Tepid: only update indexes that have changed attributes

.clangd

@@ -0,0 +1,43 @@
+Diagnostics:
+  MissingIncludes: None
+InlayHints:
+  Enabled: true
+  ParameterNames: true
+  DeducedTypes: true
+CompileFlags:
+  CompilationDatabase: build/       # Search build/ directory for compile_commands.json
+  Remove: [ -Werror ]
+  Add:
+  - -DDEBUG
+  - -DLOCAL
+  - -DPGDLLIMPORT=
+  - -DPIC
+  - -O2
+  - -Wall
+  - -Wcast-function-type
+  - -Wconversion
+  - -Wdeclaration-after-statement
+  - -Wendif-labels
+  - -Werror=vla
+  - -Wextra
+  - -Wfloat-equal
+  - -Wformat-security
+  - -Wimplicit-fallthrough=3
+  - -Wmissing-format-attribute
+  - -Wmissing-prototypes
+  - -Wno-format-truncation
+  - -Wno-sign-conversion
+  - -Wno-stringop-truncation
+  - -Wno-unused-const-variable
+  - -Wpointer-arith
+  - -Wshadow
+  - -Wshadow=compatible-local
+  - -fPIC
+  - -fexcess-precision=standard
+  - -fno-strict-aliasing
+  - -fvisibility=hidden
+  - -fwrapv
+  - -g
+  - -std=c11
+  - -I.
+  - -I../../../../src/include

