Let table AM insertion methods control index insertion

Previously, the executor did index insert unconditionally after calling
table AM interface methods tuple_insert() and multi_insert().  This commit
introduces the new parameter insert_indexes for these two methods.  Setting
'*insert_indexes' to true saves the current logic.  Setting it to false
indicates that table AM cares about index inserts itself and doesn't want the
caller to do that.

Discussion: https://postgr.es/m/CAPpHfdurb9ycV8udYqM%3Do0sPS66PJ4RCBM1g-bBpvzUfogY0EA%40mail.gmail.com
Reviewed-by: Pavel Borisov, Matthias van de Meent, Mark Dilger

src/backend/commands/copyfrom.c

@@ -397,6 +397,7 @@ CopyMultiInsertBufferFlush(CopyMultiInsertInfo *miinfo,
 		bool		line_buf_valid = cstate->line_buf_valid;
 		uint64		save_cur_lineno = cstate->cur_lineno;
 		MemoryContext oldcontext;
+		bool		insertIndexes;
 
 		Assert(buffer->bistate != NULL);
 
@@ -416,7 +417,8 @@ CopyMultiInsertBufferFlush(CopyMultiInsertInfo *miinfo,
 						   nused,
 						   mycid,
 						   ti_options,
-						   buffer->bistate);
+						   buffer->bistate,
+						   &insertIndexes);
 		MemoryContextSwitchTo(oldcontext);
 
 		for (i = 0; i < nused; i++)
@@ -425,7 +427,7 @@ CopyMultiInsertBufferFlush(CopyMultiInsertInfo *miinfo,
 			 * If there are any indexes, update them for all the inserted
 			 * tuples, and run AFTER ROW INSERT triggers.
 			 */
-			if (resultRelInfo->ri_NumIndices > 0)
+			if (insertIndexes && resultRelInfo->ri_NumIndices > 0)
 			{
 				List	   *recheckIndexes;
 
@@ -1265,11 +1267,14 @@ CopyFrom(CopyFromState cstate)
 					}
 					else
 					{
+						bool		insertIndexes;
+
 						/* OK, store the tuple and create index entries for it */
 						table_tuple_insert(resultRelInfo->ri_RelationDesc,
-										   myslot, mycid, ti_options, bistate);
+										   myslot, mycid, ti_options, bistate,
+										   &insertIndexes);
 
-						if (resultRelInfo->ri_NumIndices > 0)
+						if (insertIndexes && resultRelInfo->ri_NumIndices > 0)
 							recheckIndexes = ExecInsertIndexTuples(resultRelInfo,
 																   myslot,
 																   estate,

src/backend/commands/createas.c

@@ -578,6 +578,7 @@ static bool
 intorel_receive(TupleTableSlot *slot, DestReceiver *self)
 {
 	DR_intorel *myState = (DR_intorel *) self;
+	bool		insertIndexes;
 
 	/* Nothing to insert if WITH NO DATA is specified. */
 	if (!myState->into->skipData)
@@ -594,7 +595,8 @@ intorel_receive(TupleTableSlot *slot, DestReceiver *self)
 						   slot,
 						   myState->output_cid,
 						   myState->ti_options,
-						   myState->bistate);
+						   myState->bistate,
+						   &insertIndexes);
 	}
 
 	/* We know this is a newly created relation, so there are no indexes */

src/backend/commands/matview.c

@@ -476,6 +476,7 @@ static bool
 transientrel_receive(TupleTableSlot *slot, DestReceiver *self)
 {
 	DR_transientrel *myState = (DR_transientrel *) self;
+	bool		insertIndexes;
 
 	/*
 	 * Note that the input slot might not be of the type of the target
@@ -490,7 +491,8 @@ transientrel_receive(TupleTableSlot *slot, DestReceiver *self)
 					   slot,
 					   myState->output_cid,
 					   myState->ti_options,
-					   myState->bistate);
+					   myState->bistate,
+					   &insertIndexes);
 
 	/* We know this is a newly created relation, so there are no indexes */
 

src/backend/commands/tablecmds.c

@@ -6360,8 +6360,12 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 
 			/* Write the tuple out to the new relation */
 			if (newrel)
+			{
+				bool		insertIndexes;
+
 				table_tuple_insert(newrel, insertslot, mycid,
-								   ti_options, bistate);
+								   ti_options, bistate, &insertIndexes);
+			}
 
 			ResetExprContext(econtext);