdesc);
 		}
 		else if (functypclass == TYPEFUNC_RECORD)
 		{
@@ -1940,6 +1941,7 @@ addRangeTableEntryForFunction(ParseState *pstate,
 
 				i++;
 			}
+			TupleDescFinalize(tupdesc);
 
 			/*
 			 * Ensure that the coldeflist defines a legal set of names (no
@@ -2008,7 +2010,7 @@ addRangeTableEntryForFunction(ParseState *pstate,
 							   0);
 			/* no need to set collation */
 		}
-
+		TupleDescFinalize(tupdesc);
 		Assert(natts == totalatts);
 	}
 	else
diff --git a/src/backend/parser/parse_target.c b/src/backend/parser/parse_target.c
index 3bcfc1f5e3d..f57c4d41080 100644
--- a/src/backend/parser/parse_target.c
+++ b/src/backend/parser/parse_target.c
@@ -1572,6 +1572,8 @@ expandRecordVariable(ParseState *pstate, Var *var, int levelsup)
 		}
 		Assert(lname == NULL && lvar == NULL);	/* lists same length? */
 
+		TupleDescFinalize(tupleDesc);
+
 		return tupleDesc;
 	}
 
diff --git a/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c b/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c
index 7c8639b32e9..9f04c9ed25d 100644
--- a/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c
+++ b/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c
@@ -1073,6 +1073,7 @@ libpqrcv_processTuples(PGresult *pgres, WalRcvExecResult *walres,
 	for (coln = 0; coln < nRetTypes; coln++)
 		TupleDescInitEntry(walres->tupledesc, (AttrNumber) coln + 1,
 						   PQfname(pgres, coln), retTypes[coln], -1, 0);
+	TupleDescFinalize(walres->tupledesc);
 	attinmeta = TupleDescGetAttInMetadata(walres->tupledesc);
 
 	/* No point in doing more here if there were no tuples returned. */
diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c
index 2cde8ebc729..33a9e8d7f21 100644
--- a/src/backend/replication/walsender.c
+++ b/src/backend/replication/walsender.c
@@ -451,6 +451,7 @@ IdentifySystem(void)
 							  TEXTOID, -1, 0);
 	TupleDescInitBuiltinEntry(tupdesc, (AttrNumber) 4, "dbname",
 							  TEXTOID, -1, 0);
+	TupleDescFinalize(tupdesc);
 
 	/* prepare for projection of tuples */
 	tstate = begin_tup_output_tupdesc(dest, tupdesc, &TTSOpsVirtual);
@@ -496,6 +497,7 @@ ReadReplicationSlot(ReadReplicationSlotCmd *cmd)
 	/* TimeLineID is unsigned, so int4 is not wide enough. */
 	TupleDescInitBuiltinEntry(tupdesc, (AttrNumber) 3, "restart_tli",
 							  INT8OID, -1, 0);
+	TupleDescFinalize(tupdesc);
 
 	memset(nulls, true, READ_REPLICATION_SLOT_COLS * sizeof(bool));
 
@@ -598,6 +600,7 @@ SendTimeLineHistory(TimeLineHistoryCmd *cmd)
 	tupdesc = CreateTemplateTupleDesc(2);
 	TupleDescInitBuiltinEntry(tupdesc, (AttrNumber) 1, "filename", TEXTOID, -1, 0);
 	TupleDescInitBuiltinEntry(tupdesc, (AttrNumber) 2, "content", TEXTOID, -1, 0);
+	TupleDescFinalize(tupdesc);
 
 	TLHistoryFileName(histfname, cmd->timeline);
 	TLHistoryFilePath(path, cmd->timeline);
@@ -1015,6 +1018,7 @@ StartReplication(StartReplicationCmd *cmd)
 								  INT8OID, -1, 0);
 		TupleDescInitBuiltinEntry(tupdesc, (AttrNumber) 2, "next_tli_startpos",
 								  TEXTOID, -1, 0);
+		TupleDescFinalize(tupdesc);
 
 		/* prepare for projection of tuple */
 		tstate = begin_tup_output_tupdesc(dest, tupdesc, &TTSOpsVirtual);
@@ -1369,6 +1373,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd)
 							  TEXTOID, -1, 0);
 	TupleDescInitBuiltinEntry(tupdesc, (AttrNumber) 4, "output_plugin",
 							  TEXTOID, -1, 0);
+	TupleDescFinalize(tupdesc);
 
 	/* prepare for projection of tuples */
 	tstate = begin_tup_output_tupdesc(dest, tupdesc, &TTSOpsVirtual);
diff --git a/src/backend/utils/adt/acl.c b/src/backend/utils/adt/acl.c
index 071e3f2c49e..e210d6472be 100644
--- a/src/backend/utils/adt/acl.c
+++ b/src/backend/utils/adt/acl.c
@@ -1831,6 +1831,7 @@ aclexplode(PG_FUNCTION_ARGS)
 		TupleDescInitEntry(tupdesc, (AttrNumber) 4, "is_grantable",
 						   BOOLOID, -1, 0);
 
+		TupleDescFinalize(tupdesc);
 		funcctx->tuple_desc = BlessTupleDesc(tupdesc);
 
 		/* allocate memory for user context */
diff --git a/src/backend/utils/adt/genfile.c b/src/backend/utils/adt/genfile.c
index c083608b1d5..bfb949401d0 100644
--- a/src/backend/utils/adt/genfile.c
+++ b/src/backend/utils/adt/genfile.c
@@ -454,6 +454,7 @@ pg_stat_file(PG_FUNCTION_ARGS)
 					   "creation", TIMESTAMPTZOID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 6,
 					   "isdir", BOOLOID, -1, 0);
+	TupleDescFinalize(tupdesc);
 	BlessTupleDesc(tupdesc);
 
 	memset(isnull, false, sizeof(isnull));
diff --git a/src/backend/utils/adt/lockfuncs.c b/src/backend/utils/adt/lockfuncs.c
index 9dadd6da672..4481c354fd6 100644
--- a/src/backend/utils/adt/lockfuncs.c
+++ b/src/backend/utils/adt/lockfuncs.c
@@ -146,6 +146,7 @@ pg_lock_status(PG_FUNCTION_ARGS)
 		TupleDescInitEntry(tupdesc, (AttrNumber) 16, "waitstart",
 						   TIMESTAMPTZOID, -1, 0);
 
+		TupleDescFinalize(tupdesc);
 		funcctx->tuple_desc = BlessTupleDesc(tupdesc);
 
 		/*
diff --git a/src/backend/utils/adt/orderedsetaggs.c b/src/backend/utils/adt/orderedsetaggs.c
index 3b6da8e36ac..fd8b8676470 100644
--- a/src/backend/utils/adt/orderedsetaggs.c
+++ b/src/backend/utils/adt/orderedsetaggs.c
@@ -233,6 +233,7 @@ ordered_set_startup(FunctionCallInfo fcinfo, bool use_tuples)
 								   -1,
 								   0);
 
+				TupleDescFinalize(newdesc);
 				FreeTupleDesc(qstate->tupdesc);
 				qstate->tupdesc = newdesc;
 			}
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index b1df96e7b0b..0b10da3b180 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -769,6 +769,7 @@ pg_stat_get_backend_subxact(PG_FUNCTION_ARGS)
 	TupleDescInitEntry(tupdesc, (AttrNumber) 2, "subxact_overflow",
 					   BOOLOID, -1, 0);
 
+	TupleDescFinalize(tupdesc);
 	BlessTupleDesc(tupdesc);
 
 	if ((local_beentry = pgstat_get_local_beentry_by_proc_number(procNumber)) != NULL)
@@ -1670,6 +1671,7 @@ pg_stat_wal_build_tuple(PgStat_WalCounters wal_counters,
 	TupleDescInitEntry(tupdesc, (AttrNumber) 6, "stats_reset",
 					   TIMESTAMPTZOID, -1, 0);
 
+	TupleDescFinalize(tupdesc);
 	BlessTupleDesc(tupdesc);
 
 	/* Fill values and NULLs */
@@ -2097,6 +2099,7 @@ pg_stat_get_archiver(PG_FUNCTION_ARGS)
 	TupleDescInitEntry(tupdesc, (AttrNumber) 7, "stats_reset",
 					   TIMESTAMPTZOID, -1, 0);
 
+	TupleDescFinalize(tupdesc);
 	BlessTupleDesc(tupdesc);
 
 	/* Get statistics about the archiver process */
@@ -2178,6 +2181,7 @@ pg_stat_get_replication_slot(PG_FUNCTION_ARGS)
 					   TIMESTAMPTZOID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 13, "stats_reset",
 					   TIMESTAMPTZOID, -1, 0);
+	TupleDescFinalize(tupdesc);
 	BlessTupleDesc(tupdesc);
 
 	namestrcpy(&slotname, text_to_cstring(slotname_text));
@@ -2265,6 +2269,7 @@ pg_stat_get_subscription_stats(PG_FUNCTION_ARGS)
 					   INT8OID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 13, "stats_reset",
 					   TIMESTAMPTZOID, -1, 0);
+	TupleDescFinalize(tupdesc);
 	BlessTupleDesc(tupdesc);
 
 	if (!subentry)
diff --git a/src/backend/utils/adt/tsvector_op.c b/src/backend/utils/adt/tsvector_op.c
index 71c7c7d3b3c..d8dece42b9b 100644
--- a/src/backend/utils/adt/tsvector_op.c
+++ b/src/backend/utils/adt/tsvector_op.c
@@ -651,6 +651,7 @@ tsvector_unnest(PG_FUNCTION_ARGS)
 						   TEXTARRAYOID, -1, 0);
 		if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
 			elog(ERROR, "return type must be a row type");
+		TupleDescFinalize(tupdesc);
 		funcctx->tuple_desc = tupdesc;
 
 		funcctx->user_fctx = PG_GETARG_TSVECTOR_COPY(0);
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index a1c88c6b1b6..d27ac216e6d 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -729,6 +729,8 @@ RelationBuildTupleDesc(Relation relation)
 		pfree(constr);
 		relation->rd_att->constr = NULL;
 	}
+
+	TupleDescFinalize(relation->rd_att);
 }
 
 /*
@@ -1985,6 +1987,7 @@ formrdesc(const char *relationName, Oid relationReltype,
 
 	/* initialize first attribute's attcacheoff, cf RelationBuildTupleDesc */
 	TupleDescCompactAttr(relation->rd_att, 0)->attcacheoff = 0;
+	TupleDescFinalize(relation->rd_att);
 
 	/* mark not-null status */
 	if (has_not_null)
@@ -3688,6 +3691,8 @@ RelationBuildLocalRelation(const char *relname,
 	for (i = 0; i < natts; i++)
 		TupleDescAttr(rel->rd_att, i)->attrelid = relid;
 
+	TupleDescFinalize(rel->rd_att);
+
 	rel->rd_rel->reltablespace = reltablespace;
 
 	if (mapped_relation)
@@ -4443,6 +4448,7 @@ BuildHardcodedDescriptor(int natts, const FormData_pg_attribute *attrs)
 
 	/* initialize first attribute's attcacheoff, cf RelationBuildTupleDesc */
 	TupleDescCompactAttr(result, 0)->attcacheoff = 0;
+	TupleDescFinalize(result);
 
 	/* Note: we don't bother to set up a TupleConstr entry */
 
@@ -6291,6 +6297,8 @@ load_relcache_init_file(bool shared)
 			populate_compact_attribute(rel->rd_att, i);
 		}
 
+		TupleDescFinalize(rel->rd_att);
+
 		/* next read the access method specific field */
 		if (fread(&len, 1, sizeof(len), fp) != sizeof(len))
 			goto read_failed;
diff --git a/src/backend/utils/fmgr/funcapi.c b/src/backend/utils/fmgr/funcapi.c
index 8a934ea8dca..516d02cfb82 100644
--- a/src/backend/utils/fmgr/funcapi.c
+++ b/src/backend/utils/fmgr/funcapi.c
@@ -340,6 +340,8 @@ get_expr_result_type(Node *expr,
 										exprCollation(col));
 			i++;
 		}
+		TupleDescFinalize(tupdesc);
+
 		if (resultTypeId)
 			*resultTypeId = rexpr->row_typeid;
 		if (resultTupleDesc)
@@ -1044,6 +1046,7 @@ resolve_polymorphic_tupdesc(TupleDesc tupdesc, oidvector *declared_args,
 		}
 	}
 
+	TupleDescFinalize(tupdesc);
 	return true;
 }
 
@@ -1853,6 +1856,8 @@ build_function_result_tupdesc_d(char prokind,
 						   0);
 	}
 
+	TupleDescFinalize(desc);
+
 	return desc;
 }
 
@@ -1970,6 +1975,7 @@ TypeGetTupleDesc(Oid typeoid, List *colaliases)
 						   typeoid,
 						   -1,
 						   0);
+		TupleDescFinalize(tupdesc);
 	}
 	else if (functypclass == TYPEFUNC_RECORD)
 	{
diff --git a/src/backend/utils/misc/guc_funcs.c b/src/backend/utils/misc/guc_funcs.c
index 8524dd3a981..472cb5393ce 100644
--- a/src/backend/utils/misc/guc_funcs.c
+++ b/src/backend/utils/misc/guc_funcs.c
@@ -444,6 +444,7 @@ GetPGVariableResultDesc(const char *name)
 		TupleDescInitEntry(tupdesc, (AttrNumber) 1, varname,
 						   TEXTOID, -1, 0);
 	}
+	TupleDescFinalize(tupdesc);
 	return tupdesc;
 }
 
@@ -465,6 +466,7 @@ ShowGUCConfigOption(const char *name, DestReceiver *dest)
 	tupdesc = CreateTemplateTupleDesc(1);
 	TupleDescInitBuiltinEntry(tupdesc, (AttrNumber) 1, varname,
 							  TEXTOID, -1, 0);
+	TupleDescFinalize(tupdesc);
 
 	/* prepare for projection of tuples */
 	tstate = begin_tup_output_tupdesc(dest, tupdesc, &TTSOpsVirtual);
@@ -499,6 +501,7 @@ ShowAllGUCConfig(DestReceiver *dest)
 							  TEXTOID, -1, 0);
 	TupleDescInitBuiltinEntry(tupdesc, (AttrNumber) 3, "description",
 							  TEXTOID, -1, 0);
+	TupleDescFinalize(tupdesc);
 
 	/* prepare for projection of tuples */
 	tstate = begin_tup_output_tupdesc(dest, tupdesc, &TTSOpsVirtual);
@@ -934,6 +937,8 @@ show_all_settings(PG_FUNCTION_ARGS)
 		TupleDescInitEntry(tupdesc, (AttrNumber) 17, "pending_restart",
 						   BOOLOID, -1, 0);
 
+		TupleDescFinalize(tupdesc);
+
 		/*
 		 * Generate attribute metadata needed later to produce tuples from raw
 		 * C strings
diff --git a/src/include/access/tupdesc.h b/src/include/access/tupdesc.h
index d46cdbf7a3c..595413dbbc5 100644
--- a/src/include/access/tupdesc.h
+++ b/src/include/access/tupdesc.h
@@ -195,6 +195,7 @@ extern TupleDesc CreateTupleDescTruncatedCopy(TupleDesc tupdesc, int natts);
 
 extern TupleDesc CreateTupleDescCopyConstr(TupleDesc tupdesc);
 
+#define TupleDescFinalize(d) ((void) 0)
 #define TupleDescSize(src) \
 	(offsetof(struct TupleDescData, compact_attrs) + \
 	 (src)->natts * sizeof(CompactAttribute) + \
diff --git a/src/pl/plpgsql/src/pl_comp.c b/src/pl/plpgsql/src/pl_comp.c
index 5ecc7766757..b72c963b3be 100644
--- a/src/pl/plpgsql/src/pl_comp.c
+++ b/src/pl/plpgsql/src/pl_comp.c
@@ -1912,6 +1912,8 @@ build_row_from_vars(PLpgSQL_variable **vars, int numvars)
 		TupleDescInitEntryCollation(row->rowtupdesc, i + 1, typcoll);
 	}
 
+	TupleDescFinalize(row->rowtupdesc);
+
 	return row;
 }
 
diff --git a/src/test/modules/test_custom_stats/test_custom_fixed_stats.c b/src/test/modules/test_custom_stats/test_custom_fixed_stats.c
index 485e08e5c19..f9e7c717280 100644
--- a/src/test/modules/test_custom_stats/test_custom_fixed_stats.c
+++ b/src/test/modules/test_custom_stats/test_custom_fixed_stats.c
@@ -206,6 +206,7 @@ test_custom_stats_fixed_report(PG_FUNCTION_ARGS)
 					   INT8OID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 2, "stats_reset",
 					   TIMESTAMPTZOID, -1, 0);
+	TupleDescFinalize(tupdesc);
 	BlessTupleDesc(tupdesc);
 
 	values[0] = Int64GetDatum(stats->numcalls);
diff --git a/src/test/modules/test_predtest/test_predtest.c b/src/test/modules/test_predtest/test_predtest.c
index 679a5de456d..48ca2a4ea70 100644
--- a/src/test/modules/test_predtest/test_predtest.c
+++ b/src/test/modules/test_predtest/test_predtest.c
@@ -230,6 +230,7 @@ test_predtest(PG_FUNCTION_ARGS)
 					   "s_r_holds", BOOLOID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 8,
 					   "w_r_holds", BOOLOID, -1, 0);
+	TupleDescFinalize(tupdesc);
 	tupdesc = BlessTupleDesc(tupdesc);
 
 	values[0] = BoolGetDatum(strong_implied_by);
-- 
2.51.0

From d46c106325c6dd7f456fe5d28d47a83cc295a9c7 Mon Sep 17 00:00:00 2001
From: David Rowley <[email-masked]>
Date: Tue, 31 Dec 2024 09:19:24 +1300
Subject: [PATCH v12 4/6] Optimize tuple deformation

This commit includes various optimizations to improve the performance of
tuple deformation.

We now precalculate CompactAttribute's attcacheoff, which allows us to
remove the code from the deform routines which was setting the
attcacheoff.  Setting the attcacheoff is handled by TupleDescFinalize(),
which must be called before the TupleDesc is used for anything.  Having
this TupleDescFinalize() function means we can store the first
attribute in the TupleDesc which does not have an offset cached.  That
allows us to add a dedicated deforming loop to deform all attributes up
to the final one with an attcacheoff set, or up to the first NULL
attribute, whichever comes first.

We also record the maximum attribute number which is guaranteed to exist
in the tuple, that is, has a NOT NULL constraint and isn't an
atthasmissing attribute.  When deforming only attributes prior to the
guaranteed attnum, we've no need to access the tuple's natt count.  As an
additional optimization, we only count fixed-width columns when
calculating the maximum guaranteed column as this eliminates the need to
emit code to fetch byref types in the deformation loop for guaranteed
attributes.

Some locations in the code deform tuples that have yet to go through NOT
NULL constraint validation.  We're unable to perform the guaranteed
attribute optimization when that's the case.  The optimization is opt-in
via the TupleTableSlot using the TTS_FLAG_OBEYS_NOT_NULL_CONSTRAINTS
flag.

This commit also adds a more efficient way of populating the isnull
array by using a bit-wise trick which performs multiplication on the
inverse of the tuple's bitmap byte and masking out all but the lower bit
of each of the boolean's byte.  This results in much more optimal code
when compared to determining the NULLness via att_isnull().  8 isnull
elements are processed at once using this method, which means we need to
round the tts_isnull array size up to the next 8 bytes.  The palloc code
does this anyway, but the round-up needed to be formalized so as not to
overwrite the sentinel byte in debug builds.
---
 src/backend/access/common/heaptuple.c         | 360 +++++++--------
 src/backend/access/common/indextuple.c        | 363 ++++++---------
 src/backend/access/common/tupdesc.c           |  51 +++
 src/backend/access/spgist/spgutils.c          |   3 -
 src/backend/executor/execMain.c               |   8 +-
 src/backend/executor/execTuples.c             | 417 ++++++++++--------
 src/backend/executor/execUtils.c              |   2 +-
 src/backend/executor/nodeAgg.c                |   2 +-
 src/backend/executor/nodeBitmapHeapscan.c     |   5 +-
 src/backend/executor/nodeCtescan.c            |   2 +-
 src/backend/executor/nodeCustom.c             |   4 +-
 src/backend/executor/nodeForeignscan.c        |   4 +-
 src/backend/executor/nodeFunctionscan.c       |   2 +-
 src/backend/executor/nodeIndexonlyscan.c      |   7 +-
 src/backend/executor/nodeIndexscan.c          |   5 +-
 .../executor/nodeNamedtuplestorescan.c        |   2 +-
 src/backend/executor/nodeSamplescan.c         |   6 +-
 src/backend/executor/nodeSeqscan.c            |   3 +-
 src/backend/executor/nodeSubqueryscan.c       |   3 +-
 src/backend/executor/nodeTableFuncscan.c      |   2 +-
 src/backend/executor/nodeTidrangescan.c       |   5 +-
 src/backend/executor/nodeTidscan.c            |   5 +-
 src/backend/executor/nodeValuesscan.c         |   2 +-
 src/backend/executor/nodeWorktablescan.c      |   2 +-
 src/backend/jit/llvm/llvmjit_deform.c         |   6 -
 src/backend/replication/pgoutput/pgoutput.c   |   4 +-
 src/backend/utils/cache/relcache.c            |  12 -
 src/include/access/tupdesc.h                  |  20 +-
 src/include/access/tupmacs.h                  | 224 +++++++++-
 src/include/executor/executor.h               |   3 +-
 src/include/executor/tuptable.h               |  28 +-
 src/test/modules/deform_bench/deform_bench.c  |   4 +-
 32 files changed, 902 insertions(+), 664 deletions(-)

diff --git a/src/backend/access/common/heaptuple.c b/src/backend/access/common/heaptuple.c
index 11bec20e82e..b2ac7fef35b 100644
--- a/src/backend/access/common/heaptuple.c
+++ b/src/backend/access/common/heaptuple.c
@@ -498,19 +498,7 @@ heap_attisnull(HeapTuple tup, int attnum, TupleDesc tupleDesc)
  *		nocachegetattr
  *
  *		This only gets called from fastgetattr(), in cases where we
- *		can't use a cacheoffset and the value is not null.
- *
- *		This caches attribute offsets in the attribute descriptor.
- *
- *		An alternative way to speed things up would be to cache offsets
- *		with the tuple, but that seems more difficult unless you take
- *		the storage hit of actually putting those offsets into the
- *		tuple you send to disk.  Yuck.
- *
- *		This scheme will be slightly slower than that, but should
- *		perform well for queries which hit large #'s of tuples.  After
- *		you cache the offsets once, examining all the other tuples using
- *		the same attribute descriptor will go much quicker. -cim 5/4/91
+ *		can't use the attcacheoff and the value is not null.
  *
  *		NOTE: if you need to change this code, see also heap_deform_tuple.
  *		Also see nocache_index_getattr, which is the same code for index
@@ -522,194 +510,125 @@ nocachegetattr(HeapTuple tup,
 			   int attnum,
 			   TupleDesc tupleDesc)
 {
+	CompactAttribute *cattr;
 	HeapTupleHeader td = tup->t_data;
 	char	   *tp;				/* ptr to data part of tuple */
 	bits8	   *bp = td->t_bits;	/* ptr to null bitmap in tuple */
-	bool		slow = false;	/* do we have to walk attrs? */
 	int			off;			/* current offset within data */
+	int			startAttr;
+	int			firstNullAttr;
+	int			i;
+	bool		hasnulls = HeapTupleHasNulls(tup);
 
-	/* ----------------
-	 *	 Three cases:
-	 *
-	 *	 1: No nulls and no variable-width attributes.
-	 *	 2: Has a null or a var-width AFTER att.
-	 *	 3: Has nulls or var-widths BEFORE att.
-	 * ----------------
-	 */
+	/* Did someone forget to call TupleDescFinalize()? */
+	Assert(tupleDesc->firstNonCachedOffsetAttr >= 0);
 
 	attnum--;
 
-	if (!HeapTupleNoNulls(tup))
+	/*
+	 * To minimize the number of attributes we need to look at, start walking
+	 * the tuple at the attribute with the highest attcacheoff prior to attnum
+	 * or the first NULL attribute prior to attnum, whichever comes first.
+	 */
+	if (hasnulls)
+		firstNullAttr = first_null_attr(bp, attnum);
+	else
+		firstNullAttr = attnum;
+
+	if (tupleDesc->firstNonCachedOffsetAttr > 0)
 	{
 		/*
-		 * there's a null somewhere in the tuple
-		 *
-		 * check to see if any preceding bits are null...
+		 * Start at the highest attcacheoff attribute with no NULLs in prior
+		 * attributes.
 		 */
-		int			byte = attnum >> 3;
-		int			finalbit = attnum & 0x07;
-
-		/* check for nulls "before" final bit of last byte */
-		if ((~bp[byte]) & ((1 << finalbit) - 1))
-			slow = true;
-		else
-		{
-			/* check for nulls in any "earlier" bytes */
-			int			i;
-
-			for (i = 0; i < byte; i++)
-			{
-				if (bp[i] != 0xFF)
-				{
-					slow = true;
-					break;
-				}
-			}
-		}
+		startAttr = Min(tupleDesc->firstNonCachedOffsetAttr - 1, firstNullAttr);
+		off = TupleDescCompactAttr(tupleDesc, startAttr)->attcacheoff;
+	}
+	else
+	{
+		/* Otherwise, start at the beginning... */
+		startAttr = 0;
+		off = 0;
 	}
 
 	tp = (char *) td + td->t_hoff;
 
-	if (!slow)
+	/*
+	 * Calculate 'off' up to the first NULL attr.  We use two cheaper loops
+	 * when the tuple has no variable-width columns.  When variable-width
+	 * columns exists, we use att_addlength_pointer() to move the offset
+	 * beyond the current attribute.
+	 */
+	if (!HeapTupleHasVarWidth(tup))
 	{
-		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 = TupleDescCompactAttr(tupleDesc, attnum);
-		if (att->attcacheoff >= 0)
-			return fetchatt(att, tp + att->attcacheoff);
-
-		/*
-		 * Otherwise, check for non-fixed-length attrs up to and including
-		 * target.  If there aren't any, it's safe to cheaply initialize the
-		 * cached offsets for these attrs.
-		 */
-		if (HeapTupleHasVarWidth(tup))
+		for (i = startAttr; i < firstNullAttr; i++)
 		{
-			int			j;
+			cattr = TupleDescCompactAttr(tupleDesc, i);
 
