Provide DSM segment to ExecXXXInitializeWorker functions.

Previously, executor nodes running in parallel worker processes didn't
have access to the dsm_segment object used for parallel execution.  In
order to support resource management based on DSM segment lifetime,
they need that.  So create a ParallelWorkerContext object to hold it
and pass it to all InitializeWorker functions.

Author: Thomas Munro
Reviewed-By: Andres Freund
Discussion: https://postgr.es/m/CAEepm=2W=cOkiZxcg6qiFQP-dHUe09aqTrEMM7yJDrHMhDv_RA@mail.gmail.com

src/backend/executor/execParallel.c

@@ -1122,7 +1122,7 @@ ExecParallelReportInstrumentation(PlanState *planstate,
  * is allocated and initialized by executor; that is, after ExecutorStart().
  */
 static bool
-ExecParallelInitializeWorker(PlanState *planstate, shm_toc *toc)
+ExecParallelInitializeWorker(PlanState *planstate, ParallelWorkerContext *pwcxt)
 {
 	if (planstate == NULL)
 		return false;
@@ -1131,40 +1131,44 @@ ExecParallelInitializeWorker(PlanState *planstate, shm_toc *toc)
 	{
 		case T_SeqScanState:
 			if (planstate->plan->parallel_aware)
-				ExecSeqScanInitializeWorker((SeqScanState *) planstate, toc);
+				ExecSeqScanInitializeWorker((SeqScanState *) planstate, pwcxt);
 			break;
 		case T_IndexScanState:
 			if (planstate->plan->parallel_aware)
-				ExecIndexScanInitializeWorker((IndexScanState *) planstate, toc);
+				ExecIndexScanInitializeWorker((IndexScanState *) planstate,
+											  pwcxt);
 			break;
 		case T_IndexOnlyScanState:
 			if (planstate->plan->parallel_aware)
-				ExecIndexOnlyScanInitializeWorker((IndexOnlyScanState *) planstate, toc);
+				ExecIndexOnlyScanInitializeWorker((IndexOnlyScanState *) planstate,
+												  pwcxt);
 			break;
 		case T_ForeignScanState:
 			if (planstate->plan->parallel_aware)
 				ExecForeignScanInitializeWorker((ForeignScanState *) planstate,
-												toc);
+												pwcxt);
 			break;
 		case T_CustomScanState:
 			if (planstate->plan->parallel_aware)
 				ExecCustomScanInitializeWorker((CustomScanState *) planstate,
-											   toc);
+											   pwcxt);
 			break;
 		case T_BitmapHeapScanState:
 			if (planstate->plan->parallel_aware)
-				ExecBitmapHeapInitializeWorker((BitmapHeapScanState *) planstate, toc);
+				ExecBitmapHeapInitializeWorker((BitmapHeapScanState *) planstate,
+											   pwcxt);
 			break;
 		case T_SortState:
 			/* even when not parallel-aware */
-			ExecSortInitializeWorker((SortState *) planstate, toc);
+			ExecSortInitializeWorker((SortState *) planstate, pwcxt);
 			break;
 
 		default:
 			break;
 	}
 
-	return planstate_tree_walker(planstate, ExecParallelInitializeWorker, toc);
+	return planstate_tree_walker(planstate, ExecParallelInitializeWorker,
+								 pwcxt);
 }
 
 /*
@@ -1194,6 +1198,7 @@ ParallelQueryMain(dsm_segment *seg, shm_toc *toc)
 	int			instrument_options = 0;
 	void	   *area_space;
 	dsa_area   *area;
+	ParallelWorkerContext pwcxt;
 
 	/* Get fixed-size state. */
 	fpes = shm_toc_lookup(toc, PARALLEL_KEY_EXECUTOR_FIXED, false);
@@ -1231,7 +1236,9 @@ ParallelQueryMain(dsm_segment *seg, shm_toc *toc)
 		RestoreParamExecParams(paramexec_space, queryDesc->estate);
 
