[PATCH] Add pg_lfind8_nonzero()

From ee5da25dbba924c1c9a399568c27db8ac603e2d8 Mon Sep 17 00:00:00 2001
From: ChangAo Chen <cca5507@qq.com>
Date: Sun, 14 Dec 2025 18:13:31 +0800
Subject: [PATCH v1 1/3] Add pg_lfind8_nonzero().

---
 src/include/port/pg_lfind.h                   | 40 +++++++++++++++++++
 .../test_lfind/expected/test_lfind.out        |  6 +++
 .../modules/test_lfind/sql/test_lfind.sql     |  1 +
 .../modules/test_lfind/test_lfind--1.0.sql    |  4 ++
 src/test/modules/test_lfind/test_lfind.c      | 17 ++++++++
 5 files changed, 68 insertions(+)

diff --git a/src/include/port/pg_lfind.h b/src/include/port/pg_lfind.h
index 20f7497dcb7..8dd7b81ebba 100644
--- a/src/include/port/pg_lfind.h
+++ b/src/include/port/pg_lfind.h
@@ -80,6 +80,46 @@ pg_lfind8_le(uint8 key, uint8 *base, uint32 nelem)
 	return false;
 }
 
+/*
+ * pg_lfind8_nonzero
+ *
+ * Return true if there is an element in 'base' that is not equal to
+ * zero, otherwise return false.
+ */
+static inline bool
+pg_lfind8_nonzero(uint8 *base, uint32 nelem)
+{
+	uint32      i;
+	uint32		tail_idx;
+	uint64      chunk;
+
+	/* Search the array one-by-one if there aren't enough elements. */
+	if (nelem < sizeof(chunk))
+	{
+		for (i = 0; i < nelem; i++)
+		{
+			if (base[i] != 0)
+				return true;
+		}
+		return false;
+	}
+
+	/* Round down to multiple of chunk length. */
+	tail_idx = nelem & ~(sizeof(chunk) - 1);
+
+	for (i = 0; i < tail_idx; i += sizeof(chunk))
+	{
+		/* memcpy() to avoid unaligned access. */
+		memcpy(&chunk, &base[i], sizeof(chunk));
+		if (chunk != 0)
+			return true;
+	}
+
+	/* Process the last chunk in the array. */
+	memcpy(&chunk, &base[nelem - sizeof(chunk)], sizeof(chunk));
+	return chunk != 0;
+}
+
 /*
  * pg_lfind32_one_by_one_helper
  *
diff --git a/src/test/modules/test_lfind/expected/test_lfind.out b/src/test/modules/test_lfind/expected/test_lfind.out
index 1d4b14e7032..4f43a729b51 100644
--- a/src/test/modules/test_lfind/expected/test_lfind.out
+++ b/src/test/modules/test_lfind/expected/test_lfind.out
@@ -16,6 +16,12 @@ SELECT test_lfind8_le();
  
 (1 row)
 
+SELECT test_lfind8_nonzero();
+ test_lfind8_nonzero 
+---------------------
+ 
+(1 row)
+
 SELECT test_lfind32();
  test_lfind32 
 --------------
diff --git a/src/test/modules/test_lfind/sql/test_lfind.sql b/src/test/modules/test_lfind/sql/test_lfind.sql
index 766c640831f..7894fa61e78 100644
--- a/src/test/modules/test_lfind/sql/test_lfind.sql
+++ b/src/test/modules/test_lfind/sql/test_lfind.sql
@@ -7,4 +7,5 @@ CREATE EXTENSION test_lfind;
 --
 SELECT test_lfind8();
 SELECT test_lfind8_le();
+SELECT test_lfind8_nonzero();
 SELECT test_lfind32();
diff --git a/src/test/modules/test_lfind/test_lfind--1.0.sql b/src/test/modules/test_lfind/test_lfind--1.0.sql
index 81801926ae8..bb72cc6e56a 100644
--- a/src/test/modules/test_lfind/test_lfind--1.0.sql
+++ b/src/test/modules/test_lfind/test_lfind--1.0.sql
@@ -14,3 +14,7 @@ CREATE FUNCTION test_lfind8()
 CREATE FUNCTION test_lfind8_le()
 	RETURNS pg_catalog.void
 	AS 'MODULE_PATHNAME' LANGUAGE C;
+
+CREATE FUNCTION test_lfind8_nonzero()
+	RETURNS pg_catalog.void
+	AS 'MODULE_PATHNAME' LANGUAGE C;
diff --git a/src/test/modules/test_lfind/test_lfind.c b/src/test/modules/test_lfind/test_lfind.c
index 8dcaa8f9fda..52ae6783ec9 100644
--- a/src/test/modules/test_lfind/test_lfind.c
+++ b/src/test/modules/test_lfind/test_lfind.c
@@ -115,6 +115,23 @@ test_lfind8_le(PG_FUNCTION_ARGS)
 	PG_RETURN_VOID();
 }
 
