alternative example of foreach with index tracking

src/backend/distributed/deparser/deparse_statistics_stmts.c

@@ -220,14 +220,15 @@ AppendStatTypes(StringInfo buf, CreateStatsStmt *stmt)
 	appendStringInfoString(buf, " (");
 
 	Value *statType = NULL;
-	foreach_ptr(statType, stmt->stat_types)
+	int statTypeIndex = 0;
+	foreach_ptr_with_index(statType, stmt->stat_types, statTypeIndex)
 	{
-		appendStringInfoString(buf, strVal(statType));
+		if (statTypeIndex != 0)
-
-		if (statType != llast(stmt->stat_types))
 		{
 			appendStringInfoString(buf, ", ");
 		}
+
+		appendStringInfoString(buf, strVal(statType));
 	}
 
 	appendStringInfoString(buf, ")");
@@ -240,7 +241,8 @@ AppendColumnNames(StringInfo buf, CreateStatsStmt *stmt)
 {
 	StatsElem *column = NULL;
 
-	foreach_ptr(column, stmt->exprs)
+	int columnIndex = 0;
+	foreach_ptr_with_index(column, stmt->exprs, columnIndex)
 	{
 		if (!column->name)
 		{
@@ -250,14 +252,13 @@ AppendColumnNames(StringInfo buf, CreateStatsStmt *stmt)
 						 "only simple column references are allowed in CREATE STATISTICS")));
 		}
 
-		const char *columnName = quote_identifier(column->name);
+		if (columnIndex != 0)
-
-		appendStringInfoString(buf, columnName);
-
-		if (column != llast(stmt->exprs))
 		{
 			appendStringInfoString(buf, ", ");
 		}
+
+		const char *columnName = quote_identifier(column->name);
+		appendStringInfoString(buf, columnName);
 	}
 }
 

src/backend/distributed/executor/distributed_intermediate_results.c

@@ -637,26 +637,24 @@ QueryStringForFragmentsTransfer(NodeToNodeFragmentsTransfer *fragmentsTransfer)
 {
 	StringInfo queryString = makeStringInfo();
 	StringInfo fragmentNamesArrayString = makeStringInfo();
-	int fragmentCount = 0;
 	NodePair *nodePair = &fragmentsTransfer->nodes;
 	WorkerNode *sourceNode = LookupNodeByNodeIdOrError(nodePair->sourceNodeId);
 
 	appendStringInfoString(fragmentNamesArrayString, "ARRAY[");
 
 	DistributedResultFragment *fragment = NULL;
-	foreach_ptr(fragment, fragmentsTransfer->fragmentList)
+	int fragmentIndex = 0;
+	foreach_ptr_with_index(fragment, fragmentsTransfer->fragmentList, fragmentIndex)
 	{
 		const char *fragmentName = fragment->resultId;
 
-		if (fragmentCount > 0)
+		if (fragmentIndex != 0)
 		{
 			appendStringInfoString(fragmentNamesArrayString, ",");
 		}
 
 		appendStringInfoString(fragmentNamesArrayString,
 							   quote_literal_cstr(fragmentName));
-
-		fragmentCount++;
 	}
 
 	appendStringInfoString(fragmentNamesArrayString, "]::text[]");

src/backend/distributed/executor/insert_select_executor.c

@@ -580,20 +580,18 @@ static int
 PartitionColumnIndexFromColumnList(Oid relationId, List *columnNameList)
 {
 	Var *partitionColumn = PartitionColumn(relationId, 0);
-	int partitionColumnIndex = 0;
 
 	const char *columnName = NULL;
-	foreach_ptr(columnName, columnNameList)
+	int columnNameIndex = 0;
+	foreach_ptr_with_index(columnName, columnNameList, columnNameIndex)
 	{
 		AttrNumber attrNumber = get_attnum(relationId, columnName);
 