 	}
-	ExecParallelInitializeWorker(queryDesc->planstate, toc);
+	pwcxt.toc = toc;
+	pwcxt.seg = seg;
+	ExecParallelInitializeWorker(queryDesc->planstate, &pwcxt);
 
 	/* Pass down any tuple bound */
 	ExecSetTupleBound(fpes->tuples_needed, queryDesc->planstate);

src/backend/executor/nodeBitmapHeapscan.c

@@ -1102,12 +1102,13 @@ ExecBitmapHeapReInitializeDSM(BitmapHeapScanState *node,
  * ----------------------------------------------------------------
  */
 void
-ExecBitmapHeapInitializeWorker(BitmapHeapScanState *node, shm_toc *toc)
+ExecBitmapHeapInitializeWorker(BitmapHeapScanState *node,
+							   ParallelWorkerContext *pwcxt)
 {
 	ParallelBitmapHeapState *pstate;
 	Snapshot	snapshot;
 
-	pstate = shm_toc_lookup(toc, node->ss.ps.plan->plan_node_id, false);
+	pstate = shm_toc_lookup(pwcxt->toc, node->ss.ps.plan->plan_node_id, false);
 	node->pstate = pstate;
 
 	snapshot = RestoreSnapshot(pstate->phs_snapshot_data);

src/backend/executor/nodeCustom.c

@@ -210,7 +210,8 @@ ExecCustomScanReInitializeDSM(CustomScanState *node, ParallelContext *pcxt)
 }
 
 void
-ExecCustomScanInitializeWorker(CustomScanState *node, shm_toc *toc)
+ExecCustomScanInitializeWorker(CustomScanState *node,
+							   ParallelWorkerContext *pwcxt)
 {
 	const CustomExecMethods *methods = node->methods;
 
@@ -219,8 +220,8 @@ ExecCustomScanInitializeWorker(CustomScanState *node, shm_toc *toc)
 		int			plan_node_id = node->ss.ps.plan->plan_node_id;
 		void	   *coordinate;
 
-		coordinate = shm_toc_lookup(toc, plan_node_id, false);
-		methods->InitializeWorkerCustomScan(node, toc, coordinate);
+		coordinate = shm_toc_lookup(pwcxt->toc, plan_node_id, false);
+		methods->InitializeWorkerCustomScan(node, pwcxt->toc, coordinate);
 	}
 }
 

src/backend/executor/nodeForeignscan.c

@@ -359,7 +359,8 @@ ExecForeignScanReInitializeDSM(ForeignScanState *node, ParallelContext *pcxt)
  * ----------------------------------------------------------------
  */
 void
-ExecForeignScanInitializeWorker(ForeignScanState *node, shm_toc *toc)
+ExecForeignScanInitializeWorker(ForeignScanState *node,
+								ParallelWorkerContext *pwcxt)
 {
 	FdwRoutine *fdwroutine = node->fdwroutine;
 
@@ -368,8 +369,8 @@ ExecForeignScanInitializeWorker(ForeignScanState *node, shm_toc *toc)
 		int			plan_node_id = node->ss.ps.plan->plan_node_id;
 		void	   *coordinate;
 
-		coordinate = shm_toc_lookup(toc, plan_node_id, false);
-		fdwroutine->InitializeWorkerForeignScan(node, toc, coordinate);
+		coordinate = shm_toc_lookup(pwcxt->toc, plan_node_id, false);
+		fdwroutine->InitializeWorkerForeignScan(node, pwcxt->toc, coordinate);
 	}
 }
 

src/backend/executor/nodeIndexonlyscan.c

@@ -678,11 +678,12 @@ ExecIndexOnlyScanReInitializeDSM(IndexOnlyScanState *node,
  * ----------------------------------------------------------------
  */
 void
-ExecIndexOnlyScanInitializeWorker(IndexOnlyScanState *node, shm_toc *toc)
+ExecIndexOnlyScanInitializeWorker(IndexOnlyScanState *node,
+								  ParallelWorkerContext *pwcxt)
 {
 	ParallelIndexScanDesc piscan;
 