.gdbinit

@@ -0,0 +1,156 @@
+# HOT Indexed Updates — GDB breakpoints for code review
+#
+# Usage:  gdb -x .gdbinit <postgres-binary>
+# Or from gdb:  source .gdbinit
+#
+# These breakpoints cover the major code paths introduced or modified by
+# the HOT indexed updates patch series.  They are organized by subsystem
+# to make it easy to enable/disable groups during debugging.
+#
+# Tip: to skip to a specific subsystem, disable all then enable selectively:
+#   disable breakpoints
+#   enable 1 2 3          # just the update-decision group
+
+# =========================================================================
+# 1. UPDATE DECISION — heap_update() HOT/HOT-indexed/non-HOT choice
+#    src/backend/access/heap/heapam.c
+# =========================================================================
+
+# Main entry: heap_update
+break heapam.c:3210
+
+# HOT decision block: pure HOT vs HOT indexed vs non-HOT
+# Line 4019: pure HOT (no indexed columns changed)
+# Line 4024: HOT indexed path (non-catalog, some indexed columns changed)
+# Line 4031: predict augmented tuple size
+# Line 4033: size+space check before creating augmented tuple
+break heapam.c:4019
+break heapam.c:4024
+break heapam.c:4033
+
+# Set HEAP_INDEXED_UPDATED flag on new tuple before page insertion
+break heapam.c:4101
+
+# Restore HEAP_INDEXED_UPDATED on old tuple (only if it previously had it)
+break heapam.c:4147
+
+# =========================================================================
+# 2. TUPLE CREATION — building the augmented tuple with embedded bitmap
+#    src/backend/access/heap/heapam.c
+# =========================================================================
+
+# Predict augmented tuple size (returns 0 if t_hoff would overflow)
+break heap_hot_indexed_tuple_size
+
+# Create augmented tuple with embedded modified-column bitmap
+break heap_hot_indexed_create_tuple
+
+# Serialize Bitmapset into raw bytes in tuple header
+break heap_hot_indexed_serialize_bitmap
+
+# =========================================================================
+# 3. BITMAP UTILITIES — raw bitmap operations for chain following
+#    src/backend/access/heap/heapam.c
+# =========================================================================
+
+# Compute raw bitmap byte size from natts
+break heap_hot_indexed_bitmap_raw_size
+
+# Check if tuple header has room for bitmap between null bitmap and data
+break heap_hot_indexed_has_bitmap_space
+
+# Read HOT indexed bitmap from tuple header (returns Bitmapset)
+break heap_hot_indexed_read_bitmap
+
+# Fast overlap check: does tuple's raw bitmap overlap with indexed_attrs?
+break heap_hot_indexed_bitmap_overlaps_raw
+
+# OR a tuple's raw bitmap into an accumulator buffer
+break heap_hot_indexed_bitmap_or_raw
+
+# Check if accumulated raw bitmap overlaps with indexed_attrs
+break heap_hot_indexed_accum_overlaps
+
+# Merge bitmaps from dead tuples into a target tuple on the page
+break heap_hot_indexed_merge_bitmaps_raw
+
+# Deserialize raw bytes back to Bitmapset
+break heap_hot_indexed_deserialize_bitmap
+
+# =========================================================================
+# 4. INDEX SCAN — HOT chain following with stale-entry detection
+#    src/backend/access/heap/heapam_indexscan.c
+# =========================================================================
+
+# Main HOT chain search with indexed update awareness
+break heap_hot_search_buffer
+
+# Redirect-with-data: initialize bitmap accumulator from collapsed redirect
+break heapam_indexscan.c:182
+
+# Accumulate bitmap from INDEXED_UPDATED tuple in chain
+break heapam_indexscan.c:250
+
+# Stale entry detection: accumulated bitmap overlaps this index's attrs
+break heapam_indexscan.c:297
+
+# =========================================================================
+# 5. INDEX SCAN SETUP — indexed_attrs bitmap computation
+#    src/backend/access/index/indexam.c
+# =========================================================================
+
+# Compute indexed_attrs for HOT indexed update chain following
+break indexam.c:299
+
+# =========================================================================
+# 6. INDEX INSERTION — skip unchanged indexes for HOT indexed updates
+#    src/backend/executor/execIndexing.c
+# =========================================================================
+
+# Entry: insert/update index tuples
+break ExecInsertIndexTuples
+
+# Index skip decision: skip indexes whose attrs don't overlap modified set
+break execIndexing.c:370
+
+# =========================================================================
+# 7. PRUNING — chain collapsing and redirect-with-data
+#    src/backend/access/heap/pruneheap.c
+# =========================================================================
+
+# Main prune function
+break heap_page_prune_and_freeze
+
+# Per-chain pruning entry
+break heap_prune_chain
+
+# Chain collapsing: collect bitmaps from dead INDEXED_UPDATED intermediates
+break pruneheap.c:1802
+
+# OR dead tuple bitmaps into combined bitmap
+break pruneheap.c:1836
+
+# Record redirect-with-data for execute phase
+break pruneheap.c:1863
+
+# Execute phase: apply redirect-with-data entries on the page
+break pruneheap.c:1287
+
+# =========================================================================
+# 8. WAL REPLAY — recovery of HOT indexed updates
+#    src/backend/access/heap/heapam_xlog.c
+# =========================================================================
+
+# WAL replay for XLOG_HEAP2_INDEXED_UPDATE
+break heap_xlog_indexed_update
+
+# =========================================================================
+# 9. WAL LOGGING — writing HOT indexed update records
+#    src/backend/access/heap/heapam.c
+# =========================================================================
+
+# WAL logging for heap updates (handles indexed_update flag)
+break log_heap_update
+
+# Serialize redirect-with-data into WAL record (pruneheap.c)
+break pruneheap.c:2936

