lab2.patch

diff --git a/src/backend/executor/nodeNestloop.c b/src/backend/executor/nodeNestloop.c
index b479358..87ac2b6 100644
--- a/src/backend/executor/nodeNestloop.c
+++ b/src/backend/executor/nodeNestloop.c
@@ -56,13 +56,55 @@
  *			   are prepared to return the first tuple.
  * ----------------------------------------------------------------
  */
+
+static inline TupleTableSlot *duplicateSlot(TupleTableSlot *slot) {
+	TupleTableSlot *ret = MakeSingleTupleTableSlot(slot->tts_tupleDescriptor);
+	ExecCopySlot(ret, slot);
+
+	return ret;
+}
+
+static inline TupleTableSlot **fetchNextBlock(PlanState *plan) {
+	/* NEVER set outerTupleSlots[BLOCK_SIZE] to value other than NULL, it's the terimiator of the loop! */
+	TupleTableSlot **blockData = palloc(sizeof(TupleTableSlot *) * (BLOCK_SIZE + 1));
+	TupleTableSlot *data;
+	blockData[BLOCK_SIZE] = NULL;
+	unsigned long idx;
+	elog(DEBUG1, "fetchNextBlock");
+	for (idx = 0; idx < BLOCK_SIZE; ++ idx) {
+		data = ExecProcNode(plan);
+		if (TupIsNull(data)) {
+			blockData[idx] = NULL;
+			if (idx == 0) {
+				elog(DEBUG1, "end of plan");
+				return NULL;
+			} else {
+				elog(DEBUG1, "blockSize: %lu", idx);
+				return blockData;
+			}
+		}
+		blockData[idx] = duplicateSlot(data);
+		// elog(DEBUG1, "heapdata: %lu", blockData[idx]->tts_tuple);
+	}
+	elog(DEBUG1, "fullBlock: %lu", idx);
+	return blockData;
+}
+
+static inline void freeBlock(TupleTableSlot **block) {
+	void *ptr = block;
+	for ( ;!TupIsNull(*block); ++ block) {
+		ExecDropSingleTupleTableSlot(*block);
+	}
+	pfree(ptr);
+}
+
 TupleTableSlot *
 ExecNestLoop(NestLoopState *node)
 {
 	NestLoop   *nl;
 	PlanState  *innerPlan;
 	PlanState  *outerPlan;
-	TupleTableSlot *outerTupleSlot;
+	TupleTableSlot *outerTupleSlot = NULL;
 	TupleTableSlot *innerTupleSlot;
 	List	   *joinqual;
 	List	   *otherqual;
@@ -90,7 +132,6 @@ ExecNestLoop(NestLoopState *node)
 	{
 		TupleTableSlot *result;
 		ExprDoneCond isDone;
-
 		result = ExecProject(node->js.ps.ps_ProjInfo, &isDone);
 		if (isDone == ExprMultipleResult)
 			return result;
@@ -119,8 +160,24 @@ ExecNestLoop(NestLoopState *node)
 		 */
 		if (node->nl_NeedNewOuter)
 		{
-			ENL1_printf("getting new outer tuple");
-			outerTupleSlot = ExecProcNode(outerPlan);
+			ENL1_printf("getting new outer tuples");
+			if (econtext->ecxt_outertuples) {
+				outerTupleSlot = *(++ econtext->ecxt_outertuples);
+				// elog(DEBUG1, "Next item");
+			}
+			if (TupIsNull(outerTupleSlot)) {
+				// elog(DEBUG1, "New block");
+				if (econtext->ecxt_outertuples_head) {
+					freeBlock(econtext->ecxt_outertuples_head);
+					if (econtext->ecxt_outertuples - (TupleTableSlot **)econtext->ecxt_outertuples_head != BLOCK_SIZE) return NULL;
+				}
+				if ((econtext->ecxt_outertuples = fetchNextBlock(outerPlan)) == NULL) {
+					ENL1_printf("no outer tuple, ending join");
+					return NULL;
+				}
+				econtext->ecxt_outertuples_head = econtext->ecxt_outertuples;
+				outerTupleSlot = *econtext->ecxt_outertuples;
+			}
 
 			/*
 			 * if there are no more outer tuples, then the join is complete..
@@ -439,3 +496,5 @@ ExecReScanNestLoop(NestLoopState *node)
 	node->nl_NeedNewOuter = true;
 	node->nl_MatchedOuter = false;
 }
+
+
diff --git a/src/include/executor/nodeNestloop.h b/src/include/executor/nodeNestloop.h
index f249d9d..e4a9635 100644
--- a/src/include/executor/nodeNestloop.h
+++ b/src/include/executor/nodeNestloop.h
@@ -21,4 +21,6 @@ extern TupleTableSlot *ExecNestLoop(NestLoopState *node);
 extern void ExecEndNestLoop(NestLoopState *node);
 extern void ExecReScanNestLoop(NestLoopState *node);
 
+#define BLOCK_SIZE 1024
+
 #endif   /* NODENESTLOOP_H */
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 187c70a..a863472 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -116,6 +116,8 @@ typedef struct ExprContext
 	TupleTableSlot *ecxt_scantuple;
 	TupleTableSlot *ecxt_innertuple;
 	TupleTableSlot *ecxt_outertuple;
+	TupleTableSlot **ecxt_outertuples;
+	void *ecxt_outertuples_head;
 
 	/* Memory contexts for expression evaluation --- see notes above */
 	MemoryContext ecxt_per_query_memory;