 		/* check whether this is the partition column */
 		if (partitionColumn != NULL && attrNumber == partitionColumn->varattno)
 		{
-			return partitionColumnIndex;
+			return columnNameIndex;
 		}
-
-		partitionColumnIndex++;
 	}
 
 	return -1;
@@ -727,15 +725,13 @@ static int
 PartitionColumnIndex(List *insertTargetList, Var *partitionColumn)
 {
 	TargetEntry *insertTargetEntry = NULL;
-	int targetEntryIndex = 0;
+	int insertTargetEntryIndex = 0;
-	foreach_ptr(insertTargetEntry, insertTargetList)
+	foreach_ptr_with_index(insertTargetEntry, insertTargetList, insertTargetEntryIndex)
 	{
 		if (insertTargetEntry->resno == partitionColumn->varattno)
 		{
-			return targetEntryIndex;
+			return insertTargetEntryIndex;
 		}
-
-		targetEntryIndex++;
 	}
 
 	return -1;
@@ -803,11 +799,11 @@ static void
 WrapTaskListForProjection(List *taskList, List *projectedTargetEntries)
 {
 	StringInfo projectedColumnsString = makeStringInfo();
-	int entryIndex = 0;
 	TargetEntry *targetEntry = NULL;
-	foreach_ptr(targetEntry, projectedTargetEntries)
+	int targetEntryIndex = 0;
+	foreach_ptr_with_index(targetEntry, projectedTargetEntries, targetEntryIndex)
 	{
-		if (entryIndex != 0)
+		if (targetEntryIndex != 0)
 		{
 			appendStringInfoChar(projectedColumnsString, ',');
 		}
@@ -815,8 +811,6 @@ WrapTaskListForProjection(List *taskList, List *projectedTargetEntries)
 		char *columnName = targetEntry->resname;
 		Assert(columnName != NULL);
 		appendStringInfoString(projectedColumnsString, quote_identifier(columnName));
-
-		entryIndex++;
 	}
 
 	Task *task = NULL;

src/backend/distributed/executor/multi_executor.c

@@ -460,14 +460,13 @@ SortTupleStore(CitusScanState *scanState)
 	Oid *collations = (Oid *) palloc(numberOfSortKeys * sizeof(Oid));
 	bool *nullsFirst = (bool *) palloc(numberOfSortKeys * sizeof(bool));
 
-	int sortKeyIndex = 0;
-
 	/*
 	 * Iterate on the returning target list and generate the necessary information
 	 * for sorting the tuples.
 	 */
 	TargetEntry *returningEntry = NULL;
-	foreach_ptr(returningEntry, targetList)
+	int returningEntryIndex = 0;
+	foreach_ptr_with_index(returningEntry, targetList, returningEntryIndex)
 	{
 		Oid sortop = InvalidOid;
 
@@ -477,12 +476,10 @@ SortTupleStore(CitusScanState *scanState)
 								 &sortop, NULL, NULL,
 								 NULL);
 
-		sortColIdx[sortKeyIndex] = sortKeyIndex + 1;
+		sortColIdx[returningEntryIndex] = returningEntryIndex + 1;
-		sortOperators[sortKeyIndex] = sortop;
+		sortOperators[returningEntryIndex] = sortop;
-		collations[sortKeyIndex] = exprCollation((Node *) returningEntry->expr);
+		collations[returningEntryIndex] = exprCollation((Node *) returningEntry->expr);
-		nullsFirst[sortKeyIndex] = false;
+		nullsFirst[returningEntryIndex] = false;
-
-		sortKeyIndex++;
 	}
 
 	Tuplesortstate *tuplesortstate =

src/backend/distributed/metadata/metadata_cache.c

@@ -1477,7 +1477,6 @@ BuildCachedShardList(CitusTableCacheEntry *cacheEntry)
 	{
 		Relation distShardRelation = table_open(DistShardRelationId(), AccessShareLock);
 		TupleDesc distShardTupleDesc = RelationGetDescr(distShardRelation);
-		int arrayIndex = 0;
 
 		shardIntervalArray = MemoryContextAllocZero(MetadataCacheMemoryContext,
 													shardIntervalArrayLength *
@@ -1493,7 +1492,8 @@ BuildCachedShardList(CitusTableCacheEntry *cacheEntry)
 								   sizeof(int));
 
