#include "parser/parse_type.h"
#include "rewrite/rewriteSupport.h"
#include "storage/lmgr.h"
+#include "storage/sinval.h"
#include "utils/acl.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
List *objname, bool missing_ok);
static ObjectAddress get_object_address_opcf(ObjectType objtype, List *objname,
List *objargs, bool missing_ok);
-static bool object_exists(ObjectAddress address);
static ObjectPropertyType *get_object_property_data(Oid class_id);
/*
Relation *relp, LOCKMODE lockmode, bool missing_ok)
{
ObjectAddress address;
+ ObjectAddress old_address = {InvalidOid, InvalidOid, 0};
Relation relation = NULL;
+ uint64 inval_count;
/* Some kind of lock must be taken. */
Assert(lockmode != NoLock);
- switch (objtype)
+ for (;;)
{
- case OBJECT_INDEX:
- case OBJECT_SEQUENCE:
- case OBJECT_TABLE:
- case OBJECT_VIEW:
- case OBJECT_FOREIGN_TABLE:
- address =
- get_relation_by_qualified_name(objtype, objname,
- &relation, lockmode,
- missing_ok);
- break;
- case OBJECT_COLUMN:
- address =
- get_object_address_attribute(objtype, objname,
- &relation, lockmode,
- missing_ok);
- break;
- case OBJECT_RULE:
- case OBJECT_TRIGGER:
- case OBJECT_CONSTRAINT:
- address = get_object_address_relobject(objtype, objname,
- &relation, missing_ok);
- break;
- case OBJECT_DATABASE:
- case OBJECT_EXTENSION:
- case OBJECT_TABLESPACE:
- case OBJECT_ROLE:
- case OBJECT_SCHEMA:
- case OBJECT_LANGUAGE:
- case OBJECT_FDW:
- case OBJECT_FOREIGN_SERVER:
- address = get_object_address_unqualified(objtype,
- objname, missing_ok);
- break;
- case OBJECT_TYPE:
- case OBJECT_DOMAIN:
- address = get_object_address_type(objtype, objname, missing_ok);
- break;
- case OBJECT_AGGREGATE:
- address.classId = ProcedureRelationId;
- address.objectId =
- LookupAggNameTypeNames(objname, objargs, missing_ok);
- address.objectSubId = 0;
- break;
- case OBJECT_FUNCTION:
- address.classId = ProcedureRelationId;
- address.objectId =
- LookupFuncNameTypeNames(objname, objargs, missing_ok);
- address.objectSubId = 0;
- break;
- case OBJECT_OPERATOR:
- Assert(list_length(objargs) == 2);
- address.classId = OperatorRelationId;
- address.objectId =
- LookupOperNameTypeNames(NULL, objname,
- (TypeName *) linitial(objargs),
- (TypeName *) lsecond(objargs),
- missing_ok, -1);
- address.objectSubId = 0;
- break;
- case OBJECT_COLLATION:
- address.classId = CollationRelationId;
- address.objectId = get_collation_oid(objname, missing_ok);
- address.objectSubId = 0;
- break;
- case OBJECT_CONVERSION:
- address.classId = ConversionRelationId;
- address.objectId = get_conversion_oid(objname, missing_ok);
- address.objectSubId = 0;
- break;
- case OBJECT_OPCLASS:
- case OBJECT_OPFAMILY:
- address = get_object_address_opcf(objtype,
- objname, objargs, missing_ok);
- break;
- case OBJECT_LARGEOBJECT:
- Assert(list_length(objname) == 1);
- address.classId = LargeObjectRelationId;
- address.objectId = oidparse(linitial(objname));
- address.objectSubId = 0;
- if (!LargeObjectExists(address.objectId))
- {
- if (!missing_ok)
- ereport(ERROR,
- (errcode(ERRCODE_UNDEFINED_OBJECT),
- errmsg("large object %u does not exist",
- address.objectId)));
- }
- break;
- case OBJECT_CAST:
- {
- TypeName *sourcetype = (TypeName *) linitial(objname);
- TypeName *targettype = (TypeName *) linitial(objargs);
- Oid sourcetypeid = typenameTypeId(NULL, sourcetype);
- Oid targettypeid = typenameTypeId(NULL, targettype);
+ /*
+ * Remember this value, so that, after looking up the object name
+ * and locking it, we can check whether any invalidation messages
+ * have been processed that might require a do-over.
