Explicitly track if a subplan has been executed and a valid value is computed

or not.

This works around a problem noted in issue #102, but not a full solution to the
problem. It seems there are places where InitPlan is attached to a node which
will be executed on the remote node. Even so coordinator tries to find push a
PARAM_EXEC parameter value for a remote subplan and fails because the value is
not and will never be computed on the coordinator. We for now send NULL value
for such cases to avoid a server crash

4 files changed, 12 insertions, 0 deletions

diff --git a/src/backend/executor/nodeNestloop.c b/src/backend/executor/nodeNestloop.c
index e66bcdade7..27fcf2e562 100644
--- a/src/backend/executor/nodeNestloop.c
+++ b/src/backend/executor/nodeNestloop.c
@@ -154,6 +154,7 @@ ExecNestLoop(NestLoopState *node)
 				prm->value = slot_getattr(outerTupleSlot,
 										  nlp->paramval->varattno,
 										  &(prm->isnull));
+				prm->done = true;
 				/* Flag parameter value as changed */
 				innerPlan->chgParam = bms_add_member(innerPlan->chgParam,
 													 paramno);
diff --git a/src/backend/executor/nodeSubplan.c b/src/backend/executor/nodeSubplan.c
index 4c6453766e..aaad6b2c19 100644
--- a/src/backend/executor/nodeSubplan.c
+++ b/src/backend/executor/nodeSubplan.c
@@ -289,6 +289,7 @@ ExecScanSubPlan(SubPlanState *node,
 											   econtext,
 											   &(prm->isnull),
 											   NULL);
+		prm->done = true;
 		planstate->chgParam = bms_add_member(planstate->chgParam, paramid);
 	}
 
@@ -996,6 +997,7 @@ ExecSetParamPlan(SubPlanState *node, ExprContext *econtext)
 											   econtext,
 											   &(prm->isnull),
 											   NULL);
+		prm->done = true;
 		planstate->chgParam = bms_add_member(planstate->chgParam, paramid);
 	}
 
@@ -1017,6 +1019,7 @@ ExecSetParamPlan(SubPlanState *node, ExprContext *econtext)
 			ParamExecData *prm = &(econtext->ecxt_param_exec_vals[paramid]);
 
 			prm->execPlan = NULL;
+			prm->done = true;
 			prm->value = BoolGetDatum(true);
 			prm->isnull = false;
 			found = true;
@@ -1067,6 +1070,7 @@ ExecSetParamPlan(SubPlanState *node, ExprContext *econtext)
 			ParamExecData *prm = &(econtext->ecxt_param_exec_vals[paramid]);
 
 			prm->execPlan = NULL;
+			prm->done = true;
 			prm->value = heap_getattr(node->curTuple, i, tdesc,
 									  &(prm->isnull));
 			i++;
@@ -1090,6 +1094,7 @@ ExecSetParamPlan(SubPlanState *node, ExprContext *econtext)
 											econtext->ecxt_per_query_memory,
 											true);
 		prm->execPlan = NULL;
+		prm->done = true;
 		prm->value = node->curArray;
 		prm->isnull = false;
 	}
@@ -1102,6 +1107,7 @@ ExecSetParamPlan(SubPlanState *node, ExprContext *econtext)
 			ParamExecData *prm = &(econtext->ecxt_param_exec_vals[paramid]);
 
 			prm->execPlan = NULL;
+			prm->done = true;
 			prm->value = BoolGetDatum(false);
 			prm->isnull = false;
 		}
@@ -1114,6 +1120,7 @@ ExecSetParamPlan(SubPlanState *node, ExprContext *econtext)
 				ParamExecData *prm = &(econtext->ecxt_param_exec_vals[paramid]);
 
 				prm->execPlan = NULL;
+				prm->done = true;
 				prm->value = (Datum) 0;
 				prm->isnull = true;
 			}
diff --git a/src/backend/pgxc/pool/execRemote.c b/src/backend/pgxc/pool/execRemote.c
index 930dc2d52b..380626bea4 100644
--- a/src/backend/pgxc/pool/execRemote.c
+++ b/src/backend/pgxc/pool/execRemote.c
@@ -5712,7 +5712,10 @@ static int encode_parameters(int nparams, RemoteParam *remoteparams,
 				/* ExecSetParamPlan should have processed this param... */
 				Assert(param->execPlan == NULL);
 			}
+			if (!param->done)
+				param->isnull = true;
 			append_param_data(&buf, ptype, param->value, param->isnull);
+
 		}
 	}
 
diff --git a/src/include/nodes/params.h b/src/include/nodes/params.h
index 5f7df26ba8..96613c72c8 100644
--- a/src/include/nodes/params.h
+++ b/src/include/nodes/params.h
@@ -100,6 +100,7 @@ typedef struct ParamExecData
 	bool		isnull;
 #ifdef XCP
 	Oid			ptype;
+	bool		done;
 #endif
 } ParamExecData;