-			for (j = 0; j <= attnum; j++)
-			{
-				if (TupleDescCompactAttr(tupleDesc, j)->attlen <= 0)
-				{
-					slow = true;
-					break;
-				}
-			}
+			off = att_nominal_alignby(off, cattr->attalignby);
+			off += cattr->attlen;
 		}
-	}
-
-	if (!slow)
-	{
-		int			natts = tupleDesc->natts;
-		int			j = 1;
-
-		/*
-		 * If we get here, we have a tuple with no nulls or var-widths up to
-		 * and including the target attribute, so we can use the cached offset
-		 * ... only we don't have it yet, or we'd not have got here.  Since
-		 * it's cheap to compute offsets for fixed-width columns, we take the
-		 * opportunity to initialize the cached offsets for *all* the leading
-		 * fixed-width columns, in hope of avoiding future visits to this
-		 * routine.
-		 */
-		TupleDescCompactAttr(tupleDesc, 0)->attcacheoff = 0;
-
-		/* we might have set some offsets in the slow path previously */
-		while (j < natts && TupleDescCompactAttr(tupleDesc, j)->attcacheoff > 0)
-			j++;
-
-		off = TupleDescCompactAttr(tupleDesc, j - 1)->attcacheoff +
-			TupleDescCompactAttr(tupleDesc, j - 1)->attlen;
 
-		for (; j < natts; j++)
+		for (; i < attnum; i++)
 		{
-			CompactAttribute *att = TupleDescCompactAttr(tupleDesc, j);
+			if (att_isnull(i, bp))
+				continue;
 
-			if (att->attlen <= 0)
-				break;
-
-			off = att_nominal_alignby(off, att->attalignby);
+			cattr = TupleDescCompactAttr(tupleDesc, i);
 
-			att->attcacheoff = off;
-
-			off += att->attlen;
+			off = att_nominal_alignby(off, cattr->attalignby);
+			off += cattr->attlen;
 		}
-
-		Assert(j > attnum);
-
-		off = TupleDescCompactAttr(tupleDesc, attnum)->attcacheoff;
 	}
 	else
 	{
-		bool		usecache = true;
-		int			i;
-
-		/*
-		 * Now we know that we have to walk the tuple CAREFULLY.  But we still
-		 * might be able to cache some offsets for next time.
-		 *
-		 * Note - This loop is a little tricky.  For each non-null attribute,
-		 * we have to first account for alignment padding before the attr,
-		 * then advance over the attr based on its length.  Nulls have no
-		 * storage and no alignment padding either.  We can use/set
-		 * attcacheoff until we reach either a null or a var-width attribute.
-		 */
-		off = 0;
-		for (i = 0;; i++)		/* loop exit is at "break" */
+		for (i = startAttr; i < firstNullAttr; i++)
 		{
-			CompactAttribute *att = TupleDescCompactAttr(tupleDesc, i);
+			int			attlen;
 
-			if (HeapTupleHasNulls(tup) && att_isnull(i, bp))
-			{
-				usecache = false;
-				continue;		/* this cannot be the target att */
-			}
+			cattr = TupleDescCompactAttr(tupleDesc, i);
+			attlen = cattr->attlen;
 
-			/* If we know the next offset, we can skip the rest */
-			if (usecache && att->attcacheoff >= 0)
-				off = att->attcacheoff;
-			else if (att->attlen == -1)
-			{
-				/*
-				 * We can only cache the offset for a varlena attribute if the
-				 * offset is already suitably aligned, so that there would be
-				 * no pad bytes in any case: then the offset will be valid for
-				 * either an aligned or unaligned value.
-				 */
-				if (usecache &&
-					off == att_nominal_alignby(off, att->attalignby))
-					att->attcacheoff = off;
-				else
-				{
-					off = att_pointer_alignby(off, att->attalignby, -1,
-											  tp + off);
-					usecache = false;
-				}
-			}
-			else
-			{
-				/* not varlena, so safe to use att_nominal_alignby */
-				off = att_nominal_alignby(off, att->attalignby);
+			/*
+			 * cstrings don't exist in heap tuples.  Use pg_assume to instruct
+			 * the compiler not to emit the cstring-related code in
+			 * att_addlength_pointer().
+			 */
+			pg_assume(attlen > 0 || attlen == -1);
 
-				if (usecache)
-					att->attcacheoff = off;
-			}
+			off = att_pointer_alignby(off,
+									  cattr->attalignby,
+									  attlen,
+									  tp + off);
+			off = att_addlength_pointer(off, attlen, tp + off);
+		}
 
-			if (i == attnum)
-				break;
+		for (; i < attnum; i++)
+		{
+			int			attlen;
 
-			off = att_addlength_pointer(off, att->attlen, tp + off);
+			if (att_isnull(i, bp))
+				continue;
 
-			if (usecache && att->attlen <= 0)
-				usecache = false;
+			cattr = TupleDescCompactAttr(tupleDesc, i);
+			attlen = cattr->attlen;
+
+			/* As above, heaptuples have no cstrings */
+			pg_assume(attlen > 0 || attlen == -1);
+
+			off = att_pointer_alignby(off, cattr->attalignby, attlen,
+									  tp + off);
+			off = att_addlength_pointer(off, attlen, tp + off);
 		}
 	}
 
-	return fetchatt(TupleDescCompactAttr(tupleDesc, attnum), tp + off);
+	cattr = TupleDescCompactAttr(tupleDesc, attnum);
+	off = att_pointer_alignby(off,
+							  cattr->attalignby,
+							  cattr->attlen,
+							  tp + off);
+
+	return fetchatt(cattr, tp + off);
 }
 
 /* ----------------
@@ -1347,6 +1266,7 @@ heap_deform_tuple(HeapTuple tuple, TupleDesc tupleDesc,
 				  Datum *values, bool *isnull)
 {
 	HeapTupleHeader tup = tuple->t_data;
+	CompactAttribute *cattr;
 	bool		hasnulls = HeapTupleHasNulls(tuple);
 	int			tdesc_natts = tupleDesc->natts;
 	int			natts;			/* number of atts to extract */
@@ -1354,70 +1274,98 @@ heap_deform_tuple(HeapTuple tuple, TupleDesc tupleDesc,
 	char	   *tp;				/* ptr to tuple data */
 	uint32		off;			/* offset in tuple data */
 	bits8	   *bp = tup->t_bits;	/* ptr to null bitmap in tuple */
-	bool		slow = false;	/* can we use/set attcacheoff? */
+	int			firstNonCacheOffsetAttr;
+	int			firstNullAttr;
 
 	natts = HeapTupleHeaderGetNatts(tup);
 
+	/* Did someone forget to call TupleDescFinalize()? */
+	Assert(tupleDesc->firstNonCachedOffsetAttr >= 0);
+
 	/*
 	 * In inheritance situations, it is possible that the given tuple actually
 	 * has more fields than the caller is expecting.  Don't run off the end of
 	 * the caller's arrays.
 	 */
 	natts = Min(natts, tdesc_natts);
+	firstNonCacheOffsetAttr = Min(tupleDesc->firstNonCachedOffsetAttr, natts);
+
+	if (hasnulls)
+	{
+		firstNullAttr = first_null_attr(bp, natts);
+
+		/*
+		 * XXX: it'd be nice to use populate_isnull_array() here, but that
+		 * requires that the isnull array's size is rounded up to the next
+		 * multiple of 8.  Doing that would require adjusting many locations
+		 * that allocate the array.
+		 */
+		firstNonCacheOffsetAttr = Min(firstNonCacheOffsetAttr, firstNullAttr);
+	}
+	else
+		firstNullAttr = natts;
 
 	tp = (char *) tup + tup->t_hoff;
+	attnum = 0;
 
-	off = 0;
+	if (firstNonCacheOffsetAttr > 0)
+	{
+#ifdef USE_ASSERT_CHECKING
+		/* In Assert enabled builds, verify attcacheoff is correct */
+		int			offcheck = 0;
+#endif
+		do
+		{
+			isnull[attnum] = false;
+			cattr = TupleDescCompactAttr(tupleDesc, attnum);
+			off = cattr->attcacheoff;
 
-	for (attnum = 0; attnum < natts; attnum++)
+#ifdef USE_ASSERT_CHECKING
+			offcheck = att_nominal_alignby(offcheck, cattr->attalignby);
+			Assert(offcheck == cattr->attcacheoff);
+			offcheck += cattr->attlen;
+#endif
+
+			values[attnum] = fetch_att_noerr(tp + off,
+											 cattr->attbyval,
+											 cattr->attlen);
+		} while (++attnum < firstNonCacheOffsetAttr);
+		off += cattr->attlen;
+	}
+	else
+		off = 0;
+
+	for (; attnum < firstNullAttr; attnum++)
 	{
-		CompactAttribute *thisatt = TupleDescCompactAttr(tupleDesc, attnum);
+		isnull[attnum] = false;
+		cattr = TupleDescCompactAttr(tupleDesc, attnum);
+		values[attnum] = align_fetch_then_add(tp,
+											  &off,
+											  cattr->attbyval,
+											  cattr->attlen,
+											  cattr->attalignby);
+	}
+
+	for (; attnum < natts; attnum++)
+	{
+		Assert(hasnulls);
 
-		if (hasnulls && att_isnull(attnum, bp))
+		if (att_isnull(attnum, bp))
 		{
 			values[attnum] = (Datum) 0;
 			isnull[attnum] = true;
-			slow = true;		/* can't use attcacheoff anymore */
 			continue;
 		}
 
 		isnull[attnum] = false;
-
-		if (!slow && thisatt->attcacheoff >= 0)
-			off = thisatt->attcacheoff;
-		else if (thisatt->attlen == -1)
-		{
-			/*
-			 * We can only cache the offset for a varlena attribute if the
-			 * offset is already suitably aligned, so that there would be no
-			 * pad bytes in any case: then the offset will be valid for either
-			 * an aligned or unaligned value.
-			 */
-			if (!slow &&
-				off == att_nominal_alignby(off, thisatt->attalignby))
-				thisatt->attcacheoff = off;
-			else
-			{
-				off = att_pointer_alignby(off, thisatt->attalignby, -1,
-										  tp + off);
-				slow = true;
-			}
-		}
-		else
-		{
-			/* not varlena, so safe to use att_nominal_alignby */
-			off = att_nominal_alignby(off, thisatt->attalignby);
-
-			if (!slow)
-				thisatt->attcacheoff = off;
-		}
-
-		values[attnum] = fetchatt(thisatt, tp + off);
-
-		off = att_addlength_pointer(off, thisatt->attlen, tp + off);
-
-		if (thisatt->attlen <= 0)
-			slow = true;		/* can't use attcacheoff anymore */
+		cattr = TupleDescCompactAttr(tupleDesc, attnum);
+
+		/* align 'off', fetch the datum, and increment off beyond the datum */
+		values[attnum] = align_fetch_then_add(tp,
+											  &off,
+											  cattr->attbyval,
+											  cattr->attlen,
+											  cattr->attalignby);
 	}
 
 	/*
diff --git a/src/backend/access/common/indextuple.c b/src/backend/access/common/indextuple.c
index d6350201e01..8c410853191 100644
--- a/src/backend/access/common/indextuple.c
+++ b/src/backend/access/common/indextuple.c
@@ -223,18 +223,6 @@ index_form_tuple_context(TupleDesc tupleDescriptor,
  *
  *		This gets called from index_getattr() macro, and only in cases
  *		where we can't use cacheoffset and the value is not null.
- *
- *		This caches attribute offsets in the attribute descriptor.
- *
- *		An alternative way to speed things up would be to cache offsets
- *		with the tuple, but that seems more difficult unless you take
- *		the storage hit of actually putting those offsets into the
- *		tuple you send to disk.  Yuck.
- *
- *		This scheme will be slightly slower than that, but should
- *		perform well for queries which hit large #'s of tuples.  After
- *		you cache the offsets once, examining all the other tuples using
- *		the same attribute descriptor will go much quicker. -cim 5/4/91
  * ----------------
  */
 Datum
@@ -242,205 +230,124 @@ nocache_index_getattr(IndexTuple tup,
 					  int attnum,
 					  TupleDesc tupleDesc)
 {
+	CompactAttribute *cattr;
 	char	   *tp;				/* ptr to data part of tuple */
 	bits8	   *bp = NULL;		/* ptr to null bitmap in tuple */
-	bool		slow = false;	/* do we have to walk attrs? */
 	int			data_off;		/* tuple data offset */
 	int			off;			/* current offset within data */
+	int			startAttr;
+	int			firstNullAttr;
+	bool		hasnulls = IndexTupleHasNulls(tup);
+	int			i;
 
-	/* ----------------
-	 *	 Three cases:
-	 *
-	 *	 1: No nulls and no variable-width attributes.
-	 *	 2: Has a null or a var-width AFTER att.
-	 *	 3: Has nulls or var-widths BEFORE att.
-	 * ----------------
-	 */
-
-	data_off = IndexInfoFindDataOffset(tup->t_info);
+	/* Did someone forget to call TupleDescFinalize()? */
+	Assert(tupleDesc->firstNonCachedOffsetAttr >= 0);
 
 	attnum--;
 
-	if (IndexTupleHasNulls(tup))
-	{
-		/*
-		 * there's a null somewhere in the tuple
-		 *
-		 * check to see if desired att is null
-		 */
+	data_off = IndexInfoFindDataOffset(tup->t_info);
+	tp = (char *) tup + data_off;
 
-		/* XXX "knows" t_bits are just after fixed tuple header! */
+	/*
+	 * To minimize the number of attributes we need to look at, start walking
+	 * the tuple at the attribute with the highest attcacheoff prior to attnum
+	 * or the first NULL attribute prior to attnum, whichever comes first.
+	 */
+	if (hasnulls)
+	{
 		bp = (bits8 *) ((char *) tup + sizeof(IndexTupleData));
-
-		/*
-		 * Now check to see if any preceding bits are null...
-		 */
-		{
-			int			byte = attnum >> 3;
-			int			finalbit = attnum & 0x07;
-
-			/* check for nulls "before" final bit of last byte */
-			if ((~bp[byte]) & ((1 << finalbit) - 1))
-				slow = true;
-			else
-			{
-				/* check for nulls in any "earlier" bytes */
-				int			i;
-
-				for (i = 0; i < byte; i++)
-				{
-					if (bp[i] != 0xFF)
-					{
-						slow = true;
-						break;
-					}
-				}
-			}
-		}
+		firstNullAttr = first_null_attr(bp, attnum);
 	}
+	else
+		firstNullAttr = attnum;
 
-	tp = (char *) tup + data_off;
-
-	if (!slow)
+	if (tupleDesc->firstNonCachedOffsetAttr > 0)
 	{
-		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 = TupleDescCompactAttr(tupleDesc, attnum);
-		if (att->attcacheoff >= 0)
-			return fetchatt(att, tp + att->attcacheoff);
-
 		/*
-		 * Otherwise, check for non-fixed-length attrs up to and including
-		 * target.  If there aren't any, it's safe to cheaply initialize the
-		 * cached offsets for these attrs.
+		 * Start at the highest attcacheoff attribute with no NULLs in prior
+		 * attributes.
 		 */
-		if (IndexTupleHasVarwidths(tup))
-		{
-			int			j;
-
-			for (j = 0; j <= attnum; j++)
-			{
-				if (TupleDescCompactAttr(tupleDesc, j)->attlen <= 0)
-				{
-					slow = true;
-					break;
-				}
-			}
-		}
+		startAttr = Min(tupleDesc->firstNonCachedOffsetAttr - 1, firstNullAttr);
+		off = TupleDescCompactAttr(tupleDesc, startAttr)->attcacheoff;
 	}
-
-	if (!slow)
+	else
 	{
-		int			natts = tupleDesc->natts;
-		int			j = 1;
-
-		/*
-		 * If we get here, we have a tuple with no nulls or var-widths up to
-		 * and including the target attribute, so we can use the cached offset
-		 * ... only we don't have it yet, or we'd not have got here.  Since
-		 * it's cheap to compute offsets for fixed-width columns, we take the
-		 * opportunity to initialize the cached offsets for *all* the leading
-		 * fixed-width columns, in hope of avoiding future visits to this
-		 * routine.
-		 */
-		TupleDescCompactAttr(tupleDesc, 0)->attcacheoff = 0;
+		/* Otherwise, start at the beginning... */
+		startAttr = 0;
+		off = 0;
+	}
 
-		/* we might have set some offsets in the slow path previously */
-		while (j < natts && TupleDescCompactAttr(tupleDesc, j)->attcacheoff > 0)
-			j++;
+	/*
+	 * Calculate 'off' up to the first NULL attr.  We use two cheaper loops
+	 * when the tuple has no variable-width columns.  When variable-width
+	 * columns exists, we use att_addlength_pointer() to move the offset
+	 * beyond the current attribute.
+	 */
+	if (IndexTupleHasVarwidths(tup))
+	{
+		/* Calculate the offset up until the first NULL */
+		for (i = startAttr; i < firstNullAttr; i++)
+		{
+			cattr = TupleDescCompactAttr(tupleDesc, i);
 
-		off = TupleDescCompactAttr(tupleDesc, j - 1)->attcacheoff +
-			TupleDescCompactAttr(tupleDesc, j - 1)->attlen;
+			off = att_pointer_alignby(off,
+									  cattr->attalignby,
+									  cattr->attlen,
+									  tp + off);
+			off = att_addlength_pointer(off, cattr->attlen, tp + off);
+		}
 
-		for (; j < natts; j++)
+		/* Calculate the offset for any remaining columns. */
+		for (; i < attnum; i++)
 		{
-			CompactAttribute *att = TupleDescCompactAttr(tupleDesc, j);
+			Assert(hasnulls);
 
-			if (att->attlen <= 0)
-				break;
+			if (att_isnull(i, bp))
+				continue;
 
-			off = att_nominal_alignby(off, att->attalignby);
+			cattr = TupleDescCompactAttr(tupleDesc, i);
 
-			att->attcacheoff = off;
-
-			off += att->attlen;
+			off = att_pointer_alignby(off,
+									  cattr->attalignby,
+									  cattr->attlen,
+									  tp + off);
+			off = att_addlength_pointer(off, cattr->attlen, tp + off);
 		}
-
-		Assert(j > attnum);
-
-		off = TupleDescCompactAttr(tupleDesc, attnum)->attcacheoff;
 	}
 	else
 	{
-		bool		usecache = true;
-		int			i;
+		/* Handle tuples with only fixed-width attributes */
 
-		/*
-		 * Now we know that we have to walk the tuple CAREFULLY.  But we still
-		 * might be able to cache some offsets for next time.
-		 *
-		 * Note - This loop is a little tricky.  For each non-null attribute,
-		 * we have to first account for alignment padding before the attr,
-		 * then advance over the attr based on its length.  Nulls have no
-		 * storage and no alignment padding either.  We can use/set
-		 * attcacheoff until we reach either a null or a var-width attribute.
-		 */
-		off = 0;
-		for (i = 0;; i++)		/* loop exit is at "break" */
+		/* Calculate the offset up until the first NULL */
+		for (i = startAttr; i < firstNullAttr; i++)
 		{
-			CompactAttribute *att = TupleDescCompactAttr(tupleDesc, i);
+			cattr = TupleDescCompactAttr(tupleDesc, i);
 
-			if (IndexTupleHasNulls(tup) && att_isnull(i, bp))
-			{
-				usecache = false;
-				continue;		/* this cannot be the target att */
-			}
-
-			/* If we know the next offset, we can skip the rest */
-			if (usecache && att->attcacheoff >= 0)
-				off = att->attcacheoff;
-			else if (att->attlen == -1)
-			{
-				/*
-				 * We can only cache the offset for a varlena attribute if the
-				 * offset is already suitably aligned, so that there would be
-				 * no pad bytes in any case: then the offset will be valid for
-				 * either an aligned or unaligned value.
-				 */
-				if (usecache &&
-					off == att_nominal_alignby(off, att->attalignby))
-					att->attcacheoff = off;
-				else
-				{
-					off = att_pointer_alignby(off, att->attalignby, -1,
-											  tp + off);
-					usecache = false;
-				}
-			}
-			else
-			{
-				/* not varlena, so safe to use att_nominal_alignby */
-				off = att_nominal_alignby(off, att->attalignby);
+			Assert(cattr->attlen > 0);
+			off = att_nominal_alignby(off, cattr->attalignby);
+			off += cattr->attlen;
+		}
 
-				if (usecache)
-					att->attcacheoff = off;
-			}
+		/* Calculate the offset for any remaining columns. */
+		for (; i < attnum; i++)
+		{
+			Assert(hasnulls);
 
-			if (i == attnum)
-				break;
+			if (att_isnull(i, bp))
+				continue;
 
-			off = att_addlength_pointer(off, att->attlen, tp + off);
+			cattr = TupleDescCompactAttr(tupleDesc, i);
 
-			if (usecache && att->attlen <= 0)
-				usecache = false;
+			Assert(cattr->attlen > 0);
+			off = att_nominal_alignby(off, cattr->attalignby);
+			off += cattr->attlen;
 		}
 	}
 
-	return fetchatt(TupleDescCompactAttr(tupleDesc, attnum), tp + off);
+	cattr = TupleDescCompactAttr(tupleDesc, attnum);
+	off = att_pointer_alignby(off, cattr->attalignby,
+							  cattr->attlen, tp + off);
+	return fetchatt(cattr, tp + off);
 }
 
 /*
@@ -480,63 +387,87 @@ index_deform_tuple_internal(TupleDesc tupleDescriptor,
 							Datum *values, bool *isnull,
 							char *tp, bits8 *bp, int hasnulls)
 {
+	CompactAttribute *cattr;
 	int			natts = tupleDescriptor->natts; /* number of atts to extract */
-	int			attnum;
-	int			off = 0;		/* offset in tuple data */
-	bool		slow = false;	/* can we use/set attcacheoff? */
+	int			attnum = 0;
+	uint32		off = 0;		/* offset in tuple data */
+	int			firstNonCacheOffsetAttr;
+	int			firstNullAttr;
 
 	/* Assert to protect callers who allocate fixed-size arrays */
 	Assert(natts <= INDEX_MAX_KEYS);
 
-	for (attnum = 0; attnum < natts; attnum++)
+	/* Did someone forget to call TupleDescFinalize()? */
+	Assert(tupleDescriptor->firstNonCachedOffsetAttr >= 0);
+
+	firstNonCacheOffsetAttr = Min(tupleDescriptor->firstNonCachedOffsetAttr, natts);
+
+	if (hasnulls)
+	{
+		firstNullAttr = first_null_attr(bp, natts);
+		firstNonCacheOffsetAttr = Min(firstNonCacheOffsetAttr, firstNullAttr);
+	}
+	else
+		firstNullAttr = natts;
+
+	if (firstNonCacheOffsetAttr > 0)
 	{
-		CompactAttribute *thisatt = TupleDescCompactAttr(tupleDescriptor, attnum);
+#ifdef USE_ASSERT_CHECKING
+		/* In Assert enabled builds, verify attcacheoff is correct */
+		off = 0;
+#endif
 
-		if (hasnulls && att_isnull(attnum, bp))
+		do
 		{
-			values[attnum] = (Datum) 0;
-			isnull[attnum] = true;
-			slow = true;		/* can't use attcacheoff anymore */
-			continue;
-		}
+			isnull[attnum] = false;
+			cattr = TupleDescCompactAttr(tupleDescriptor, attnum);
 
-		isnull[attnum] = false;
+#ifdef USE_ASSERT_CHECKING
+			off = att_nominal_alignby(off, cattr->attalignby);
+			Assert(off == cattr->attcacheoff);
+			off += cattr->attlen;
+#endif
 
-		if (!slow && thisatt->attcacheoff >= 0)
-			off = thisatt->attcacheoff;
-		else if (thisatt->attlen == -1)
-		{
-			/*
-			 * We can only cache the offset for a varlena attribute if the
-			 * offset is already suitably aligned, so that there would be no
-			 * pad bytes in any case: then the offset will be valid for either
-			 * an aligned or unaligned value.
-			 */
-			if (!slow &&
-				off == att_nominal_alignby(off, thisatt->attalignby))
-				thisatt->attcacheoff = off;
-			else
-			{
-				off = att_pointer_alignby(off, thisatt->attalignby, -1,
-										  tp + off);
-				slow = true;
-			}
-		}
-		else
-		{
-			/* not varlena, so safe to use att_nominal_alignby */
-			off = att_nominal_alignby(off, thisatt->attalignby);
+			values[attnum] = fetch_att_noerr(tp + cattr->attcacheoff, cattr->attbyval,
+											 cattr->attlen);
+		} while (++attnum < firstNonCacheOffsetAttr);
 
-			if (!slow)
-				thisatt->attcacheoff = off;
-		}
+		off = cattr->attcacheoff + cattr->attlen;
+	}
 
-		values[attnum] = fetchatt(thisatt, tp + off);
+	for (; attnum < firstNullAttr; attnum++)
+	{
+		isnull[attnum] = false;
+		cattr = TupleDescCompactAttr(tupleDescriptor, attnum);
+
+		/* align 'off', fetch the datum, and increment off beyond the datum */
+		values[attnum] = align_fetch_then_add(tp,
+											  &off,
+											  cattr->attbyval,
+											  cattr->attlen,
+											  cattr->attalignby);
+	}
 
-		off = att_addlength_pointer(off, thisatt->attlen, tp + off);
+	for (; attnum < natts; attnum++)
+	{
+		Assert(hasnulls);
 
-		if (thisatt->attlen <= 0)
-			slow = true;		/* can't use attcacheoff anymore */
+		if (att_isnull(attnum, bp))
+		{
+			values[attnum] = (Datum) 0;
+			isnull[attnum] = true;
+			continue;
+		}
+
+		isnull[attnum] = false;
+		cattr = TupleDescCompactAttr(tupleDescriptor, attnum);
+
+		/* align 'off', fetch the datum, and increment off beyond the datum */
+		values[attnum] = align_fetch_then_add(tp,
+											  &off,
+											  cattr->attbyval,
+											  cattr->attlen,
+											  cattr->attalignby);
 	}
 }
 
diff --git a/src/backend/access/common/tupdesc.c b/src/backend/access/common/tupdesc.c
index 2137385a833..c68561337d7 100644
--- a/src/backend/access/common/tupdesc.c
+++ b/src/backend/access/common/tupdesc.c
@@ -197,6 +197,10 @@ CreateTemplateTupleDesc(int natts)
 	desc->tdtypmod = -1;
 	desc->tdrefcount = -1;		/* assume not reference-counted */
 
+	/* This will be set to the correct value by TupleDescFinalize() */
+	desc->firstNonCachedOffsetAttr = -1;
+	desc->firstNonGuaranteedAttr = -1;
+
 	return desc;
 }
 
@@ -457,6 +461,9 @@ TupleDescCopy(TupleDesc dst, TupleDesc src)
  *		descriptor to another.
  *
  * !!! Constraints and defaults are not copied !!!
+ *
+ * The caller must take care of calling TupleDescFinalize() on 'dst' once all
+ * TupleDesc changes have been made.
  */
 void
 TupleDescCopyEntry(TupleDesc dst, AttrNumber dstAttno,
@@ -489,6 +496,50 @@ TupleDescCopyEntry(TupleDesc dst, AttrNumber dstAttno,
 	populate_compact_attribute(dst, dstAttno - 1);
 }
 