 		HeapTuple shardTuple = NULL;
-		foreach_ptr(shardTuple, distShardTupleList)
+		int shardTupleIndex = 0;
+		foreach_ptr_with_index(shardTuple, distShardTupleList, shardTupleIndex)
 		{
 			ShardInterval *shardInterval = TupleToShardInterval(shardTuple,
 																distShardTupleDesc,
@@ -1501,13 +1501,11 @@ BuildCachedShardList(CitusTableCacheEntry *cacheEntry)
 																intervalTypeMod);
 			MemoryContext oldContext = MemoryContextSwitchTo(MetadataCacheMemoryContext);
 
-			shardIntervalArray[arrayIndex] = CopyShardInterval(shardInterval);
+			shardIntervalArray[shardTupleIndex] = CopyShardInterval(shardInterval);
 
 			MemoryContextSwitchTo(oldContext);
 
 			heap_freetuple(shardTuple);
-
-			arrayIndex++;
 		}
 
 		table_close(distShardRelation, AccessShareLock);
@@ -1603,7 +1601,6 @@ BuildCachedShardList(CitusTableCacheEntry *cacheEntry)
 	{
 		ShardInterval *shardInterval = sortedShardIntervalArray[shardIndex];
 		int64 shardId = shardInterval->shardId;
-		int placementOffset = 0;
 
 		/*
 		 * Enable quick lookups of this shard ID by adding it to ShardIdCacheHash
@@ -1631,10 +1628,10 @@ BuildCachedShardList(CitusTableCacheEntry *cacheEntry)
 		GroupShardPlacement *placementArray = palloc0(numberOfPlacements *
 													  sizeof(GroupShardPlacement));
 		GroupShardPlacement *srcPlacement = NULL;
-		foreach_ptr(srcPlacement, placementList)
+		int srcPlacementIndex = 0;
+		foreach_ptr_with_index(srcPlacement, placementList, srcPlacementIndex)
 		{
-			placementArray[placementOffset] = *srcPlacement;
+			placementArray[srcPlacementIndex] = *srcPlacement;
-			placementOffset++;
 		}
 		MemoryContextSwitchTo(oldContext);
 

src/backend/distributed/metadata/metadata_sync.c

@@ -754,7 +754,6 @@ NodeListInsertCommand(List *workerNodeList)
 {
 	StringInfo nodeListInsertCommand = makeStringInfo();
 	int workerCount = list_length(workerNodeList);
-	int processedWorkerNodeCount = 0;
 	Oid primaryRole = PrimaryNodeRoleId();
 
 	/* if there are no workers, return NULL */
@@ -779,7 +778,8 @@ NodeListInsertCommand(List *workerNodeList)
 
 	/* iterate over the worker nodes, add the values */
 	WorkerNode *workerNode = NULL;
-	foreach_ptr(workerNode, workerNodeList)
+	int workerNodeIndex = 0;
+	foreach_ptr_with_index(workerNode, workerNodeList, workerNodeIndex)
 	{
 		char *hasMetadataString = workerNode->hasMetadata ? "TRUE" : "FALSE";
 		char *metadataSyncedString = workerNode->metadataSynced ? "TRUE" : "FALSE";
@@ -790,6 +790,11 @@ NodeListInsertCommand(List *workerNodeList)
 		Datum nodeRoleStringDatum = DirectFunctionCall1(enum_out, nodeRoleOidDatum);
 		char *nodeRoleString = DatumGetCString(nodeRoleStringDatum);
 
+		if (workerNodeIndex != 0)
+		{
+			appendStringInfo(nodeListInsertCommand, ",");
+		}
+
 		appendStringInfo(nodeListInsertCommand,
 						 "(%d, %d, %s, %d, %s, %s, %s, %s, '%s'::noderole, %s, %s)",
 						 workerNode->nodeId,
@@ -803,12 +808,6 @@ NodeListInsertCommand(List *workerNodeList)
 						 nodeRoleString,
 						 quote_literal_cstr(workerNode->nodeCluster),
 						 shouldHaveShards);
-
-		processedWorkerNodeCount++;
-		if (processedWorkerNodeCount != workerCount)
-		{
-			appendStringInfo(nodeListInsertCommand, ",");
-		}
 	}
 
 	return nodeListInsertCommand->data;
@@ -963,7 +962,8 @@ ShardListInsertCommand(List *shardIntervalList)
 					 "WITH shard_data(relationname, shardid, storagetype, "
 					 "shardminvalue, shardmaxvalue)  AS (VALUES ");
 
