Code beautification for ATExecAttachPartition.

Amit Langote

Discussion: http://postgr.es/m/CAFjFpReT_kq_uwU_B8aWDxR7jNGE=P0iELycdq5oupi=xSQTOw@mail.gmail.com

src/backend/commands/tablecmds.c

@@ -13419,10 +13419,10 @@ ComputePartitionAttrs(Relation rel, List *partParams, AttrNumber *partattrs,
 static ObjectAddress
 ATExecAttachPartition(List **wqueue, Relation rel, PartitionCmd *cmd)
 {
-	Relation	attachRel,
+	Relation	attachrel,
 				catalog;
-	List	   *childrels;
-	TupleConstr *attachRel_constr;
+	List	   *attachrel_children;
+	TupleConstr *attachrel_constr;
 	List	   *partConstraint,
 			   *existConstraint;
 	SysScanDesc scan;
@@ -13434,22 +13434,22 @@ ATExecAttachPartition(List **wqueue, Relation rel, PartitionCmd *cmd)
 	ObjectAddress address;
 	const char *trigger_name;
 
-	attachRel = heap_openrv(cmd->name, AccessExclusiveLock);
+	attachrel = heap_openrv(cmd->name, AccessExclusiveLock);
 
 	/*
 	 * Must be owner of both parent and source table -- parent was checked by
 	 * ATSimplePermissions call in ATPrepCmd
 	 */
-	ATSimplePermissions(attachRel, ATT_TABLE | ATT_FOREIGN_TABLE);
+	ATSimplePermissions(attachrel, ATT_TABLE | ATT_FOREIGN_TABLE);
 
 	/* A partition can only have one parent */
-	if (attachRel->rd_rel->relispartition)
+	if (attachrel->rd_rel->relispartition)
 		ereport(ERROR,
 				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
 				 errmsg("\"%s\" is already a partition",
-						RelationGetRelationName(attachRel))));
+						RelationGetRelationName(attachrel))));
 
-	if (OidIsValid(attachRel->rd_rel->reloftype))
+	if (OidIsValid(attachrel->rd_rel->reloftype))
 		ereport(ERROR,
 				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
 				 errmsg("cannot attach a typed table as partition")));
@@ -13462,7 +13462,7 @@ ATExecAttachPartition(List **wqueue, Relation rel, PartitionCmd *cmd)
 	ScanKeyInit(&skey,
 				Anum_pg_inherits_inhrelid,
 				BTEqualStrategyNumber, F_OIDEQ,
-				ObjectIdGetDatum(RelationGetRelid(attachRel)));
+				ObjectIdGetDatum(RelationGetRelid(attachrel)));
 	scan = systable_beginscan(catalog, InheritsRelidSeqnoIndexId, true,
 							  NULL, 1, &skey);
 	if (HeapTupleIsValid(systable_getnext(scan)))
@@ -13475,11 +13475,11 @@ ATExecAttachPartition(List **wqueue, Relation rel, PartitionCmd *cmd)
 	ScanKeyInit(&skey,
 				Anum_pg_inherits_inhparent,
 				BTEqualStrategyNumber, F_OIDEQ,
-				ObjectIdGetDatum(RelationGetRelid(attachRel)));
+				ObjectIdGetDatum(RelationGetRelid(attachrel)));
 	scan = systable_beginscan(catalog, InheritsParentIndexId, true, NULL,
 							  1, &skey);
 	if (HeapTupleIsValid(systable_getnext(scan)) &&
-		attachRel->rd_rel->relkind == RELKIND_RELATION)
+		attachrel->rd_rel->relkind == RELKIND_RELATION)
 		ereport(ERROR,
 				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
 				 errmsg("cannot attach inheritance parent as partition")));
@@ -13487,22 +13487,22 @@ ATExecAttachPartition(List **wqueue, Relation rel, PartitionCmd *cmd)
 	heap_close(catalog, AccessShareLock);
 
 	/*
-	 * Prevent circularity by seeing if rel is a partition of attachRel. (In
+	 * Prevent circularity by seeing if rel is a partition of attachrel. (In
 	 * particular, this disallows making a rel a partition of itself.)
 	 */
-	childrels = find_all_inheritors(RelationGetRelid(attachRel),
-									AccessShareLock, NULL);
-	if (list_member_oid(childrels, RelationGetRelid(rel)))
+	attachrel_children = find_all_inheritors(RelationGetRelid(attachrel),
+											 AccessShareLock, NULL);
+	if (list_member_oid(attachrel_children, RelationGetRelid(rel)))
 		ereport(ERROR,
 				(errcode(ERRCODE_DUPLICATE_TABLE),
 				 errmsg("circular inheritance not allowed"),
 				 errdetail("\"%s\" is already a child of \"%s\".",
 						   RelationGetRelationName(rel),
-						   RelationGetRelationName(attachRel))));
+						   RelationGetRelationName(attachrel))));
 