+/*
+ * TupleDescFinalize
+ *		Finalize the given TupleDesc.  This must be called after the
+ *		attributes arrays have been populated or adjusted by any code.
+ *
+ * Must be called after populate_compact_attribute() and before
+ * BlessTupleDesc().
+ */
+void
+TupleDescFinalize(TupleDesc tupdesc)
+{
+	int			firstNonCachedOffsetAttr = 0;
+	int			firstNonGuaranteedAttr = tupdesc->natts;
+	int			off = 0;
+
+	for (int i = 0; i < tupdesc->natts; i++)
+	{
+		CompactAttribute *cattr = TupleDescCompactAttr(tupdesc, i);
+
+		/*
+		 * Find the highest attnum which is guaranteed to exist in all tuples
+		 * in the table.  We currently only pay attention to byval attributes
+		 * to allow additional optimizations during tuple deformation.
+		 */
+		if (firstNonGuaranteedAttr == tupdesc->natts &&
+			(cattr->attnullability != ATTNULLABLE_VALID || !cattr->attbyval ||
+			 cattr->atthasmissing || cattr->attisdropped || cattr->attlen <= 0))
+			firstNonGuaranteedAttr = i;
+
+		if (cattr->attlen <= 0)
+			break;
+
+		off = att_nominal_alignby(off, cattr->attalignby);
+
+		cattr->attcacheoff = off;
+
+		off += cattr->attlen;
+		firstNonCachedOffsetAttr = i + 1;
+	}
+
+	tupdesc->firstNonCachedOffsetAttr = firstNonCachedOffsetAttr;
+	tupdesc->firstNonGuaranteedAttr = firstNonGuaranteedAttr;
+}
+
 /*
  * Free a TupleDesc including all substructure
  */
diff --git a/src/backend/access/spgist/spgutils.c b/src/backend/access/spgist/spgutils.c
index b246e8127db..a4694bd8065 100644
--- a/src/backend/access/spgist/spgutils.c
+++ b/src/backend/access/spgist/spgutils.c
@@ -335,9 +335,6 @@ getSpGistTupleDesc(Relation index, SpGistTypeDesc *keyType)
 		/* We shouldn't need to bother with making these valid: */
 		att->attcompression = InvalidCompressionMethod;
 		att->attcollation = InvalidOid;
-		/* In case we changed typlen, we'd better reset following offsets */
-		for (int i = spgFirstIncludeColumn; i < outTupDesc->natts; i++)
-			TupleDescCompactAttr(outTupDesc, i)->attcacheoff = -1;
 
 		populate_compact_attribute(outTupDesc, spgKeyColumn);
 		TupleDescFinalize(outTupDesc);
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index bfd3ebc601e..0b635486993 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -1944,7 +1944,7 @@ ExecPartitionCheckEmitError(ResultRelInfo *resultRelInfo,
 		 */
 		if (map != NULL)
 			slot = execute_attr_map_slot(map, slot,
-										 MakeTupleTableSlot(tupdesc, &TTSOpsVirtual));
+										 MakeTupleTableSlot(tupdesc, &TTSOpsVirtual, 0));
 		modifiedCols = bms_union(ExecGetInsertedCols(rootrel, estate),
 								 ExecGetUpdatedCols(rootrel, estate));
 	}
@@ -2060,7 +2060,7 @@ ExecConstraints(ResultRelInfo *resultRelInfo,
 				 */
 				if (map != NULL)
 					slot = execute_attr_map_slot(map, slot,
-												 MakeTupleTableSlot(tupdesc, &TTSOpsVirtual));
+												 MakeTupleTableSlot(tupdesc, &TTSOpsVirtual, 0));
 				modifiedCols = bms_union(ExecGetInsertedCols(rootrel, estate),
 										 ExecGetUpdatedCols(rootrel, estate));
 				rel = rootrel->ri_RelationDesc;
@@ -2196,7 +2196,7 @@ ReportNotNullViolationError(ResultRelInfo *resultRelInfo, TupleTableSlot *slot,
 		 */
 		if (map != NULL)
 			slot = execute_attr_map_slot(map, slot,
-										 MakeTupleTableSlot(tupdesc, &TTSOpsVirtual));
+										 MakeTupleTableSlot(tupdesc, &TTSOpsVirtual, 0));
 		modifiedCols = bms_union(ExecGetInsertedCols(rootrel, estate),
 								 ExecGetUpdatedCols(rootrel, estate));
 		rel = rootrel->ri_RelationDesc;
@@ -2304,7 +2304,7 @@ ExecWithCheckOptions(WCOKind kind, ResultRelInfo *resultRelInfo,
 						 */
 						if (map != NULL)
 							slot = execute_attr_map_slot(map, slot,
-														 MakeTupleTableSlot(tupdesc, &TTSOpsVirtual));
+														 MakeTupleTableSlot(tupdesc, &TTSOpsVirtual, 0));
 
 						modifiedCols = bms_union(ExecGetInsertedCols(rootrel, estate),
 												 ExecGetUpdatedCols(rootrel, estate));
diff --git a/src/backend/executor/execTuples.c b/src/backend/executor/execTuples.c
index 07b248aa5f3..14b2a9f0af6 100644
--- a/src/backend/executor/execTuples.c
+++ b/src/backend/executor/execTuples.c
@@ -992,118 +992,6 @@ tts_buffer_heap_store_tuple(TupleTableSlot *slot, HeapTuple tuple,
 	}
 }
 
-/*
- * slot_deform_heap_tuple_internal
- *		An always inline helper function for use in slot_deform_heap_tuple to
- *		allow the compiler to emit specialized versions of this function for
- *		various combinations of "slow" and "hasnulls".  For example, if a
- *		given tuple has no nulls, then we needn't check "hasnulls" for every
- *		attribute that we're deforming.  The caller can just call this
- *		function with hasnulls set to constant-false and have the compiler
- *		remove the constant-false branches and emit more optimal code.
- *
- * Returns the next attnum to deform, which can be equal to natts when the
- * function manages to deform all requested attributes.  *offp is an input and
- * output parameter which is the byte offset within the tuple to start deforming
- * from which, on return, gets set to the offset where the next attribute
- * should be deformed from.  *slowp is set to true when subsequent deforming
- * of this tuple must use a version of this function with "slow" passed as
- * true.
- *
- * Callers cannot assume when we return "attnum" (i.e. all requested
- * attributes have been deformed) that slow mode isn't required for any
- * additional deforming as the final attribute may have caused a switch to
- * slow mode.
- */
-static pg_attribute_always_inline int
-slot_deform_heap_tuple_internal(TupleTableSlot *slot, HeapTuple tuple,
-								int attnum, int natts, bool slow,
-								bool hasnulls, uint32 *offp, bool *slowp)
-{
-	TupleDesc	tupleDesc = slot->tts_tupleDescriptor;
-	Datum	   *values = slot->tts_values;
-	bool	   *isnull = slot->tts_isnull;
-	HeapTupleHeader tup = tuple->t_data;
-	char	   *tp;				/* ptr to tuple data */
-	bits8	   *bp = tup->t_bits;	/* ptr to null bitmap in tuple */
-	bool		slownext = false;
-
-	tp = (char *) tup + tup->t_hoff;
-
-	for (; attnum < natts; attnum++)
-	{
-		CompactAttribute *thisatt = TupleDescCompactAttr(tupleDesc, attnum);
-
-		if (hasnulls && att_isnull(attnum, bp))
-		{
-			values[attnum] = (Datum) 0;
-			isnull[attnum] = true;
-			if (!slow)
-			{
-				*slowp = true;
-				return attnum + 1;
-			}
-			else
-				continue;
-		}
-
-		isnull[attnum] = false;
-
-		/* calculate the offset of this attribute */
-		if (!slow && thisatt->attcacheoff >= 0)
-			*offp = thisatt->attcacheoff;
-		else if (thisatt->attlen == -1)
-		{
-			/*
-			 * We can only cache the offset for a varlena attribute if the
-			 * offset is already suitably aligned, so that there would be no
-			 * pad bytes in any case: then the offset will be valid for either
-			 * an aligned or unaligned value.
-			 */
-			if (!slow && *offp == att_nominal_alignby(*offp, thisatt->attalignby))
-				thisatt->attcacheoff = *offp;
-			else
-			{
-				*offp = att_pointer_alignby(*offp,
-											thisatt->attalignby,
-											-1,
-											tp + *offp);
-
-				if (!slow)
-					slownext = true;
-			}
-		}
-		else
-		{
-			/* not varlena, so safe to use att_nominal_alignby */
-			*offp = att_nominal_alignby(*offp, thisatt->attalignby);
-
-			if (!slow)
-				thisatt->attcacheoff = *offp;
-		}
-
-		values[attnum] = fetchatt(thisatt, tp + *offp);
-
-		*offp = att_addlength_pointer(*offp, thisatt->attlen, tp + *offp);
-
-		/* check if we need to switch to slow mode */
-		if (!slow)
-		{
-			/*
-			 * We're unable to deform any further if the above code set
-			 * 'slownext', or if this isn't a fixed-width attribute.
-			 */
-			if (slownext || thisatt->attlen <= 0)
-			{
-				*slowp = true;
-				return attnum + 1;
-			}
-		}
-	}
-
-	return natts;
-}
-
 /*
  * slot_deform_heap_tuple
  *		Given a TupleTableSlot, extract data from the slot's physical tuple
@@ -1125,94 +1013,228 @@ static pg_attribute_always_inline void
 slot_deform_heap_tuple(TupleTableSlot *slot, HeapTuple tuple, uint32 *offp,
 					   int reqnatts)
 {
-	bool		hasnulls = HeapTupleHasNulls(tuple);
-	int			attnum;
+	CompactAttribute *cattr;
+	TupleDesc	tupleDesc = slot->tts_tupleDescriptor;
+	HeapTupleHeader tup = tuple->t_data;
+	size_t		attnum;
+	int			firstNonCacheOffsetAttr;
+	int			firstNonGuaranteedAttr;
+	int			firstNullAttr;
 	int			natts;
+	Datum	   *values;
+	bool	   *isnull;
+	char	   *tp;				/* ptr to tuple data */
 	uint32		off;			/* offset in tuple data */
-	bool		slow;			/* can we use/set attcacheoff? */
 
-	/* We can only fetch as many attributes as the tuple has. */
-	natts = Min(HeapTupleHeaderGetNatts(tuple->t_data), reqnatts);
+	/* Did someone forget to call TupleDescFinalize()? */
+	Assert(tupleDesc->firstNonCachedOffsetAttr >= 0);
+
+	isnull = slot->tts_isnull;
 
 	/*
-	 * Check whether the first call for this tuple, and initialize or restore
-	 * loop state.
+	 * Some callers may form and deform tuples prior to NOT NULL constraints
+	 * being checked.  Here we'd like to optimize the case where we only need
+	 * to fetch attributes before or up to the point where the attribute is
+	 * guaranteed to exist in the tuple.  We rely on the slot flag being set
+	 * correctly to only enable this optimization when it's valid to do so.
+	 * This optimization allows us to save fetching the number of attributes
+	 * from the tuple and saves the additional cost of handling non-byval
+	 * attrs.
 	 */
+	firstNonGuaranteedAttr = Min(reqnatts, slot->tts_first_nonguaranteed);
+
+	firstNonCacheOffsetAttr = tupleDesc->firstNonCachedOffsetAttr;
+
+	if (HeapTupleHasNulls(tuple))
+	{
+		natts = HeapTupleHeaderGetNatts(tup);
+		tp = (char *) tup + MAXALIGN(offsetof(HeapTupleHeaderData, t_bits) +
+									 BITMAPLEN(natts));
+
+		natts = Min(natts, reqnatts);
+		if (natts > firstNonGuaranteedAttr)
+		{
+			bits8	   *bp = tup->t_bits;
+
+			/* Find the first NULL attr */
+			firstNullAttr = first_null_attr(bp, natts);
+
+			/*
+			 * And populate the isnull array for all attributes being fetched
+			 * from the tuple.
+			 */
+			populate_isnull_array(bp, natts, isnull);
+
+			/* We can only use any cached offsets until the first NULL attr */
+			firstNonCacheOffsetAttr = Min(firstNonCacheOffsetAttr,
+										  firstNullAttr);
+		}
+		else
+		{
+			/* Otherwise all required columns are guaranteed to exist */
+			firstNullAttr = natts;
+		}
+	}
+	else
+	{
+		tp = (char *) tup + MAXALIGN(offsetof(HeapTupleHeaderData, t_bits));
+
+		/*
+		 * We only need to look at the tuple's natts if we need more than the
+		 * guaranteed number of columns
+		 */
+		if (reqnatts > firstNonGuaranteedAttr)
+			natts = Min(HeapTupleHeaderGetNatts(tup), reqnatts);
+		else
+		{
+			/* No need to access the number of attributes in the tuple */
+			natts = reqnatts;
+		}
+
+		/* All attrs can be fetched without checking for NULLs */
+		firstNullAttr = natts;
+	}
+
 	attnum = slot->tts_nvalid;
+	values = slot->tts_values;
 	slot->tts_nvalid = reqnatts;
-	if (attnum == 0)
+
+	/* Ensure we calculated tp correctly */
+	Assert(tp == (char *) tup + tup->t_hoff);
+
+	if (attnum < firstNonGuaranteedAttr)
 	{
-		/* Start from the first attribute */
-		off = 0;
-		slow = false;
+		int			attlen;
+
+		for (; attnum < firstNonGuaranteedAttr; attnum++)
+		{
+			isnull[attnum] = false;
+			cattr = TupleDescCompactAttr(tupleDesc, attnum);
+			attlen = cattr->attlen;
+
+			/* We don't expect any non-byval types */
+			pg_assume(attlen > 0);
+			Assert(cattr->attbyval == true);
+
+			off = cattr->attcacheoff;
+			values[attnum] = fetch_att_noerr(tp + off, true, attlen);
+		}
+
+		off += attlen;
+
+		if (attnum == reqnatts)
+			goto done;
 	}
 	else
 	{
 		/* Restore state from previous execution */
 		off = *offp;
-		slow = TTS_SLOW(slot);
+
+		/* We expect *offp to be set to 0 when attnum == 0 */
+		Assert(off == 0 || attnum > 0);
 	}
 
+	/* We can only fetch as many attributes as the tuple has. */
+	firstNonCacheOffsetAttr = Min(firstNonCacheOffsetAttr, natts);
+
 	/*
-	 * If 'slow' isn't set, try deforming using deforming code that does not
-	 * contain any of the extra checks required for non-fixed offset
-	 * deforming.  During deforming, if or when we find a NULL or a variable
-	 * length attribute, we'll switch to a deforming method which includes the
-	 * extra code required for non-fixed offset deforming, a.k.a slow mode.
-	 * Because this is performance critical, we inline
-	 * slot_deform_heap_tuple_internal passing the 'slow' and 'hasnull'
-	 * parameters as constants to allow the compiler to emit specialized code
-	 * with the known-const false comparisons and subsequent branches removed.
+	 * Handle the portion of the tuple that we have cached the offset for up
+	 * to the first NULL attribute.  The offset is effectively fixed for
+	 * these, so we can use the CompactAttribute's attcacheoff.
 	 */
-	if (!slow)
+	if (attnum < firstNonCacheOffsetAttr)
 	{
-		/* Tuple without any NULLs? We can skip doing any NULL checking */
-		if (!hasnulls)
-			attnum = slot_deform_heap_tuple_internal(slot,
-													 tuple,
-													 attnum,
-													 natts,
-													 false, /* slow */
-													 false, /* hasnulls */
-													 &off,
-													 &slow);
-		else
-			attnum = slot_deform_heap_tuple_internal(slot,
-													 tuple,
-													 attnum,
-													 natts,
-													 false, /* slow */
-													 true,	/* hasnulls */
-													 &off,
-													 &slow);
+		int			attlen;
+
+		for (; attnum < firstNonCacheOffsetAttr; attnum++)
+		{
+			isnull[attnum] = false;
+			cattr = TupleDescCompactAttr(tupleDesc, attnum);
+			attlen = cattr->attlen;
+
+			off = cattr->attcacheoff;
+			values[attnum] = fetch_att_noerr(tp + off,
+											 cattr->attbyval,
+											 attlen);
+		}
+
+		/*
+		 * Point the offset after the end of the last attribute with a cached
+		 * offset.  We expect the final cached offset attribute to have a
+		 * fixed width, so just add the attlen to the attcacheoff
+		 */
+		Assert(attlen > 0);
+		off += attlen;
 	}
 
-	/* If there's still work to do then we must be in slow mode */
-	if (attnum < natts)
+	/*
+	 * Handle any portion of the tuple that doesn't have a fixed offset up
+	 * until the first NULL attribute.  This loop only differs from the one
+	 * after it by the NULL checks.
+	 */
+	for (; attnum < firstNullAttr; attnum++)
 	{
-		/* XXX is it worth adding a separate call when hasnulls is false? */
-		attnum = slot_deform_heap_tuple_internal(slot,
-												 tuple,
-												 attnum,
-												 natts,
-												 true,	/* slow */
-												 hasnulls,
-												 &off,
-												 &slow);
+		int			attlen;
+
+		isnull[attnum] = false;
+		cattr = TupleDescCompactAttr(tupleDesc, attnum);
+		attlen = cattr->attlen;
+
+		/*
+		 * cstrings don't exist in heap tuples.  Use pg_assume to instruct the
+		 * compiler not to emit the cstring-related code in
+		 * align_fetch_then_add().
+		 */
+		pg_assume(attlen > 0 || attlen == -1);
+
+		/* align 'off', fetch the datum, and increment off beyond the datum */
+		values[attnum] = align_fetch_then_add(tp,
+											  &off,
+											  cattr->attbyval,
+											  attlen,
+											  cattr->attalignby);
 	}
 
 	/*
-	 * Save state for next execution
+	 * Now handle any remaining attributes in the tuple up to the requested
+	 * attnum.  This time, include NULL checks as we're now at the first NULL
+	 * attribute.
 	 */
-	*offp = off;
-	if (slow)
-		slot->tts_flags |= TTS_FLAG_SLOW;
-	else
-		slot->tts_flags &= ~TTS_FLAG_SLOW;
+	for (; attnum < natts; attnum++)
+	{
+		int			attlen;
 
-	/* Fetch any missing attrs and raise an error if reqnatts is invalid. */
+		if (isnull[attnum])
+		{
+			values[attnum] = (Datum) 0;
+			continue;
+		}
+
+		cattr = TupleDescCompactAttr(tupleDesc, attnum);
+		attlen = cattr->attlen;
+
+		/* As above, we don't expect cstrings */
+		pg_assume(attlen > 0 || attlen == -1);
+
+		/* align 'off', fetch the datum, and increment off beyond the datum */
+		values[attnum] = align_fetch_then_add(tp,
+											  &off,
+											  cattr->attbyval,
+											  attlen,
+											  cattr->attalignby);
+	}
+
+	/* Fetch any missing attrs and raise an error if reqnatts is invalid */
 	if (unlikely(attnum < reqnatts))
+	{
+		*offp = off;
 		slot_getmissingattrs(slot, attnum, reqnatts);
+		return;
+	}
+done:
+
+	/* Save current offset for next execution */
+	*offp = off;
 }
 
 const TupleTableSlotOps TTSOpsVirtual = {
@@ -1307,7 +1329,7 @@ const TupleTableSlotOps TTSOpsBufferHeapTuple = {
  */
 TupleTableSlot *
 MakeTupleTableSlot(TupleDesc tupleDesc,
-				   const TupleTableSlotOps *tts_ops)
+				   const TupleTableSlotOps *tts_ops, uint16 flags)
 {
 	Size		basesz,
 				allocsz;
@@ -1331,6 +1353,7 @@ MakeTupleTableSlot(TupleDesc tupleDesc,
 	*((const TupleTableSlotOps **) &slot->tts_ops) = tts_ops;
 	slot->type = T_TupleTableSlot;
 	slot->tts_flags |= TTS_FLAG_EMPTY;
+	slot->tts_flags |= flags;
 	if (tupleDesc != NULL)
 		slot->tts_flags |= TTS_FLAG_FIXED;
 	slot->tts_tupleDescriptor = tupleDesc;
@@ -1342,12 +1365,31 @@ MakeTupleTableSlot(TupleDesc tupleDesc,
 		slot->tts_values = (Datum *)
 			(((char *) slot)
 			 + MAXALIGN(basesz));
+
+		/*
+		 * We round the size of tts_isnull up to the next highest multiple of
+		 * 8.  This is needed as populate_isnull_array() operates on 8
+		 * elements at a time when converting a tuple's NULL bitmap into a
+		 * boolean array.
+		 */
 		slot->tts_isnull = (bool *)
 			(((char *) slot)
 			 + MAXALIGN(basesz)
-			 + MAXALIGN(tupleDesc->natts * sizeof(Datum)));
+			 + TYPEALIGN(8, tupleDesc->natts * sizeof(Datum)));
 
 		PinTupleDesc(tupleDesc);
+
+		/*
+		 * Precalculate the maximum guaranteed attribute that has to exist in
+		 * every tuple which gets deformed into this slot.  When the
+		 * TTS_FLAG_OBEYS_NOT_NULL_CONSTRAINTS flag is enabled, we simply take
+		 * the precalculated value from the tupleDesc, otherwise the
+		 * optimization is disabled, and we set the value to 0.
+		 */
+		if ((flags & TTS_FLAG_OBEYS_NOT_NULL_CONSTRAINTS) != 0)
+			slot->tts_first_nonguaranteed = tupleDesc->firstNonGuaranteedAttr;
+		else
+			slot->tts_first_nonguaranteed = 0;
 	}
 
 	/*
@@ -1366,9 +1408,9 @@ MakeTupleTableSlot(TupleDesc tupleDesc,
  */
 TupleTableSlot *
 ExecAllocTableSlot(List **tupleTable, TupleDesc desc,
-				   const TupleTableSlotOps *tts_ops)
+				   const TupleTableSlotOps *tts_ops, uint16 flags)
 {
-	TupleTableSlot *slot = MakeTupleTableSlot(desc, tts_ops);
+	TupleTableSlot *slot = MakeTupleTableSlot(desc, tts_ops, flags);
 
 	*tupleTable = lappend(*tupleTable, slot);
 
@@ -1435,7 +1477,7 @@ TupleTableSlot *
 MakeSingleTupleTableSlot(TupleDesc tupdesc,
 						 const TupleTableSlotOps *tts_ops)
 {
-	TupleTableSlot *slot = MakeTupleTableSlot(tupdesc, tts_ops);
+	TupleTableSlot *slot = MakeTupleTableSlot(tupdesc, tts_ops, 0);
 
 	return slot;
 }
@@ -1515,8 +1557,14 @@ ExecSetSlotDescriptor(TupleTableSlot *slot, /* slot to change */
 	 */
 	slot->tts_values = (Datum *)
 		MemoryContextAlloc(slot->tts_mcxt, tupdesc->natts * sizeof(Datum));
+
+	/*
+	 * We round the size of tts_isnull up to the next highest multiple of 8.
+	 * This is needed as populate_isnull_array() operates on 8 elements at a
+	 * time when converting a tuple's NULL bitmap into a boolean array.
+	 */
 	slot->tts_isnull = (bool *)
-		MemoryContextAlloc(slot->tts_mcxt, tupdesc->natts * sizeof(bool));
+		MemoryContextAlloc(slot->tts_mcxt, TYPEALIGN(8, tupdesc->natts * sizeof(bool)));
 }
 
 /* --------------------------------
@@ -1978,7 +2026,7 @@ ExecInitResultSlot(PlanState *planstate, const TupleTableSlotOps *tts_ops)
 	TupleTableSlot *slot;
 
 	slot = ExecAllocTableSlot(&planstate->state->es_tupleTable,
-							  planstate->ps_ResultTupleDesc, tts_ops);
+							  planstate->ps_ResultTupleDesc, tts_ops, 0);
 	planstate->ps_ResultTupleSlot = slot;
 
 	planstate->resultopsfixed = planstate->ps_ResultTupleDesc != NULL;
@@ -2006,10 +2054,11 @@ ExecInitResultTupleSlotTL(PlanState *planstate,
  */
 void
 ExecInitScanTupleSlot(EState *estate, ScanState *scanstate,
-					  TupleDesc tupledesc, const TupleTableSlotOps *tts_ops)
+					  TupleDesc tupledesc, const TupleTableSlotOps *tts_ops,
+					  uint16 flags)
 {
 	scanstate->ss_ScanTupleSlot = ExecAllocTableSlot(&estate->es_tupleTable,
-													 tupledesc, tts_ops);
+													 tupledesc, tts_ops, flags);
 	scanstate->ps.scandesc = tupledesc;
 	scanstate->ps.scanopsfixed = tupledesc != NULL;
 	scanstate->ps.scanops = tts_ops;
@@ -2029,7 +2078,7 @@ ExecInitExtraTupleSlot(EState *estate,
 					   TupleDesc tupledesc,
 					   const TupleTableSlotOps *tts_ops)
 {
-	return ExecAllocTableSlot(&estate->es_tupleTable, tupledesc, tts_ops);
+	return ExecAllocTableSlot(&estate->es_tupleTable, tupledesc, tts_ops, 0);
 }
 
 /* ----------------
@@ -2261,10 +2310,16 @@ ExecTypeSetColNames(TupleDesc typeInfo, List *namesList)
  * This happens "for free" if the tupdesc came from a relcache entry, but
  * not if we have manufactured a tupdesc for a transient RECORD datatype.
  * In that case we have to notify typcache.c of the existence of the type.
+ *
+ * TupleDescFinalize() must be called on the TupleDesc before calling this
+ * function.
  */
 TupleDesc
 BlessTupleDesc(TupleDesc tupdesc)
 {
+	/* Did someone forget to call TupleDescFinalize()? */
+	Assert(tupdesc->firstNonCachedOffsetAttr >= 0);
+
 	if (tupdesc->tdtypeid == RECORDOID &&
 		tupdesc->tdtypmod < 0)
 		assign_record_type_typmod(tupdesc);
diff --git a/src/backend/executor/execUtils.c b/src/backend/executor/execUtils.c
index a7955e476f9..f62582859f9 100644
--- a/src/backend/executor/execUtils.c
+++ b/src/backend/executor/execUtils.c
@@ -711,7 +711,7 @@ ExecCreateScanSlotFromOuterPlan(EState *estate,
 	outerPlan = outerPlanState(scanstate);
 	tupDesc = ExecGetResultType(outerPlan);
 
-	ExecInitScanTupleSlot(estate, scanstate, tupDesc, tts_ops);
+	ExecInitScanTupleSlot(estate, scanstate, tupDesc, tts_ops, 0);
 }
 
 /* ----------------------------------------------------------------
diff --git a/src/backend/executor/nodeAgg.c b/src/backend/executor/nodeAgg.c
index 7d487a165fa..c5c321b4f42 100644
--- a/src/backend/executor/nodeAgg.c
+++ b/src/backend/executor/nodeAgg.c
@@ -1682,7 +1682,7 @@ find_hash_columns(AggState *aggstate)
 							  &perhash->hashfunctions);
 		perhash->hashslot =
 			ExecAllocTableSlot(&estate->es_tupleTable, hashDesc,
-							   &TTSOpsMinimalTuple);
+							   &TTSOpsMinimalTuple, 0);
 
 		list_free(hashTlist);
 		bms_free(colnos);
diff --git a/src/backend/executor/nodeBitmapHeapscan.c b/src/backend/executor/nodeBitmapHeapscan.c
index c68c26cbf38..dcb7599b96c 100644
--- a/src/backend/executor/nodeBitmapHeapscan.c
+++ b/src/backend/executor/nodeBitmapHeapscan.c
@@ -381,7 +381,10 @@ ExecInitBitmapHeapScan(BitmapHeapScan *node, EState *estate, int eflags)
 	 */
 	ExecInitScanTupleSlot(estate, &scanstate->ss,
 						  RelationGetDescr(currentRelation),
-						  table_slot_callbacks(currentRelation));
+						  table_slot_callbacks(currentRelation), 0);
+
+	scanstate->ss.ss_ScanTupleSlot->tts_flags |=
+		TTS_FLAG_OBEYS_NOT_NULL_CONSTRAINTS;
 
