diff --git a/contrib/tcn/tcn.c b/contrib/tcn/tcn.c
index 314632dd893..2f0d3d6639d 100644
--- a/contrib/tcn/tcn.c
+++ b/contrib/tcn/tcn.c
@@ -140,8 +140,8 @@ triggered_change_notification(PG_FUNCTION_ARGS)
if (!HeapTupleIsValid(indexTuple)) /* should not happen */
elog(ERROR, "cache lookup failed for index %u", indexoid);
index = (Form_pg_index) GETSTRUCT(indexTuple);
- /* we're only interested if it is the primary key */
- if (index->indisprimary)
+ /* we're only interested if it is the primary key and valid */
+ if (index->indisprimary && IndexIsValid(index))
{
int numatts = index->indnatts;
diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index 5f95046746f..4851ae198f4 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -3389,11 +3389,12 @@
bool
- If true, the index is currently valid for queries. False means the
+ If both this flag and indisready are
+ true, the index is currently valid for queries. False means the
index is possibly incomplete: it must still be modified by
INSERT/UPDATE operations, but it cannot safely
be used for queries. If it is unique, the uniqueness property is not
- true either.
+ guaranteed true either.
diff --git a/doc/src/sgml/ref/drop_index.sgml b/doc/src/sgml/ref/drop_index.sgml
index 343f7aca003..98fd9c966c3 100644
--- a/doc/src/sgml/ref/drop_index.sgml
+++ b/doc/src/sgml/ref/drop_index.sgml
@@ -40,34 +40,33 @@ DROP INDEX [ CONCURRENTLY ] [ IF EXISTS ] name
- IF EXISTS
+ CONCURRENTLY
- Do not throw an error if the index does not exist. A notice is issued
- in this case.
+ Drop the index without locking out concurrent selects, inserts, updates,
+ and deletes on the index's table. A normal DROP INDEX
+ acquires exclusive lock on the table, blocking other accesses until the
+ index drop can be completed. With this option, the command instead
+ waits until conflicting transactions have completed.
+
+
+ There are several caveats to be aware of when using this option.
+ Only one index name can be specified, and the CASCADE option
+ is not supported. (Thus, an index that supports a UNIQUE or
+ PRIMARY KEY constraint cannot be dropped this way.)
+ Also, regular DROP INDEX commands can be
+ performed within a transaction block, but
+ DROP INDEX CONCURRENTLY cannot.
- CONCURRENTLY
+ IF EXISTS
- When this option is used, PostgreSQL will drop the
- index without taking any locks that prevent concurrent selects, inserts,
- updates, or deletes on the table; whereas a standard index drop
- waits for a lock that locks out everything on the table until it's done.
- Concurrent drop index is a two stage process. First, we mark the index
- both invalid and not ready then commit the change. Next we wait until
- there are no users locking the table who can see the index.
-
-
- There are several caveats to be aware of when using this option.
- Only one index name can be specified if the CONCURRENTLY
- parameter is specified. Regular DROP INDEX command can be
- performed within a transaction block, but
- DROP INDEX CONCURRENTLY cannot.
- The CASCADE option is not supported when dropping an index concurrently.
+ Do not throw an error if the index does not exist. A notice is issued
+ in this case.
diff --git a/src/backend/access/heap/README.HOT b/src/backend/access/heap/README.HOT
index f12cad44e56..df1d21a51bf 100644
--- a/src/backend/access/heap/README.HOT
+++ b/src/backend/access/heap/README.HOT
@@ -386,6 +386,37 @@ from the index, as well as ensuring that no one can see any inconsistent
rows in a broken HOT chain (the first condition is stronger than the
second). Finally, we can mark the index valid for searches.
+Note that we do not need to set pg_index.indcheckxmin in this code path,
+because we have outwaited any transactions that would need to avoid using
+the index. (indcheckxmin is only needed because non-concurrent CREATE
+INDEX doesn't want to wait; its stronger lock would create too much risk of
+deadlock if it did.)
+
+
+DROP INDEX CONCURRENTLY
+-----------------------
+
+DROP INDEX CONCURRENTLY is sort of the reverse sequence of CREATE INDEX
+CONCURRENTLY. We first mark the index as not indisvalid, and then wait for
+any transactions that could be using it in queries to end. (During this
+time, index updates must still be performed as normal, since such
+transactions might expect freshly inserted tuples to be findable.)
+Then, we clear indisready and set indisvalid, and again wait for transactions
+that could be updating the index to end. Finally we can drop the index
+normally (though taking only ShareUpdateExclusiveLock on its parent table).
+
+The reason we need the unobvious choice of setting indisvalid is that after
+the second wait step begins, we don't want transactions to be touching the
+index at all; otherwise they might suffer errors if the DROP finally
+commits while they are reading catalog entries for the index. If we set
+both indisvalid and indisready false, this state would be indistinguishable
+from the first stage of CREATE INDEX CONCURRENTLY --- but in that state, we
+*do* want transactions to examine the index, since they must consider it in
+HOT-safety checks. So we use this nonsensical combination instead. Note
+this means that places that might otherwise test just indisvalid must now
+test both flags. If possible, use the IndexIsValid() macro instead.