-	piscan = shm_toc_lookup(toc, node->ss.ps.plan->plan_node_id, false);
+	piscan = shm_toc_lookup(pwcxt->toc, node->ss.ps.plan->plan_node_id, false);
 	node->ioss_ScanDesc =
 		index_beginscan_parallel(node->ss.ss_currentRelation,
 								 node->ioss_RelationDesc,

src/backend/executor/nodeIndexscan.c

@@ -1716,11 +1716,12 @@ ExecIndexScanReInitializeDSM(IndexScanState *node,
  * ----------------------------------------------------------------
  */
 void
-ExecIndexScanInitializeWorker(IndexScanState *node, shm_toc *toc)
+ExecIndexScanInitializeWorker(IndexScanState *node,
+							  ParallelWorkerContext *pwcxt)
 {
 	ParallelIndexScanDesc piscan;
 
-	piscan = shm_toc_lookup(toc, node->ss.ps.plan->plan_node_id, false);
+	piscan = shm_toc_lookup(pwcxt->toc, node->ss.ps.plan->plan_node_id, false);
 	node->iss_ScanDesc =
 		index_beginscan_parallel(node->ss.ss_currentRelation,
 								 node->iss_RelationDesc,

src/backend/executor/nodeSeqscan.c

@@ -348,11 +348,12 @@ ExecSeqScanReInitializeDSM(SeqScanState *node,
  * ----------------------------------------------------------------
  */
 void
-ExecSeqScanInitializeWorker(SeqScanState *node, shm_toc *toc)
+ExecSeqScanInitializeWorker(SeqScanState *node,
+							ParallelWorkerContext *pwcxt)
 {
 	ParallelHeapScanDesc pscan;
 
-	pscan = shm_toc_lookup(toc, node->ss.ps.plan->plan_node_id, false);
+	pscan = shm_toc_lookup(pwcxt->toc, node->ss.ps.plan->plan_node_id, false);
 	node->ss.ss_currentScanDesc =
 		heap_beginscan_parallel(node->ss.ss_currentRelation, pscan);
 }

src/backend/executor/nodeSort.c

@@ -420,10 +420,10 @@ ExecSortReInitializeDSM(SortState *node, ParallelContext *pcxt)
  * ----------------------------------------------------------------
  */
 void
-ExecSortInitializeWorker(SortState *node, shm_toc *toc)
+ExecSortInitializeWorker(SortState *node, ParallelWorkerContext *pwcxt)
 {
 	node->shared_info =
-		shm_toc_lookup(toc, node->ss.ps.plan->plan_node_id, true);
+		shm_toc_lookup(pwcxt->toc, node->ss.ps.plan->plan_node_id, true);
 	node->am_worker = true;
 }
 

src/include/access/parallel.h

@@ -45,6 +45,12 @@ typedef struct ParallelContext
 	ParallelWorkerInfo *worker;
 } ParallelContext;
 
+typedef struct ParallelWorkerContext
+{
+	dsm_segment *seg;
+	shm_toc    *toc;
+} ParallelWorkerContext;
+
 extern volatile bool ParallelMessagePending;
 extern int	ParallelWorkerNumber;
 extern bool InitializingParallelWorker;

src/include/executor/nodeBitmapHeapscan.h

@@ -27,6 +27,6 @@ extern void ExecBitmapHeapInitializeDSM(BitmapHeapScanState *node,
 extern void ExecBitmapHeapReInitializeDSM(BitmapHeapScanState *node,
 							  ParallelContext *pcxt);
 extern void ExecBitmapHeapInitializeWorker(BitmapHeapScanState *node,
-							   shm_toc *toc);
+							   ParallelWorkerContext *pwcxt);
 