-	foreach_ptr(shardInterval, shardIntervalList)
+	int shardIntervalIndex = 0;
+	foreach_ptr_with_index(shardInterval, shardIntervalList, shardIntervalIndex)
 	{
 		uint64 shardId = shardInterval->shardId;
 		Oid distributedRelationId = shardInterval->relationId;
@@ -992,6 +992,11 @@ ShardListInsertCommand(List *shardIntervalList)
 			appendStringInfo(maxHashToken, "NULL");
 		}
 
+		if (shardIntervalIndex != 0)
+		{
+			appendStringInfo(insertShardCommand, ", ");
+		}
+
 		appendStringInfo(insertShardCommand,
 						 "(%s::regclass, %ld, '%c'::\"char\", %s, %s)",
 						 quote_literal_cstr(qualifiedRelationName),
@@ -999,11 +1004,6 @@ ShardListInsertCommand(List *shardIntervalList)
 						 shardInterval->storageType,
 						 minHashToken->data,
 						 maxHashToken->data);
-
-		if (llast(shardIntervalList) != shardInterval)
-		{
-			appendStringInfo(insertShardCommand, ", ");
-		}
 	}
 
 	appendStringInfo(insertShardCommand, ") ");

src/backend/distributed/operations/shard_rebalancer.c

@@ -280,12 +280,12 @@ CheckRebalanceStateInvariants(const RebalanceState *state)
 {
 	NodeFillState *fillState = NULL;
 	NodeFillState *prevFillState = NULL;
-	int fillStateIndex = 0;
 	int fillStateLength = list_length(state->fillStateListAsc);
 
 	Assert(state != NULL);
 	Assert(list_length(state->fillStateListAsc) == list_length(state->fillStateListDesc));
-	foreach_ptr(fillState, state->fillStateListAsc)
+	int fillStateIndex = 0;
+	foreach_ptr_with_index(fillState, state->fillStateListAsc, fillStateIndex)
 	{
 		float4 totalCost = 0;
 		ShardCost *shardCost = NULL;
@@ -333,7 +333,6 @@ CheckRebalanceStateInvariants(const RebalanceState *state)
 			   1000);
 
 		prevFillState = fillState;
-		fillStateIndex++;
 	}
 }
 

src/backend/distributed/test/distribution_metadata.c

@@ -62,7 +62,6 @@ Datum
 load_shard_id_array(PG_FUNCTION_ARGS)
 {
 	Oid distributedTableId = PG_GETARG_OID(0);
-	int shardIdIndex = 0;
 	Oid shardIdTypeId = INT8OID;
 
 	List *shardList = LoadShardIntervalList(distributedTableId);
@@ -71,12 +70,12 @@ load_shard_id_array(PG_FUNCTION_ARGS)
 	Datum *shardIdDatumArray = palloc0(shardIdCount * sizeof(Datum));
 
 	ShardInterval *shardInterval = NULL;
-	foreach_ptr(shardInterval, shardList)
+	int shardIntervalIndex = 0;
+	foreach_ptr_with_index(shardInterval, shardList, shardIntervalIndex)
 	{
 		Datum shardIdDatum = Int64GetDatum(shardInterval->shardId);
 
-		shardIdDatumArray[shardIdIndex] = shardIdDatum;
+		shardIdDatumArray[shardIntervalIndex] = shardIdDatum;
-		shardIdIndex++;
 	}
 
 	ArrayType *shardIdArrayType = DatumArrayToArrayType(shardIdDatumArray, shardIdCount,
@@ -122,7 +121,6 @@ load_shard_placement_array(PG_FUNCTION_ARGS)
 	int64 shardId = PG_GETARG_INT64(0);
 	bool onlyActive = PG_GETARG_BOOL(1);
 	List *placementList = NIL;
-	int placementIndex = 0;
 	Oid placementTypeId = TEXTOID;
 	StringInfo placementInfo = makeStringInfo();
 
@@ -141,13 +139,13 @@ load_shard_placement_array(PG_FUNCTION_ARGS)
 	Datum *placementDatumArray = palloc0(placementCount * sizeof(Datum));
 