+PG_FUNCTION_INFO_V1(test_lfind8_nonzero);
+Datum
+test_lfind8_nonzero(PG_FUNCTION_ARGS)
+{
+	uint8		charbuf[64] = {0};
+
+	charbuf[32] = 1;
+
+	if (pg_lfind8_nonzero(charbuf, 32))
+		elog(ERROR, "pg_lfind8_nonzero() found nonexistent nonzero");
+
+	if (!pg_lfind8_nonzero(charbuf, 64))
+		elog(ERROR, "pg_lfind8_nonzero() did not find existing nonzero");
+
+	PG_RETURN_VOID();
+}
+
 PG_FUNCTION_INFO_V1(test_lfind32);
 Datum
 test_lfind32(PG_FUNCTION_ARGS)
-- 
2.52.0

From f465c2609f5be4500145293d42a5704fa6e61dec Mon Sep 17 00:00:00 2001
From: ChangAo Chen <cca5507@qq.com>
Date: Sun, 14 Dec 2025 18:43:40 +0800
Subject: [PATCH v1 2/3] Use pg_lfind8_nonzero().

---
 src/backend/access/common/heaptuple.c  | 23 +++++------------------
 src/backend/access/common/indextuple.c | 11 +++--------
 src/backend/utils/adt/expandedrecord.c | 11 +++--------
 3 files changed, 11 insertions(+), 34 deletions(-)

diff --git a/src/backend/access/common/heaptuple.c b/src/backend/access/common/heaptuple.c
index b7820d692e2..77d2a6f9751 100644
--- a/src/backend/access/common/heaptuple.c
+++ b/src/backend/access/common/heaptuple.c
@@ -61,6 +61,7 @@
 #include "access/sysattr.h"
 #include "access/tupdesc_details.h"
 #include "common/hashfn.h"
+#include "port/pg_lfind.h"
 #include "utils/datum.h"
 #include "utils/expandeddatum.h"
 #include "utils/hsearch.h"
@@ -1125,7 +1126,6 @@ heap_form_tuple(TupleDesc tupleDescriptor,
 	int			hoff;
 	bool		hasnull = false;
 	int			numberOfAttributes = tupleDescriptor->natts;
-	int			i;
 
 	if (numberOfAttributes > MaxTupleAttributeNumber)
 		ereport(ERROR,
@@ -1136,14 +1136,8 @@ heap_form_tuple(TupleDesc tupleDescriptor,
 	/*
 	 * Check for nulls
 	 */
-	for (i = 0; i < numberOfAttributes; i++)
-	{
-		if (isnull[i])
-		{
-			hasnull = true;
-			break;
-		}
-	}
+	if (likely(numberOfAttributes > 0))
+		hasnull = pg_lfind8_nonzero((uint8 *) isnull, numberOfAttributes);
 
 	/*
 	 * Determine total space needed
@@ -1462,7 +1456,6 @@ heap_form_minimal_tuple(TupleDesc tupleDescriptor,
 	int			hoff;
 	bool		hasnull = false;
 	int			numberOfAttributes = tupleDescriptor->natts;
-	int			i;
 
 	Assert(extra == MAXALIGN(extra));
 