 	/*
 	 * Initialize result type and projection.
diff --git a/src/backend/executor/nodeCtescan.c b/src/backend/executor/nodeCtescan.c
index e6e476388e5..45b09d93b93 100644
--- a/src/backend/executor/nodeCtescan.c
+++ b/src/backend/executor/nodeCtescan.c
@@ -261,7 +261,7 @@ ExecInitCteScan(CteScan *node, EState *estate, int eflags)
 	 */
 	ExecInitScanTupleSlot(estate, &scanstate->ss,
 						  ExecGetResultType(scanstate->cteplanstate),
-						  &TTSOpsMinimalTuple);
+						  &TTSOpsMinimalTuple, 0);
 
 	/*
 	 * Initialize result type and projection.
diff --git a/src/backend/executor/nodeCustom.c b/src/backend/executor/nodeCustom.c
index a9ad5af6a98..b7cc890cd20 100644
--- a/src/backend/executor/nodeCustom.c
+++ b/src/backend/executor/nodeCustom.c
@@ -79,14 +79,14 @@ ExecInitCustomScan(CustomScan *cscan, EState *estate, int eflags)
 		TupleDesc	scan_tupdesc;
 
 		scan_tupdesc = ExecTypeFromTL(cscan->custom_scan_tlist);
-		ExecInitScanTupleSlot(estate, &css->ss, scan_tupdesc, slotOps);
+		ExecInitScanTupleSlot(estate, &css->ss, scan_tupdesc, slotOps, 0);
 		/* Node's targetlist will contain Vars with varno = INDEX_VAR */
 		tlistvarno = INDEX_VAR;
 	}
 	else
 	{
 		ExecInitScanTupleSlot(estate, &css->ss, RelationGetDescr(scan_rel),
-							  slotOps);
+							  slotOps, 0);
 		/* Node's targetlist will contain Vars with varno = scanrelid */
 		tlistvarno = scanrelid;
 	}
diff --git a/src/backend/executor/nodeForeignscan.c b/src/backend/executor/nodeForeignscan.c
index 8721b67b7cc..6f0daddce07 100644
--- a/src/backend/executor/nodeForeignscan.c
+++ b/src/backend/executor/nodeForeignscan.c
@@ -191,7 +191,7 @@ ExecInitForeignScan(ForeignScan *node, EState *estate, int eflags)
 
 		scan_tupdesc = ExecTypeFromTL(node->fdw_scan_tlist);
 		ExecInitScanTupleSlot(estate, &scanstate->ss, scan_tupdesc,
-							  &TTSOpsHeapTuple);
+							  &TTSOpsHeapTuple, 0);
 		/* Node's targetlist will contain Vars with varno = INDEX_VAR */
 		tlistvarno = INDEX_VAR;
 	}
@@ -202,7 +202,7 @@ ExecInitForeignScan(ForeignScan *node, EState *estate, int eflags)
 		/* don't trust FDWs to return tuples fulfilling NOT NULL constraints */
 		scan_tupdesc = CreateTupleDescCopy(RelationGetDescr(currentRelation));
 		ExecInitScanTupleSlot(estate, &scanstate->ss, scan_tupdesc,
-							  &TTSOpsHeapTuple);
+							  &TTSOpsHeapTuple, 0);
 		/* Node's targetlist will contain Vars with varno = scanrelid */
 		tlistvarno = scanrelid;
 	}
diff --git a/src/backend/executor/nodeFunctionscan.c b/src/backend/executor/nodeFunctionscan.c
index feb82d64967..222741adf3b 100644
--- a/src/backend/executor/nodeFunctionscan.c
+++ b/src/backend/executor/nodeFunctionscan.c
@@ -494,7 +494,7 @@ ExecInitFunctionScan(FunctionScan *node, EState *estate, int eflags)
 	 * Initialize scan slot and type.
 	 */
 	ExecInitScanTupleSlot(estate, &scanstate->ss, scan_tupdesc,
-						  &TTSOpsMinimalTuple);
+						  &TTSOpsMinimalTuple, 0);
 
 	/*
 	 * Initialize result slot, type and projection.
diff --git a/src/backend/executor/nodeIndexonlyscan.c b/src/backend/executor/nodeIndexonlyscan.c
index c2d09374517..144a57fde95 100644
--- a/src/backend/executor/nodeIndexonlyscan.c
+++ b/src/backend/executor/nodeIndexonlyscan.c
@@ -567,7 +567,10 @@ ExecInitIndexOnlyScan(IndexOnlyScan *node, EState *estate, int eflags)
 	 */
 	tupDesc = ExecTypeFromTL(node->indextlist);
 	ExecInitScanTupleSlot(estate, &indexstate->ss, tupDesc,
-						  &TTSOpsVirtual);
+						  &TTSOpsVirtual, 0);
+
+	indexstate->ss.ss_ScanTupleSlot->tts_flags |=
+		TTS_FLAG_OBEYS_NOT_NULL_CONSTRAINTS;
 
 	/*
 	 * We need another slot, in a format that's suitable for the table AM, for
@@ -576,7 +579,7 @@ ExecInitIndexOnlyScan(IndexOnlyScan *node, EState *estate, int eflags)
 	indexstate->ioss_TableSlot =
 		ExecAllocTableSlot(&estate->es_tupleTable,
 						   RelationGetDescr(currentRelation),
-						   table_slot_callbacks(currentRelation));
+						   table_slot_callbacks(currentRelation), 0);
 
 	/*
 	 * Initialize result type and projection info.  The node's targetlist will
diff --git a/src/backend/executor/nodeIndexscan.c b/src/backend/executor/nodeIndexscan.c
index a616abff04c..e7bebb89517 100644
--- a/src/backend/executor/nodeIndexscan.c
+++ b/src/backend/executor/nodeIndexscan.c
@@ -938,7 +938,10 @@ ExecInitIndexScan(IndexScan *node, EState *estate, int eflags)
 	 */
 	ExecInitScanTupleSlot(estate, &indexstate->ss,
 						  RelationGetDescr(currentRelation),
-						  table_slot_callbacks(currentRelation));
+						  table_slot_callbacks(currentRelation), 0);
+
+	indexstate->ss.ss_ScanTupleSlot->tts_flags |=
+		TTS_FLAG_OBEYS_NOT_NULL_CONSTRAINTS;
 
 	/*
 	 * Initialize result type and projection.
diff --git a/src/backend/executor/nodeNamedtuplestorescan.c b/src/backend/executor/nodeNamedtuplestorescan.c
index fdfccc8169f..29d862a4001 100644
--- a/src/backend/executor/nodeNamedtuplestorescan.c
+++ b/src/backend/executor/nodeNamedtuplestorescan.c
@@ -137,7 +137,7 @@ ExecInitNamedTuplestoreScan(NamedTuplestoreScan *node, EState *estate, int eflag
 	 * The scan tuple type is specified for the tuplestore.
 	 */
 	ExecInitScanTupleSlot(estate, &scanstate->ss, scanstate->tupdesc,
-						  &TTSOpsMinimalTuple);
+						  &TTSOpsMinimalTuple, 0);
 
 	/*
 	 * Initialize result type and projection.
diff --git a/src/backend/executor/nodeSamplescan.c b/src/backend/executor/nodeSamplescan.c
index 1b0af70fd7a..a1da05ecc18 100644
--- a/src/backend/executor/nodeSamplescan.c
+++ b/src/backend/executor/nodeSamplescan.c
@@ -128,7 +128,11 @@ ExecInitSampleScan(SampleScan *node, EState *estate, int eflags)
 	/* and create slot with appropriate rowtype */
 	ExecInitScanTupleSlot(estate, &scanstate->ss,
 						  RelationGetDescr(scanstate->ss.ss_currentRelation),
-						  table_slot_callbacks(scanstate->ss.ss_currentRelation));
+						  table_slot_callbacks(scanstate->ss.ss_currentRelation),
+						  0);
+
+	scanstate->ss.ss_ScanTupleSlot->tts_flags |=
+		TTS_FLAG_OBEYS_NOT_NULL_CONSTRAINTS;
 
 	/*
 	 * Initialize result type and projection.
diff --git a/src/backend/executor/nodeSeqscan.c b/src/backend/executor/nodeSeqscan.c
index af3c788ce8b..8f219f60a93 100644
--- a/src/backend/executor/nodeSeqscan.c
+++ b/src/backend/executor/nodeSeqscan.c
@@ -244,7 +244,8 @@ ExecInitSeqScan(SeqScan *node, EState *estate, int eflags)
 	/* and create slot with the appropriate rowtype */
 	ExecInitScanTupleSlot(estate, &scanstate->ss,
 						  RelationGetDescr(scanstate->ss.ss_currentRelation),
-						  table_slot_callbacks(scanstate->ss.ss_currentRelation));
+						  table_slot_callbacks(scanstate->ss.ss_currentRelation),
+						  TTS_FLAG_OBEYS_NOT_NULL_CONSTRAINTS);
 
 	/*
 	 * Initialize result type and projection.
diff --git a/src/backend/executor/nodeSubqueryscan.c b/src/backend/executor/nodeSubqueryscan.c
index 4fd6f6fb4a5..70914e8189c 100644
--- a/src/backend/executor/nodeSubqueryscan.c
+++ b/src/backend/executor/nodeSubqueryscan.c
@@ -130,7 +130,8 @@ ExecInitSubqueryScan(SubqueryScan *node, EState *estate, int eflags)
 	 */
 	ExecInitScanTupleSlot(estate, &subquerystate->ss,
 						  ExecGetResultType(subquerystate->subplan),
-						  ExecGetResultSlotOps(subquerystate->subplan, NULL));
+						  ExecGetResultSlotOps(subquerystate->subplan, NULL),
+						  0);
 
 	/*
 	 * The slot used as the scantuple isn't the slot above (outside of EPQ),
diff --git a/src/backend/executor/nodeTableFuncscan.c b/src/backend/executor/nodeTableFuncscan.c
index 52070d147a4..769b9766542 100644
--- a/src/backend/executor/nodeTableFuncscan.c
+++ b/src/backend/executor/nodeTableFuncscan.c
@@ -148,7 +148,7 @@ ExecInitTableFuncScan(TableFuncScan *node, EState *estate, int eflags)
 								 tf->colcollations);
 	/* and the corresponding scan slot */
 	ExecInitScanTupleSlot(estate, &scanstate->ss, tupdesc,
-						  &TTSOpsMinimalTuple);
+						  &TTSOpsMinimalTuple, 0);
 
 	/*
 	 * Initialize result type and projection.
diff --git a/src/backend/executor/nodeTidrangescan.c b/src/backend/executor/nodeTidrangescan.c
index 503817da65b..decc3167ba7 100644
--- a/src/backend/executor/nodeTidrangescan.c
+++ b/src/backend/executor/nodeTidrangescan.c
@@ -394,7 +394,10 @@ ExecInitTidRangeScan(TidRangeScan *node, EState *estate, int eflags)
 	 */
 	ExecInitScanTupleSlot(estate, &tidrangestate->ss,
 						  RelationGetDescr(currentRelation),
-						  table_slot_callbacks(currentRelation));
+						  table_slot_callbacks(currentRelation), 0);
+
+	tidrangestate->ss.ss_ScanTupleSlot->tts_flags |=
+		TTS_FLAG_OBEYS_NOT_NULL_CONSTRAINTS;
 
 	/*
 	 * Initialize result type and projection.
diff --git a/src/backend/executor/nodeTidscan.c b/src/backend/executor/nodeTidscan.c
index 4eddb0828b5..26593b930af 100644
--- a/src/backend/executor/nodeTidscan.c
+++ b/src/backend/executor/nodeTidscan.c
@@ -536,7 +536,10 @@ ExecInitTidScan(TidScan *node, EState *estate, int eflags)
 	 */
 	ExecInitScanTupleSlot(estate, &tidstate->ss,
 						  RelationGetDescr(currentRelation),
-						  table_slot_callbacks(currentRelation));
+						  table_slot_callbacks(currentRelation), 0);
+
+	tidstate->ss.ss_ScanTupleSlot->tts_flags |=
+		TTS_FLAG_OBEYS_NOT_NULL_CONSTRAINTS;
 
 	/*
 	 * Initialize result type and projection.
diff --git a/src/backend/executor/nodeValuesscan.c b/src/backend/executor/nodeValuesscan.c
index e663fb68cfc..effc896ea1c 100644
--- a/src/backend/executor/nodeValuesscan.c
+++ b/src/backend/executor/nodeValuesscan.c
@@ -247,7 +247,7 @@ ExecInitValuesScan(ValuesScan *node, EState *estate, int eflags)
 	 * Get info about values list, initialize scan slot with it.
 	 */
 	tupdesc = ExecTypeFromExprList((List *) linitial(node->values_lists));
-	ExecInitScanTupleSlot(estate, &scanstate->ss, tupdesc, &TTSOpsVirtual);
+	ExecInitScanTupleSlot(estate, &scanstate->ss, tupdesc, &TTSOpsVirtual, 0);
 
 	/*
 	 * Initialize result type and projection.
diff --git a/src/backend/executor/nodeWorktablescan.c b/src/backend/executor/nodeWorktablescan.c
index 210cc44f911..66e904c7636 100644
--- a/src/backend/executor/nodeWorktablescan.c
+++ b/src/backend/executor/nodeWorktablescan.c
@@ -165,7 +165,7 @@ ExecInitWorkTableScan(WorkTableScan *node, EState *estate, int eflags)
 	scanstate->ss.ps.resultopsset = true;
 	scanstate->ss.ps.resultopsfixed = false;
 
-	ExecInitScanTupleSlot(estate, &scanstate->ss, NULL, &TTSOpsMinimalTuple);
+	ExecInitScanTupleSlot(estate, &scanstate->ss, NULL, &TTSOpsMinimalTuple, 0);
 
 	/*
 	 * initialize child expressions
diff --git a/src/backend/jit/llvm/llvmjit_deform.c b/src/backend/jit/llvm/llvmjit_deform.c
index 3eb087eb56b..12521e3e46a 100644
--- a/src/backend/jit/llvm/llvmjit_deform.c
+++ b/src/backend/jit/llvm/llvmjit_deform.c
@@ -62,7 +62,6 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 	LLVMValueRef v_tts_values;
 	LLVMValueRef v_tts_nulls;
 	LLVMValueRef v_slotoffp;
-	LLVMValueRef v_flagsp;
 	LLVMValueRef v_nvalidp;
 	LLVMValueRef v_nvalid;
 	LLVMValueRef v_maxatt;
@@ -178,7 +177,6 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 	v_tts_nulls =
 		l_load_struct_gep(b, StructTupleTableSlot, v_slot, FIELDNO_TUPLETABLESLOT_ISNULL,
 						  "tts_ISNULL");
-	v_flagsp = l_struct_gep(b, StructTupleTableSlot, v_slot, FIELDNO_TUPLETABLESLOT_FLAGS, "");
 	v_nvalidp = l_struct_gep(b, StructTupleTableSlot, v_slot, FIELDNO_TUPLETABLESLOT_NVALID, "");
 
 	if (ops == &TTSOpsHeapTuple || ops == &TTSOpsBufferHeapTuple)
@@ -747,14 +745,10 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 
 	{
 		LLVMValueRef v_off = l_load(b, TypeSizeT, v_offp, "");
-		LLVMValueRef v_flags;
 
 		LLVMBuildStore(b, l_int16_const(lc, natts), v_nvalidp);
 		v_off = LLVMBuildTrunc(b, v_off, LLVMInt32TypeInContext(lc), "");
 		LLVMBuildStore(b, v_off, v_slotoffp);
-		v_flags = l_load(b, LLVMInt16TypeInContext(lc), v_flagsp, "tts_flags");
-		v_flags = LLVMBuildOr(b, v_flags, l_int16_const(lc, TTS_FLAG_SLOW), "");
-		LLVMBuildStore(b, v_flags, v_flagsp);
 		LLVMBuildRetVoid(b);
 	}
 
diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
index 857ebf7d6fb..4ecfcbff7ab 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -1559,7 +1559,7 @@ pgoutput_change(LogicalDecodingContext *ctx, ReorderBufferTXN *txn,
 		if (relentry->attrmap)
 		{
 			TupleTableSlot *slot = MakeTupleTableSlot(RelationGetDescr(targetrel),
-													  &TTSOpsVirtual);
+													  &TTSOpsVirtual, 0);
 
 			old_slot = execute_attr_map_slot(relentry->attrmap, old_slot, slot);
 		}
@@ -1574,7 +1574,7 @@ pgoutput_change(LogicalDecodingContext *ctx, ReorderBufferTXN *txn,
 		if (relentry->attrmap)
 		{
 			TupleTableSlot *slot = MakeTupleTableSlot(RelationGetDescr(targetrel),
-													  &TTSOpsVirtual);
+													  &TTSOpsVirtual, 0);
 
 			new_slot = execute_attr_map_slot(relentry->attrmap, new_slot, slot);
 		}
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index d27ac216e6d..597de687b45 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -666,14 +666,6 @@ RelationBuildTupleDesc(Relation relation)
 		elog(ERROR, "pg_attribute catalog is missing %d attribute(s) for relation OID %u",
 			 need, RelationGetRelid(relation));
 
-	/*
-	 * 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)
-		TupleDescCompactAttr(relation->rd_att, 0)->attcacheoff = 0;
-
 	/*
 	 * Set up constraint/default info
 	 */
@@ -1985,8 +1977,6 @@ formrdesc(const char *relationName, Oid relationReltype,
 		populate_compact_attribute(relation->rd_att, i);
 	}
 
-	/* initialize first attribute's attcacheoff, cf RelationBuildTupleDesc */
-	TupleDescCompactAttr(relation->rd_att, 0)->attcacheoff = 0;
 	TupleDescFinalize(relation->rd_att);
 
 	/* mark not-null status */
@@ -4446,8 +4436,6 @@ BuildHardcodedDescriptor(int natts, const FormData_pg_attribute *attrs)
 		populate_compact_attribute(result, i);
 	}
 
-	/* initialize first attribute's attcacheoff, cf RelationBuildTupleDesc */
-	TupleDescCompactAttr(result, 0)->attcacheoff = 0;
 	TupleDescFinalize(result);
 
 	/* Note: we don't bother to set up a TupleConstr entry */
diff --git a/src/include/access/tupdesc.h b/src/include/access/tupdesc.h
index 595413dbbc5..ad7bc013812 100644
--- a/src/include/access/tupdesc.h
+++ b/src/include/access/tupdesc.h
@@ -131,6 +131,19 @@ typedef struct CompactAttribute
  * Any code making changes manually to and fields in the FormData_pg_attribute
  * array must subsequently call populate_compact_attribute() to flush the
  * changes out to the corresponding 'compact_attrs' element.
+ *
+ * firstNonCachedOffsetAttr stores the index into the compact_attrs array for
+ * the first attribute that we don't have a known attcacheoff for.
+ *
+ * firstNonGuaranteedAttr stores the index to into the compact_attrs array for
+ * the first attribute that is either NULLable, missing, or !attbyval.  This
+ * can be used in locations as a guarantee that attributes before this will
+ * always exist in tuples.  The !attbyval part isn't required for this, but
+ * including this allows various tuple deforming routines to forego any checks
+ * for !attbyval.
+ *
+ * Once a TupleDesc has been populated, before it is used for any purpose,
+ * TupleDescFinalize() must be called on it.
  */
 typedef struct TupleDescData
 {
@@ -138,6 +151,11 @@ typedef struct TupleDescData
 	Oid			tdtypeid;		/* composite type ID for tuple type */
 	int32		tdtypmod;		/* typmod for tuple type */
 	int			tdrefcount;		/* reference count, or -1 if not counting */
+	int			firstNonCachedOffsetAttr;	/* index of the first att without
+											 * an attcacheoff */
+	int			firstNonGuaranteedAttr; /* index of the first nullable,
+										 * missing, dropped, or !attbyval
+										 * attribute. */
 	TupleConstr *constr;		/* constraints, or NULL if none */
 	/* compact_attrs[N] is the compact metadata of Attribute Number N+1 */
 	CompactAttribute compact_attrs[FLEXIBLE_ARRAY_MEMBER];
@@ -195,7 +213,6 @@ extern TupleDesc CreateTupleDescTruncatedCopy(TupleDesc tupdesc, int natts);
 
 extern TupleDesc CreateTupleDescCopyConstr(TupleDesc tupdesc);
 
-#define TupleDescFinalize(d) ((void) 0)
 #define TupleDescSize(src) \
 	(offsetof(struct TupleDescData, compact_attrs) + \
 	 (src)->natts * sizeof(CompactAttribute) + \
@@ -206,6 +223,7 @@ extern void TupleDescCopy(TupleDesc dst, TupleDesc src);
 extern void TupleDescCopyEntry(TupleDesc dst, AttrNumber dstAttno,
 							   TupleDesc src, AttrNumber srcAttno);
 
+extern void TupleDescFinalize(TupleDesc tupdesc);
 extern void FreeTupleDesc(TupleDesc tupdesc);
 
 extern void IncrTupleDescRefCount(TupleDesc tupdesc);
diff --git a/src/include/access/tupmacs.h b/src/include/access/tupmacs.h
index d64c18b950b..87dbeb76618 100644
--- a/src/include/access/tupmacs.h
+++ b/src/include/access/tupmacs.h
@@ -15,7 +15,9 @@
 #define TUPMACS_H
 
 #include "catalog/pg_type_d.h"	/* for TYPALIGN macros */
-
+#include "port/pg_bitutils.h"
+#include "port/pg_bswap.h"
+#include "varatt.h"
 
 /*
  * Check a tuple's null bitmap to determine whether the attribute is null.
@@ -28,6 +30,62 @@ att_isnull(int ATT, const bits8 *BITS)
 	return !(BITS[ATT >> 3] & (1 << (ATT & 0x07)));
 }
 
+/*
+ * populate_isnull_array
+ *		Transform a tuple's null bitmap into a boolean array.
+ *
+ * Caller must ensure that the isnull array is sized so it contains
+ * at least as many elements as there are bits in the 'bits' array.
+ * Callers should be aware that isnull is populated 8 elements at a time,
+ * effectively as if natts is rounded up to the next multiple of 8.
+ */
+static inline void
+populate_isnull_array(const bits8 *bits, int natts, bool *isnull)
+{
+	int			nbytes = (natts + 7) >> 3;
+
+	/*
+	 * Multiplying the inverted NULL bitmap byte by this value results in the
+	 * lowest bit in each byte being set the same as each bit of the inverted
+	 * byte.  We perform this as 2 32-bit operations rather than a single
+	 * 64-bit operation as multiplying by the required value to do this in
+	 * 64-bits would result in overflowing a uint64 in some cases.
+	 *
+	 * XXX if we ever require BMI2 (-march=x86-64-v3), then this could be done
+	 * more efficiently on most X86-64 CPUs with the PDEP instruction.  Beware
+	 * that some chips (e.g. AMD's Zen2) are horribly inefficient at PDEP.
+	 */
+#define SPREAD_BITS_MULTIPLIER_32 0x204081U
+
+	for (int i = 0; i < nbytes; i++, isnull += 8)
+	{
+		uint64		isnull_8;
+		bits8		nullbyte = ~bits[i];
+
+		/* Convert the lower 4 bits of NULL bitmap word into a 64 bit int */
+		isnull_8 = (nullbyte & 0xf) * SPREAD_BITS_MULTIPLIER_32;
+
+		/*
+		 * Convert the upper 4 bits of null bitmap word into a 64 bit int,
+		 * shift into the upper 32 bit and bitwise-OR with the result of the
+		 * lower 4 bits.
+		 */
+		isnull_8 |= ((uint64) ((nullbyte >> 4) * SPREAD_BITS_MULTIPLIER_32)) << 32;
+
+		/* Mask out all other bits apart from the lowest bit of each byte. */
+		isnull_8 &= UINT64CONST(0x0101010101010101);
+
+#ifdef WORDS_BIGENDIAN
+
+		/*
+		 * Fix byte order on big-endian machines before copying to the array.
+		 */
+		isnull_8 = pg_bswap64(isnull_8);
+#endif
+		memcpy(isnull, &isnull_8, sizeof(uint64));
+	}
+}
+
 #ifndef FRONTEND
 /*
  * Given an attbyval and an attlen from either a Form_pg_attribute or
@@ -69,6 +127,170 @@ fetch_att(const void *T, bool attbyval, int attlen)
 	else
 		return PointerGetDatum(T);
 }
+
+/*
+ * Same, but no error checking for invalid attlens for byval types.  This
+ * is safe to use when attlen comes from CompactAttribute as we validate the
+ * length when populating that struct.
+ */
+static inline Datum
+fetch_att_noerr(const void *T, bool attbyval, int attlen)
+{
+	if (attbyval)
+	{
+		switch (attlen)
+		{
+			case sizeof(int32):
+				return Int32GetDatum(*((const int32 *) T));
+			case sizeof(int16):
+				return Int16GetDatum(*((const int16 *) T));
+			case sizeof(char):
+				return CharGetDatum(*((const char *) T));
+			default:
+				Assert(attlen == sizeof(int64));
+				return Int64GetDatum(*((const int64 *) T));
+		}
+	}
+	else
+		return PointerGetDatum(T);
+}
+
+
+/*
+ * align_fetch_then_add
+ *		Applies all the functionality of att_pointer_alignby(),
+ *		fetch_att_noerr() and att_addlength_pointer(), resulting in the *off
+ *		pointer to the perhaps unaligned number of bytes into 'tupptr', ready
+ *		to deform the next attribute.
+ *
+ * tupptr: pointer to the beginning of the tuple, after the header and any
+ * NULL bitmask.
+ * off: offset in bytes for reading tuple data, possibly unaligned.
+ * attbyval, attlen and attalignby are values from CompactAttribute.
+ */
+static inline Datum
+align_fetch_then_add(const char *tupptr, uint32 *off, bool attbyval, int attlen,
+					 uint8 attalignby)
+{
+	Datum		res;
+
+	if (attlen > 0)
+	{
+		const char *offset_ptr;
+
+		*off = TYPEALIGN(attalignby, *off);
+		offset_ptr = tupptr + *off;
+		*off += attlen;
+		if (attbyval)
+		{
+			switch (attlen)
+			{
+				case sizeof(char):
+					return CharGetDatum(*((const char *) offset_ptr));
+				case sizeof(int16):
+					return Int16GetDatum(*((const int16 *) offset_ptr));
+				case sizeof(int32):
+					return Int32GetDatum(*((const int32 *) offset_ptr));
+				default:
+
+					/*
+					 * populate_compact_attribute_internal() should have
+					 * checked
+					 */
+					Assert(attlen == sizeof(int64));
+					return Int64GetDatum(*((const int64 *) offset_ptr));
+			}
+		}
+		return PointerGetDatum(offset_ptr);
+	}
+	else if (attlen == -1)
+	{
+		if (!VARATT_IS_SHORT(tupptr + *off))
+			*off = TYPEALIGN(attalignby, *off);
+
+		res = PointerGetDatum(tupptr + *off);
+		*off += VARSIZE_ANY(DatumGetPointer(res));
+		return res;
+	}
+	else
+	{
+		Assert(attlen == -2);
+		*off = TYPEALIGN(attalignby, *off);
+		res = PointerGetDatum(tupptr + *off);
+		*off += strlen(tupptr + *off) + 1;
+		return res;
+	}
+}
+
+/*
+ * first_null_attr
+ *		Inspect a NULL bitmap from a tuple and return the 0-based attnum of the
+ *		first NULL attribute.  Returns natts if no NULLs were found.
+ *
+ * This is coded to expect that 'bits' contains at least one 0 bit somewhere
+ * in the array, but not necessarily < natts.  Note that natts may be passed
+ * as a value lower than the number of bits physically stored in the tuple's
+ * NULL bitmap, in which case we may not find a NULL and return natts.
+ *
+ * The reason we require at least one 0 bit somewhere in the NULL bitmap is
+ * that the for loop that checks 0xFF bytes would loop to the last byte in
+ * the array if all bytes were 0xFF, and the subsequent code that finds the
+ * right-most 0 bit would access the first byte beyond the bitmap.  Provided
+ * we find a 0 bit before then, that won't happen.  Since tuples which have no
+ * NULLs don't have a NULL bitmap, this function won't get called for that
+ * case.
+ */
+static inline int
+first_null_attr(const bits8 *bits, int natts)
+{
+	int			nattByte = natts >> 3;
+	int			bytenum;
+	int			res;
+
+#ifdef USE_ASSERT_CHECKING
+	int			firstnull_check = natts;
+
+	/* Do it the slow way and check we get the same answer. */
+	for (int i = 0; i < natts; i++)
+	{
+		if (att_isnull(i, bits))
+		{
+			firstnull_check = i;
+			break;
+		}
+	}
+#endif
+
+	/* Process all bytes up to just before the byte for the natts attribute */
+	for (bytenum = 0; bytenum < nattByte; bytenum++)
+	{
+		/* break if there's any NULL attrs (a 0 bit) */
+		if (bits[bytenum] != 0xFF)
+			break;
+	}
+
+	/*
+	 * Look for the highest 0-bit in the 'bytenum' element.  To do this, we
+	 * promote the uint8 to uint32 before performing the bitwise NOT and
+	 * looking for the first 1-bit.  This works even when the byte is 0xFF, as
+	 * the bitwise NOT of 0xFF in 32 bits is 0xFFFFFF00, in which case
+	 * pg_rightmost_one_pos32() will return 8.  We may end up with a value
+	 * higher than natts here, but we'll fix that with the Min() below.
+	 */
+	res = bytenum << 3;
+	res += pg_rightmost_one_pos32(~((uint32) bits[bytenum]));
+
+	/*
+	 * Since we did no masking to mask out bits beyond the natt'th bit, we may
+	 * have found a bit higher than natts, so we must cap res to natts
+	 */
+	res = Min(res, natts);
+
+	/* Ensure we got the same answer as the att_isnull() loop got */
+	Assert(res == firstnull_check);
+
+	return res;
+}
 #endif							/* FRONTEND */
 