 	ShardPlacement *placement = NULL;
-	foreach_ptr(placement, placementList)
+	int placementIndex = 0;
+	foreach_ptr_with_index(placement, placementList, placementIndex)
 	{
 		appendStringInfo(placementInfo, "%s:%d", placement->nodeName,
 						 placement->nodePort);
 
 		placementDatumArray[placementIndex] = CStringGetTextDatum(placementInfo->data);
-		placementIndex++;
 		resetStringInfo(placementInfo);
 	}
 

src/backend/distributed/test/metadata_sync.c

@@ -44,7 +44,6 @@ master_metadata_snapshot(PG_FUNCTION_ARGS)
 	List *dropSnapshotCommands = MetadataDropCommands();
 	List *createSnapshotCommands = MetadataCreateCommands();
 	List *snapshotCommandList = NIL;
-	int snapshotCommandIndex = 0;
 	Oid ddlCommandTypeId = TEXTOID;
 
 	snapshotCommandList = list_concat(snapshotCommandList, dropSnapshotCommands);
@@ -54,12 +53,14 @@ master_metadata_snapshot(PG_FUNCTION_ARGS)
 	Datum *snapshotCommandDatumArray = palloc0(snapshotCommandCount * sizeof(Datum));
 
 	const char *metadataSnapshotCommand = NULL;
-	foreach_ptr(metadataSnapshotCommand, snapshotCommandList)
+	int metadataSnapshotCommandIndex = 0;
+	foreach_ptr_with_index(metadataSnapshotCommand, snapshotCommandList,
+						   metadataSnapshotCommandIndex)
 	{
 		Datum metadataSnapshotCommandDatum = CStringGetTextDatum(metadataSnapshotCommand);
 
-		snapshotCommandDatumArray[snapshotCommandIndex] = metadataSnapshotCommandDatum;
+		snapshotCommandDatumArray[metadataSnapshotCommandIndex] =
-		snapshotCommandIndex++;
+			metadataSnapshotCommandDatum;
 	}
 
 	ArrayType *snapshotCommandArrayType = DatumArrayToArrayType(snapshotCommandDatumArray,

src/backend/distributed/test/prune_shard_list.c

@@ -207,7 +207,6 @@ MakeTextPartitionExpression(Oid distributedTableId, text *value)
 static ArrayType *
 PrunedShardIdsForTable(Oid distributedTableId, List *whereClauseList)
 {
-	int shardIdIndex = 0;
 	Oid shardIdTypeId = INT8OID;
 	Index tableId = 1;
 
@@ -218,12 +217,12 @@ PrunedShardIdsForTable(Oid distributedTableId, List *whereClauseList)
 	Datum *shardIdDatumArray = palloc0(shardIdCount * sizeof(Datum));
 
 	ShardInterval *shardInterval = NULL;
-	foreach_ptr(shardInterval, shardList)
+	int shardIntervalIndex = 0;
+	foreach_ptr_with_index(shardInterval, shardList, shardIntervalIndex)
 	{
 		Datum shardIdDatum = Int64GetDatum(shardInterval->shardId);
 
-		shardIdDatumArray[shardIdIndex] = shardIdDatum;
+		shardIdDatumArray[shardIntervalIndex] = shardIdDatum;
-		shardIdIndex++;
 	}
 
 	ArrayType *shardIdArrayType = DatumArrayToArrayType(shardIdDatumArray, shardIdCount,

src/backend/distributed/transaction/distributed_deadlock_detection.c

@@ -669,9 +669,10 @@ WaitsForToString(List *waitsFor)
 	StringInfo transactionIdStr = makeStringInfo();
 
 	TransactionNode *waitingNode = NULL;
-	foreach_ptr(waitingNode, waitsFor)
+	int waitingNodeIndex = 0;
+	foreach_ptr_with_index(waitingNode, waitsFor, waitingNodeIndex)
 	{
-		if (transactionIdStr->len != 0)
+		if (waitingNodeIndex != 0)
 		{
 			appendStringInfoString(transactionIdStr, ",");
 		}

src/backend/distributed/utils/colocation_utils.c

@@ -182,17 +182,17 @@ get_colocated_shard_array(PG_FUNCTION_ARGS)
 	int colocatedShardCount = list_length(colocatedShardList);
 	Datum *colocatedShardsDatumArray = palloc0(colocatedShardCount * sizeof(Datum));
 	Oid arrayTypeId = OIDOID;
-	int colocatedShardIndex = 0;
 