@@ -1475,14 +1468,8 @@ heap_form_minimal_tuple(TupleDesc tupleDescriptor,
 	/*
 	 * Check for nulls
 	 */
-	for (i = 0; i < numberOfAttributes; i++)
-	{
-		if (isnull[i])
-		{
-			hasnull = true;
-			break;
-		}
-	}
+	if (likely(numberOfAttributes > 0))
+		hasnull = pg_lfind8_nonzero((uint8 *) isnull, numberOfAttributes);
 
 	/*
 	 * Determine total space needed
diff --git a/src/backend/access/common/indextuple.c b/src/backend/access/common/indextuple.c
index 3efa3889c6f..eac509fd580 100644
--- a/src/backend/access/common/indextuple.c
+++ b/src/backend/access/common/indextuple.c
@@ -21,6 +21,7 @@
 #include "access/htup_details.h"
 #include "access/itup.h"
 #include "access/toast_internals.h"
+#include "port/pg_lfind.h"
 
 /*
  * This enables de-toasting of index entries.  Needed until VACUUM is
@@ -139,14 +140,8 @@ index_form_tuple_context(TupleDesc tupleDescriptor,
 	}
 #endif
 
-	for (i = 0; i < numberOfAttributes; i++)
-	{
-		if (isnull[i])
-		{
-			hasnull = true;
-			break;
-		}
-	}
+	if (likely(numberOfAttributes > 0))
+		hasnull = pg_lfind8_nonzero((uint8 *) isnull, numberOfAttributes);
 
 	if (hasnull)
 		infomask |= INDEX_NULL_MASK;
diff --git a/src/backend/utils/adt/expandedrecord.c b/src/backend/utils/adt/expandedrecord.c
index 495d48fb581..13709e204a6 100644
--- a/src/backend/utils/adt/expandedrecord.c
+++ b/src/backend/utils/adt/expandedrecord.c
@@ -23,6 +23,7 @@
 #include "access/htup_details.h"
 #include "catalog/heap.h"
 #include "catalog/pg_type.h"
+#include "port/pg_lfind.h"
 #include "utils/builtins.h"
 #include "utils/datum.h"
 #include "utils/expandedrecord.h"
@@ -727,14 +728,8 @@ ER_get_flat_size(ExpandedObjectHeader *eohptr)
 
 	/* Test if we currently have any null values */
 	hasnull = false;
-	for (i = 0; i < erh->nfields; i++)
-	{
-		if (erh->dnulls[i])
-		{
-			hasnull = true;
-			break;
-		}
-	}
+	if (likely(erh->nfields > 0))
+		hasnull = pg_lfind8_nonzero((uint8 *) erh->dnulls, erh->nfields);
 
 	/* Determine total space needed */
 	len = offsetof(HeapTupleHeaderData, t_bits);
-- 
2.52.0

From 4da2c4c88cc3a42ea04cefd9ebf70bffcbfd04e1 Mon Sep 17 00:00:00 2001
From: ChangAo Chen <cca5507@qq.com>
Date: Sun, 14 Dec 2025 20:19:16 +0800
Subject: [PATCH v1 3/3] Test pg_lfind8_nonzero().

---
 contrib/test_patch/Makefile            | 19 +++++++
 contrib/test_patch/test_patch--1.0.sql |  9 ++++
 contrib/test_patch/test_patch.c        | 71 ++++++++++++++++++++++++++
 contrib/test_patch/test_patch.control  |  3 ++
 4 files changed, 102 insertions(+)
 create mode 100644 contrib/test_patch/Makefile
 create mode 100644 contrib/test_patch/test_patch--1.0.sql
 create mode 100644 contrib/test_patch/test_patch.c
 create mode 100644 contrib/test_patch/test_patch.control