 /*
diff --git a/src/include/executor/executor.h b/src/include/executor/executor.h
index d46ba59895d..bf239fc156f 100644
--- a/src/include/executor/executor.h
+++ b/src/include/executor/executor.h
@@ -595,7 +595,8 @@ extern void ExecInitResultTupleSlotTL(PlanState *planstate,
 									  const TupleTableSlotOps *tts_ops);
 extern void ExecInitScanTupleSlot(EState *estate, ScanState *scanstate,
 								  TupleDesc tupledesc,
-								  const TupleTableSlotOps *tts_ops);
+								  const TupleTableSlotOps *tts_ops,
+								  uint16 flags);
 extern TupleTableSlot *ExecInitExtraTupleSlot(EState *estate,
 											  TupleDesc tupledesc,
 											  const TupleTableSlotOps *tts_ops);
diff --git a/src/include/executor/tuptable.h b/src/include/executor/tuptable.h
index 3b09abbf99f..78558098fa3 100644
--- a/src/include/executor/tuptable.h
+++ b/src/include/executor/tuptable.h
@@ -84,9 +84,6 @@
  * tts_values/tts_isnull are allocated either when the slot is created (when
  * the descriptor is provided), or when a descriptor is assigned to the slot;
  * they are of length equal to the descriptor's natts.
- *
- * The TTS_FLAG_SLOW flag is saved state for
- * slot_deform_heap_tuple, and should not be touched by any other code.
  *----------
  */
 
@@ -98,9 +95,13 @@
 #define			TTS_FLAG_SHOULDFREE		(1 << 2)
 #define TTS_SHOULDFREE(slot) (((slot)->tts_flags & TTS_FLAG_SHOULDFREE) != 0)
 
-/* saved state for slot_deform_heap_tuple */
-#define			TTS_FLAG_SLOW		(1 << 3)
-#define TTS_SLOW(slot) (((slot)->tts_flags & TTS_FLAG_SLOW) != 0)
+/*
+ * true = slot's formed tuple guaranteed to not have NULLs in NOT NULLable
+ * columns.
+ */
+#define			TTS_FLAG_OBEYS_NOT_NULL_CONSTRAINTS		(1 << 3)
+#define TTS_OBEYS_NOT_NULL_CONSTRAINTS(slot) \
+	(((slot)->tts_flags & TTS_FLAG_OBEYS_NOT_NULL_CONSTRAINTS) != 0)
 
 /* fixed tuple descriptor */
 #define			TTS_FLAG_FIXED		(1 << 4)
@@ -123,7 +124,14 @@ typedef struct TupleTableSlot
 #define FIELDNO_TUPLETABLESLOT_VALUES 5
 	Datum	   *tts_values;		/* current per-attribute values */
 #define FIELDNO_TUPLETABLESLOT_ISNULL 6
-	bool	   *tts_isnull;		/* current per-attribute isnull flags */
+	bool	   *tts_isnull;		/* current per-attribute isnull flags.  Array
+								 * size must always be rounded up to the next
+								 * multiple of 8 elements. */
+	int			tts_first_nonguaranteed;	/* The value from the TupleDesc's
+											 * firstNonGuaranteedAttr, or 0
+											 * when tts_flags does not contain
+											 * TTS_FLAG_OBEYS_NOT_NULL_CONSTRAINTS */
+
 	MemoryContext tts_mcxt;		/* slot itself is in this context */
 	ItemPointerData tts_tid;	/* stored tuple's tid */
 	Oid			tts_tableOid;	/* table oid of tuple */
@@ -313,9 +321,11 @@ typedef struct MinimalTupleTableSlot
 
 /* in executor/execTuples.c */
 extern TupleTableSlot *MakeTupleTableSlot(TupleDesc tupleDesc,
-										  const TupleTableSlotOps *tts_ops);
+										  const TupleTableSlotOps *tts_ops,
+										  uint16 flags);
 extern TupleTableSlot *ExecAllocTableSlot(List **tupleTable, TupleDesc desc,
-										  const TupleTableSlotOps *tts_ops);
+										  const TupleTableSlotOps *tts_ops,
+										  uint16 flags);
 extern void ExecResetTupleTable(List *tupleTable, bool shouldFree);
 extern TupleTableSlot *MakeSingleTupleTableSlot(TupleDesc tupdesc,
 												const TupleTableSlotOps *tts_ops);
diff --git a/src/test/modules/deform_bench/deform_bench.c b/src/test/modules/deform_bench/deform_bench.c
index 7838f639bef..4f104989297 100644
--- a/src/test/modules/deform_bench/deform_bench.c
+++ b/src/test/modules/deform_bench/deform_bench.c
@@ -48,7 +48,9 @@ deform_bench(PG_FUNCTION_ARGS)
 				 errmsg("only heap AM is supported")));
 
 	tupdesc = RelationGetDescr(rel);
-	slot = MakeTupleTableSlot(tupdesc, &TTSOpsBufferHeapTuple);
+	slot = MakeTupleTableSlot(tupdesc,
+							  &TTSOpsBufferHeapTuple,
+							  TTS_FLAG_OBEYS_NOT_NULL_CONSTRAINTS);
 	scan = table_beginscan_strat(rel, GetActiveSnapshot(), 0, NULL, true, false);
 
 	/*
-- 
2.51.0

From 8e1a945f172e3c6e9cc0092e5c2168151ed8c6d1 Mon Sep 17 00:00:00 2001
From: David Rowley <[email-masked]>
Date: Mon, 23 Feb 2026 09:39:37 +1300
Subject: [PATCH v12 5/6] Reduce size of CompactAttribute struct to 8 bytes

Previously, this was 16 bytes.  With the use of some bitflags and by
reducing the attcacheoff field size to a 16-bit type, we can halve the
size of the struct.

It's unlikely that caching the offsets for offsets larger than what will
fit in a 16-bit int will help much as the tuple is very likely to have
some non-fixed-width types anyway, the offsets of which we cannot cache.
---
 src/backend/access/common/tupdesc.c | 10 ++++++++++
 src/backend/executor/execTuples.c   | 17 ++++++++++++-----
 src/include/access/tupdesc.h        | 16 ++++++++--------
 3 files changed, 30 insertions(+), 13 deletions(-)

diff --git a/src/backend/access/common/tupdesc.c b/src/backend/access/common/tupdesc.c
index c68561337d7..71461ba6096 100644
--- a/src/backend/access/common/tupdesc.c
+++ b/src/backend/access/common/tupdesc.c
@@ -530,6 +530,16 @@ TupleDescFinalize(TupleDesc tupdesc)
 
 		off = att_nominal_alignby(off, cattr->attalignby);
 
+		/*
+		 * attcacheoff is an int16, so don't try to cache any offsets larger
+		 * than will fit in that type.  Any attributes which are offset more
+		 * than 2^15 are likely due to variable-length attributes.  Since we
+		 * don't cache offsets for or beyond variable-length attributes, using
+		 * an int16 rather than an int32 here is unlikely to cost us anything.
+		 */
+		if (off > PG_INT16_MAX)
+			break;
+
 		cattr->attcacheoff = off;
 
 		off += cattr->attlen;
diff --git a/src/backend/executor/execTuples.c b/src/backend/executor/execTuples.c
index 14b2a9f0af6..1b5e1ebd334 100644
--- a/src/backend/executor/execTuples.c
+++ b/src/backend/executor/execTuples.c
@@ -1013,6 +1013,7 @@ static pg_attribute_always_inline void
 slot_deform_heap_tuple(TupleTableSlot *slot, HeapTuple tuple, uint32 *offp,
 					   int reqnatts)
 {
+	CompactAttribute *cattrs;
 	CompactAttribute *cattr;
 	TupleDesc	tupleDesc = slot->tts_tupleDescriptor;
 	HeapTupleHeader tup = tuple->t_data;
@@ -1099,6 +1100,13 @@ slot_deform_heap_tuple(TupleTableSlot *slot, HeapTuple tuple, uint32 *offp,
 	values = slot->tts_values;
 	slot->tts_nvalid = reqnatts;
 
+	/*
+	 * We store the tupleDesc's CompactAttribute array in 'cattrs' as gcc
+	 * seems to be unwilling to optimize accessing the CompactAttribute
+	 * element efficiently when accessing it via TupleDescCompactAttr().
+	 */
+	cattrs = tupleDesc->compact_attrs;
+
 	/* Ensure we calculated tp correctly */
 	Assert(tp == (char *) tup + tup->t_hoff);
 
@@ -1109,7 +1117,7 @@ slot_deform_heap_tuple(TupleTableSlot *slot, HeapTuple tuple, uint32 *offp,
 		for (; attnum < firstNonGuaranteedAttr; attnum++)
 		{
 			isnull[attnum] = false;
-			cattr = TupleDescCompactAttr(tupleDesc, attnum);
+			cattr = &cattrs[attnum];
 			attlen = cattr->attlen;
 
 			/* We don't expect any non-byval types */
@@ -1149,9 +1157,8 @@ slot_deform_heap_tuple(TupleTableSlot *slot, HeapTuple tuple, uint32 *offp,
 		for (; attnum < firstNonCacheOffsetAttr; attnum++)
 		{
 			isnull[attnum] = false;
-			cattr = TupleDescCompactAttr(tupleDesc, attnum);
+			cattr = &cattrs[attnum];
 			attlen = cattr->attlen;
-
 			off = cattr->attcacheoff;
 			values[attnum] = fetch_att_noerr(tp + off,
 											 cattr->attbyval,
@@ -1177,7 +1184,7 @@ slot_deform_heap_tuple(TupleTableSlot *slot, HeapTuple tuple, uint32 *offp,
 		int			attlen;
 
 		isnull[attnum] = false;
-		cattr = TupleDescCompactAttr(tupleDesc, attnum);
+		cattr = &cattrs[attnum];
 		attlen = cattr->attlen;
 
 		/*
@@ -1210,7 +1217,7 @@ slot_deform_heap_tuple(TupleTableSlot *slot, HeapTuple tuple, uint32 *offp,
 			continue;
 		}
 
-		cattr = TupleDescCompactAttr(tupleDesc, attnum);
+		cattr = &cattrs[attnum];
 		attlen = cattr->attlen;
 
 		/* As above, we don't expect cstrings */
diff --git a/src/include/access/tupdesc.h b/src/include/access/tupdesc.h
index ad7bc013812..e98036b58bf 100644
--- a/src/include/access/tupdesc.h
+++ b/src/include/access/tupdesc.h
@@ -55,7 +55,7 @@ typedef struct TupleConstr
  *		directly after the FormData_pg_attribute struct is populated or
  *		altered in any way.
  *
- * Currently, this struct is 16 bytes.  Any code changes which enlarge this
+ * Currently, this struct is 8 bytes.  Any code changes which enlarge this
  * struct should be considered very carefully.
  *
  * Code which must access a TupleDesc's attribute data should always make use
@@ -67,17 +67,17 @@ typedef struct TupleConstr
  */
 typedef struct CompactAttribute
 {
-	int32		attcacheoff;	/* fixed offset into tuple, if known, or -1 */
+	int16		attcacheoff;	/* fixed offset into tuple, if known, or -1 */
 	int16		attlen;			/* attr len in bytes or -1 = varlen, -2 =
 								 * cstring */
 	bool		attbyval;		/* as FormData_pg_attribute.attbyval */
-	bool		attispackable;	/* FormData_pg_attribute.attstorage !=
-								 * TYPSTORAGE_PLAIN */
-	bool		atthasmissing;	/* as FormData_pg_attribute.atthasmissing */
-	bool		attisdropped;	/* as FormData_pg_attribute.attisdropped */
-	bool		attgenerated;	/* FormData_pg_attribute.attgenerated != '\0' */
-	char		attnullability; /* status of not-null constraint, see below */
 	uint8		attalignby;		/* alignment requirement in bytes */
+	bool		attispackable:1;	/* FormData_pg_attribute.attstorage !=
+									 * TYPSTORAGE_PLAIN */
+	bool		atthasmissing:1;	/* as FormData_pg_attribute.atthasmissing */
+	bool		attisdropped:1; /* as FormData_pg_attribute.attisdropped */
+	bool		attgenerated:1; /* FormData_pg_attribute.attgenerated != '\0' */
+	char		attnullability; /* status of not-null constraint, see below */
 } CompactAttribute;
 
 /* Valid values for CompactAttribute->attnullability */
-- 
2.51.0

From 894745116658acec4a5a53657af465255cca7068 Mon Sep 17 00:00:00 2001
From: David Rowley <[email-masked]>
Date: Wed, 4 Mar 2026 16:55:09 +1300
Subject: [PATCH v12 6/6] WIP: Introduce selective tuple deforming

Up until now, we have always deformed every attribute of each tuple up
until the last attribute that we require.  This did once make sense to
do as we often had to walk the tuple in order to determine the byte
offset to any attribute that we deform.  Now, since we proactively
populate the CompactAttribute.attcacheoff, in some cases we might be in
a better position to only deform the attributes that we need to deform
by directly jumping to the cached byte offset and skipping deforming any
attributes which are not required.  In some cases the savings can be
very large as it not only allows tts_values and tts_isnull for unneeded
attributes to be left unpopulated, but it might also mean we can skip
loading entire cachelines when the tuple is wide enough to span multiple
cachelines.

We don't want to exclusively always deform tuples this way as doing this
means paying attention to an additional array which states which attnums
we must deform.  Looking at that array for a SELECT * query, which
requires us to deform all attributes, would add overhead.  To support
this a new expression evaluation operator has been added called
EEOP_SCAN_SELECTSOME and each function which builds an ExprState now
accepts a variant function that allows the caller to specify which attnums
are required from the scan side.  This puts it on the caller to decide
which type of deforming should be done.  When the caller provides
the attnums, the expression will be built with EEOP_SCAN_SELECTSOME
rather than EEOP_SCAN_FETCHSOME.  This currently does not interact well
with the physical tlist optimization.  Currently it's the planner's job
to figure out which attributes are actually required.

TODO: JIT support
---
 src/backend/executor/execExpr.c         | 166 ++++++++++-
 src/backend/executor/execExprInterp.c   |  13 +
 src/backend/executor/execScan.c         |  18 ++
 src/backend/executor/execTuples.c       | 362 +++++++++++++++++++++++-
 src/backend/executor/execUtils.c        |  47 ++-
 src/backend/executor/nodeSeqscan.c      |   8 +-
 src/backend/optimizer/plan/createplan.c |  43 ++-
 src/include/executor/execExpr.h         |  24 +-
 src/include/executor/executor.h         |  19 ++
 src/include/executor/tuptable.h         |  22 ++
 src/include/nodes/plannodes.h           |   8 +
 11 files changed, 702 insertions(+), 28 deletions(-)

diff --git a/src/backend/executor/execExpr.c b/src/backend/executor/execExpr.c
index 088eca24021..8a2bf04598b 100644
--- a/src/backend/executor/execExpr.c
+++ b/src/backend/executor/execExpr.c
@@ -66,6 +66,14 @@ typedef struct ExprSetupInfo
 	AttrNumber	last_new;
 	/* MULTIEXPR SubPlan nodes appearing in the expression: */
 	List	   *multiexpr_subplans;
+
+	/*
+	 * Fetch only these attnums from the scan with EEOP_SCAN_SELECTSOME. Empty
+	 * set means use EEOP_SCAN_FETCHSOME (i.e fetch all up until last_scan).
+	 * The first user attribute is based at member 0.  System attributes not
+	 * represented.
+	 */
+	Bitmapset  *scan_attrs;
 } ExprSetupInfo;
 
 static void ExecReadyExpr(ExprState *state);
@@ -77,7 +85,8 @@ static void ExecInitFunc(ExprEvalStep *scratch, Expr *node, List *args,
 static void ExecInitSubPlanExpr(SubPlan *subplan,
 								ExprState *state,
 								Datum *resv, bool *resnull);
-static void ExecCreateExprSetupSteps(ExprState *state, Node *node);
+static void ExecCreateExprSetupSteps(ExprState *state, Node *node,
+									 Bitmapset *scan_attrs);
 static void ExecPushExprSetupSteps(ExprState *state, ExprSetupInfo *info);
 static bool expr_setup_walker(Node *node, ExprSetupInfo *info);
 static bool ExecComputeSlotInfo(ExprState *state, ExprEvalStep *op);
@@ -141,6 +150,19 @@ static void ExecInitJsonCoercion(ExprState *state, JsonReturning *returning,
  */
 ExprState *
 ExecInitExpr(Expr *node, PlanState *parent)
+{
+	return ExecInitExprWithScanAttrs(node, parent, NULL);
+}
+
+/*
+ * ExecInitExprWithScanAttrs
+ *		As ExecInitExpr but when 'scan_attrs' is set, use
+ *		EEOP_SCAN_SELECTSOME instead of EEOP_SCAN_FETCHSOME to deform only
+ *		the mentioned 'scan_attrs' from the scan tuple.
+ */
+ExprState *
+ExecInitExprWithScanAttrs(Expr *node, PlanState *parent,
+						  Bitmapset *scan_attrs)
 {
 	ExprState  *state;
 	ExprEvalStep scratch = {0};
@@ -156,7 +178,7 @@ ExecInitExpr(Expr *node, PlanState *parent)
 	state->ext_params = NULL;
 
 	/* Insert setup steps as needed */
-	ExecCreateExprSetupSteps(state, (Node *) node);
+	ExecCreateExprSetupSteps(state, (Node *) node, scan_attrs);
 
 	/* Compile the expression proper */
 	ExecInitExprRec(node, state, &state->resvalue, &state->resnull);
@@ -193,7 +215,7 @@ ExecInitExprWithParams(Expr *node, ParamListInfo ext_params)
 	state->ext_params = ext_params;
 
 	/* Insert setup steps as needed */
-	ExecCreateExprSetupSteps(state, (Node *) node);
+	ExecCreateExprSetupSteps(state, (Node *) node, NULL);
 
 	/* Compile the expression proper */
 	ExecInitExprRec(node, state, &state->resvalue, &state->resnull);
@@ -227,6 +249,19 @@ ExecInitExprWithParams(Expr *node, ParamListInfo ext_params)
  */
 ExprState *
 ExecInitQual(List *qual, PlanState *parent)
+{
+	return ExecInitQualWithScanAttrs(qual, parent, NULL);
+}
+
+/*
+ * ExecInitQualWithScanAttrs
+ *		As ExecInitQual but when 'scan_attrs' is set, use
+ *		EEOP_SCAN_SELECTSOME instead of EEOP_SCAN_FETCHSOME to deform only
+ *		the mentioned 'scan_attrs' from the scan tuple.
+ */
+ExprState *
+ExecInitQualWithScanAttrs(List *qual, PlanState *parent,
+						  Bitmapset *scan_attrs)
 {
 	ExprState  *state;
 	ExprEvalStep scratch = {0};
@@ -247,7 +282,7 @@ ExecInitQual(List *qual, PlanState *parent)
 	state->flags = EEO_FLAG_IS_QUAL;
 
 	/* Insert setup steps as needed */
-	ExecCreateExprSetupSteps(state, (Node *) qual);
+	ExecCreateExprSetupSteps(state, (Node *) qual, scan_attrs);
 
 	/*
 	 * ExecQual() needs to return false for an expression returning NULL. That
@@ -372,6 +407,28 @@ ExecBuildProjectionInfo(List *targetList,
 						TupleTableSlot *slot,
 						PlanState *parent,
 						TupleDesc inputDesc)
+{
+	return ExecBuildProjectionInfoWithScanAttrs(targetList,
+												econtext,
+												slot,
+												parent,
+												inputDesc,
+												NULL);
+}
+
+/*
+ * ExecBuildProjectionInfoWithScanAttrs
+ *		As ExecBuildProjectionInfo but when 'scan_attrs' is set, use
+ *		EEOP_SCAN_SELECTSOME instead of EEOP_SCAN_FETCHSOME to deform only
+ *		the mentioned 'scan_attrs' from the scan tuple.
+ */
+ProjectionInfo *
+ExecBuildProjectionInfoWithScanAttrs(List *targetList,
+									 ExprContext *econtext,
+									 TupleTableSlot *slot,
+									 PlanState *parent,
+									 TupleDesc inputDesc,
+									 Bitmapset *scan_attrs)
 {
 	ProjectionInfo *projInfo = makeNode(ProjectionInfo);
 	ExprState  *state;
@@ -389,7 +446,7 @@ ExecBuildProjectionInfo(List *targetList,
 	state->resultslot = slot;
 
 	/* Insert setup steps as needed */
-	ExecCreateExprSetupSteps(state, (Node *) targetList);
+	ExecCreateExprSetupSteps(state, (Node *) targetList, scan_attrs);
 
 	/* Now compile each tlist column */
 	foreach(lc, targetList)
@@ -2871,11 +2928,19 @@ ExecInitSubPlanExpr(SubPlan *subplan,
 /*
  * Add expression steps performing setup that's needed before any of the
  * main execution of the expression.
+ *
+ * 'scan_attrs' may be given an empty set, in which case deforming the scan
+ * tuple is done via EEOP_SCAN_FETCHSOME, which fetches every attribute from
+ * the scan tuple up until the maximum attribute used by this expression.
+ * When 'scan_attrs' is set, EEOP_SCAN_SELECTSOME is used to only fetch the
+ * attributes mentioned.  Callers must create a unioned set of the attributes
+ * needed from the scan for all expressions using the given slot so that we
+ * incrementally fetch the attributes required by all ExprStates.
  */
 static void
-ExecCreateExprSetupSteps(ExprState *state, Node *node)
+ExecCreateExprSetupSteps(ExprState *state, Node *node, Bitmapset *scan_attrs)
 {
-	ExprSetupInfo info = {0, 0, 0, 0, 0, NIL};
+	ExprSetupInfo info = {0, 0, 0, 0, 0, NIL, scan_attrs};
 