 	/* Temp parent cannot have a partition that is itself not a temp */
 	if (rel->rd_rel->relpersistence == RELPERSISTENCE_TEMP &&
-		attachRel->rd_rel->relpersistence != RELPERSISTENCE_TEMP)
+		attachrel->rd_rel->relpersistence != RELPERSISTENCE_TEMP)
 		ereport(ERROR,
 				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
 				 errmsg("cannot attach a permanent relation as partition of temporary relation \"%s\"",
@@ -13516,30 +13516,30 @@ ATExecAttachPartition(List **wqueue, Relation rel, PartitionCmd *cmd)
 				 errmsg("cannot attach as partition of temporary relation of another session")));
 
 	/* Ditto for the partition */
-	if (attachRel->rd_rel->relpersistence == RELPERSISTENCE_TEMP &&
-		!attachRel->rd_islocaltemp)
+	if (attachrel->rd_rel->relpersistence == RELPERSISTENCE_TEMP &&
+		!attachrel->rd_islocaltemp)
 		ereport(ERROR,
 				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
 				 errmsg("cannot attach temporary relation of another session as partition")));
 
 	/* If parent has OIDs then child must have OIDs */
-	if (rel->rd_rel->relhasoids && !attachRel->rd_rel->relhasoids)
+	if (rel->rd_rel->relhasoids && !attachrel->rd_rel->relhasoids)
 		ereport(ERROR,
 				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
 				 errmsg("cannot attach table \"%s\" without OIDs as partition of"
-						" table \"%s\" with OIDs", RelationGetRelationName(attachRel),
+						" table \"%s\" with OIDs", RelationGetRelationName(attachrel),
 						RelationGetRelationName(rel))));
 
-	/* OTOH, if parent doesn't have them, do not allow in attachRel either */
-	if (attachRel->rd_rel->relhasoids && !rel->rd_rel->relhasoids)
+	/* OTOH, if parent doesn't have them, do not allow in attachrel either */
+	if (attachrel->rd_rel->relhasoids && !rel->rd_rel->relhasoids)
 		ereport(ERROR,
 				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
 				 errmsg("cannot attach table \"%s\" with OIDs as partition of table"
-						" \"%s\" without OIDs", RelationGetRelationName(attachRel),
+						" \"%s\" without OIDs", RelationGetRelationName(attachrel),
 						RelationGetRelationName(rel))));
 
-	/* Check if there are any columns in attachRel that aren't in the parent */
-	tupleDesc = RelationGetDescr(attachRel);
+	/* Check if there are any columns in attachrel that aren't in the parent */
+	tupleDesc = RelationGetDescr(attachrel);
 	natts = tupleDesc->natts;
 	for (attno = 1; attno <= natts; attno++)
 	{
@@ -13557,7 +13557,7 @@ ATExecAttachPartition(List **wqueue, Relation rel, PartitionCmd *cmd)
 			ereport(ERROR,
 					(errcode(ERRCODE_DATATYPE_MISMATCH),
 					 errmsg("table \"%s\" contains column \"%s\" not found in parent \"%s\"",
-							RelationGetRelationName(attachRel), attributeName,
+							RelationGetRelationName(attachrel), attributeName,
 							RelationGetRelationName(rel)),
 					 errdetail("New partition should contain only the columns present in parent.")));
 	}
@@ -13567,34 +13567,34 @@ ATExecAttachPartition(List **wqueue, Relation rel, PartitionCmd *cmd)
 	 * currently don't allow it to become a partition.  See also prohibitions
 	 * in ATExecAddInherit() and CreateTrigger().
 	 */
-	trigger_name = FindTriggerIncompatibleWithInheritance(attachRel->trigdesc);
+	trigger_name = FindTriggerIncompatibleWithInheritance(attachrel->trigdesc);
 	if (trigger_name != NULL)
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 				 errmsg("trigger \"%s\" prevents table \"%s\" from becoming a partition",
-						trigger_name, RelationGetRelationName(attachRel)),
+						trigger_name, RelationGetRelationName(attachrel)),
 				 errdetail("ROW triggers with transition tables are not supported on partitions")));
 
 	/* OK to create inheritance.  Rest of the checks performed there */
-	CreateInheritance(attachRel, rel);
+	CreateInheritance(attachrel, rel);
 
 	/*
 	 * Check that the new partition's bound is valid and does not overlap any
 	 * of existing partitions of the parent - note that it does not return on
 	 * error.
 	 */
-	check_new_partition_bound(RelationGetRelationName(attachRel), rel,
+	check_new_partition_bound(RelationGetRelationName(attachrel), rel,
 							  cmd->bound);
 
 	/* Update the pg_class entry. */
-	StorePartitionBound(attachRel, rel, cmd->bound);
+	StorePartitionBound(attachrel, rel, cmd->bound);
 