+ */
+ inval_count = SharedInvalidMessageCounter;
- address.classId = CastRelationId;
+ /* Look up object address. */
+ switch (objtype)
+ {
+ case OBJECT_INDEX:
+ case OBJECT_SEQUENCE:
+ case OBJECT_TABLE:
+ case OBJECT_VIEW:
+ case OBJECT_FOREIGN_TABLE:
+ address =
+ get_relation_by_qualified_name(objtype, objname,
+ &relation, lockmode,
+ missing_ok);
+ break;
+ case OBJECT_COLUMN:
+ address =
+ get_object_address_attribute(objtype, objname,
+ &relation, lockmode,
+ missing_ok);
+ break;
+ case OBJECT_RULE:
+ case OBJECT_TRIGGER:
+ case OBJECT_CONSTRAINT:
+ address = get_object_address_relobject(objtype, objname,
+ &relation, missing_ok);
+ break;
+ case OBJECT_DATABASE:
+ case OBJECT_EXTENSION:
+ case OBJECT_TABLESPACE:
+ case OBJECT_ROLE:
+ case OBJECT_SCHEMA:
+ case OBJECT_LANGUAGE:
+ case OBJECT_FDW:
+ case OBJECT_FOREIGN_SERVER:
+ address = get_object_address_unqualified(objtype,
+ objname, missing_ok);
+ break;
+ case OBJECT_TYPE:
+ case OBJECT_DOMAIN:
+ address = get_object_address_type(objtype, objname, missing_ok);
+ break;
+ case OBJECT_AGGREGATE:
+ address.classId = ProcedureRelationId;
+ address.objectId =
+ LookupAggNameTypeNames(objname, objargs, missing_ok);
+ address.objectSubId = 0;
+ break;
+ case OBJECT_FUNCTION:
+ address.classId = ProcedureRelationId;
+ address.objectId =
+ LookupFuncNameTypeNames(objname, objargs, missing_ok);
+ address.objectSubId = 0;
+ break;
+ case OBJECT_OPERATOR:
+ Assert(list_length(objargs) == 2);
+ address.classId = OperatorRelationId;
address.objectId =
- get_cast_oid(sourcetypeid, targettypeid, missing_ok);
+ LookupOperNameTypeNames(NULL, objname,
+ (TypeName *) linitial(objargs),
+ (TypeName *) lsecond(objargs),
+ missing_ok, -1);
address.objectSubId = 0;
+ break;
+ case OBJECT_COLLATION:
+ address.classId = CollationRelationId;
+ address.objectId = get_collation_oid(objname, missing_ok);
+ address.objectSubId = 0;
+ break;
+ case OBJECT_CONVERSION:
+ address.classId = ConversionRelationId;
+ address.objectId = get_conversion_oid(objname, missing_ok);
+ address.objectSubId = 0;
+ break;
+ case OBJECT_OPCLASS:
+ case OBJECT_OPFAMILY:
+ address = get_object_address_opcf(objtype,
+ objname, objargs, missing_ok);
+ break;
+ case OBJECT_LARGEOBJECT:
+ Assert(list_length(objname) == 1);
+ address.classId = LargeObjectRelationId;
+ address.objectId = oidparse(linitial(objname));
+ address.objectSubId = 0;
+ if (!LargeObjectExists(address.objectId))
+ {
+ if (!missing_ok)
+ ereport(ERROR,
+ (errcode(ERRCODE_UNDEFINED_OBJECT),
+ errmsg("large object %u does not exist",
+ address.objectId)));
+ }
+ break;
+ case OBJECT_CAST:
+ {
+ TypeName *sourcetype = (TypeName *) linitial(objname);
+ TypeName *targettype = (TypeName *) linitial(objargs);
+ Oid sourcetypeid = typenameTypeId(NULL, sourcetype);
+ Oid targettypeid = typenameTypeId(NULL, targettype);
+
+ address.classId = CastRelationId;
+ address.objectId =
+ get_cast_oid(sourcetypeid, targettypeid, missing_ok);
+ address.objectSubId = 0;
+ }
+ break;
+ case OBJECT_TSPARSER:
+ address.classId = TSParserRelationId;
+ address.objectId = get_ts_parser_oid(objname, missing_ok);
+ address.objectSubId = 0;
+ break;
