Move interrupt checking from ExecProcNode() to executor nodes.

In a followup commit ExecProcNode(), and especially the large switch
it contains, will largely be replaced by a function pointer directly
to the correct node. The node functions will then get invoked by a
thin inline function wrapper. To avoid having to include miscadmin.h
in headers - CHECK_FOR_INTERRUPTS() - move the interrupt checks into
the individual executor routines.

While looking through all executor nodes, I noticed a number of
arguably missing interrupt checks, add these too.

Author: Andres Freund, Tom Lane
Reviewed-By: Tom Lane
Discussion:
    https://postgr.es/m/22833.1490390175@sss.pgh.pa.us

Author: anarazel

src/backend/executor/execProcnode.c

@@ -399,8 +399,6 @@ ExecProcNode(PlanState *node)
 {
 	TupleTableSlot *result;
 
-	CHECK_FOR_INTERRUPTS();
-
 	if (node->chgParam != NULL) /* something changed */
 		ExecReScan(node);		/* let ReScan handle this */
 

src/backend/executor/nodeAgg.c

@@ -677,6 +677,8 @@ fetch_input_tuple(AggState *aggstate)
 
 	if (aggstate->sort_in)
 	{
+		/* make sure we check for interrupts in either path through here */
+		CHECK_FOR_INTERRUPTS();
 		if (!tuplesort_gettupleslot(aggstate->sort_in, true, false,
 									aggstate->sort_slot, NULL))
 			return NULL;
@@ -1414,6 +1416,8 @@ process_ordered_aggregate_multi(AggState *aggstate,
 	while (tuplesort_gettupleslot(pertrans->sortstates[aggstate->current_set],
 								  true, true, slot1, &newAbbrevVal))
 	{
+		CHECK_FOR_INTERRUPTS();
+
 		/*
 		 * Extract the first numTransInputs columns as datums to pass to the
 		 * transfn.  (This will help execTuplesMatch too, so we do it
@@ -2100,6 +2104,8 @@ ExecAgg(AggState *node)
 {
 	TupleTableSlot *result = NULL;
 
+	CHECK_FOR_INTERRUPTS();
+
 	if (!node->agg_done)
 	{
 		/* Dispatch based on strategy */
@@ -2563,6 +2569,8 @@ agg_retrieve_hash_table(AggState *aggstate)
 		TupleTableSlot *hashslot = perhash->hashslot;
 		int			i;
 
+		CHECK_FOR_INTERRUPTS();
+
 		/*
 		 * Find the next entry in the hash table
 		 */

src/backend/executor/nodeAppend.c

@@ -59,6 +59,7 @@
 
 #include "executor/execdebug.h"
 #include "executor/nodeAppend.h"
+#include "miscadmin.h"
 
 static bool exec_append_initialize_next(AppendState *appendstate);
 
@@ -204,6 +205,8 @@ ExecAppend(AppendState *node)
 		PlanState  *subnode;
 		TupleTableSlot *result;
 
+		CHECK_FOR_INTERRUPTS();
+
 		/*
 		 * figure out which subplan we are currently processing
 		 */

src/backend/executor/nodeBitmapHeapscan.c

@@ -41,6 +41,7 @@
 #include "access/transam.h"
 #include "executor/execdebug.h"
 #include "executor/nodeBitmapHeapscan.h"
+#include "miscadmin.h"
 #include "pgstat.h"
 #include "storage/bufmgr.h"
 #include "storage/predicate.h"
@@ -192,6 +193,8 @@ BitmapHeapNext(BitmapHeapScanState *node)
 		Page		dp;
 		ItemId		lp;
 