 	/*
 	 * Generate partition constraint from the partition bound specification.
 	 * If the parent itself is a partition, make sure to include its
 	 * constraint as well.
 	 */
-	partConstraint = list_concat(get_qual_from_partbound(attachRel, rel,
+	partConstraint = list_concat(get_qual_from_partbound(attachrel, rel,
 														 cmd->bound),
 								 RelationGetPartitionQual(rel));
 	partConstraint = (List *) eval_const_expressions(NULL,
@@ -13612,20 +13612,20 @@ ATExecAttachPartition(List **wqueue, Relation rel, PartitionCmd *cmd)
 	 * There is a case in which we cannot rely on just the result of the
 	 * proof.
 	 */
-	attachRel_constr = tupleDesc->constr;
+	attachrel_constr = tupleDesc->constr;
 	existConstraint = NIL;
-	if (attachRel_constr != NULL)
+	if (attachrel_constr != NULL)
 	{
-		int			num_check = attachRel_constr->num_check;
+		int			num_check = attachrel_constr->num_check;
 		int			i;
 
-		if (attachRel_constr->has_not_null)
+		if (attachrel_constr->has_not_null)
 		{
-			int			natts = attachRel->rd_att->natts;
+			int			natts = attachrel->rd_att->natts;
 
 			for (i = 1; i <= natts; i++)
 			{
-				Form_pg_attribute att = attachRel->rd_att->attrs[i - 1];
+				Form_pg_attribute att = attachrel->rd_att->attrs[i - 1];
 
 				if (att->attnotnull && !att->attisdropped)
 				{
@@ -13659,10 +13659,10 @@ ATExecAttachPartition(List **wqueue, Relation rel, PartitionCmd *cmd)
 			 * If this constraint hasn't been fully validated yet, we must
 			 * ignore it here.
 			 */
-			if (!attachRel_constr->check[i].ccvalid)
+			if (!attachrel_constr->check[i].ccvalid)
 				continue;
 
-			cexpr = stringToNode(attachRel_constr->check[i].ccbin);
+			cexpr = stringToNode(attachrel_constr->check[i].ccbin);
 
 			/*
 			 * Run each expression through const-simplification and
@@ -13684,28 +13684,25 @@ ATExecAttachPartition(List **wqueue, Relation rel, PartitionCmd *cmd)
 			skip_validate = true;
 	}
 
-	/* It's safe to skip the validation scan after all */
 	if (skip_validate)
+	{
+		/* No need to scan the table after all. */
 		ereport(INFO,
 				(errmsg("partition constraint for table \"%s\" is implied by existing constraints",
-						RelationGetRelationName(attachRel))));
-
-	/*
-	 * Set up to have the table be scanned to validate the partition
-	 * constraint (see partConstraint above).  If it's a partitioned table, we
-	 * instead schedule its leaf partitions to be scanned.
-	 */
-	if (!skip_validate)
+						RelationGetRelationName(attachrel))));
+	}
+	else
 	{
+		/* Constraints proved insufficient, so we need to scan the table. */
 		List	   *all_parts;
 		ListCell   *lc;
 
 		/* Take an exclusive lock on the partitions to be checked */
-		if (attachRel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
-			all_parts = find_all_inheritors(RelationGetRelid(attachRel),
+		if (attachrel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
+			all_parts = find_all_inheritors(RelationGetRelid(attachrel),
 											AccessExclusiveLock, NULL);
 		else
-			all_parts = list_make1_oid(RelationGetRelid(attachRel));
+			all_parts = list_make1_oid(RelationGetRelid(attachrel));
 
 		foreach(lc, all_parts)
 		{
@@ -13716,23 +13713,23 @@ ATExecAttachPartition(List **wqueue, Relation rel, PartitionCmd *cmd)
 			bool		found_whole_row;
 
 			/* Lock already taken */
-			if (part_relid != RelationGetRelid(attachRel))
+			if (part_relid != RelationGetRelid(attachrel))
 				part_rel = heap_open(part_relid, NoLock);
 			else
-				part_rel = attachRel;
+				part_rel = attachrel;
 
 			/*
-			 * Skip if it's a partitioned table.  Only RELKIND_RELATION
-			 * relations (ie, leaf partitions) need to be scanned.
+			 * Skip if the partition is itself a partitioned table.  We can
+			 * only ever scan RELKIND_RELATION relations.
 			 */
-			if (part_rel != attachRel &&
-				part_rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
+			if (part_rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
 			{
-				heap_close(part_rel, NoLock);
+				if (part_rel != attachrel)
+					heap_close(part_rel, NoLock);
 				continue;
 			}
 
-			/* Grab a work queue entry */
+			/* Grab a work queue entry. */
 			tab = ATGetQueueEntry(wqueue, part_rel);
 
 			/* Adjust constraint to match this partition */
@@ -13746,15 +13743,15 @@ ATExecAttachPartition(List **wqueue, Relation rel, PartitionCmd *cmd)
 				elog(ERROR, "unexpected whole-row reference found in partition key");
 
 			/* keep our lock until commit */
-			if (part_rel != attachRel)
+			if (part_rel != attachrel)
 				heap_close(part_rel, NoLock);
 		}
 	}
 
-	ObjectAddressSet(address, RelationRelationId, RelationGetRelid(attachRel));
+	ObjectAddressSet(address, RelationRelationId, RelationGetRelid(attachrel));
 
 	/* keep our lock until commit */
-	heap_close(attachRel, NoLock);
+	heap_close(attachrel, NoLock);
 
 	return address;
 }