refactoring, new log messages (DEBUG2), fix function find_inheritance_children_array()

funbringer · funbringer · commit 9555f744b01a · 2016-12-22T15:16:03.000+03:00
diff --git a/src/init.c b/src/init.c
@@ -486,25 +486,28 @@ find_inheritance_children_array(Oid parentrelId,
 	SysScanDesc scan;
 	ScanKeyData key[1];
 	HeapTuple	inheritsTuple;
-	Oid			inhrelid;
+
 	Oid		   *oidarr;
 	uint32		maxoids,
-				numoids,
-				i;
+				numoids;
+
+	Oid		   *result = NULL;
+	uint32		nresult = 0;
+
+	uint32		i;
+
+	Assert(lockmode != NoLock);
+
+	/* Init safe return values */
+	*children_size = 0;
+	*children = NULL;
 
 	/*
-	 * Can skip the scan if pg_class shows the relation has never had a
-	 * subclass.
+	 * Can skip the scan if pg_class shows the
+	 * relation has never had a subclass.
 	 */
 	if (!has_subclass(parentrelId))
-	{
-		/* Init return values */
-		*children_size = 0;
-		children = NULL;
-
-		/* Ok, could not find any children */
 		return FCS_NO_CHILDREN;
-	}
 
 	/*
 	 * Scan pg_inherits and build a working array of subclass OIDs.
@@ -525,6 +528,8 @@ find_inheritance_children_array(Oid parentrelId,
 
 	while ((inheritsTuple = systable_getnext(scan)) != NULL)
 	{
+		Oid inhrelid;
+
 		inhrelid = ((Form_pg_inherits) GETSTRUCT(inheritsTuple))->inhrelid;
 		if (numoids >= maxoids)
 		{
@@ -547,12 +552,10 @@ find_inheritance_children_array(Oid parentrelId,
 	if (numoids > 1)
 		qsort(oidarr, numoids, sizeof(Oid), oid_cmp);
 
-	/*
-	 * Acquire locks and build the result list.
-	 */
+	/* Acquire locks and build the result list */
 	for (i = 0; i < numoids; i++)
 	{
-		inhrelid = oidarr[i];
+		Oid inhrelid = oidarr[i];
 
 		if (lockmode != NoLock)
 		{
@@ -567,9 +570,7 @@ find_inheritance_children_array(Oid parentrelId,
 					for (j = 0; j < i; j++)
 						UnlockRelationOid(oidarr[j], lockmode);
 
-					/* Init return values */
-					*children_size = numoids;
-					*children = oidarr;
+					pfree(oidarr);
 
 					/* We couldn't lock this child, retreat! */
 					return FCS_COULD_NOT_LOCK;
@@ -586,18 +587,28 @@ find_inheritance_children_array(Oid parentrelId,
 			{
 				/* Release useless lock */
 				UnlockRelationOid(inhrelid, lockmode);
+
 				/* And ignore this relation */
 				continue;
 			}
 		}
+
+		/* Alloc array if it's the first time */
+		if (nresult == 0)
+			result = palloc(numoids * sizeof(Oid));
+
+		/* Save Oid of the existing relation */
+		result[nresult++] = inhrelid;
 	}
 
-	/* Init return values */
-	*children_size = numoids;
-	*children = oidarr;
+	/* Set return values */
+	*children_size = nresult;
+	*children = result;
+
+	pfree(oidarr);
 
-	/* Ok, we have children */
-	return FCS_FOUND;
+	/* Do we have children? */
+	return nresult > 0 ? FCS_FOUND : FCS_NO_CHILDREN;
 }
 
 /*
diff --git a/src/partition_creation.c b/src/partition_creation.c
@@ -236,11 +236,6 @@ create_partitions_for_value(Oid relid, Datum value, Oid value_type)
 	/* Check that table is partitioned and fetch xmin */
 	if (pathman_config_contains_relation(relid, NULL, NULL, &rel_xmin))
 	{
-		/* Was table partitioned in some previous transaction? */
-		bool	part_in_prev_xact =
-					TransactionIdPrecedes(rel_xmin, GetCurrentTransactionId()) ||
-					TransactionIdEquals(rel_xmin, FrozenTransactionId);
-
 		/* Take default values */
 		bool	spawn_using_bgw	= DEFAULT_SPAWN_USING_BGW,
 				enable_auto		= DEFAULT_AUTO;
@@ -264,7 +259,8 @@ create_partitions_for_value(Oid relid, Datum value, Oid value_type)
 		 * If table has been partitioned in some previous xact AND
 		 * we don't hold any conflicting locks, run BGWorker.
 		 */
-		if (spawn_using_bgw && part_in_prev_xact &&
+		if (spawn_using_bgw &&
+			xact_object_is_visible(rel_xmin) &&
 			!xact_bgw_conflicting_lock_exists(relid))
 		{
 			elog(DEBUG2, "create_partitions(): chose BGWorker [%u]", MyProcPid);
diff --git a/src/pathman_workers.c b/src/pathman_workers.c
@@ -19,6 +19,7 @@
 #include "pathman_workers.h"
 #include "relation_info.h"
 #include "utils.h"
+#include "xact_handling.h"
 