+		CHECK_FOR_INTERRUPTS();
+
 		/*
 		 * Get next page of results if needed
 		 */

src/backend/executor/nodeCustom.c

@@ -15,6 +15,7 @@
 #include "executor/nodeCustom.h"
 #include "nodes/execnodes.h"
 #include "nodes/plannodes.h"
+#include "miscadmin.h"
 #include "parser/parsetree.h"
 #include "utils/hsearch.h"
 #include "utils/memutils.h"
@@ -104,6 +105,8 @@ ExecInitCustomScan(CustomScan *cscan, EState *estate, int eflags)
 TupleTableSlot *
 ExecCustomScan(CustomScanState *node)
 {
+	CHECK_FOR_INTERRUPTS();
+
 	Assert(node->methods->ExecCustomScan != NULL);
 	return node->methods->ExecCustomScan(node);
 }

src/backend/executor/nodeGather.c

@@ -128,6 +128,8 @@ ExecGather(GatherState *node)
 	TupleTableSlot *slot;
 	ExprContext *econtext;
 
+	CHECK_FOR_INTERRUPTS();
+
 	/*
 	 * Initialize the parallel context and workers on first execution. We do
 	 * this on first execution rather than during node initialization, as it
@@ -247,6 +249,8 @@ gather_getnext(GatherState *gatherstate)
 
 	while (gatherstate->reader != NULL || gatherstate->need_to_scan_locally)
 	{
+		CHECK_FOR_INTERRUPTS();
+
 		if (gatherstate->reader != NULL)
 		{
 			MemoryContext oldContext;

src/backend/executor/nodeGatherMerge.c

@@ -164,6 +164,8 @@ ExecGatherMerge(GatherMergeState *node)
 	ExprContext *econtext;
 	int			i;
 
+	CHECK_FOR_INTERRUPTS();
+
 	/*
 	 * As with Gather, we don't launch workers until this node is actually
 	 * executed.
@@ -393,6 +395,8 @@ gather_merge_init(GatherMergeState *gm_state)
 reread:
 	for (i = 0; i < nreaders + 1; i++)
 	{
+		CHECK_FOR_INTERRUPTS();
+
 		if (!gm_state->gm_tuple_buffers[i].done &&
 			(TupIsNull(gm_state->gm_slots[i]) ||
 			 gm_state->gm_slots[i]->tts_isempty))

src/backend/executor/nodeGroup.c

@@ -24,6 +24,7 @@
 
 #include "executor/executor.h"
 #include "executor/nodeGroup.h"
+#include "miscadmin.h"
 
 
 /*
@@ -40,6 +41,8 @@ ExecGroup(GroupState *node)
 	TupleTableSlot *firsttupleslot;
 	TupleTableSlot *outerslot;
 
+	CHECK_FOR_INTERRUPTS();
+
 	/*
 	 * get state info from node
 	 */

src/backend/executor/nodeHash.c

@@ -810,6 +810,9 @@ ExecHashIncreaseNumBuckets(HashJoinTable hashtable)
 			idx += MAXALIGN(HJTUPLE_OVERHEAD +
 							HJTUPLE_MINTUPLE(hashTuple)->t_len);
 		}
+
+		/* allow this loop to be cancellable */
+		CHECK_FOR_INTERRUPTS();
 	}
 }
 
@@ -1192,6 +1195,9 @@ ExecScanHashTableForUnmatched(HashJoinState *hjstate, ExprContext *econtext)
 
 			hashTuple = hashTuple->next;
 		}
+
+		/* allow this loop to be cancellable */
+		CHECK_FOR_INTERRUPTS();
 	}
 
 	/*

src/backend/executor/nodeHashjoin.c

@@ -92,6 +92,14 @@ ExecHashJoin(HashJoinState *node)
 	 */
 	for (;;)
 	{
+		/*
+		 * It's possible to iterate this loop many times before returning a
+		 * tuple, in some pathological cases such as needing to move much of
+		 * the current batch to a later batch.  So let's check for interrupts
+		 * each time through.
+		 */
+		CHECK_FOR_INTERRUPTS();
+
 		switch (node->hj_JoinState)
 		{
 			case HJ_BUILD_HASHTABLE:
@@ -246,13 +254,6 @@ ExecHashJoin(HashJoinState *node)
 
 			case HJ_SCAN_BUCKET:
 
-				/*
-				 * We check for interrupts here because this corresponds to
-				 * where we'd fetch a row from a child plan node in other join
-				 * types.
-				 */
-				CHECK_FOR_INTERRUPTS();
-
 				/*
 				 * Scan the selected hash bucket for matches to current outer
 				 */