contrib/amcheck/expected/check_heap.out

@@ -231,6 +231,46 @@ SELECT * FROM verify_heapam('test_foreign_table',
 							endblock := NULL);
 ERROR:  cannot check relation "test_foreign_table"
 DETAIL:  This operation is not supported for foreign tables.
+-- HOT-indexed (HOT/SIU) on-page artifacts:
+--
+-- A HOT-indexed UPDATE keeps the new tuple on the same page as a heap-only
+-- tuple marked HEAP_INDEXED_UPDATED and plants index entries pointing at its
+-- own TID.  Pruning a chain of such updates collapses dead members to
+-- LP_REDIRECT forwarders and preserves the LP of a live HOT-indexed member
+-- whose index entries may not yet be swept.  verify_heapam must treat all of
+-- these as legitimate.  This scenario exercises them and asserts that
+-- verify_heapam reports zero corruption against legitimate HOT-indexed
+-- activity.
+CREATE TABLE hot_indexed_check (id int PRIMARY KEY, c1 int, c2 int, c3 int)
+	WITH (fillfactor = 70);
+CREATE INDEX hot_indexed_check_c1 ON hot_indexed_check (c1);
+CREATE INDEX hot_indexed_check_c2 ON hot_indexed_check (c2);
+INSERT INTO hot_indexed_check
+	SELECT g, g, g, g FROM generate_series(1, 200) g;
+-- Single-step UPDATEs: each row gets one HOT-indexed update.  Each
+-- successful HOT-indexed update keeps its new tuple on-page and inserts an
+-- entry only into the index whose attribute changed.
+UPDATE hot_indexed_check SET c1 = c1 + 1000;
+-- Multi-step UPDATEs: drive several successive HOT-indexed updates against
+-- the same rows so prune sees a chain of dead intermediates and collapses
+-- them to LP_REDIRECT forwarders.  An explicit VACUUM runs the prune path
+-- and exercises chain collapse.
+UPDATE hot_indexed_check SET c2 = c2 + 1 WHERE id <= 50;
+UPDATE hot_indexed_check SET c2 = c2 + 1 WHERE id <= 50;
+UPDATE hot_indexed_check SET c2 = c2 + 1 WHERE id <= 50;
+VACUUM (INDEX_CLEANUP off) hot_indexed_check;
+-- verify_heapam must not report any corruption against legitimate HOT-
+-- indexed artifacts.  Selecting the corrupting message makes any
+-- regression unmistakable in the regress diff.
+SELECT blkno, offnum, attnum, msg
+	FROM verify_heapam('hot_indexed_check',
+					   startblock := NULL,
+					   endblock := NULL);
+ blkno | offnum | attnum | msg 
+-------+--------+--------+-----
+(0 rows)
+
+DROP TABLE hot_indexed_check;
 -- cleanup
 DROP TABLE heaptest;
 DROP TABLESPACE regress_test_stats_tblspc;

contrib/amcheck/sql/check_heap.sql

@@ -138,6 +138,43 @@ SELECT * FROM verify_heapam('test_foreign_table',
 							startblock := NULL,
 							endblock := NULL);
 
+-- HOT-indexed (HOT/SIU) on-page artifacts:
+--
+-- A HOT-indexed UPDATE keeps the new tuple on the same page as a heap-only
+-- tuple marked HEAP_INDEXED_UPDATED and plants index entries pointing at its
+-- own TID.  Pruning a chain of such updates collapses dead members to
+-- LP_REDIRECT forwarders and preserves the LP of a live HOT-indexed member
+-- whose index entries may not yet be swept.  verify_heapam must treat all of
+-- these as legitimate.  This scenario exercises them and asserts that
+-- verify_heapam reports zero corruption against legitimate HOT-indexed
+-- activity.
+CREATE TABLE hot_indexed_check (id int PRIMARY KEY, c1 int, c2 int, c3 int)
+	WITH (fillfactor = 70);
+CREATE INDEX hot_indexed_check_c1 ON hot_indexed_check (c1);
+CREATE INDEX hot_indexed_check_c2 ON hot_indexed_check (c2);
+INSERT INTO hot_indexed_check
+	SELECT g, g, g, g FROM generate_series(1, 200) g;
+-- Single-step UPDATEs: each row gets one HOT-indexed update.  Each
+-- successful HOT-indexed update keeps its new tuple on-page and inserts an
+-- entry only into the index whose attribute changed.
+UPDATE hot_indexed_check SET c1 = c1 + 1000;
+-- Multi-step UPDATEs: drive several successive HOT-indexed updates against
+-- the same rows so prune sees a chain of dead intermediates and collapses
+-- them to LP_REDIRECT forwarders.  An explicit VACUUM runs the prune path
+-- and exercises chain collapse.
+UPDATE hot_indexed_check SET c2 = c2 + 1 WHERE id <= 50;
+UPDATE hot_indexed_check SET c2 = c2 + 1 WHERE id <= 50;
+UPDATE hot_indexed_check SET c2 = c2 + 1 WHERE id <= 50;
+VACUUM (INDEX_CLEANUP off) hot_indexed_check;
+-- verify_heapam must not report any corruption against legitimate HOT-
+-- indexed artifacts.  Selecting the corrupting message makes any
+-- regression unmistakable in the regress diff.
+SELECT blkno, offnum, attnum, msg
+	FROM verify_heapam('hot_indexed_check',
+					   startblock := NULL,
+					   endblock := NULL);
+DROP TABLE hot_indexed_check;
+
 -- cleanup
 DROP TABLE heaptest;
 DROP TABLESPACE regress_test_stats_tblspc;