Re: Unify drop-by-OID functions - Mailing list pgsql-hackers

Very good.

I can suggest improvements?

1. In case Object is cached, delay open_table until the last moment, for the row to be blocked as little as possible and close the table as quickly as possible.

2. In case Object is cached and the tuple is invalid, do not open table.

3. Otherwise, is it possible to call systable_endscan, after table_close?

I think that lock resources, for as little time as possible, it is an advantage..

+static void
+DropGenericById(const ObjectAddress *object)
+{
+ int cacheId;
+ Relation rel;
+ HeapTuple tup;
+
+ cacheId = get_object_catcache_oid(object->classId);
+
+ /*
+ * Use the system cache for the oid column, if one exists.
+ */
+ if (cacheId >= 0)
+ {
+ tup = SearchSysCache1(cacheId, ObjectIdGetDatum(object->objectId));
+ if (!HeapTupleIsValid(tup))
+ elog(ERROR, "cache lookup failed for %s entry %u",
+ get_object_class_descr(object->classId), object->objectId);
+
+        rel = table_open(object->classId, RowExclusiveLock);
+ CatalogTupleDelete(rel, &tup->t_self);
+        table_close(rel, RowExclusiveLock);
+
+ ReleaseSysCache(tup);
+ }
+ else
+ {
+ ScanKeyData skey[1];
+ SysScanDesc scan;
+
+ ScanKeyInit(&skey[0],
+ get_object_attnum_oid(object->classId),
+ BTEqualStrategyNumber, F_OIDEQ,
+ ObjectIdGetDatum(object->objectId));
+
+        rel = table_open(object->classId, RowExclusiveLock);
+ scan = systable_beginscan(rel, get_object_oid_index(object->classId), true,
+  NULL, 1, skey);
+
+ /* we expect exactly one match */
+ tup = systable_getnext(scan);
+ if (!HeapTupleIsValid(tup))
+ elog(ERROR, "could not find tuple for class %u entry %u",
+ object->classId, object->objectId);
+
+ CatalogTupleDelete(rel, &tup->t_self);
+ systable_endscan(scan);
+        table_close(rel, RowExclusiveLock);
+ }
+}
+

regards,

Ranier Vilela