 	/* Prescan to find out what we need. */
 	expr_setup_walker(node, &info);
@@ -2923,11 +2988,75 @@ ExecPushExprSetupSteps(ExprState *state, ExprSetupInfo *info)
 	}
 	if (info->last_scan > 0)
 	{
-		scratch.opcode = EEOP_SCAN_FETCHSOME;
-		scratch.d.fetch.last_var = info->last_scan;
-		scratch.d.fetch.fixed = false;
-		scratch.d.fetch.kind = NULL;
-		scratch.d.fetch.known_desc = NULL;
+		/*
+		 * We have two operators for fetching attributes out of a tuple during
+		 * scans.  EEOP_SCAN_FETCHSOME deforms all attributes in the tuple up
+		 * to the 'last_scan' attnum.  This isn't ideal in some cases, as we
+		 * may only need a few attributes, and those might be deep into the
+		 * tuple.  EEOP_SCAN_SELECTSOME is an operator that fetches only the
+		 * required attributes from the tuple.  When the attcacheoff for these
+		 * attributes is known and no NULLs exist in the tuple prior to the
+		 * required attributes, then this can be a very fast operation.
+		 * EEOP_SCAN_FETCHSOME is still supported as many cases require all
+		 * attributes, and EEOP_SCAN_FETCHSOME can do this more efficiently.
+		 */
+		if (bms_is_empty(info->scan_attrs))
+		{
+			scratch.opcode = EEOP_SCAN_FETCHSOME;
+			scratch.d.fetch.last_var = info->last_scan;
+			scratch.d.fetch.fixed = false;
+			scratch.d.fetch.kind = NULL;
+			scratch.d.fetch.known_desc = NULL;
+		}
+		else
+		{
+			int			nattrs = bms_num_members(info->scan_attrs);
+			AttrNumber *atts;
+			int			a;
+			int			i;
+
+			scratch.opcode = EEOP_SCAN_SELECTSOME;
+			scratch.d.fetch.last_var = info->last_scan;
+			scratch.d.fetch.fixed = false;
+			scratch.d.fetch.natts = nattrs;
+			scratch.d.fetch.kind = NULL;
+			scratch.d.fetch.known_desc = NULL;
+
+			/*
+			 * Allocate these two arrays as a single allocation.  The
+			 * req_attnums array needs 1 element for each attnum that's being
+			 * selected, plus a sentinel attnum which we set to the
+			 * 'last_scan' attnum so that we correctly terminate each of the
+			 * loops during selective deformation before walking off the end
+			 * of the array.
+			 */
+			atts = palloc_array(AttrNumber, nattrs + 1 + info->last_scan + 1);
+
+			scratch.d.fetch.req_attnums = atts;
+			scratch.d.fetch.next_req_attnums_index = &atts[nattrs + 1];
+
+			/* Store each attnum in the Bitmapset into the req_attnum array */
+			a = -1;
+			i = 0;
+			while ((a = bms_next_member(info->scan_attrs, a)) >= 0)
+				scratch.d.fetch.req_attnums[i++] = a;
+
+			/* install sentinel */
+			scratch.d.fetch.req_attnums[nattrs] = info->last_scan;
+
+			/*
+			 * Populate the next_req_attnums_index array.  This allows the
+			 * deforming function to refind the position in the
+			 * next_req_attnums_index array from tts_nvalid.
+			 */
+			a = 0;
+			for (i = 0; i <= info->last_scan; i++)
+			{
+				scratch.d.fetch.next_req_attnums_index[i] = a;
+				if (bms_is_member(i, info->scan_attrs))
+					a++;
+			}
+		}
 		if (ExecComputeSlotInfo(state, &scratch))
 			ExprEvalPushStep(state, &scratch);
 	}
@@ -3000,6 +3129,13 @@ expr_setup_walker(Node *node, ExprSetupInfo *info)
 				switch (variable->varreturningtype)
 				{
 					case VAR_RETURNING_DEFAULT:
+
+						/*
+						 * scan_attrs must contain a member for this attnum or
+						 * be completely empty
+						 */
+						Assert(attnum < 0 || bms_is_empty(info->scan_attrs) ||
+							   bms_is_member(attnum - 1, info->scan_attrs));
 						info->last_scan = Max(info->last_scan, attnum);
 						break;
 					case VAR_RETURNING_OLD:
@@ -3066,7 +3202,8 @@ ExecComputeSlotInfo(ExprState *state, ExprEvalStep *op)
 		   opcode == EEOP_OUTER_FETCHSOME ||
 		   opcode == EEOP_SCAN_FETCHSOME ||
 		   opcode == EEOP_OLD_FETCHSOME ||
-		   opcode == EEOP_NEW_FETCHSOME);
+		   opcode == EEOP_NEW_FETCHSOME ||
+		   opcode == EEOP_SCAN_SELECTSOME);
 
 	if (op->d.fetch.known_desc != NULL)
 	{
@@ -3119,6 +3256,7 @@ ExecComputeSlotInfo(ExprState *state, ExprEvalStep *op)
 		}
 	}
 	else if (opcode == EEOP_SCAN_FETCHSOME ||
+			 opcode == EEOP_SCAN_SELECTSOME ||
 			 opcode == EEOP_OLD_FETCHSOME ||
 			 opcode == EEOP_NEW_FETCHSOME)
 	{
@@ -4311,7 +4449,7 @@ ExecBuildHash32Expr(TupleDesc desc, const TupleTableSlotOps *ops,
 	state->parent = parent;
 
 	/* Insert setup steps as needed. */
-	ExecCreateExprSetupSteps(state, (Node *) hash_exprs);
+	ExecCreateExprSetupSteps(state, (Node *) hash_exprs, NULL);
 
 	/*
 	 * Make a place to store intermediate hash values between subsequent
diff --git a/src/backend/executor/execExprInterp.c b/src/backend/executor/execExprInterp.c
index 61ff5ddc74c..76965826f83 100644
--- a/src/backend/executor/execExprInterp.c
+++ b/src/backend/executor/execExprInterp.c
@@ -479,6 +479,7 @@ ExecInterpExpr(ExprState *state, ExprContext *econtext, bool *isnull)
 		&&CASE_EEOP_SCAN_FETCHSOME,
 		&&CASE_EEOP_OLD_FETCHSOME,
 		&&CASE_EEOP_NEW_FETCHSOME,
+		&&CASE_EEOP_SCAN_SELECTSOME,
 		&&CASE_EEOP_INNER_VAR,
 		&&CASE_EEOP_OUTER_VAR,
 		&&CASE_EEOP_SCAN_VAR,
@@ -676,6 +677,18 @@ ExecInterpExpr(ExprState *state, ExprContext *econtext, bool *isnull)
 			EEO_NEXT();
 		}
 
+		EEO_CASE(EEOP_SCAN_SELECTSOME)
+		{
+			CheckOpSlotCompatibility(op, scanslot);
+
+			slot_selectattrs(scanslot,
+							 op->d.fetch.last_var,
+							 op->d.fetch.req_attnums,
+							 op->d.fetch.next_req_attnums_index);
+
+			EEO_NEXT();
+		}
+
 		EEO_CASE(EEOP_INNER_VAR)
 		{
 			int			attnum = op->d.var.attnum;
diff --git a/src/backend/executor/execScan.c b/src/backend/executor/execScan.c
index 9f68be17b99..525af11aa08 100644
--- a/src/backend/executor/execScan.c
+++ b/src/backend/executor/execScan.c
@@ -86,6 +86,24 @@ ExecAssignScanProjectionInfo(ScanState *node)
 	ExecConditionalAssignProjectionInfo(&node->ps, tupdesc, scan->scanrelid);
 }
 
+/*
+ * ExecAssignScanProjectionInfoWithScanAttrs
+ *		As ExecAssignScanProjectionInfo but when 'scan_attrs' is set, use
+ *		EEOP_SCAN_SELECTSOME instead of EEOP_SCAN_FETCHSOME to deform only
+ *		the mentioned 'scan_attrs' from the scan tuple.
+ */
+void
+ExecAssignScanProjectionInfoWithScanAttrs(ScanState *node,
+										  Bitmapset *scan_attrs)
+{
+	Scan	   *scan = (Scan *) node->ps.plan;
+	TupleDesc	tupdesc = node->ss_ScanTupleSlot->tts_tupleDescriptor;
+
+	ExecConditionalAssignProjectionInfoWithScanAttrs(&node->ps, tupdesc,
+													 scan->scanrelid,
+													 scan_attrs);
+}
+
 /*
  * ExecAssignScanProjectionInfoWithVarno
  *		As above, but caller can specify varno expected in Vars in the tlist.
diff --git a/src/backend/executor/execTuples.c b/src/backend/executor/execTuples.c
index 1b5e1ebd334..5e502bfdbb8 100644
--- a/src/backend/executor/execTuples.c
+++ b/src/backend/executor/execTuples.c
@@ -74,6 +74,12 @@ static TupleDesc ExecTypeFromTLInternal(List *targetList,
 										bool skipjunk);
 static pg_attribute_always_inline void slot_deform_heap_tuple(TupleTableSlot *slot, HeapTuple tuple, uint32 *offp,
 															  int reqnatts);
+static pg_attribute_always_inline void slot_selectively_deform_heap_tuple(TupleTableSlot *slot,
+																		  HeapTuple tuple,
+																		  uint32 *offp,
+																		  int last_attnum,
+																		  AttrNumber *attnums,
+																		  AttrNumber *attnum_map);
 static inline void tts_buffer_heap_store_tuple(TupleTableSlot *slot,
 											   HeapTuple tuple,
 											   Buffer buffer,
@@ -129,7 +135,22 @@ tts_virtual_clear(TupleTableSlot *slot)
 static void
 tts_virtual_getsomeattrs(TupleTableSlot *slot, int natts)
 {
-	elog(ERROR, "getsomeattrs is not required to be called on a virtual tuple table slot");
+	elog(ERROR,
+		 "%s is not required to be called on a virtual tuple table slot",
+		 "getsomeattrs");
+}
+
+/*
+ * VirtualTupleTableSlots always have fully populated tts_values and
+ * tts_isnull arrays.  So this function should never be called.
+ */
+static void
+tts_virtual_selectattrs(TupleTableSlot *slot, int last_attnum,
+						AttrNumber *attnums, AttrNumber *attnum_map)
+{
+	elog(ERROR,
+		 "%s is not required to be called on a virtual tuple table slot",
+		 "selectattrs");
 }
 
 /*
@@ -352,6 +373,22 @@ tts_heap_getsomeattrs(TupleTableSlot *slot, int natts)
 	slot_deform_heap_tuple(slot, hslot->tuple, &hslot->off, natts);
 }
 
+static void
+tts_heap_selectattrs(TupleTableSlot *slot, int last_attnum,
+					 AttrNumber *attnums, AttrNumber *attnum_map)
+{
+	HeapTupleTableSlot *hslot = (HeapTupleTableSlot *) slot;
+
+	Assert(!TTS_EMPTY(slot));
+
+	slot_selectively_deform_heap_tuple(slot,
+									   hslot->tuple,
+									   &hslot->off,
+									   last_attnum,
+									   attnums,
+									   attnum_map);
+}
+
 static Datum
 tts_heap_getsysattr(TupleTableSlot *slot, int attnum, bool *isnull)
 {
@@ -550,6 +587,22 @@ tts_minimal_getsomeattrs(TupleTableSlot *slot, int natts)
 	slot_deform_heap_tuple(slot, mslot->tuple, &mslot->off, natts);
 }
 
+static void
+tts_minimal_selectattrs(TupleTableSlot *slot, int last_attnum,
+						AttrNumber *attnums, AttrNumber *attnum_map)
+{
+	MinimalTupleTableSlot *mslot = (MinimalTupleTableSlot *) slot;
+
+	Assert(!TTS_EMPTY(slot));
+
+	slot_selectively_deform_heap_tuple(slot,
+									   mslot->tuple,
+									   &mslot->off,
+									   last_attnum,
+									   attnums,
+									   attnum_map);
+}
+
 /*
  * MinimalTupleTableSlots never provide system attributes. We generally
  * shouldn't get here, but provide a user-friendly message if we do.
@@ -757,6 +810,23 @@ tts_buffer_heap_getsomeattrs(TupleTableSlot *slot, int natts)
 	slot_deform_heap_tuple(slot, bslot->base.tuple, &bslot->base.off, natts);
 }
 
+static void
+tts_buffer_heap_selectattrs(TupleTableSlot *slot, int last_attnum,
+							AttrNumber *attnums, AttrNumber *attnum_map)
+{
+	BufferHeapTupleTableSlot *bslot = (BufferHeapTupleTableSlot *) slot;
+
+	Assert(!TTS_EMPTY(slot));
+
+	slot_selectively_deform_heap_tuple(slot,
+									   bslot->base.tuple,
+									   &bslot->base.off,
+									   last_attnum,
+									   attnums,
+									   attnum_map);
+}
+
+
 static Datum
 tts_buffer_heap_getsysattr(TupleTableSlot *slot, int attnum, bool *isnull)
 {
@@ -1244,12 +1314,299 @@ done:
 	*offp = off;
 }
 
+/*
+ * slot_selectively_deform_heap_tuple
+ *		Deform attributes of 'tuple' into the Datum/isnull arrays in 'slot'.
+ *		Unlike slot_deform_heap_tuple, which deforms every attribute up to the
+ *		given attribute number, here we deform only the attribute numbers
+ *		mentioned in the 'attnums' array.  When only a few attributes are
+ *		required, this can be more efficient.  When the attributes have a
+ *		known attcacheoff and it's valid to use that, then this version can be
+ *		much more efficient than slot_deform_heap_tuple when only a small
+ *		number of the total attributes are required.
+ */
+static pg_attribute_always_inline void
+slot_selectively_deform_heap_tuple(TupleTableSlot *slot, HeapTuple tuple,
+								   uint32 *offp, int last_attnum,
+								   AttrNumber *attnums,
+								   AttrNumber *attnum_map)
+{
+	CompactAttribute *cattrs;
+	CompactAttribute *cattr;
+	TupleDesc	tupleDesc = slot->tts_tupleDescriptor;
+	HeapTupleHeader tup = tuple->t_data;
+	size_t		attnum;
+	int			attnums_idx;
+	int			firstNonCacheOffsetAttr;
+	int			firstNonGuaranteedAttr;
+	int			firstNullAttr;
+	int			natts;
+	Datum	   *values;
+	bool	   *isnull;
+	char	   *tp;				/* ptr to tuple data */
+	uint32		off;			/* offset in tuple data */
+	int			off_attnum;		/* the attnum that 'off' points to */
+
+	/* Did someone forget to call TupleDescFinalize()? */
+	Assert(tupleDesc->firstNonCachedOffsetAttr >= 0);
+
+	isnull = slot->tts_isnull;
+
+	/*
+	 * Some callers may form and deform tuples prior to NOT NULL constraints
+	 * being checked.  Here we'd like to optimize the case where we only need
+	 * to fetch attributes before or up to the point where the attribute is
+	 * guaranteed to exist in the tuple.  We rely on the slot flag being set
+	 * correctly to only enable this optimization when it's valid to do so.
+	 * This optimization allows us to save fetching the number of attributes
+	 * from the tuple and saves the additional cost of handling non-byval
+	 * attrs.
+	 */
+	firstNonGuaranteedAttr = Min(last_attnum, slot->tts_first_nonguaranteed);
+
+	firstNonCacheOffsetAttr = tupleDesc->firstNonCachedOffsetAttr;
+
+	if (HeapTupleHasNulls(tuple))
+	{
+		natts = HeapTupleHeaderGetNatts(tup);
+		tp = (char *) tup + MAXALIGN(offsetof(HeapTupleHeaderData, t_bits) +
+									 BITMAPLEN(natts));
+
+		natts = Min(natts, last_attnum);
+		if (natts > firstNonGuaranteedAttr)
+		{
+			bits8	   *bp = tup->t_bits;
+
+			/* Find the first NULL attr */
+			firstNullAttr = first_null_attr(bp, natts);
+
+			/*
+			 * And populate the isnull array for all attributes up to the last
+			 * attribute we're deforming.  When not using attcacheoff, we need
+			 * to know if an attribute is NULL even when we're not deforming
+			 * it, so that we can skip over it when calculating the offset to
+			 * attributes that we are deforming.
+			 */
+			populate_isnull_array(bp, natts, isnull);
+
+			/* We can only use any cached offsets until the first NULL attr */
+			firstNonCacheOffsetAttr = Min(firstNonCacheOffsetAttr,
+										  firstNullAttr);
+		}
+		else
+		{
+			/* Otherwise all required columns are guaranteed to exist */
+			firstNullAttr = natts;
+		}
+	}
+	else
+	{
+		tp = (char *) tup + MAXALIGN(offsetof(HeapTupleHeaderData, t_bits));
+
+		/*
+		 * We only need to look at the tuple's natts if we need more than the
+		 * guaranteed number of columns
+		 */
+		if (last_attnum > firstNonGuaranteedAttr)
+			natts = Min(HeapTupleHeaderGetNatts(tup), last_attnum);
+		else
+		{
+			/* No need to access the number of attributes in the tuple */
+			natts = last_attnum;
+		}
+
+		/* All attrs can be fetched without checking for NULLs */
+		firstNullAttr = natts;
+	}
+
+	attnums_idx = attnum_map[slot->tts_nvalid];
+	attnum = attnums[attnums_idx];
+	values = slot->tts_values;
+
+	/*
+	 * We store the tupleDesc's CompactAttribute array in 'cattrs' as gcc
+	 * seems to be unwilling to optimize accessing the CompactAttribute
+	 * element efficiently when accessing it via TupleDescCompactAttr().
+	 */
+	cattrs = tupleDesc->compact_attrs;
+
+	/* Ensure we calculated tp correctly */
+	Assert(tp == (char *) tup + tup->t_hoff);
+
+	if (attnum < firstNonGuaranteedAttr)
+	{
+		int			attlen;
+
+		for (; attnum < firstNonGuaranteedAttr; attnum = attnums[++attnums_idx])
+		{
+			isnull[attnum] = false;
+			cattr = &cattrs[attnum];
+			attlen = cattr->attlen;
+
+			/* We don't expect any non-byval types */
+			pg_assume(attlen > 0);
+			Assert(cattr->attbyval == true);
+
+			off = cattr->attcacheoff;
+			values[attnum] = fetch_att_noerr(tp + off, true, attlen);
+		}
+
+		off += attlen;
+
+		if (attnum == last_attnum)
+			goto done;
+	}
+
+	/* We can only fetch as many attributes as the tuple has. */
+	firstNonCacheOffsetAttr = Min(firstNonCacheOffsetAttr, natts);
+
+	/*
+	 * Handle the portion of the tuple that we have cached the offset for up
+	 * to the first NULL attribute.  The offset is effectively fixed for
+	 * these, so we can use the CompactAttribute's attcacheoff.
+	 */
+	if (attnum < firstNonCacheOffsetAttr)
+	{
+		int			attlen;
+
+		for (; attnum < firstNonCacheOffsetAttr; attnum = attnums[++attnums_idx])
+		{
+			isnull[attnum] = false;
+			cattr = &cattrs[attnum];
+			attlen = cattr->attlen;
+
+			off = cattr->attcacheoff;
+			values[attnum] = fetch_att_noerr(tp + off, cattr->attbyval,
+											 attlen);
+		}
+
+		off += attlen;
+		Assert(attlen > 0);
+
+		if (attnum == last_attnum)
+			goto done;
+	}
+
+
+	if (slot->tts_nvalid >= firstNonCacheOffsetAttr)
+	{
+		/* Restore state from previous execution */
+		off_attnum = slot->tts_nvalid;
+		off = *offp;
+	}
+	else
+	{
+		off_attnum = firstNonCacheOffsetAttr - 1;
+		off = cattrs[off_attnum].attcacheoff;
+	}
+
+	/*
+	 * We no longer have the ability to use attcacheoff, so we must look
+	 * through all attributes from this point on.  For attributes that we are
+	 * not selecting, we only calculate the offset to skip them, and don't do
+	 * the actual fetch.  Here we loop up to the first NULL attribute.
+	 */
+	for (; off_attnum < firstNullAttr; off_attnum++)
+	{
+		int			attlen;
+
+		cattr = &cattrs[off_attnum];
+		attlen = cattr->attlen;
+
+		/*
+		 * cstrings don't exist in heap tuples.  Use pg_assume to instruct the
+		 * compiler not to emit the cstring-related code in
+		 * align_fetch_then_add().
+		 */
+		pg_assume(attlen > 0 || attlen == -1);
+
+		off = att_pointer_alignby(off, cattr->attalignby, attlen, tp + off);
+
+		/*
+		 * If this is an attribute we want, do the fetch and then move attnum
+		 * to the next attribute we want.
+		 */
+		if (off_attnum == attnum)
+		{
+			isnull[off_attnum] = false;
+			values[off_attnum] =
+				fetch_att_noerr(tp + off, cattr->attbyval,
+								attlen);
+			attnum = attnums[++attnums_idx];
+
+		}
+		/* Move offset beyond this attribute */
+		off = att_addlength_pointer(off, attlen, tp + off);
+	}
+
+	/*
+	 * Now handle any remaining attributes in the tuple up to the requested
+	 * attnum.  This time, include NULL checks as we're now at the first NULL
+	 * attribute.
+	 */
+	for (; off_attnum < natts; off_attnum++)
+	{
+		int			attlen;
+
+		cattr = &cattrs[off_attnum];
+		attlen = cattr->attlen;
+
+		/* As above, we don't expect cstrings */
+		pg_assume(attlen > 0 || attlen == -1);
+
+		/* Is this an attribute we're selecting? */
+		if (off_attnum == attnum)
+		{
+			attnum = attnums[++attnums_idx];
+
+			if (isnull[off_attnum])
+			{
+				values[off_attnum] = (Datum) 0;
+				continue;
+			}
+
+			/*
+			 * align 'off', fetch the datum, and increment off beyond the
+			 * datum
+			 */
+			values[off_attnum] = align_fetch_then_add(tp,
+													  &off,
+													  cattr->attbyval,
+													  attlen,
+													  cattr->attalignby);
+		}
+		else if (!isnull[off_attnum])
+		{
+			/* We don't want this attribute, move beyond it */
+			off = att_pointer_alignby(off, cattr->attalignby, attlen, tp + off);
+			off = att_addlength_pointer(off, attlen, tp + off);
+		}
+
+	}
+
+	/* Fetch any missing attrs and raise an error if reqnatts is invalid */
+	if (unlikely(attnum < last_attnum))
+	{
+		*offp = off;
+		/* XXX worth doing this selectively too? */
+		slot_getmissingattrs(slot, attnum, last_attnum);
+		slot->tts_nvalid = last_attnum;
+		return;
+	}
+done:
+
+	slot->tts_nvalid = last_attnum;
+	/* Save current offset for next execution */
+	*offp = off;
+}
+
 const TupleTableSlotOps TTSOpsVirtual = {
 	.base_slot_size = sizeof(VirtualTupleTableSlot),
 	.init = tts_virtual_init,
 	.release = tts_virtual_release,
 	.clear = tts_virtual_clear,
 	.getsomeattrs = tts_virtual_getsomeattrs,
+	.selectattrs = tts_virtual_selectattrs,
 	.getsysattr = tts_virtual_getsysattr,
 	.materialize = tts_virtual_materialize,
 	.is_current_xact_tuple = tts_virtual_is_current_xact_tuple,
@@ -1271,6 +1628,7 @@ const TupleTableSlotOps TTSOpsHeapTuple = {
 	.release = tts_heap_release,
 	.clear = tts_heap_clear,
 	.getsomeattrs = tts_heap_getsomeattrs,
+	.selectattrs = tts_heap_selectattrs,
 	.getsysattr = tts_heap_getsysattr,
 	.is_current_xact_tuple = tts_heap_is_current_xact_tuple,
 	.materialize = tts_heap_materialize,
@@ -1289,6 +1647,7 @@ const TupleTableSlotOps TTSOpsMinimalTuple = {
 	.release = tts_minimal_release,
 	.clear = tts_minimal_clear,
 	.getsomeattrs = tts_minimal_getsomeattrs,
+	.selectattrs = tts_minimal_selectattrs,
 	.getsysattr = tts_minimal_getsysattr,
 	.is_current_xact_tuple = tts_minimal_is_current_xact_tuple,
 	.materialize = tts_minimal_materialize,
@@ -1307,6 +1666,7 @@ const TupleTableSlotOps TTSOpsBufferHeapTuple = {
 	.release = tts_buffer_heap_release,
 	.clear = tts_buffer_heap_clear,
 	.getsomeattrs = tts_buffer_heap_getsomeattrs,
+	.selectattrs = tts_buffer_heap_selectattrs,
 	.getsysattr = tts_buffer_heap_getsysattr,
 	.is_current_xact_tuple = tts_buffer_is_current_xact_tuple,
 	.materialize = tts_buffer_heap_materialize,
diff --git a/src/backend/executor/execUtils.c b/src/backend/executor/execUtils.c
index f62582859f9..252e8306631 100644
--- a/src/backend/executor/execUtils.c
+++ b/src/backend/executor/execUtils.c
@@ -580,8 +580,7 @@ ExecGetCommonChildSlotOps(PlanState *ps)
  * ----------------
  */
 void
-ExecAssignProjectionInfo(PlanState *planstate,
-						 TupleDesc inputDesc)
+ExecAssignProjectionInfo(PlanState *planstate, TupleDesc inputDesc)
 {
 	planstate->ps_ProjInfo =
 		ExecBuildProjectionInfo(planstate->plan->targetlist,
@@ -591,6 +590,28 @@ ExecAssignProjectionInfo(PlanState *planstate,
 								inputDesc);
 }
 
+/* ----------------
+ *		ExecAssignProjectionInfoWithScanAttrs
+ *
+ * As ExecAssignScanProjectionInfo but when 'scan_attrs' is set, use
+ * EEOP_SCAN_SELECTSOME instead of EEOP_SCAN_FETCHSOME to deform only the
+ * mentioned 'scan_attrs' from the scan tuple.
+ * ----------------
+*/
+void
+ExecAssignProjectionInfoWithScanAttrs(PlanState *planstate,
+									  TupleDesc inputDesc,
+									  Bitmapset *scan_attrs)
+{
+	planstate->ps_ProjInfo =
+		ExecBuildProjectionInfoWithScanAttrs(planstate->plan->targetlist,
+											 planstate->ps_ExprContext,
+											 planstate->ps_ResultTupleSlot,
+											 planstate,
+											 inputDesc,
+											 scan_attrs);
+}
+
 
 /* ----------------
  *		ExecConditionalAssignProjectionInfo
@@ -602,6 +623,26 @@ ExecAssignProjectionInfo(PlanState *planstate,
 void
 ExecConditionalAssignProjectionInfo(PlanState *planstate, TupleDesc inputDesc,
 									int varno)
+{
+	ExecConditionalAssignProjectionInfoWithScanAttrs(planstate,
+													 inputDesc,
+													 varno,
+													 NULL);
+}
+
+/* ----------------
+ *		ExecConditionalAssignProjectionInfoWithScanAttrs
+ *
+ * As ExecConditionalAssignProjectionInfo but when 'scan_attrs' is set, use
+ * EEOP_SCAN_SELECTSOME instead of EEOP_SCAN_FETCHSOME to deform only the
+ * mentioned 'scan_attrs' from the scan tuple.
+ * ----------------
+*/
+void
+ExecConditionalAssignProjectionInfoWithScanAttrs(PlanState *planstate,
+												 TupleDesc inputDesc,
+												 int varno,
+												 Bitmapset *scan_attrs)
 {
 	if (tlist_matches_tupdesc(planstate,
 							  planstate->plan->targetlist,
@@ -622,7 +663,7 @@ ExecConditionalAssignProjectionInfo(PlanState *planstate, TupleDesc inputDesc,
 			planstate->resultopsfixed = true;
 			planstate->resultopsset = true;
 		}
-		ExecAssignProjectionInfo(planstate, inputDesc);
+		ExecAssignProjectionInfoWithScanAttrs(planstate, inputDesc, scan_attrs);
 	}
 }
 
diff --git a/src/backend/executor/nodeSeqscan.c b/src/backend/executor/nodeSeqscan.c
index 8f219f60a93..41de367832c 100644
--- a/src/backend/executor/nodeSeqscan.c
+++ b/src/backend/executor/nodeSeqscan.c
@@ -251,13 +251,15 @@ ExecInitSeqScan(SeqScan *node, EState *estate, int eflags)
 	 * Initialize result type and projection.
 	 */
 	ExecInitResultTypeTL(&scanstate->ss.ps);
-	ExecAssignScanProjectionInfo(&scanstate->ss);
+	ExecAssignScanProjectionInfoWithScanAttrs(&scanstate->ss,
+											  node->scan.scan_varattnos);
 