+ case OBJECT_TSDICTIONARY:
+ address.classId = TSDictionaryRelationId;
+ address.objectId = get_ts_dict_oid(objname, missing_ok);
+ address.objectSubId = 0;
+ break;
+ case OBJECT_TSTEMPLATE:
+ address.classId = TSTemplateRelationId;
+ address.objectId = get_ts_template_oid(objname, missing_ok);
+ address.objectSubId = 0;
+ break;
+ case OBJECT_TSCONFIGURATION:
+ address.classId = TSConfigRelationId;
+ address.objectId = get_ts_config_oid(objname, missing_ok);
+ address.objectSubId = 0;
+ break;
+ default:
+ elog(ERROR, "unrecognized objtype: %d", (int) objtype);
+ /* placate compiler, in case it thinks elog might return */
+ address.classId = InvalidOid;
+ address.objectId = InvalidOid;
+ address.objectSubId = 0;
+ }
+
+ /*
+ * If we could not find the supplied object, return without locking.
+ */
+ if (!OidIsValid(address.objectId))
+ {
+ Assert(missing_ok);
+ return address;
+ }
+
+ /*
+ * If we're retrying, see if we got the same answer as last time. If
+ * so, we're done; if not, we locked the wrong thing, so give up our
+ * lock.
+ */
+ if (OidIsValid(old_address.classId))
+ {
+ if (old_address.classId == address.classId
+ && old_address.objectId == address.objectId
+ && old_address.objectSubId == address.objectSubId)
+ break;
+ if (old_address.classId != RelationRelationId)
+ {
+ if (IsSharedRelation(old_address.classId))
+ UnlockSharedObject(old_address.classId,
+ old_address.objectId,
+ 0, lockmode);
+ else
+ UnlockDatabaseObject(old_address.classId,
+ old_address.objectId,
+ 0, lockmode);
}
- break;
- case OBJECT_TSPARSER:
- address.classId = TSParserRelationId;
- address.objectId = get_ts_parser_oid(objname, missing_ok);
- address.objectSubId = 0;
- break;
- case OBJECT_TSDICTIONARY:
- address.classId = TSDictionaryRelationId;
- address.objectId = get_ts_dict_oid(objname, missing_ok);
- address.objectSubId = 0;
- break;
- case OBJECT_TSTEMPLATE:
- address.classId = TSTemplateRelationId;
- address.objectId = get_ts_template_oid(objname, missing_ok);
- address.objectSubId = 0;
- break;
- case OBJECT_TSCONFIGURATION:
- address.classId = TSConfigRelationId;
- address.objectId = get_ts_config_oid(objname, missing_ok);
- address.objectSubId = 0;
- break;
- default:
- elog(ERROR, "unrecognized objtype: %d", (int) objtype);
- /* placate compiler, in case it thinks elog might return */
- address.classId = InvalidOid;
- address.objectId = InvalidOid;
- address.objectSubId = 0;
- }
+ }
- /*
- * If we could not find the supplied object, return without locking.
- */
- if (!OidIsValid(address.objectId))
- {
- Assert(missing_ok);
- return address;
- }
+ /*
+ * If we're dealing with a relation or attribute, then the relation is
+ * already locked. Otherwise, we lock it now.
+ */
+ if (address.classId != RelationRelationId)
+ {
+ if (IsSharedRelation(address.classId))
+ LockSharedObject(address.classId, address.objectId, 0,
+ lockmode);
+ else
+ LockDatabaseObject(address.classId, address.objectId, 0,
+ lockmode);
+ }
- /*
- * If we're dealing with a relation or attribute, then the relation is
- * already locked. If we're dealing with any other type of object, we
- * need to lock it and then verify that it still exists.