 #include "access/htup_details.h"
 #include "access/xact.h"
@@ -601,11 +602,12 @@ bgw_main_concurrent_part(Datum main_arg)
 Datum
 partition_table_concurrently(PG_FUNCTION_ARGS)
 {
-	Oid		relid = PG_GETARG_OID(0);
-	int32	batch_size = PG_GETARG_INT32(1);
-	float8	sleep_time = PG_GETARG_FLOAT8(2);
-	int		empty_slot_idx = -1,		/* do we have a slot for BGWorker? */
-			i;
+	Oid				relid = PG_GETARG_OID(0);
+	int32			batch_size = PG_GETARG_INT32(1);
+	float8			sleep_time = PG_GETARG_FLOAT8(2);
+	int				empty_slot_idx = -1,		/* do we have a slot for BGWorker? */
+					i;
+	TransactionId	rel_xmin;
 
 	/* Check batch_size */
 	if (batch_size < 1 || batch_size > 10000)
@@ -622,6 +624,16 @@ partition_table_concurrently(PG_FUNCTION_ARGS)
 							 get_pathman_relation_info_after_lock(relid, true, NULL),
 							 /* Partitioning type does not matter here */
 							 PT_INDIFFERENT);
+
+	/* Check that partitioning operation result is visible */
+	if (pathman_config_contains_relation(relid, NULL, NULL, &rel_xmin))
+	{
+		if (!xact_object_is_visible(rel_xmin))
+			ereport(ERROR, (errmsg("cannot start %s", concurrent_part_bgw),
+							errdetail("table is being partitioned now")));
+	}
+	else elog(ERROR, "cannot find relation %d", relid);
+
 	/*
 	 * Look for an empty slot and also check that a concurrent
 	 * partitioning operation for this table hasn't been started yet
@@ -686,7 +698,8 @@ partition_table_concurrently(PG_FUNCTION_ARGS)
 	/* Tell user everything's fine */
 	elog(NOTICE,
 		 "worker started, you can stop it "
-		 "with the following command: select %s('%s');",
+		 "with the following command: select %s.%s('%s');",
+		 get_namespace_name(get_pathman_schema()),
 		 CppAsString(stop_concurrent_part_task),
 		 get_rel_name(relid));
 
diff --git a/src/relation_info.c b/src/relation_info.c
@@ -162,17 +162,26 @@ refresh_pathman_relation_info(Oid relid,
 	{
 		/* If there's no children at all, remove this entry */
 		case FCS_NO_CHILDREN:
+			elog(DEBUG2, "refresh: relation %u has no children [%u]",
+						 relid, MyProcPid);
+
 			UnlockRelationOid(relid, lockmode);
 			remove_pathman_relation_info(relid);
 			return NULL; /* exit */
 
 		/* If can't lock children, leave an invalid entry */
 		case FCS_COULD_NOT_LOCK:
+			elog(DEBUG2, "refresh: cannot lock children of relation %u [%u]",
+						 relid, MyProcPid);
+
 			UnlockRelationOid(relid, lockmode);
 			return NULL; /* exit */
 
 		/* Found some children, just unlock parent */
 		case FCS_FOUND:
+			elog(DEBUG2, "refresh: found children of relation %u [%u]",
+						 relid, MyProcPid);
+
 			UnlockRelationOid(relid, lockmode);
 			break; /* continue */
 
@@ -200,7 +209,8 @@ refresh_pathman_relation_info(Oid relid,
 		UnlockRelationOid(prel_children[i], lockmode);
 	}
 
-	pfree(prel_children);
+	if (prel_children)
+		pfree(prel_children);
 
 	/* Read additional parameters ('enable_parent' and 'auto' at the moment) */
 	if (read_pathman_params(relid, param_values, param_isnull))
@@ -292,6 +302,9 @@ get_pathman_relation_info(Oid relid)
 		 "Fetching %s record for relation %u from pg_pathman's cache [%u]",
 		 (prel ? "live" : "NULL"), relid, MyProcPid);
 
+	/* Make sure that 'prel' is valid */
+	Assert(PrelIsValid(prel));
+
 	return prel;
 }
 
diff --git a/src/xact_handling.c b/src/xact_handling.c
@@ -11,6 +11,7 @@
 #include "xact_handling.h"
 
 #include "postgres.h"
+#include "access/transam.h"
 #include "access/xact.h"
 #include "catalog/catalog.h"
 #include "miscadmin.h"
@@ -156,6 +157,16 @@ xact_is_set_transaction_stmt(Node *stmt)
 	return false;
 }
 
+/*
+ * Check if object is visible in newer transactions.
+ */
+bool
+xact_object_is_visible(TransactionId obj_xmin)
+{
+	return TransactionIdPrecedes(obj_xmin, GetCurrentTransactionId()) ||
+		   TransactionIdEquals(obj_xmin, FrozenTransactionId);
+}
+
 /*
  * Do we hold the specified lock?
  */
diff --git a/src/xact_handling.h b/src/xact_handling.h
@@ -33,6 +33,7 @@ bool xact_bgw_conflicting_lock_exists(Oid relid);
 bool xact_is_level_read_committed(void);
 bool xact_is_transaction_stmt(Node *stmt);
 bool xact_is_set_transaction_stmt(Node *stmt);
+bool xact_object_is_visible(TransactionId obj_xmin);
 
 
 #endif /* XACT_HANDLING_H */