 	ShardInterval *colocatedShardInterval = NULL;
-	foreach_ptr(colocatedShardInterval, colocatedShardList)
+	int colocatedShardIntervalIndex = 0;
+	foreach_ptr_with_index(colocatedShardInterval, colocatedShardList,
+						   colocatedShardIntervalIndex)
 	{
 		uint64 colocatedShardId = colocatedShardInterval->shardId;
 
 		Datum colocatedShardDatum = Int64GetDatum(colocatedShardId);
 
-		colocatedShardsDatumArray[colocatedShardIndex] = colocatedShardDatum;
+		colocatedShardsDatumArray[colocatedShardIntervalIndex] = colocatedShardDatum;
-		colocatedShardIndex++;
 	}
 
 	ArrayType *colocatedShardsArrayType = DatumArrayToArrayType(colocatedShardsDatumArray,

src/backend/distributed/utils/listutils.c

@@ -41,11 +41,10 @@ SortList(List *pointerList, int (*comparisonFunction)(const void *, const void *
 	void **array = (void **) palloc0(arraySize * sizeof(void *));
 
 	void *pointer = NULL;
-	foreach_ptr(pointer, pointerList)
+	int pointerIndex = 0;
+	foreach_ptr_with_index(pointer, pointerList, pointerIndex)
 	{
-		array[arrayIndex] = pointer;
+		array[pointerIndex] = pointer;
-
-		arrayIndex++;
 	}
 
 	/* sort the array of pointers using the comparison function */
@@ -77,13 +76,12 @@ PointerArrayFromList(List *pointerList)
 {
 	int pointerCount = list_length(pointerList);
 	void **pointerArray = (void **) palloc0(pointerCount * sizeof(void *));
-	int pointerIndex = 0;
 
 	void *pointer = NULL;
-	foreach_ptr(pointer, pointerList)
+	int pointerIndex = 0;
+	foreach_ptr_with_index(pointer, pointerList, pointerIndex)
 	{
 		pointerArray[pointerIndex] = pointer;
-		pointerIndex += 1;
 	}
 
 	return pointerArray;
@@ -188,15 +186,14 @@ StringJoin(List *stringList, char delimiter)
 	StringInfo joinedString = makeStringInfo();
 
 	const char *command = NULL;
-	int curIndex = 0;
+	int commandIndex = 0;
-	foreach_ptr(command, stringList)
+	foreach_ptr_with_index(command, stringList, commandIndex)
 	{
-		if (curIndex > 0)
+		if (commandIndex != 0)
 		{
 			appendStringInfoChar(joinedString, delimiter);
 		}
 		appendStringInfoString(joinedString, command);
-		curIndex++;
 	}
 
 	return joinedString->data;
@@ -212,14 +209,12 @@ List *
 ListTake(List *pointerList, int size)
 {
 	List *result = NIL;
-	int listIndex = 0;
 
 	void *pointer = NULL;
 	foreach_ptr(pointer, pointerList)
 	{
 		result = lappend(result, pointer);
-		listIndex++;
+		if (list_length(result) >= size)
-		if (listIndex >= size)
 		{
 			break;
 		}

src/backend/distributed/utils/resource_lock.c

@@ -216,8 +216,6 @@ static void
 LockShardListResourcesOnFirstWorker(LOCKMODE lockmode, List *shardIntervalList)
 {
 	StringInfo lockCommand = makeStringInfo();
-	int processedShardIntervalCount = 0;
-	int totalShardIntervalCount = list_length(shardIntervalList);
 	WorkerNode *firstWorkerNode = GetFirstPrimaryWorkerNode();
 	int connectionFlags = 0;
 	const char *superuser = CurrentUserName();
@@ -225,17 +223,16 @@ LockShardListResourcesOnFirstWorker(LOCKMODE lockmode, List *shardIntervalList)
 	appendStringInfo(lockCommand, "SELECT lock_shard_resources(%d, ARRAY[", lockmode);
 