- */
- if (address.classId != RelationRelationId)
- {
- if (IsSharedRelation(address.classId))
- LockSharedObject(address.classId, address.objectId, 0, lockmode);
- else
- LockDatabaseObject(address.classId, address.objectId, 0, lockmode);
- /* Did it go away while we were waiting for the lock? */
- if (!object_exists(address))
- elog(ERROR, "cache lookup failed for class %u object %u subobj %d",
- address.classId, address.objectId, address.objectSubId);
+ /*
+ * At this point, we've resolved the name to an OID and locked the
+ * corresponding database object. However, it's possible that by the
+ * time we acquire the lock on the object, concurrent DDL has modified
+ * the database in such a way that the name we originally looked up
+ * no longer resolves to that OID.
+ *
+ * We can be certain that this isn't an issue if (a) no shared
+ * invalidation messages have been processed or (b) we've locked a
+ * relation somewhere along the line. All the relation name lookups
+ * in this module ultimately use RangeVarGetRelid() to acquire a
+ * relation lock, and that function protects against the same kinds of
+ * races we're worried about here. Even when operating on a
+ * constraint, rule, or trigger, we still acquire AccessShareLock on
+ * the relation, which is enough to freeze out any concurrent DDL.
+ *
+ * In all other cases, however, it's possible that the name we looked
+ * up no longer refers to the object we locked, so we retry the
+ * lookup and see whether we get the same answer.
+ */
+ if (inval_count == SharedInvalidMessageCounter || relation != NULL)
+ break;
+ old_address = address;
}
/* Return the object address and the relation. */
return address;
}
-/*
- * Test whether an object exists.
- */
-static bool
-object_exists(ObjectAddress address)
-{
- int cache = -1;
- Oid indexoid = InvalidOid;
- Relation rel;
- ScanKeyData skey[1];
- SysScanDesc sd;
- bool found;
- ObjectPropertyType *property;
-
- /* Sub-objects require special treatment. */
- if (address.objectSubId != 0)
- {
- HeapTuple atttup;
-
- /* Currently, attributes are the only sub-objects. */
- Assert(address.classId == RelationRelationId);
- atttup = SearchSysCache2(ATTNUM, ObjectIdGetDatum(address.objectId),
- Int16GetDatum(address.objectSubId));
- if (!HeapTupleIsValid(atttup))
- found = false;
- else
- {
- found = ((Form_pg_attribute) GETSTRUCT(atttup))->attisdropped;
- ReleaseSysCache(atttup);
- }
- return found;
- }
-
- /*
- * Weird backward compatibility hack: ObjectAddress notation uses
- * LargeObjectRelationId for large objects, but since PostgreSQL
- * 9.0, the relevant catalog is actually LargeObjectMetadataRelationId.
- */
- if (address.classId == LargeObjectRelationId)
- address.classId = LargeObjectMetadataRelationId;
-
- /*
- * For object types that have a relevant syscache, we use it; for
- * everything else, we'll have to do an index-scan.
- */
- property = get_object_property_data(address.classId);
- cache = property->oid_catcache_id;
- indexoid = property->oid_index_oid;
-
- /* Found a syscache? */
- if (cache != -1)
- return SearchSysCacheExists1(cache, ObjectIdGetDatum(address.objectId));
-
- /* No syscache, so examine the table directly. */
- Assert(OidIsValid(indexoid));
- ScanKeyInit(&skey[0],
- ObjectIdAttributeNumber,
- BTEqualStrategyNumber, F_OIDEQ,
- ObjectIdGetDatum(address.objectId));
- rel = heap_open(address.classId, AccessShareLock);
- sd = systable_beginscan(rel, indexoid, true, SnapshotNow, 1, skey);
- found = HeapTupleIsValid(systable_getnext(sd));
- systable_endscan(sd);
- heap_close(rel, AccessShareLock);
- return found;
-}
-
/*
* Check ownership of an object previously identified by get_object_address.
*/
projects / postgresql / commitdiff