 	/*
 	 * initialize child expressions
 	 */
-	scanstate->ss.ps.qual =
-		ExecInitQual(node->scan.plan.qual, (PlanState *) scanstate);
+	scanstate->ss.ps.qual = ExecInitQualWithScanAttrs(node->scan.plan.qual,
+													  (PlanState *) scanstate,
+													  node->scan.scan_varattnos);
 
 	/*
 	 * When EvalPlanQual() is not in use, assign ExecProcNode for this node
diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c
index 50b0e10308b..4522ac4d4c0 100644
--- a/src/backend/optimizer/plan/createplan.c
+++ b/src/backend/optimizer/plan/createplan.c
@@ -118,7 +118,8 @@ static ModifyTable *create_modifytable_plan(PlannerInfo *root, ModifyTablePath *
 static Limit *create_limit_plan(PlannerInfo *root, LimitPath *best_path,
 								int flags);
 static SeqScan *create_seqscan_plan(PlannerInfo *root, Path *best_path,
-									List *tlist, List *scan_clauses);
+									List *tlist, List *scan_clauses,
+									Bitmapset *tlist_varattnos);
 static SampleScan *create_samplescan_plan(PlannerInfo *root, Path *best_path,
 										  List *tlist, List *scan_clauses);
 static Scan *create_indexscan_plan(PlannerInfo *root, IndexPath *best_path,
@@ -178,7 +179,8 @@ static void label_sort_with_costsize(PlannerInfo *root, Sort *plan,
 									 double limit_tuples);
 static void label_incrementalsort_with_costsize(PlannerInfo *root, IncrementalSort *plan,
 												List *pathkeys, double limit_tuples);
-static SeqScan *make_seqscan(List *qptlist, List *qpqual, Index scanrelid);
+static SeqScan *make_seqscan(List *qptlist, List *qpqual, Index scanrelid,
+							 Bitmapset *scan_varattnos);
 static SampleScan *make_samplescan(List *qptlist, List *qpqual, Index scanrelid,
 								   TableSampleClause *tsc);
 static IndexScan *make_indexscan(List *qptlist, List *qpqual, Index scanrelid,
@@ -550,6 +552,7 @@ create_plan_recurse(PlannerInfo *root, Path *best_path, int flags)
 static Plan *
 create_scan_plan(PlannerInfo *root, Path *best_path, int flags)
 {
+	Bitmapset  *tlist_varattnos = NULL;
 	RelOptInfo *rel = best_path->parent;
 	List	   *scan_clauses;
 	List	   *gating_clauses;
@@ -579,6 +582,14 @@ create_scan_plan(PlannerInfo *root, Path *best_path, int flags)
 			break;
 	}
 
+	/*
+	 * Figure out which attributes we need from the scan before applying the
+	 * physical tlist optimization.
+	 */
+	pull_varattnos((Node *) best_path->pathtarget->exprs,
+				   rel->relid,
+				   &tlist_varattnos);
+
 	/*
 	 * If this is a parameterized scan, we also need to enforce all the join
 	 * clauses available from the outer relation(s).
@@ -672,7 +683,8 @@ create_scan_plan(PlannerInfo *root, Path *best_path, int flags)
 			plan = (Plan *) create_seqscan_plan(root,
 												best_path,
 												tlist,
-												scan_clauses);
+												scan_clauses,
+												tlist_varattnos);
 			break;
 
 		case T_SampleScan:
@@ -2752,10 +2764,13 @@ create_limit_plan(PlannerInfo *root, LimitPath *best_path, int flags)
  */
 static SeqScan *
 create_seqscan_plan(PlannerInfo *root, Path *best_path,
-					List *tlist, List *scan_clauses)
+					List *tlist, List *scan_clauses, Bitmapset *tlist_varattnos)
 {
 	SeqScan    *scan_plan;
 	Index		scan_relid = best_path->parent->relid;
+	Bitmapset  *scan_varattnos = tlist_varattnos;
+	Bitmapset  *non_sys_attrs = NULL;
+	int			i;
 
 	/* it should be a base rel... */
 	Assert(scan_relid > 0);
@@ -2767,6 +2782,19 @@ create_seqscan_plan(PlannerInfo *root, Path *best_path,
 	/* Reduce RestrictInfo list to bare expressions; ignore pseudoconstants */
 	scan_clauses = extract_actual_clauses(scan_clauses, false);
 
+	/* Pull varattnos from WHERE clause Vars */
+	pull_varattnos((Node *) scan_clauses, scan_relid, &scan_varattnos);
+
+	/* Don't set these when whole-row var is present */
+	if (!bms_is_member(0 - FirstLowInvalidHeapAttributeNumber, scan_varattnos))
+	{
+		/* XXX invent bms_right_shift_members()? */
+		i = 0 - FirstLowInvalidHeapAttributeNumber;
+		while ((i = bms_next_member(scan_varattnos, i)) >= 0)
+			non_sys_attrs = bms_add_member(non_sys_attrs,
+										   i - 1 + FirstLowInvalidHeapAttributeNumber);
+	}
+
 	/* Replace any outer-relation variables with nestloop params */
 	if (best_path->param_info)
 	{
@@ -2776,7 +2804,8 @@ create_seqscan_plan(PlannerInfo *root, Path *best_path,
 
 	scan_plan = make_seqscan(tlist,
 							 scan_clauses,
-							 scan_relid);
+							 scan_relid,
+							 non_sys_attrs);
 
 	copy_generic_path_info(&scan_plan->scan.plan, best_path);
 
@@ -5487,7 +5516,8 @@ bitmap_subplan_mark_shared(Plan *plan)
 static SeqScan *
 make_seqscan(List *qptlist,
 			 List *qpqual,
-			 Index scanrelid)
+			 Index scanrelid,
+			 Bitmapset *scan_varattnos)
 {
 	SeqScan    *node = makeNode(SeqScan);
 	Plan	   *plan = &node->scan.plan;
@@ -5497,6 +5527,7 @@ make_seqscan(List *qptlist,
 	plan->lefttree = NULL;
 	plan->righttree = NULL;
 	node->scan.scanrelid = scanrelid;
+	node->scan.scan_varattnos = scan_varattnos;
 
 	return node;
 }
diff --git a/src/include/executor/execExpr.h b/src/include/executor/execExpr.h
index aa9b361fa31..f29d9dd799b 100644
--- a/src/include/executor/execExpr.h
+++ b/src/include/executor/execExpr.h
@@ -78,6 +78,9 @@ typedef enum ExprEvalOp
 	EEOP_OLD_FETCHSOME,
 	EEOP_NEW_FETCHSOME,
 
+	/* apply slot_selectattrs on the corresponding tuple slot */
+	EEOP_SCAN_SELECTSOME,
+
 	/* compute non-system Var value */
 	EEOP_INNER_VAR,
 	EEOP_OUTER_VAR,
@@ -318,15 +321,34 @@ typedef struct ExprEvalStep
 	 */
 	union
 	{
-		/* for EEOP_INNER/OUTER/SCAN/OLD/NEW_FETCHSOME */
+		/*
+		 * for EEOP_INNER/OUTER/SCAN/OLD/NEW_FETCHSOME and
+		 * EEOP_SCAN_SELECTSOME
+		 */
 		struct
 		{
 			/* attribute number up to which to fetch (inclusive) */
 			int			last_var;
 			/* will the type of slot be the same for every invocation */
 			bool		fixed;
+			/* Number of elements in req_attnums array. XXX needed? */
+			AttrNumber	natts;
+
+			/* One element for each attnum to select, ordered by attnum */
+			AttrNumber *req_attnums;
+
+			/*
+			 * Provides mapping of 0-based attnums back to the index of the
+			 * req_attnums array that deforming should continue from.  This
+			 * allows us to re-find the element of req_attnums using the
+			 * slot's tts_nvalid so that we can continue deforming from the
+			 * last defromed attribute.
+			 */
+			AttrNumber *next_req_attnums_index;
+
 			/* tuple descriptor, if known */
 			TupleDesc	known_desc;
+
 			/* type of slot, can only be relied upon if fixed is set */
 			const TupleTableSlotOps *kind;
 		}			fetch;
diff --git a/src/include/executor/executor.h b/src/include/executor/executor.h
index bf239fc156f..69f3c5da6c5 100644
--- a/src/include/executor/executor.h
+++ b/src/include/executor/executor.h
@@ -324,8 +324,12 @@ ExecProcNode(PlanState *node)
  * prototypes from functions in execExpr.c
  */
 extern ExprState *ExecInitExpr(Expr *node, PlanState *parent);
+extern ExprState *ExecInitExprWithScanAttrs(Expr *node, PlanState *parent,
+											Bitmapset *scan_attrs);
 extern ExprState *ExecInitExprWithParams(Expr *node, ParamListInfo ext_params);
 extern ExprState *ExecInitQual(List *qual, PlanState *parent);
+extern ExprState *ExecInitQualWithScanAttrs(List *qual, PlanState *parent,
+											Bitmapset *scan_attrs);
 extern ExprState *ExecInitCheck(List *qual, PlanState *parent);
 extern List *ExecInitExprList(List *nodes, PlanState *parent);
 extern ExprState *ExecBuildAggTrans(AggState *aggstate, struct AggStatePerPhaseData *phase,
@@ -364,6 +368,12 @@ extern ProjectionInfo *ExecBuildProjectionInfo(List *targetList,
 											   TupleTableSlot *slot,
 											   PlanState *parent,
 											   TupleDesc inputDesc);
+extern ProjectionInfo *ExecBuildProjectionInfoWithScanAttrs(List *targetList,
+															ExprContext *econtext,
+															TupleTableSlot *slot,
+															PlanState *parent,
+															TupleDesc inputDesc,
+															Bitmapset *scan_attrs);
 extern ProjectionInfo *ExecBuildUpdateProjection(List *targetList,
 												 bool evalTargetList,
 												 List *targetColnos,
@@ -582,6 +592,8 @@ typedef bool (*ExecScanRecheckMtd) (ScanState *node, TupleTableSlot *slot);
 extern TupleTableSlot *ExecScan(ScanState *node, ExecScanAccessMtd accessMtd,
 								ExecScanRecheckMtd recheckMtd);
 extern void ExecAssignScanProjectionInfo(ScanState *node);
+extern void ExecAssignScanProjectionInfoWithScanAttrs(ScanState *node,
+													  Bitmapset *scan_attrs);
 extern void ExecAssignScanProjectionInfoWithVarno(ScanState *node, int varno);
 extern void ExecScanReScan(ScanState *node);
 
@@ -678,8 +690,15 @@ extern const TupleTableSlotOps *ExecGetCommonSlotOps(PlanState **planstates,
 extern const TupleTableSlotOps *ExecGetCommonChildSlotOps(PlanState *ps);
 extern void ExecAssignProjectionInfo(PlanState *planstate,
 									 TupleDesc inputDesc);
+extern void ExecAssignProjectionInfoWithScanAttrs(PlanState *planstate,
+												  TupleDesc inputDesc,
+												  Bitmapset *scan_attrs);
 extern void ExecConditionalAssignProjectionInfo(PlanState *planstate,
 												TupleDesc inputDesc, int varno);
+extern void ExecConditionalAssignProjectionInfoWithScanAttrs(PlanState *planstate,
+															 TupleDesc inputDesc,
+															 int varno,
+															 Bitmapset *scan_attrs);
 extern void ExecAssignScanType(ScanState *scanstate, TupleDesc tupDesc);
 extern void ExecCreateScanSlotFromOuterPlan(EState *estate,
 											ScanState *scanstate,
diff --git a/src/include/executor/tuptable.h b/src/include/executor/tuptable.h
index 78558098fa3..cc2c5a257d0 100644
--- a/src/include/executor/tuptable.h
+++ b/src/include/executor/tuptable.h
@@ -168,6 +168,16 @@ struct TupleTableSlotOps
 	 */
 	void		(*getsomeattrs) (TupleTableSlot *slot, int natts);
 
+	/*
+	 * Populate the tts_values and tts_isnull elements of the given slot with
+	 * the values of the corresponding attribute from the tuple stored in the
+	 * slot.  Populate up as far as last_attnum and store each attribute
+	 * mentioned in the attnums array.  Use attnum_map to determine the
+	 * starting element in the attnums array from the slot's tts_nvalid.
+	 */
+	void		(*selectattrs) (TupleTableSlot *slot, int last_attnum,
+								AttrNumber *attnums, AttrNumber *attnum_map);
+
 	/*
 	 * Returns value of the given system attribute as a datum and sets isnull
 	 * to false, if it's not NULL. Throws an error if the slot type does not
@@ -374,6 +384,18 @@ slot_getsomeattrs(TupleTableSlot *slot, int attnum)
 		slot->tts_ops->getsomeattrs(slot, attnum);
 }
 
+static inline void
+slot_selectattrs(TupleTableSlot *slot, int last_attnum, AttrNumber *attnums,
+				 AttrNumber *attnum_map)
+{
+	/*
+	 * Populate slot only attributes mentioned in the attnums array, up to
+	 * 'last_attnum', if it's not already
+	 */
+	if (slot->tts_nvalid < last_attnum)
+		slot->tts_ops->selectattrs(slot, last_attnum, attnums, attnum_map);
+}
+
 /*
  * slot_getallattrs
  *		This function forces all the entries of the slot's Datum/isnull
diff --git a/src/include/nodes/plannodes.h b/src/include/nodes/plannodes.h
index 8c9321aab8c..08dcf02b8bb 100644
--- a/src/include/nodes/plannodes.h
+++ b/src/include/nodes/plannodes.h
@@ -540,6 +540,14 @@ typedef struct Scan
 	Plan		plan;
 	/* relid is index into the range table */
 	Index		scanrelid;
+
+	/*
+	 * All varattnos that are required from the scanrelid.  Does not include
+	 * any added due to the physical tlist optimization or system attributes
+	 * or whole-row attributes.  User attributes are 0 based, i.e attnum==1 is
+	 * member 0.
+	 */
+	Bitmapset  *scan_varattnos;
 } Scan;
 
 /* ----------------
-- 
2.51.0

---

From: Junwang Zhao <[email-masked]>
Date: Sun, 8 Mar 2026 00:36:42 +0800

Hi David,

> latency average = 157.599 ms

I have some comments on v12-0004.

1.

+ off += cattr->attlen;

The firstNonCachedOffsetAttr seems to be the first variable width
attribute, but it seems that the offset of this attribute can be cached,
for example, in a table defined as (int, text), the offset of
firstNonCachedOffsetAttr should be 4, is that correct?

If TupleDescFinalize records the offset firstNonCachedOffsetAttr,
it might save one iterator of the deforming loop. For example,
add something like the following after the above mentioned code.

if (firstNonCachedOffsetAttr < tupdesc->natts)
{
cattr = TupleDescCompactAttr(tupdesc, firstNonCachedOffsetAttr);
cattr->attcacheoff = off;
}

2.

in slot_deform_heap_tuple, there are multiple statements setting
firstNonCacheOffsetAttr,

Based on the logic, it seems the second one could be moved
to the third position, and the third one could then be safely
removed?

-- 
Regards
Junwang Zhao

---

From: David Rowley <[email-masked]>
Date: Sat, 14 Mar 2026 01:18:46 +1300

Thanks for having a look.

> firstNonCachedOffsetAttr should be 4, is that correct?

Yes.

> cattr->attcacheoff = off;

The problem is that short varlenas have 1 byte alignment and normal
varlenas have 4 byte alignment. It might be possible to do something
if the previous column is 4-byte aligned and has a length of 4 or 8,
since that means the offset must also be 1-byte aligned. The main
reason I don't want to do this is that the only positive is that
*maybe* 1 extra column can be deformed with a fixed offset. The
drawback is that the following code *has* to use
att_addlength_pointer(), *regardless* instead of "off += attlen;".
This means more deforming code and more complexity in
TupleDescFinalize(). I'd rather not do this.

> to the third position, and the third one could then be safely

Yeah. Well spotted. I've done that in the attached.

I've also modified the 0006 patch to add a new deform_bench_select()
function which allows the benchmark to call the new selective deform
function. See the attached graphs comparing master to v13-0001-0005
and master to v13-0001-0006. It's good to see that there's still quite
a large speedup even from the tests that don't have an attcacheoff for
the column being deformed. Tests 1 and 5 do have a attcacheoff for the
column deformed, so they're a good bit faster again.  To get the
0001-0006 results, I used the deform_test_run.sh script from [1] and
modified it to call deform_bench_select() instead of deform_bench().

I also noticed that when building with older gcc versions, I was
getting warnings about attlen and 'off' not being initialised. I ended
up switching back to the do/while loops to fix that rather than adding
needless initialisation, which would add overhead. 1 loop is
guaranteed, and the older compiler is not clever enough to work that
out.

David

[1] https://postgr.es/m/[email-masked]
From cc6d328cf1eb3e25df88afe5733d35817ac4f3e0 Mon Sep 17 00:00:00 2001
From: David Rowley <[email-masked]>
Date: Tue, 27 Jan 2026 15:08:09 +1300
Subject: [PATCH v13 1/6] Introduce deform_bench test module

 
 subdir('brin')
 subdir('commit_ts')
+subdir('deform_bench')

From 1fef8685b5ea019086f68b41fa2bfc995da4353c Mon Sep 17 00:00:00 2001
From: David Rowley <[email-masked]>
Date: Mon, 16 Feb 2026 14:20:19 +1300
Subject: [PATCH v13 2/6] Allow sibling call optimization in
 slot_getsomeattrs_int()

 
 
 	/*

 
 	if (!attrmiss)
 	{
 
 /*

 	/*

 	/*

 /*
-- 
2.51.0

From a0d67378e4b1d30b4afead1a37d7cf93490dc656 Mon Sep 17 00:00:00 2001
From: David Rowley <[email-masked]>
Date: Wed, 21 Jan 2026 15:41:37 +1300
Subject: [PATCH v13 3/6] Add empty TupleDescFinalize() function

 

 

 

 

 

 

 
 /*

 
 		/*

 		populate_compact_attribute(outTupDesc, spgKeyColumn);
+		TupleDescFinalize(outTupDesc);
 	}
 	return outTupDesc;
 }
diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c
index 55b9f38927d..d468c9774b3 100644
--- a/src/backend/access/transam/twophase.c
+++ b/src/backend/access/transam/twophase.c
@@ -745,6 +745,7 @@ pg_prepared_xact(PG_FUNCTION_ARGS)
 		TupleDescInitEntry(tupdesc, (AttrNumber) 5, "dbid",
 						   OIDOID, -1, 0);

 		/*
diff --git a/src/backend/access/transam/xlogfuncs.c b/src/backend/access/transam/xlogfuncs.c
index ecb3c8c0820..4e35311b2f3 100644
--- a/src/backend/access/transam/xlogfuncs.c
+++ b/src/backend/access/transam/xlogfuncs.c
@@ -430,6 +430,7 @@ pg_walfile_name_offset(PG_FUNCTION_ARGS)
 	TupleDescInitEntry(resultTupleDesc, (AttrNumber) 2, "file_offset",
 					   INT4OID, -1, 0);

 	/*

 
index 5ee6389d39c..0e93ababa87 100644

 

 
 
 	return tupdesc;
 
 	seqrel = try_relation_open(relid, AccessShareLock);
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index cd6d720386f..a2e3b72f156 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -1038,6 +1038,8 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 		}
 	}
 
@@ -1466,6 +1468,8 @@ BuildDescForRelation(const List *columns)

 

 

 
 				i++;
 			}
 
 			/*

 
 	/* No point in doing more here if there were no tuples returned. */
diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c
index 79fc192b171..376ff46340d 100644
--- a/src/backend/replication/walsender.c
+++ b/src/backend/replication/walsender.c
@@ -452,6 +452,7 @@ IdentifySystem(void)
 							  TEXTOID, -1, 0);
 	TupleDescInitBuiltinEntry(tupdesc, (AttrNumber) 4, "dbname",
 							  TEXTOID, -1, 0);
+	TupleDescFinalize(tupdesc);
 
@@ -497,6 +498,7 @@ ReadReplicationSlot(ReadReplicationSlotCmd *cmd)

@@ -599,6 +601,7 @@ SendTimeLineHistory(TimeLineHistoryCmd *cmd)
 
@@ -1016,6 +1019,7 @@ StartReplication(StartReplicationCmd *cmd)
 
@@ -1370,6 +1374,7 @@ CreateReplicationSlot(CreateReplicationSlotCmd *cmd)

 

 
 		/*
 
+				TupleDescFinalize(newdesc);
 				FreeTupleDesc(qstate->tupdesc);
 				qstate->tupdesc = newdesc;
 			}
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index 5ac022274a7..bad5642d9c9 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -770,6 +770,7 @@ pg_stat_get_backend_subxact(PG_FUNCTION_ARGS)
 	TupleDescInitEntry(tupdesc, (AttrNumber) 2, "subxact_overflow",
 					   BOOLOID, -1, 0);

 	if ((local_beentry = pgstat_get_local_beentry_by_proc_number(procNumber)) != NULL)
@@ -1671,6 +1672,7 @@ pg_stat_wal_build_tuple(PgStat_WalCounters wal_counters,
 	TupleDescInitEntry(tupdesc, (AttrNumber) 6, "stats_reset",
 					   TIMESTAMPTZOID, -1, 0);

 	/* Fill values and NULLs */
@@ -2098,6 +2100,7 @@ pg_stat_get_archiver(PG_FUNCTION_ARGS)
 	TupleDescInitEntry(tupdesc, (AttrNumber) 7, "stats_reset",
 					   TIMESTAMPTZOID, -1, 0);

 	/* Get statistics about the archiver process */
@@ -2179,6 +2182,7 @@ pg_stat_get_replication_slot(PG_FUNCTION_ARGS)
 					   TIMESTAMPTZOID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 13, "stats_reset",
 					   TIMESTAMPTZOID, -1, 0);
+	TupleDescFinalize(tupdesc);
 	BlessTupleDesc(tupdesc);
 
 	namestrcpy(&slotname, text_to_cstring(slotname_text));
@@ -2266,6 +2270,7 @@ pg_stat_get_subscription_stats(PG_FUNCTION_ARGS)
 					   INT8OID, -1, 0);
 	TupleDescInitEntry(tupdesc, (AttrNumber) 13, "stats_reset",
 					   TIMESTAMPTZOID, -1, 0);
+	TupleDescFinalize(tupdesc);
 	BlessTupleDesc(tupdesc);
 
 	if (!subentry)

 /*

 
 
 	if (mapped_relation)

 

 

 

 

 

 

From ab5fc2c7de7c6661d568e677eaad37c43977bef8 Mon Sep 17 00:00:00 2001
From: David Rowley <[email-masked]>
Date: Tue, 31 Dec 2024 09:19:24 +1300
Subject: [PATCH v13 4/6] Optimize tuple deformation

 src/backend/access/common/indextuple.c        | 363 +++++++--------
 src/backend/executor/execTuples.c             | 415 ++++++++++--------
 32 files changed, 900 insertions(+), 664 deletions(-)

-	/* ----------------
-	 *	 Three cases:
-	 *
 
 	attnum--;

 
-	if (!slow)
+	/*

-		for (; j < natts; j++)
 
-			if (att->attlen <= 0)
-				break;
-

 
 
-				if (usecache)
 
-			if (i == attnum)
-				break;

 
 
 /* ----------------

 
 
-	off = 0;

 
 		isnull[attnum] = false;
-
 
 	/*
 
-	/* ----------------
-	 *	 Three cases:
-	 *
 
 	attnum--;

 

 
-		for (; j < natts; j++)
 
-			if (att->attlen <= 0)
-				break;
+			if (att_isnull(i, bp))
+				continue;

 
-		/*

-				if (usecache)
 
-			if (i == attnum)
-				break;
+			if (att_isnull(i, bp))
+				continue;

 
 
 /*

 

 
-			if (!slow)

 

 
 
+/*
+ * TupleDescFinalize

index 07b248aa5f3..bfd2286ec2b 100644
 
-/*
@@ -1125,94 +1013,226 @@ static pg_attribute_always_inline void

 	/*
+			attnum++;
+		} while (attnum < firstNonGuaranteedAttr);
 
+	/* We can use attcacheoff up until the first NULL */
+			attnum++;
+		} while (attnum < firstNonCacheOffsetAttr);

 	/*

@@ -1307,7 +1327,7 @@ const TupleTableSlotOps TTSOpsBufferHeapTuple = {
@@ -1331,6 +1351,7 @@ MakeTupleTableSlot(TupleDesc tupleDesc,
@@ -1342,12 +1363,31 @@ MakeTupleTableSlot(TupleDesc tupleDesc,
 
 		PinTupleDesc(tupleDesc);
+
+		/*
 
 	/*
@@ -1366,9 +1406,9 @@ MakeTupleTableSlot(TupleDesc tupleDesc,
  */
 TupleTableSlot *

@@ -1435,7 +1475,7 @@ TupleTableSlot *
 
 	return slot;
 }
@@ -1515,8 +1555,14 @@ ExecSetSlotDescriptor(TupleTableSlot *slot, /* slot to change */
 	 */
 
 /* --------------------------------
@@ -1978,7 +2024,7 @@ ExecInitResultSlot(PlanState *planstate, const TupleTableSlotOps *tts_ops)
 	TupleTableSlot *slot;

@@ -2006,10 +2052,11 @@ ExecInitResultTupleSlotTL(PlanState *planstate,
@@ -2029,7 +2076,7 @@ ExecInitExtraTupleSlot(EState *estate,
 
 /* ----------------
@@ -2261,10 +2308,16 @@ ExecTypeSetColNames(TupleDesc typeInfo, List *namesList)

 
 		list_free(hashTlist);
 		bms_free(colnos);
index e0b6df64767..6f29954e84f 100644
@@ -382,7 +382,10 @@ ExecInitBitmapHeapScan(BitmapHeapScan *node, EState *estate, int eflags)
 
 	/*
 
 	/*

 
 	/*
 
 	/*
 
 	/*
 
 	/*
 
 	/*
 
 	/*
 
 	/*
 
 	/*
 
 	/*
 
 	/*
 
 	/*
 
 	/*

 	/*

 	{

 

-	/*

 

 

 
 
 /*
 
+/*
 
 /*
index 82c442d23f8..b1820653506 100644
@@ -597,7 +597,8 @@ extern void ExecInitResultTupleSlotTL(PlanState *planstate,
 
@@ -98,9 +95,13 @@

 

 	/*
-- 
2.51.0

From a66fa85a01d4c03c570b66afe16ab9b49044b448 Mon Sep 17 00:00:00 2001
From: David Rowley <[email-masked]>
Date: Mon, 23 Feb 2026 09:39:37 +1300
Subject: [PATCH v13 5/6] Reduce size of CompactAttribute struct to 8 bytes

 
 
+		/*
 
 		off += cattr->attlen;
index bfd2286ec2b..d24c07dca9f 100644
@@ -1095,6 +1096,13 @@ slot_deform_heap_tuple(TupleTableSlot *slot, HeapTuple tuple, uint32 *offp,
 
+	/*
 
@@ -1105,7 +1113,7 @@ slot_deform_heap_tuple(TupleTableSlot *slot, HeapTuple tuple, uint32 *offp,
 		do
 		{
 			isnull[attnum] = false;
-			cattr = TupleDescCompactAttr(tupleDesc, attnum);
+			cattr = &cattrs[attnum];
 			attlen = cattr->attlen;
 
