static List *initFileRelationIds = NIL;
/*
- * This flag lets us optimize away work in AtEO(Sub)Xact_RelationCache().
+ * eoxact_list[] stores the OIDs of relations that (might) need AtEOXact
+ * cleanup work. This list intentionally has limited size; if it overflows,
+ * we fall back to scanning the whole hashtable. There is no value in a very
+ * large list because (1) at some point, a hash_seq_search scan is faster than
+ * retail lookups, and (2) the value of this is to reduce EOXact work for
+ * short transactions, which can't have dirtied all that many tables anyway.
+ * EOXactListAdd() does not bother to prevent duplicate list entries, so the
+ * cleanup processing must be idempotent.
*/
-static bool need_eoxact_work = false;
+#define MAX_EOXACT_LIST 32
+static Oid eoxact_list[MAX_EOXACT_LIST];
+static int eoxact_list_len = 0;
+static bool eoxact_list_overflowed = false;
+
+#define EOXactListAdd(rel) \
+ do { \
+ if (eoxact_list_len < MAX_EOXACT_LIST) \
+ eoxact_list[eoxact_list_len++] = (rel)->rd_id; \
+ else \
+ eoxact_list_overflowed = true; \
+ } while (0)
/*
static void RelationReloadIndexInfo(Relation relation);
static void RelationFlushRelation(Relation relation);
+static void AtEOXact_cleanup(Relation relation, bool isCommit);
+static void AtEOSubXact_cleanup(Relation relation, bool isCommit,
+ SubTransactionId mySubid, SubTransactionId parentSubid);
static bool load_relcache_init_file(bool shared);
static void write_relcache_init_file(bool shared);
static void write_item(const void *data, Size len, FILE *fp);
{
HASH_SEQ_STATUS status;
RelIdCacheEnt *idhentry;
+ int i;
/*
- * To speed up transaction exit, we want to avoid scanning the relcache
- * unless there is actually something for this routine to do. Other than
- * the debug-only Assert checks, most transactions don't create any work
- * for us to do here, so we keep a static flag that gets set if there is
- * anything to do. (Currently, this means either a relation is created in
- * the current xact, or one is given a new relfilenode, or an index list
- * is forced.) For simplicity, the flag remains set till end of top-level
- * transaction, even though we could clear it at subtransaction end in
- * some cases.
- */
- if (!need_eoxact_work
-#ifdef USE_ASSERT_CHECKING
- && !assert_enabled
-#endif
- )
- return;
-
- hash_seq_init(&status, RelationIdCache);
-
- while ((idhentry = (RelIdCacheEnt *) hash_seq_search(&status)) != NULL)
+ * Unless the eoxact_list[] overflowed, we only need to examine the rels
+ * listed in it. Otherwise fall back on a hash_seq_search scan.
+ *
+ * For simplicity, eoxact_list[] entries are not deleted till end of
+ * top-level transaction, even though we could remove them at
+ * subtransaction end in some cases, or remove relations from the list if
+ * they are cleared for other reasons. Therefore we should expect the
+ * case that list entries are not found in the hashtable; if not, there's
+ * nothing to do for them.
+ */
+ if (eoxact_list_overflowed)
{
- Relation relation = idhentry->reldesc;
+ hash_seq_init(&status, RelationIdCache);
+ while ((idhentry = (RelIdCacheEnt *) hash_seq_search(&status)) != NULL)
+ {
+ AtEOXact_cleanup(idhentry->reldesc, isCommit);
+ }
+ }
+ else
+ {
+ for (i = 0; i < eoxact_list_len; i++)
+ {
+ idhentry = (RelIdCacheEnt *) hash_search(RelationIdCache,
+ (void *) &eoxact_list[i],
+ HASH_FIND,
+ NULL);
+ if (idhentry != NULL)
+ AtEOXact_cleanup(idhentry->reldesc, isCommit);
+ }
+ }
+ /* Now we're out of the transaction and can clear the list */
+ eoxact_list_len = 0;
+ eoxact_list_overflowed = false;
+}
+
+/*
+ * AtEOXact_cleanup
+ *
+ * Clean up a single rel at main-transaction commit or abort
+ *
+ * NB: this processing must be idempotent, because EOXactListAdd() doesn't
+ * bother to prevent duplicate entries in eoxact_list[].
+ */
+static void
+AtEOXact_cleanup(Relation relation, bool isCommit)
+{
/*
* The relcache entry's ref count should be back to its normal
* not-in-a-transaction state: 0 unless it's nailed in cache.
