Use "orphaned shards" naming in more places

We were not very consistent in how we named these shards.

src/backend/distributed/operations/repair_shards.c

@@ -1067,7 +1067,7 @@ EnsureShardCanBeCopied(int64 shardId, const char *sourceNodeName, int32 sourceNo
 			 * Trigger deletion of orphaned shards and hope that this removes
 			 * the shard.
 			 */
-			DropMarkedShardsInSeparateTransaction();
+			DropOrphanedShardsInSeparateTransaction();
 			shardPlacementList = ShardPlacementList(shardId);
 			targetPlacement = SearchShardPlacementInList(shardPlacementList,
 														 targetNodeName,

src/backend/distributed/operations/shard_cleaner.c

@@ -56,7 +56,7 @@ citus_cleanup_orphaned_shards(PG_FUNCTION_ARGS)
 	PreventInTransactionBlock(true, "citus_cleanup_orphaned_shards");
 
 	bool waitForLocks = true;
-	int droppedShardCount = DropMarkedShards(waitForLocks);
+	int droppedShardCount = DropOrphanedShards(waitForLocks);
 	if (droppedShardCount > 0)
 	{
 		ereport(NOTICE, (errmsg("cleaned up %d orphaned shards", droppedShardCount)));
@@ -78,7 +78,7 @@ isolation_cleanup_orphaned_shards(PG_FUNCTION_ARGS)
 	EnsureCoordinator();
 
 	bool waitForLocks = true;
-	int droppedShardCount = DropMarkedShards(waitForLocks);
+	int droppedShardCount = DropOrphanedShards(waitForLocks);
 	if (droppedShardCount > 0)
 	{
 		ereport(NOTICE, (errmsg("cleaned up %d orphaned shards", droppedShardCount)));
@@ -89,32 +89,32 @@ isolation_cleanup_orphaned_shards(PG_FUNCTION_ARGS)
 
 
 /*
- * DropMarkedShardsInSeparateTransaction cleans up orphaned shards by
+ * DropOrphanedShardsInSeparateTransaction cleans up orphaned shards by
  * connecting to localhost. This is done, so that the locks that
- * DropMarkedShards takes are only held for a short time.
+ * DropOrphanedShards takes are only held for a short time.
  */
 void
-DropMarkedShardsInSeparateTransaction(void)
+DropOrphanedShardsInSeparateTransaction(void)
 {
 	ExecuteCriticalCommandInSeparateTransaction("CALL citus_cleanup_orphaned_shards()");
 }
 
 
 /*
- * TryDropMarkedShards is a wrapper around DropMarkedShards that catches
+ * TryDropOrphanedShards is a wrapper around DropOrphanedShards that catches
  * any errors to make it safe to use in the maintenance daemon.
  *
  * If dropping any of the shards failed this function returns -1, otherwise it
  * returns the number of dropped shards.
  */
 int
-TryDropMarkedShards(bool waitForLocks)
+TryDropOrphanedShards(bool waitForLocks)
 {
 	int droppedShardCount = 0;
 	MemoryContext savedContext = CurrentMemoryContext;
 	PG_TRY();
 	{
-		droppedShardCount = DropMarkedShards(waitForLocks);
+		droppedShardCount = DropOrphanedShards(waitForLocks);
 	}
 	PG_CATCH();
 	{
@@ -133,7 +133,7 @@ TryDropMarkedShards(bool waitForLocks)
 
