Ignore BRIN indexes when checking for HOT updates

When determining whether an index update may be skipped by using HOT, we
can ignore attributes indexed by block summarizing indexes without
references to individual tuples that need to be cleaned up.

A new type TU_UpdateIndexes provides a signal to the executor to
determine which indexes to update - no indexes, all indexes, or only the
summarizing indexes.

This also removes rd_indexattr list, and replaces it with rd_attrsvalid
flag. The list was not used anywhere, and a simple flag is sufficient.

This was originally committed as 5753d4ee32, but then got reverted by
e3fcca0d0d because of correctness issues.

Original patch by Josef Simanek, various fixes and improvements by Tomas
Vondra and me.

Authors: Matthias van de Meent, Josef Simanek, Tomas Vondra
Reviewed-by: Tomas Vondra, Alvaro Herrera
Discussion: https://postgr.es/m/05ebcb44-f383-86e3-4f31-0a97a55634cf@enterprisedb.com
Discussion: https://postgr.es/m/CAFp7QwpMRGcDAQumN7onN9HjrJ3u4X3ZRXdGFT0K5G2JWvnbWg%40mail.gmail.com

src/include/access/amapi.h

@@ -244,6 +244,8 @@ typedef struct IndexAmRoutine
 	bool		amcaninclude;
 	/* does AM use maintenance_work_mem? */
 	bool		amusemaintenanceworkmem;
+	/* does AM store tuple information only at block granularity? */
+	bool        amsummarizing;
 	/* OR of parallel vacuum flags.  See vacuum.h for flags. */
 	uint8		amparallelvacuumoptions;
 	/* type of data stored in index, or InvalidOid if variable */

src/include/access/heapam.h

@@ -249,7 +249,8 @@ extern void heap_abort_speculative(Relation relation, ItemPointer tid);
 extern TM_Result heap_update(Relation relation, ItemPointer otid,
 							 HeapTuple newtup,
 							 CommandId cid, Snapshot crosscheck, bool wait,
-							 struct TM_FailureData *tmfd, LockTupleMode *lockmode);
+							 struct TM_FailureData *tmfd, LockTupleMode *lockmode,
+							 TU_UpdateIndexes *update_indexes);
 extern TM_Result heap_lock_tuple(Relation relation, HeapTuple tuple,
 								 CommandId cid, LockTupleMode mode, LockWaitPolicy wait_policy,
 								 bool follow_updates,
@@ -275,7 +276,7 @@ extern bool heap_tuple_needs_eventual_freeze(HeapTupleHeader tuple);
 extern void simple_heap_insert(Relation relation, HeapTuple tup);
 extern void simple_heap_delete(Relation relation, ItemPointer tid);
 extern void simple_heap_update(Relation relation, ItemPointer otid,
-							   HeapTuple tup);
+							   HeapTuple tup, TU_UpdateIndexes *update_indexes);
 
 extern TransactionId heap_index_delete_tuples(Relation rel,
 											  TM_IndexDeleteOp *delstate);

src/include/access/tableam.h

@@ -102,6 +102,22 @@ typedef enum TM_Result
 	TM_WouldBlock
 } TM_Result;
 
+/*
+ * Result codes for table_update(..., update_indexes*..).
+ * Used to determine which indexes to update.
+ */
+typedef enum TU_UpdateIndexes
+{
+	/* No indexed columns were updated (incl. TID addressing of tuple) */
+	TU_None,
+
+	/* A non-summarizing indexed column was updated, or the TID has changed */
+	TU_All,
+
+	/* Only summarized columns were updated, TID is unchanged */
+	TU_Summarizing
+} TU_UpdateIndexes;
+
 /*
  * When table_tuple_update, table_tuple_delete, or table_tuple_lock fail
  * because the target tuple is already outdated, they fill in this struct to
@@ -526,7 +542,7 @@ typedef struct TableAmRoutine
 								 bool wait,
 								 TM_FailureData *tmfd,
 								 LockTupleMode *lockmode,
-								 bool *update_indexes);
+								 TU_UpdateIndexes *update_indexes);
 
 	/* see table_tuple_lock() for reference about parameters */
 	TM_Result	(*tuple_lock) (Relation rel,
@@ -1514,7 +1530,7 @@ static inline TM_Result
 table_tuple_update(Relation rel, ItemPointer otid, TupleTableSlot *slot,
 				   CommandId cid, Snapshot snapshot, Snapshot crosscheck,
 				   bool wait, TM_FailureData *tmfd, LockTupleMode *lockmode,
-				   bool *update_indexes)
+				   TU_UpdateIndexes *update_indexes)
 {
 	return rel->rd_tableam->tuple_update(rel, otid, slot,
 										 cid, snapshot, crosscheck,
@@ -2038,7 +2054,7 @@ extern void simple_table_tuple_delete(Relation rel, ItemPointer tid,
 									  Snapshot snapshot);
 extern void simple_table_tuple_update(Relation rel, ItemPointer otid,
 									  TupleTableSlot *slot, Snapshot snapshot,
-									  bool *update_indexes);
+									  TU_UpdateIndexes *update_indexes);
 
 
 /* ----------------------------------------------------------------------------