* In bootstrap mode, this is NOT true, so don't check it --- the
* bootstrap code expects relations to stay open across start/commit
* transaction calls. (That seems bogus, but it's not worth fixing.)
+ *
+ * Note: ideally this check would be applied to every relcache entry,
+ * not just those that have eoxact work to do. But it's not worth
+ * forcing a scan of the whole relcache just for this. (Moreover,
+ * doing so would mean that assert-enabled testing never tests the
+ * hash_search code path above, which seems a bad idea.)
*/
#ifdef USE_ASSERT_CHECKING
if (!IsBootstrapProcessingMode())
else
{
RelationClearRelation(relation, false);
- continue;
+ return;
}
}
relation->rd_oidindex = InvalidOid;
relation->rd_indexvalid = 0;
}
- }
-
- /* Once done with the transaction, we can reset need_eoxact_work */
- need_eoxact_work = false;
}
/*
{
HASH_SEQ_STATUS status;
RelIdCacheEnt *idhentry;
+ int i;
/*
- * Skip the relcache scan if nothing to do --- see notes for
- * AtEOXact_RelationCache.
+ * Unless the eoxact_list[] overflowed, we only need to examine the rels
+ * listed in it. Otherwise fall back on a hash_seq_search scan. Same
+ * logic as in AtEOXact_RelationCache.
*/
- if (!need_eoxact_work)
- return;
-
- hash_seq_init(&status, RelationIdCache);
-
- while ((idhentry = (RelIdCacheEnt *) hash_seq_search(&status)) != NULL)
+ if (eoxact_list_overflowed)
{
- Relation relation = idhentry->reldesc;
+ hash_seq_init(&status, RelationIdCache);
+ while ((idhentry = (RelIdCacheEnt *) hash_seq_search(&status)) != NULL)
+ {
+ AtEOSubXact_cleanup(idhentry->reldesc, isCommit,
+ mySubid, parentSubid);
+ }
+ }
+ else
+ {
+ for (i = 0; i < eoxact_list_len; i++)
+ {
+ idhentry = (RelIdCacheEnt *) hash_search(RelationIdCache,
+ (void *) &eoxact_list[i],
+ HASH_FIND,
+ NULL);
+ if (idhentry != NULL)
+ AtEOSubXact_cleanup(idhentry->reldesc, isCommit,
+ mySubid, parentSubid);
+ }
+ }
+ /* Don't reset the list; we still need more cleanup later */
+}
+
+/*
+ * AtEOSubXact_cleanup
+ *
+ * Clean up a single rel at subtransaction commit or abort
+ *
+ * NB: this processing must be idempotent, because EOXactListAdd() doesn't
+ * bother to prevent duplicate entries in eoxact_list[].
+ */
+static void
+AtEOSubXact_cleanup(Relation relation, bool isCommit,
+ SubTransactionId mySubid, SubTransactionId parentSubid)
+{
/*
* Is it a relation created in the current subtransaction?
*
else
{
RelationClearRelation(relation, false);
- continue;
+ return;
}
}
relation->rd_oidindex = InvalidOid;
relation->rd_indexvalid = 0;
}
- }
}
rel->rd_createSubid = GetCurrentSubTransactionId();
rel->rd_newRelfilenodeSubid = InvalidSubTransactionId;
- /* must flag that we have rels created in this transaction */
- need_eoxact_work = true;
-
/*
* create a new tuple descriptor from the one passed in. We do this
* partly to copy it into the cache context, and partly because the new
*/
RelationCacheInsert(rel);
+ /*
+ * Flag relation as needing eoxact cleanup (to clear rd_createSubid).
+ * We can't do this before storing relid in it.
+ */
+ EOXactListAdd(rel);
+
/*
* done building relcache entry.
*/
* operations on the rel in the same transaction.
*/
relation->rd_newRelfilenodeSubid = GetCurrentSubTransactionId();
- /* ... and now we have eoxact cleanup work to do */
- need_eoxact_work = true;
+
+ /* Flag relation as needing eoxact cleanup (to remove the hint) */
+ EOXactListAdd(relation);
}
relation->rd_indexlist = indexIds;
relation->rd_oidindex = oidIndex;
relation->rd_indexvalid = 2; /* mark list as forced */
- /* must flag that we have a forced index list */
- need_eoxact_work = true;
+ /* Flag relation as needing eoxact cleanup (to reset the list) */
+ EOXactListAdd(relation);
}
/*
projects / postgresql.git / commitdiff