 #endif							/* NODEBITMAPHEAPSCAN_H */

src/include/executor/nodeCustom.h

@@ -37,7 +37,7 @@ extern void ExecCustomScanInitializeDSM(CustomScanState *node,
 extern void ExecCustomScanReInitializeDSM(CustomScanState *node,
 							  ParallelContext *pcxt);
 extern void ExecCustomScanInitializeWorker(CustomScanState *node,
-							   shm_toc *toc);
+							   ParallelWorkerContext *pwcxt);
 extern void ExecShutdownCustomScan(CustomScanState *node);
 
 #endif							/* NODECUSTOM_H */

src/include/executor/nodeForeignscan.h

@@ -28,7 +28,7 @@ extern void ExecForeignScanInitializeDSM(ForeignScanState *node,
 extern void ExecForeignScanReInitializeDSM(ForeignScanState *node,
 							   ParallelContext *pcxt);
 extern void ExecForeignScanInitializeWorker(ForeignScanState *node,
-								shm_toc *toc);
+								ParallelWorkerContext *pwcxt);
 extern void ExecShutdownForeignScan(ForeignScanState *node);
 
 #endif							/* NODEFOREIGNSCAN_H */

src/include/executor/nodeIndexonlyscan.h

@@ -31,6 +31,6 @@ extern void ExecIndexOnlyScanInitializeDSM(IndexOnlyScanState *node,
 extern void ExecIndexOnlyScanReInitializeDSM(IndexOnlyScanState *node,
 								 ParallelContext *pcxt);
 extern void ExecIndexOnlyScanInitializeWorker(IndexOnlyScanState *node,
-								  shm_toc *toc);
+								  ParallelWorkerContext *pwcxt);
 
 #endif							/* NODEINDEXONLYSCAN_H */

src/include/executor/nodeIndexscan.h

@@ -25,7 +25,8 @@ extern void ExecReScanIndexScan(IndexScanState *node);
 extern void ExecIndexScanEstimate(IndexScanState *node, ParallelContext *pcxt);
 extern void ExecIndexScanInitializeDSM(IndexScanState *node, ParallelContext *pcxt);
 extern void ExecIndexScanReInitializeDSM(IndexScanState *node, ParallelContext *pcxt);
-extern void ExecIndexScanInitializeWorker(IndexScanState *node, shm_toc *toc);
+extern void ExecIndexScanInitializeWorker(IndexScanState *node,
+							  ParallelWorkerContext *pwcxt);
 
 /*
  * These routines are exported to share code with nodeIndexonlyscan.c and

src/include/executor/nodeSeqscan.h

@@ -25,6 +25,7 @@ extern void ExecReScanSeqScan(SeqScanState *node);
 extern void ExecSeqScanEstimate(SeqScanState *node, ParallelContext *pcxt);
 extern void ExecSeqScanInitializeDSM(SeqScanState *node, ParallelContext *pcxt);
 extern void ExecSeqScanReInitializeDSM(SeqScanState *node, ParallelContext *pcxt);
-extern void ExecSeqScanInitializeWorker(SeqScanState *node, shm_toc *toc);
+extern void ExecSeqScanInitializeWorker(SeqScanState *node,
+							ParallelWorkerContext *pwcxt);
 
 #endif							/* NODESEQSCAN_H */

src/include/executor/nodeSort.h

@@ -27,7 +27,7 @@ extern void ExecReScanSort(SortState *node);
 extern void ExecSortEstimate(SortState *node, ParallelContext *pcxt);
 extern void ExecSortInitializeDSM(SortState *node, ParallelContext *pcxt);
 extern void ExecSortReInitializeDSM(SortState *node, ParallelContext *pcxt);
-extern void ExecSortInitializeWorker(SortState *node, shm_toc *toc);
+extern void ExecSortInitializeWorker(SortState *node, ParallelWorkerContext *pwcxt);
 extern void ExecSortRetrieveInstrumentation(SortState *node);
 
 #endif							/* NODESORT_H */

src/tools/pgindent/typedefs.list

@@ -1534,6 +1534,7 @@ ParallelHeapScanDesc
 ParallelIndexScanDesc
 ParallelSlot
 ParallelState
+ParallelWorkerContext
 ParallelWorkerInfo
 Param
 ParamExecData