 
 /*
- * DropMarkedShards removes shards that were marked SHARD_STATE_TO_DELETE before.
+ * DropOrphanedShards removes shards that were marked SHARD_STATE_TO_DELETE before.
  *
  * It does so by trying to take an exclusive lock on the shard and its
  * colocated placements before removing. If the lock cannot be obtained it
@@ -152,7 +152,7 @@ TryDropMarkedShards(bool waitForLocks)
  *
  */
 int
-DropMarkedShards(bool waitForLocks)
+DropOrphanedShards(bool waitForLocks)
 {
 	int removedShardCount = 0;
 	ListCell *shardPlacementCell = NULL;
@@ -208,7 +208,7 @@ DropMarkedShards(bool waitForLocks)
 
 	if (failedShardDropCount > 0)
 	{
-		ereport(WARNING, (errmsg("Failed to drop %d old shards out of %d",
+		ereport(WARNING, (errmsg("Failed to drop %d orphaned shards out of %d",
 								 failedShardDropCount, list_length(shardPlacementList))));
 	}
 

src/backend/distributed/operations/shard_rebalancer.c

@@ -701,7 +701,7 @@ ExecutePlacementUpdates(List *placementUpdateList, Oid shardReplicationModeOid,
 							   "unsupported")));
 	}
 
-	DropMarkedShardsInSeparateTransaction();
+	DropOrphanedShardsInSeparateTransaction();
 
 	foreach(placementUpdateCell, placementUpdateList)
 	{

src/backend/distributed/shared_library_init.c

@@ -645,7 +645,9 @@ RegisterCitusConfigVariables(void)
 
 	DefineCustomBoolVariable(
 		"citus.defer_drop_after_shard_move",
-		gettext_noop("When enabled a shard move will mark old shards for deletion"),
+		gettext_noop("When enabled a shard move will mark the original shards "
+					 "for deletion after a successful move, instead of deleting "
+					 "them right away."),
 		gettext_noop("The deletion of a shard can sometimes run into a conflict with a "
 					 "long running transactions on a the shard during the drop phase of "
 					 "the shard move. This causes some moves to be rolled back after "

src/backend/distributed/test/shard_rebalancer.c

@@ -74,13 +74,13 @@ typedef struct RebalancePlanContext
 } RebalancePlacementContext;
 
 /*
- * run_try_drop_marked_shards is a wrapper to run TryDropMarkedShards.
+ * run_try_drop_marked_shards is a wrapper to run TryDropOrphanedShards.
  */
 Datum
 run_try_drop_marked_shards(PG_FUNCTION_ARGS)
 {
 	bool waitForLocks = false;
-	TryDropMarkedShards(waitForLocks);
+	TryDropOrphanedShards(waitForLocks);
 	PG_RETURN_VOID();
 }
 

src/backend/distributed/utils/maintenanced.c

@@ -645,7 +645,7 @@ CitusMaintenanceDaemonMain(Datum main_arg)
 				lastShardCleanTime = GetCurrentTimestamp();
 
 				bool waitForLocks = false;
-				numberOfDroppedShards = TryDropMarkedShards(waitForLocks);
+				numberOfDroppedShards = TryDropOrphanedShards(waitForLocks);
 			}
 
 			CommitTransactionCommand();

src/include/distributed/shard_cleaner.h

@@ -17,8 +17,8 @@ extern bool DeferShardDeleteOnMove;
 extern double DesiredPercentFreeAfterMove;
 extern bool CheckAvailableSpaceBeforeMove;
 
-extern int TryDropMarkedShards(bool waitForLocks);
+extern int TryDropOrphanedShards(bool waitForLocks);
-extern int DropMarkedShards(bool waitForLocks);
+extern int DropOrphanedShards(bool waitForLocks);
-extern void DropMarkedShardsInSeparateTransaction(void);
+extern void DropOrphanedShardsInSeparateTransaction(void);
 
 #endif /*CITUS_SHARD_CLEANER_H */

src/test/regress/expected/isolation_rebalancer_deferred_drop.out

@@ -79,7 +79,7 @@ step s1-drop-marked-shards:
  <waiting ...>
 s1: WARNING:  canceling statement due to lock timeout
 step s1-drop-marked-shards: <... completed>
-s1: WARNING:  Failed to drop 1 old shards out of 1
+s1: WARNING:  Failed to drop 1 orphaned shards out of 1
 step s1-commit:
     COMMIT;