diff --git a/contrib/test_patch/Makefile b/contrib/test_patch/Makefile
new file mode 100644
index 00000000000..310157fdf84
--- /dev/null
+++ b/contrib/test_patch/Makefile
@@ -0,0 +1,19 @@
+MODULE_big = test_patch
+OBJS = \
+	$(WIN32RES) \
+	test_patch.o
+PGFILEDESC = "test_patch"
+
+EXTENSION = test_patch
+DATA = test_patch--1.0.sql
+
+ifdef USE_PGXS
+PG_CONFIG = pg_config
+PGXS := $(shell $(PG_CONFIG) --pgxs)
+include $(PGXS)
+else
+subdir = contrib/test_patch
+top_builddir = ../..
+include $(top_builddir)/src/Makefile.global
+include $(top_srcdir)/contrib/contrib-global.mk
+endif
diff --git a/contrib/test_patch/test_patch--1.0.sql b/contrib/test_patch/test_patch--1.0.sql
new file mode 100644
index 00000000000..0d062381a6e
--- /dev/null
+++ b/contrib/test_patch/test_patch--1.0.sql
@@ -0,0 +1,9 @@
+\echo Use "CREATE EXTENSION test_patch" to load this file. \quit
+
+CREATE FUNCTION test_head(natts int)
+	RETURNS pg_catalog.void
+	AS 'MODULE_PATHNAME' LANGUAGE C;
+
+CREATE FUNCTION test_patch(natts int)
+	RETURNS pg_catalog.void
+	AS 'MODULE_PATHNAME' LANGUAGE C;
diff --git a/contrib/test_patch/test_patch.c b/contrib/test_patch/test_patch.c
new file mode 100644
index 00000000000..5f3eea4895c
--- /dev/null
+++ b/contrib/test_patch/test_patch.c
@@ -0,0 +1,71 @@
+#include "postgres.h"
+
+#include "fmgr.h"
+#include "port/pg_lfind.h"
+#include "portability/instr_time.h"
+
+static bool isnull[2048];
+
+PG_MODULE_MAGIC;
+
+PG_FUNCTION_INFO_V1(test_head);
+Datum
+test_head(PG_FUNCTION_ARGS)
+{
+	int natts = PG_GETARG_INT32(0);
+    int loops = 1000;
+    bool hasnull = false;
+    int i;
+    instr_time start;
+    instr_time end;
+
+    INSTR_TIME_SET_CURRENT(start);
+
+    for (i = 0; i < loops; i++)
+    {
+        for (int j = 0; j < natts; j++)
+        {
+            if (isnull[j])
+            {
+                hasnull = true;
+                break;
+            }
+        }
+    }
+
+    INSTR_TIME_SET_CURRENT(end);
+
+    elog(INFO, "[HEAD] natts: %d, hasnull: %d, duration: %ld ns",
+         natts, hasnull,
+         INSTR_TIME_GET_NANOSEC(end) - INSTR_TIME_GET_NANOSEC(start));
+
+	PG_RETURN_VOID();
+}
+
+PG_FUNCTION_INFO_V1(test_patch);
+Datum
+test_patch(PG_FUNCTION_ARGS)
+{
+	int natts = PG_GETARG_INT32(0);
+    int loops = 1000;
+    bool hasnull = false;
+    int i;
+    instr_time start;
+    instr_time end;
+
+    INSTR_TIME_SET_CURRENT(start);
+
+    for (i = 0; i < loops; i++)
+    {
+        if (likely(natts > 0))
+            hasnull = pg_lfind8_nonzero((uint8 *) isnull, natts);
+    }
+
+    INSTR_TIME_SET_CURRENT(end);
+
+    elog(INFO, "[PATCH] natts: %d, hasnull: %d, duration: %ld ns",
+         natts, hasnull,
+         INSTR_TIME_GET_NANOSEC(end) - INSTR_TIME_GET_NANOSEC(start));
+
+	PG_RETURN_VOID();
+}
diff --git a/contrib/test_patch/test_patch.control b/contrib/test_patch/test_patch.control
new file mode 100644
index 00000000000..588092007ed
--- /dev/null
+++ b/contrib/test_patch/test_patch.control
@@ -0,0 +1,3 @@
+default_version = '1.0'
+module_pathname = '$libdir/test_patch'
+relocatable = true
-- 
2.52.0