diff options
Diffstat (limited to 'src/backend/access/heap/heapam.c')
| -rw-r--r-- | src/backend/access/heap/heapam.c | 72 |
1 files changed, 71 insertions, 1 deletions
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c index 0fd61fe9cec..79b92b329e1 100644 --- a/src/backend/access/heap/heapam.c +++ b/src/backend/access/heap/heapam.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/access/heap/heapam.c,v 1.264 2008/09/30 10:52:10 heikki Exp $ + * $PostgreSQL: pgsql/src/backend/access/heap/heapam.c,v 1.265 2008/10/08 01:14:44 tgl Exp $ * * * INTERFACE ROUTINES @@ -1017,6 +1017,45 @@ relation_openrv(const RangeVar *relation, LOCKMODE lockmode) } /* ---------------- + * try_relation_openrv - open any relation specified by a RangeVar + * + * Same as relation_openrv, but return NULL instead of failing for + * relation-not-found. (Note that some other causes, such as + * permissions problems, will still result in an ereport.) + * ---------------- + */ +Relation +try_relation_openrv(const RangeVar *relation, LOCKMODE lockmode) +{ + Oid relOid; + + /* + * Check for shared-cache-inval messages before trying to open the + * relation. This is needed to cover the case where the name identifies a + * rel that has been dropped and recreated since the start of our + * transaction: if we don't flush the old syscache entry then we'll latch + * onto that entry and suffer an error when we do RelationIdGetRelation. + * Note that relation_open does not need to do this, since a relation's + * OID never changes. + * + * We skip this if asked for NoLock, on the assumption that the caller has + * already ensured some appropriate lock is held. + */ + if (lockmode != NoLock) + AcceptInvalidationMessages(); + + /* Look up the appropriate relation using namespace search */ + relOid = RangeVarGetRelid(relation, true); + + /* Return NULL on not-found */ + if (!OidIsValid(relOid)) + return NULL; + + /* Let relation_open do the rest */ + return relation_open(relOid, lockmode); +} + +/* ---------------- * relation_close - close any relation * * If lockmode is not "NoLock", we then release the specified lock. @@ -1097,6 +1136,37 @@ heap_openrv(const RangeVar *relation, LOCKMODE lockmode) return r; } +/* ---------------- + * try_heap_openrv - open a heap relation specified + * by a RangeVar node + * + * As above, but return NULL instead of failing for relation-not-found. + * ---------------- + */ +Relation +try_heap_openrv(const RangeVar *relation, LOCKMODE lockmode) +{ + Relation r; + + r = try_relation_openrv(relation, lockmode); + + if (r) + { + if (r->rd_rel->relkind == RELKIND_INDEX) + ereport(ERROR, + (errcode(ERRCODE_WRONG_OBJECT_TYPE), + errmsg("\"%s\" is an index", + RelationGetRelationName(r)))); + else if (r->rd_rel->relkind == RELKIND_COMPOSITE_TYPE) + ereport(ERROR, + (errcode(ERRCODE_WRONG_OBJECT_TYPE), + errmsg("\"%s\" is a composite type", + RelationGetRelationName(r)))); + } + + return r; +} + /* ---------------- * heap_beginscan - begin relation scan |