 	ShardInterval *shardInterval = NULL;
-	foreach_ptr(shardInterval, shardIntervalList)
+	int shardIntervalIndex = 0;
+	foreach_ptr_with_index(shardInterval, shardIntervalList, shardIntervalIndex)
 	{
-		int64 shardId = shardInterval->shardId;
+		if (shardIntervalIndex != 0)
-
-		appendStringInfo(lockCommand, "%lu", shardId);
-
-		processedShardIntervalCount++;
-		if (processedShardIntervalCount != totalShardIntervalCount)
 		{
 			appendStringInfo(lockCommand, ", ");
 		}
+
+		int64 shardId = shardInterval->shardId;
+		appendStringInfo(lockCommand, "%lu", shardId);
 	}
 
 	appendStringInfo(lockCommand, "])");
@@ -303,8 +300,6 @@ void
 LockShardListMetadataOnWorkers(LOCKMODE lockmode, List *shardIntervalList)
 {
 	StringInfo lockCommand = makeStringInfo();
-	int processedShardIntervalCount = 0;
-	int totalShardIntervalCount = list_length(shardIntervalList);
 
 	if (list_length(shardIntervalList) == 0)
 	{
@@ -314,17 +309,16 @@ LockShardListMetadataOnWorkers(LOCKMODE lockmode, List *shardIntervalList)
 	appendStringInfo(lockCommand, "SELECT lock_shard_metadata(%d, ARRAY[", lockmode);
 
 	ShardInterval *shardInterval = NULL;
-	foreach_ptr(shardInterval, shardIntervalList)
+	int shardIntervalIndex = 0;
+	foreach_ptr_with_index(shardInterval, shardIntervalList, shardIntervalIndex)
 	{
-		int64 shardId = shardInterval->shardId;
+		if (shardIntervalIndex != 0)
-
-		appendStringInfo(lockCommand, "%lu", shardId);
-
-		processedShardIntervalCount++;
-		if (processedShardIntervalCount != totalShardIntervalCount)
 		{
 			appendStringInfo(lockCommand, ", ");
 		}
+
+		int64 shardId = shardInterval->shardId;
+		appendStringInfo(lockCommand, "%lu", shardId);
 	}
 
 	appendStringInfo(lockCommand, "])");

src/include/distributed/listutils.h

@@ -33,6 +33,13 @@ typedef struct ListCellAndListWrapper
 	ListCell *listCell;
 } ListCellAndListWrapper;
 
+
+typedef struct ListCellAndIndex
+{
+	ListCell *listCell;
+	int index;
+} ListCellAndIndex;
+
 /*
  * foreach_ptr -
  *	  a convenience macro which loops through a pointer list without needing a
@@ -52,9 +59,17 @@ typedef struct ListCellAndListWrapper
 	for (ListCell *(var ## CellDoNotUse) = list_head(l); \
 		 (var ## CellDoNotUse) != NULL && \
 		 (((var) = lfirst(var ## CellDoNotUse)) || true); \
-		 var ## CellDoNotUse = lnext_compat(l, var ## CellDoNotUse))
+		 (var ## CellDoNotUse) = lnext_compat(l, var ## CellDoNotUse))
 
 
+#define foreach_ptr_with_index(var, l, index) \
+	(index) = 0; \
+	for (ListCell *(var ## CellDoNotUse) = list_head(l); \
+		 (var ## CellDoNotUse) != NULL && \
+		 (((var) = lfirst(var ## CellDoNotUse)) || true); \
+		 (var ## CellDoNotUse) = lnext_compat(l, var ## CellDoNotUse), \
+		 (index)++)
+
 /*
  * foreach_int -
  *	  a convenience macro which loops through an int list without needing a
@@ -113,6 +128,7 @@ typedef struct ListCellAndListWrapper
 #define foreach_ptr_append(var, l) foreach_ptr(var, l)
 #endif
 
+
 /* utility functions declaration shared within this module */
 extern List * SortList(List *pointerList,
 					   int (*ComparisonFunction)(const void *, const void *));