 			/* We don't expect any non-byval types */
@@ -1146,9 +1154,8 @@ slot_deform_heap_tuple(TupleTableSlot *slot, HeapTuple tuple, uint32 *offp,
 		do
 		{
 			isnull[attnum] = false;
-			cattr = TupleDescCompactAttr(tupleDesc, attnum);
+			cattr = &cattrs[attnum];
 			attlen = cattr->attlen;
-
 			off = cattr->attcacheoff;
 			values[attnum] = fetch_att_noerr(tp + off,
 											 cattr->attbyval,
@@ -1175,7 +1182,7 @@ slot_deform_heap_tuple(TupleTableSlot *slot, HeapTuple tuple, uint32 *offp,
 		int			attlen;
 
 		isnull[attnum] = false;
 
 		/*
@@ -1208,7 +1215,7 @@ slot_deform_heap_tuple(TupleTableSlot *slot, HeapTuple tuple, uint32 *offp,
 			continue;
 		}

 

From ca630369d8f299c4425817479a164a6e9b37cd72 Mon Sep 17 00:00:00 2001
From: David Rowley <[email-masked]>
Date: Wed, 4 Mar 2026 16:55:09 +1300
Subject: [PATCH v13 6/6] WIP: Introduce selective tuple deforming

TODO: JIT support
---
 src/backend/executor/execExpr.c               | 182 ++++++++-
 src/backend/executor/execExprInterp.c         |  13 +
 src/backend/executor/execScan.c               |  18 +
 src/backend/executor/execTuples.c             | 364 +++++++++++++++++-
 src/backend/executor/execUtils.c              |  47 ++-
 src/backend/executor/nodeSeqscan.c            |   8 +-
 src/backend/optimizer/plan/createplan.c       |  43 ++-
 src/include/executor/execExpr.h               |  24 +-
 src/include/executor/executor.h               |  19 +
 src/include/executor/tuptable.h               |  22 ++
 src/include/nodes/plannodes.h                 |   8 +
 .../deform_bench/deform_bench--1.0.sql        |   4 +
 src/test/modules/deform_bench/deform_bench.c  |  98 +++++
 13 files changed, 821 insertions(+), 29 deletions(-)

index bd46b75e498..a9dd2842ea5 100644
@@ -66,8 +66,18 @@ typedef struct ExprSetupInfo
 
+static ExprState *ExecInitExprInternal(Expr *node, PlanState *parent,
+									   Node *escontext, Bitmapset *scan_attrs);
 static void ExecReadyExpr(ExprState *state);
 static void ExecInitExprRec(Expr *node, ExprState *state,
 							Datum *resv, bool *resnull);
@@ -77,7 +87,8 @@ static void ExecInitFunc(ExprEvalStep *scratch, Expr *node, List *args,
 static void ExecInitSubPlanExpr(SubPlan *subplan,
 								ExprState *state,
 								Datum *resv, bool *resnull);
-static void ExecCreateExprSetupSteps(ExprState *state, Node *node);
+static void ExecCreateExprSetupSteps(ExprState *state, Node *node,
+									 Bitmapset *scan_attrs);
 static void ExecPushExprSetupSteps(ExprState *state, ExprSetupInfo *info);
 static bool expr_setup_walker(Node *node, ExprSetupInfo *info);
 static bool ExecComputeSlotInfo(ExprState *state, ExprEvalStep *op);
@@ -142,7 +153,7 @@ static void ExecInitJsonCoercion(ExprState *state, JsonReturning *returning,
 ExprState *
 ExecInitExpr(Expr *node, PlanState *parent)
 {
-	return ExecInitExprWithContext(node, parent, NULL);
+	return ExecInitExprInternal(node, parent, NULL, NULL);
 }
 
 /*
@@ -161,6 +172,31 @@ ExecInitExpr(Expr *node, PlanState *parent)
  */
 ExprState *
 ExecInitExprWithContext(Expr *node, PlanState *parent, Node *escontext)
+{
+	return ExecInitExprInternal(node, parent, escontext, NULL);
+}
+
+/*
+ * ExecInitExprWithScanAttrs
+ *		As ExecInitExpr but when 'scan_attrs' is set, use
+ *		EEOP_SCAN_SELECTSOME instead of EEOP_SCAN_FETCHSOME to deform only
+ *		the mentioned 'scan_attrs' from the scan tuple.
+ */
+ExprState *
+ExecInitExprWithScanAttrs(Expr *node, PlanState *parent,
+						  Bitmapset *scan_attrs)
+{
+	return ExecInitExprInternal(node, parent, NULL, scan_attrs);
+}
+
+/*
+ * ExecInitExprInteral
+ *		Internal version to implement ExecInitExpr, ExecInitExprWithContext
+ *		and ExecInitExprWithScanAttrs.
+ */
+static ExprState *
+ExecInitExprInternal(Expr *node, PlanState *parent, Node *escontext,
+					 Bitmapset *scan_attrs)
 {
 	ExprState  *state;
 	ExprEvalStep scratch = {0};
@@ -177,7 +213,7 @@ ExecInitExprWithContext(Expr *node, PlanState *parent, Node *escontext)
 	state->escontext = (ErrorSaveContext *) escontext;

 	/* Compile the expression proper */
 	ExecInitExprRec(node, state, &state->resvalue, &state->resnull);
@@ -214,7 +250,7 @@ ExecInitExprWithParams(Expr *node, ParamListInfo ext_params)
 	state->ext_params = ext_params;

@@ -248,6 +284,19 @@ ExecInitExprWithParams(Expr *node, ParamListInfo ext_params)
@@ -268,7 +317,7 @@ ExecInitQual(List *qual, PlanState *parent)

 	/*
@@ -393,6 +442,28 @@ ExecBuildProjectionInfo(List *targetList,
@@ -410,7 +481,7 @@ ExecBuildProjectionInfo(List *targetList,

@@ -2904,11 +2975,19 @@ ExecInitSubPlanExpr(SubPlan *subplan,
 
@@ -2956,11 +3035,75 @@ ExecPushExprSetupSteps(ExprState *state, ExprSetupInfo *info)
@@ -3033,6 +3176,13 @@ expr_setup_walker(Node *node, ExprSetupInfo *info)
@@ -3099,7 +3249,8 @@ ExecComputeSlotInfo(ExprState *state, ExprEvalStep *op)
 
 	if (op->d.fetch.known_desc != NULL)
 	{
@@ -3152,6 +3303,7 @@ ExecComputeSlotInfo(ExprState *state, ExprEvalStep *op)
 		}
 	}
 	else if (opcode == EEOP_SCAN_FETCHSOME ||
+			 opcode == EEOP_SCAN_SELECTSOME ||
 			 opcode == EEOP_OLD_FETCHSOME ||
 			 opcode == EEOP_NEW_FETCHSOME)
 	{
@@ -4344,7 +4496,7 @@ ExecBuildHash32Expr(TupleDesc desc, const TupleTableSlotOps *ops,
 	state->parent = parent;

 	/*

+/*
index d24c07dca9f..a65b4ca2ee6 100644
 
 /*
 
+static void
 
+static void
 
+static void
@@ -1242,12 +1312,301 @@ done:
 	*offp = off;
 }
 
+/*
+		 * We use a do/while loop as the if condition above guarantees at
+		 * least one loop and confirms to the compiler that 'attlen' and 'off'
+		 * get initialized, which some compilers are not clever enough to
+		 * figure out if we were to use a for loop.
+		} while (attnum < firstNonGuaranteedAttr);
+	/* We can use attcacheoff up until the first NULL */
+		} while (attnum < firstNonCacheOffsetAttr);
@@ -1269,6 +1628,7 @@ const TupleTableSlotOps TTSOpsHeapTuple = {
@@ -1287,6 +1647,7 @@ const TupleTableSlotOps TTSOpsMinimalTuple = {
@@ -1305,6 +1666,7 @@ const TupleTableSlotOps TTSOpsBufferHeapTuple = {
 
+/* ----------------
 
 /* ----------------

 	/*
 
 	/*
 
+	/*
 
 		case T_SampleScan:

 

 
 	return node;
 }
 
index b1820653506..ea86c3822ee 100644
@@ -325,8 +325,12 @@ ExecProcNode(PlanState *node)
 extern ExprState *ExecInitExprWithContext(Expr *node, PlanState *parent, Node *escontext);
@@ -365,6 +369,12 @@ extern ProjectionInfo *ExecBuildProjectionInfo(List *targetList,
@@ -584,6 +594,8 @@ typedef bool (*ExecScanRecheckMtd) (ScanState *node, TupleTableSlot *slot);
 
@@ -680,8 +692,15 @@ extern const TupleTableSlotOps *ExecGetCommonSlotOps(PlanState **planstates,
 
+	/*
 
+static inline void
 
 /* ----------------
diff --git a/src/test/modules/deform_bench/deform_bench--1.0.sql b/src/test/modules/deform_bench/deform_bench--1.0.sql
index 492b71dba3b..4a419fde35c 100644
--- a/src/test/modules/deform_bench/deform_bench--1.0.sql
+++ b/src/test/modules/deform_bench/deform_bench--1.0.sql
@@ -6,3 +6,7 @@
 CREATE FUNCTION deform_bench(tableoid Oid, attnum int[]) RETURNS FLOAT
 AS 'MODULE_PATHNAME', 'deform_bench'
 LANGUAGE C VOLATILE STRICT;
+
+CREATE FUNCTION deform_bench_select(tableoid Oid, attnum int[]) RETURNS FLOAT
+AS 'MODULE_PATHNAME', 'deform_bench_select'
+LANGUAGE C VOLATILE STRICT;
diff --git a/src/test/modules/deform_bench/deform_bench.c b/src/test/modules/deform_bench/deform_bench.c
index 4f104989297..f929d952596 100644
--- a/src/test/modules/deform_bench/deform_bench.c
+++ b/src/test/modules/deform_bench/deform_bench.c
@@ -16,6 +16,7 @@
 #include "catalog/pg_type_d.h"
 #include "funcapi.h"
 #include "miscadmin.h"
+#include "nodes/bitmapset.h"
 #include "utils/array.h"
 #include "utils/arrayaccess.h"
 #include "utils/builtins.h"
@@ -23,6 +24,7 @@
 PG_MODULE_MAGIC;
 
 PG_FUNCTION_INFO_V1(deform_bench);
+PG_FUNCTION_INFO_V1(deform_bench_select);
 
 Datum
 deform_bench(PG_FUNCTION_ARGS)
@@ -104,6 +106,102 @@ deform_bench(PG_FUNCTION_ARGS)
 	relation_close(rel, AccessShareLock);

+	/* Returns the number of milliseconds to run the test */
+	PG_RETURN_FLOAT8((double) (end - start) / (CLOCKS_PER_SEC / 1000));
+}
+
+Datum
+deform_bench_select(PG_FUNCTION_ARGS)
+{
+	Oid			tableoid = PG_GETARG_OID(0);
+	ArrayType  *array = PG_GETARG_ARRAYTYPE_P(1);
+	TableScanDesc scan;
+	Relation	rel;
+	TupleDesc	tupdesc;
+	TupleTableSlot *slot;
+	Datum	   *elem_datums = NULL;
+	bool	   *elem_nulls = NULL;
+	int			elem_count;
+	int			i;
+	int			attnum;
+	int			last_attnum;
+	AttrNumber *attnums;
+	Bitmapset  *attrs = NULL;
+	clock_t		start,
+				end;
+
+	rel = relation_open(tableoid, AccessShareLock);
+
+	if (rel->rd_rel->relam != HEAP_TABLE_AM_OID)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("only heap AM is supported")));
+
+	tupdesc = RelationGetDescr(rel);
+	slot = MakeTupleTableSlot(tupdesc,
+							  &TTSOpsBufferHeapTuple,
+							  TTS_FLAG_OBEYS_NOT_NULL_CONSTRAINTS);
+	scan = table_beginscan_strat(rel, GetActiveSnapshot(), 0, NULL, true, false);
+
+	/*
+	 * The array is used to allow callers to specify which attributes to
+	 * deform.  E.g: '{1,10}'::int[] would deform only attnum=1 and attnum=10.
+	 *
+	 * You'll get an ERROR if you pass an attnum that does not exist.  NULL
+	 * elements are ignored.
+	 */
+	deconstruct_array(array,
+					  INT4OID,
+					  sizeof(int32),
+					  true,
+					  'i',
+					  &elem_datums,
+					  &elem_nulls,
+					  &elem_count);
+
+	for (i = 0; i < elem_count; i++)
+	{
+		/* Make a NULL element mean all attributes */
+		if (elem_nulls[i])
+			continue;
+
+		attnum = DatumGetInt32(elem_datums[i]);
+
+		if (attnum <= 0)
+			elog(ERROR, "only user attributes can be deformed by deform_bench_select");
+		if (attnum >= 0xffff)
+			elog(ERROR, "invalid attnum %d", attnum);
+
+		attrs = bms_add_member(attrs, attnum - 1);
+	}
+
+	attnums = palloc_array(AttrNumber, bms_num_members(attrs));
+
+	attnum = -1;
+	i = 0;
+	while ((attnum = bms_next_member(attrs, attnum)) >= 0)
+		attnums[i++] = (AttrNumber) attnum;
+
+	last_attnum = attnums[i - 1];
+
+	start = clock();
+
+	while (heap_getnextslot(scan, ForwardScanDirection, slot))
+	{
+		AttrNumber attnum_map = 0;
+		CHECK_FOR_INTERRUPTS();
+
+		/* Pass in a faked up attnum_map. tts_nvalid will always be 0 */
+		slot_selectattrs(slot, last_attnum, attnums, &attnum_map);
+	}
+
+	end = clock();
+
+	ExecDropSingleTupleTableSlot(slot);
+	table_endscan(scan);
+	relation_close(rel, AccessShareLock);
+
+
 	/* Returns the number of milliseconds to run the test */
 	PG_RETURN_FLOAT8((double) (end - start) / (CLOCKS_PER_SEC / 1000));
 }
-- 
2.51.0

---

From: Junwang Zhao <[email-masked]>
Date: Sun, 15 Mar 2026 21:50:04 +0800

> TupleDescFinalize(). I'd rather not do this.

That explains, thanks.

-- 
Regards
Junwang Zhao

---

From: Tender Wang <[email-masked]>
Date: Mon, 16 Mar 2026 15:01:10 +0800

Hi  David,

After c456e391138, I found a crash.

How to reproduce:

psql (19devel)
Type "help" for help.

postgres=# CREATE TABLE t0 (
    c0 double precision,
    c1 int4range
);
INSERT INTO public.t0 VALUES (0.013077308, '[160364071,527006655)');
INSERT INTO public.t0 VALUES (0.2488792, NULL);
INSERT INTO public.t0 VALUES ('Infinity', '[-477016999,529396556)');
INSERT INTO public.t0 VALUES (0.2687647, '[-1356493040,71686839)');
INSERT INTO public.t0 VALUES (-2019956220, NULL);
INSERT INTO public.t0 VALUES (NULL, '[-1645797683,476242219)');
INSERT INTO public.t0 VALUES (0.64798653, NULL);
INSERT INTO public.t0 VALUES (0.70265657, NULL);
INSERT INTO public.t0 VALUES (0.31205487, NULL);
INSERT INTO public.t0 VALUES (0.43003803, '[-1973503943,635641598)');
INSERT INTO public.t0 VALUES (0.7500011, '[516760684,870974126)');
INSERT INTO public.t0 VALUES (0, '[-1666589420,-456062869)');
INSERT INTO public.t0 VALUES (NULL, '[-1328295821,1687052919)');
INSERT INTO public.t0 VALUES (NULL, '[-81427373,1340586611)');
INSERT INTO public.t0 VALUES (NULL, '[1469060470,1895771979)');

CREATE TABLE t2 (
    c0 bigint,
    c1 bigint CONSTRAINT t1_c1_not_null NOT NULL
);
INSERT INTO public.t2 VALUES (NULL, 23);
INSERT INTO public.t2 VALUES (622289345, 15);
CREATE TABLE t4 (
    c0 boolean,
    c1 boolean,
    CONSTRAINT t4_c0_check CHECK (c0)
);
INSERT INTO public.t4 VALUES (true, true);
SELECT * FROM t2, t4 RIGHT OUTER JOIN t0 ON t4.c0 WHERE t4.c1 ORDER BY
t4.c0, t0.c1;
CREATE TABLE
INSERT 0 1
INSERT 0 1
INSERT 0 1
INSERT 0 1
INSERT 0 1
INSERT 0 1
INSERT 0 1
INSERT 0 1
INSERT 0 1
INSERT 0 1
INSERT 0 1
INSERT 0 1
INSERT 0 1
INSERT 0 1
INSERT 0 1
CREATE TABLE
INSERT 0 1
INSERT 0 1
CREATE TABLE
INSERT 0 1
server closed the connection unexpectedly
This probably means the server terminated abnormally
before or while processing the request.
The connection to the server was lost. Attempting reset: Succeeded.
postgres=# \q

git bisect shows c456e391138 is the first bad commit.
Please take a look.

-- 
Thanks,
Tender Wang

---

From: David Rowley <[email-masked]>
Date: Mon, 16 Mar 2026 22:17:00 +1300

> server closed the connection unexpectedly

Thanks. Looks like I didn't get the startAttr logic correct in
nocachegetattr(). Starting by using the attcacheoff of the first NULL
attribute isn't valid. It should be the attribute prior to that one.

I'm just verifying some code locally now.

David

---

From: Junwang Zhao <[email-masked]>
Date: Tue, 17 Mar 2026 00:37:56 +0800

Hi David and Tender,

> I'm just verifying some code locally now.

The following case is more simpler:

drop table if exists ty;
create table ty(c0 int not null, c1 double precision, c2 int4range);
insert into ty values (1, 1.0, '[1469060470,1895771979)');
insert into ty values(2, null, '[-1973503943,635641598)');
select * from ty order by c2;

In this case, firstNonCachedOffsetAttr is 2 and firstNullAttr is 1.
If we start from 1, the cached offset becomes 8 due to double's
alignby, and deforming int4range from offset 8 will lead to corrupted data.
Therefore, as David said, we should start from the attribute prior
to that one. PFA is a trivial fix, I think we should add the test but
I haven't found a proper regress test file for it.

-- 
Regards
Junwang Zhao

---

From: David Rowley <[email-masked]>
Date: Tue, 17 Mar 2026 10:15:45 +1300

> I'm just verifying some code locally now.

Now pushed. Some concerns about the lack of exercise in the tests for
fastgetattr() for user tables. I ended up testing by injecting the
following into slot_deform_heap_tuple()

- attnum = slot->tts_nvalid;
+ attnum2 = attnum = slot->tts_nvalid;

[...]

+ for (attnum = attnum2; attnum < natts; attnum++)
+ {
+     Datum v = values[attnum];
+     bool  b = isnull[attnum];
+     values[attnum] = fastgetattr(tuple, attnum + 1, tupleDesc,
&isnull[attnum]);
+     Assert(v == values[attnum]);
+     Assert(b == isnull[attnum]);
+ }
+
  /* Fetch any missing attrs and raise an error if reqnatts is invalid */
  if (unlikely(attnum < reqnatts))

Still considering the best way to get a bit more coverage more permanently.

David

---

From: Tender Wang <[email-masked]>
Date: Thu, 19 Mar 2026 20:39:26 +0800

Hi David,

> following into slot_deform_heap_tuple()

I encountered a crash when doing SQLSmith on TPCH (s=1) test.

How to reproduce:
1. prepare TPCH s =1 data.
2. Execute the following query

postgres=# update public.region set
          r_comment = public.region.r_comment
        returning
          5 as c0,
          pg_catalog.bittypmodout(
            cast(public.region.r_regionkey as int4)) as c1;
server closed the connection unexpectedly
This probably means the server terminated abnormally
before or while processing the request.
The connection to the server was lost. Attempting reset: Succeeded.

(gdb) bt
#0  __pthread_kill_implementation (no_tid=0, signo=6,
threadid=140696004203456) at ./nptl/pthread_kill.c:44
#1  __pthread_kill_internal (signo=6, threadid=140696004203456) at
./nptl/pthread_kill.c:78
#2  __GI___pthread_kill (threadid=140696004203456,
signo=signo@entry=6) at ./nptl/pthread_kill.c:89
#3  0x00007ff659450476 in __GI_raise (sig=sig@entry=6) at
../sysdeps/posix/raise.c:26
#4  0x00007ff6594367f3 in __GI_abort () at ./stdlib/abort.c:79
#5  0x000055d8ae8cad94 in ExceptionalCondition
(conditionName=0x55d8aeac5beb "attlen > 0 || attlen == -1",
fileName=0x55d8aeac5a18 "execTuples.c", lineNumber=1197) at
assert.c:65
#6  0x000055d8ae3afa2e in slot_deform_heap_tuple (slot=0x55d8cabf1a58,
tuple=0x55d8cabf1ab0, offp=0x55d8cabf1ac8, reqnatts=2) at
execTuples.c:1197
#7  0x000055d8ae3ae853 in tts_minimal_getsomeattrs
(slot=0x55d8cabf1a58, natts=2) at execTuples.c:550
#8  0x000055d8ae06ac3b in slot_getsomeattrs (slot=0x55d8cabf1a58,
attnum=2) at ../../../../src/include/executor/tuptable.h:380
#9  0x000055d8ae06ac62 in slot_getallattrs (slot=0x55d8cabf1a58) at
../../../../src/include/executor/tuptable.h:392
#10 0x000055d8ae06b5f5 in printtup (slot=0x55d8cabf1a58,
self=0x55d8cab11828) at printtup.c:319
#11 0x000055d8ae6bfd82 in RunFromStore (portal=0x55d8cab860a0,
direction=ForwardScanDirection, count=0, dest=0x55d8cab11828) at
pquery.c:1089
#12 0x000055d8ae6bf88b in PortalRunSelect (portal=0x55d8cab860a0,
forward=true, count=0, dest=0x55d8cab11828) at pquery.c:912
#13 0x000055d8ae6bf4ea in PortalRun (portal=0x55d8cab860a0,
count=9223372036854775807, isTopLevel=true, dest=0x55d8cab11828,
altdest=0x55d8cab11828, qc=0x7ffe1b92e4f0) at pquery.c:760
#14 0x000055d8ae6b7c2b in exec_simple_query (
    query_string=0x55d8caadb4b0 "update public.region set \n
r_comment = public.region.r_comment\n        returning \n          5
as c0, \n          pg_catalog.bittypmodout(\n", ' ' <repeats 12
times>, "cast(public.region.r_regionkey as int4)) a"...)
    at postgres.c:1278
#15 0x000055d8ae6bd47b in PostgresMain (dbname=0x55d8cab218d0
"postgres", username=0x55d8cab218b8 "ubuntu") at postgres.c:4810
#16 0x000055d8ae6b3068 in BackendMain (startup_data=0x7ffe1b92e7a0,
startup_data_len=24) at backend_startup.c:124
#17 0x000055d8ae5a17a6 in postmaster_child_launch
(child_type=B_BACKEND, child_slot=2, startup_data=0x7ffe1b92e7a0,
startup_data_len=24, client_sock=0x7ffe1b92e800) at
launch_backend.c:268
#18 0x000055d8ae5a8290 in BackendStartup (client_sock=0x7ffe1b92e800)
at postmaster.c:3606
#19 0x000055d8ae5a57d2 in ServerLoop () at postmaster.c:1713
#20 0x000055d8ae5a509c in PostmasterMain (argc=3, argv=0x55d8caad5b30)
at postmaster.c:1403
#21 0x000055d8ae430b37 in main (argc=3, argv=0x55d8caad5b30) at main.c:231
(gdb) f 6
#6  0x000055d8ae3afa2e in slot_deform_heap_tuple (slot=0x55d8cabf1a58,
tuple=0x55d8cabf1ab0, offp=0x55d8cabf1ac8, reqnatts=2) at
execTuples.c:1197
1197 pg_assume(attlen > 0 || attlen == -1);
(gdb) p attlen
$1 = -2

Please take a look.

-- 
Thanks,
Tender Wang

---

From: David Rowley <[email-masked]>
Date: Fri, 20 Mar 2026 01:56:38 +1300

> 1197 pg_assume(attlen > 0 || attlen == -1);

Thanks for the report. I'll look in detail in the morning when I'm at my
computer again. I guess i'll need to add an extra parameter (that will be
constant folded away during the inlining) to the deformed function to
specify if cstrings can exist in the tuple, which seemingly needs to be
true when deforming minimal tuples. I'd rather not lose that optimisation
with heap tuples.

David

---

From: David Rowley <[email-masked]>
Date: Fri, 20 Mar 2026 14:18:12 +1300

On Fri, 20 Mar 2026 at 01:56, David Rowley <[email-masked]> wrote:
> Thanks for the report. I'll look in detail in the morning when I'm at my computer again. I guess i'll need to add an extra parameter (that will be constant folded away during the inlining) to the deformed function to specify if cstrings can exist in the tuple, which seemingly needs to be true when deforming minimal tuples. I'd rather not lose that optimisation with heap tuples.

I've pushed a fix for this.  A more simple recreator was:

with cte as materialized (select relname::cstring as relname from
pg_class) select relname from cte;

David

---

From: Alexander Lakhin <[email-masked]>
Date: Wed, 1 Apr 2026 05:00:00 +0300

Hello David,

> After c456e391138, I found a crash.

I've also found an assertion failure:
SELECT JSON_ARRAY(VALUES (('', '')));

triggers:
TRAP: failed Assert("attlen > 0 || attlen == -1"), File: "heaptuple.c", Line: 598, PID: 2582495

Could you have a look, please?

Best regards,
Alexander

---

From: David Rowley <[email-masked]>
Date: Wed, 1 Apr 2026 16:35:14 +1300

> Could you have a look, please?

Thanks. Looking...

David

---

From: Junwang Zhao <[email-masked]>
Date: Wed, 1 Apr 2026 13:13:30 +0800

> > Could you have a look, please?

The parser transforms '' (or any cstring) into Const with UNKNOWNOID.
When building the tuple descriptor in ExecTypeFromExprList,
TupleDescInitEntry uses UNKNOWNOID to populate the attribute entry,
thus the failure in nocachegetattr.

Therefore, the assertion should be addressed by removing the pg_assume,
since this case can occur.

Just trying to learn through analysis, might be incorrect. Let's wait for
David's fix.

-- 
Regards
Junwang Zhao

---

From: jian he <[email-masked]>
Date: Wed, 1 Apr 2026 21:19:48 +0800

> Just trying to learn through analysis, might be incorrect. Let's wait for
HI.

You can also trigger it via:

SELECT row_to_json(('', ''));

In transformRowExpr, we can coerce these UNKNOWNOID Const to TEXTOID Const.
But I guess it's harder to guarantee that comment "cstrings don't
exist in heap tuples." in nocachegetattr to be true.

--
jian
https://www.enterprisedb.com/

---

From: David Rowley <[email-masked]>
Date: Thu, 2 Apr 2026 14:12:55 +1300

> > Could you have a look, please?

I've pushed a fix for this. Thanks for the report.

David