+(9.3 and later have a saner representation for this state.)
+
Limitations and Restrictions
----------------------------
diff --git a/src/backend/catalog/dependency.c b/src/backend/catalog/dependency.c
index d6145f9fe04..79107e4841c 100644
--- a/src/backend/catalog/dependency.c
+++ b/src/backend/catalog/dependency.c
@@ -991,7 +991,6 @@ deleteOneObject(const ObjectAddress *object, Relation depRel, int flags)
int nkeys;
SysScanDesc scan;
HeapTuple tup;
- Oid depRelOid = depRel->rd_id;
/* DROP hook of the objects being removed */
if (object_access_hook)
@@ -1004,9 +1003,9 @@ deleteOneObject(const ObjectAddress *object, Relation depRel, int flags)
}
/*
- * Close depRel if we are doing a drop concurrently. The individual
- * deletion has to commit the transaction and we don't want dangling
- * references.
+ * Close depRel if we are doing a drop concurrently. The object deletion
+ * subroutine will commit the current transaction, so we can't keep the
+ * relation open across doDeletion().
*/
if (flags & PERFORM_DELETION_CONCURRENTLY)
heap_close(depRel, RowExclusiveLock);
@@ -1014,24 +1013,23 @@ deleteOneObject(const ObjectAddress *object, Relation depRel, int flags)
/*
* Delete the object itself, in an object-type-dependent way.
*
- * Do this before removing outgoing dependencies as deletions can be
- * happening in concurrent mode. That will only happen for a single object
- * at once and if so the object will be invalidated inside a separate
- * transaction and only dropped inside a transaction thats in-progress when
- * doDeletion returns. This way no observer can see dangling dependency
- * entries.
+ * We used to do this after removing the outgoing dependency links, but it
+ * seems just as reasonable to do it beforehand. In the concurrent case
+ * we *must* do it in this order, because we can't make any transactional
+ * updates before calling doDeletion() --- they'd get committed right
+ * away, which is not cool if the deletion then fails.
*/
doDeletion(object, flags);
/*
- * Reopen depRel if we closed it before
+ * Reopen depRel if we closed it above
*/
if (flags & PERFORM_DELETION_CONCURRENTLY)
- depRel = heap_open(depRelOid, RowExclusiveLock);
+ depRel = heap_open(DependRelationId, RowExclusiveLock);
/*
- * Then remove any pg_depend records that link from this object to
- * others. (Any records linking to this object should be gone already.)
+ * Now remove any pg_depend records that link from this object to others.
+ * (Any records linking to this object should be gone already.)
*
* When dropping a whole object (subId = 0), remove all pg_depend records
* for its sub-objects too.
@@ -1250,15 +1248,23 @@ AcquireDeletionLock(const ObjectAddress *object, int flags)
{
if (object->classId == RelationRelationId)
{
+ /*
+ * In DROP INDEX CONCURRENTLY, take only ShareUpdateExclusiveLock on
+ * the index for the moment. index_drop() will promote the lock once
+ * it's safe to do so. In all other cases we need full exclusive
+ * lock.
+ */
if (flags & PERFORM_DELETION_CONCURRENTLY)
LockRelationOid(object->objectId, ShareUpdateExclusiveLock);
else
LockRelationOid(object->objectId, AccessExclusiveLock);
}
else
+ {
/* assume we should lock the whole object not a sub-object */
LockDatabaseObject(object->classId, object->objectId, 0,
AccessExclusiveLock);
+ }
}
/*
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index dd2408952b4..7d6346a6c85 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -124,6 +124,10 @@ static void ResetReindexPending(void);
* See whether an existing relation has a primary key.
*
* Caller must have suitable lock on the relation.
+ *
+ * Note: we intentionally do not check IndexIsValid here; that's because this
+ * is used to enforce the rule that there can be only one indisprimary index,
+ * and we want that to be true even if said index is invalid.
*/
static bool
relationHasPrimaryKey(Relation rel)
@@ -1247,8 +1251,9 @@ index_constraint_create(Relation heapRelation,
* Note: since this is a transactional update, it's unsafe against
* concurrent SnapshotNow scans of pg_index. When making an existing
* index into a constraint, caller must have a table lock that prevents
- * concurrent table updates, and there is a risk that concurrent readers
- * of the table will miss seeing this index at all.
+ * concurrent table updates; if it's less than a full exclusive lock,
+ * there is a risk that concurrent readers of the table will miss seeing
+ * this index at all.
*/
if (update_pgindex && (mark_as_primary || deferrable))
{
@@ -1306,8 +1311,8 @@ index_drop(Oid indexId, bool concurrent)
LockRelId heaprelid,
indexrelid;
LOCKTAG heaplocktag;
+ LOCKMODE lockmode;
VirtualTransactionId *old_lockholders;
- Form_pg_index indexForm;
/*
* To drop an index safely, we must grab exclusive lock on its parent
@@ -1319,105 +1324,101 @@ index_drop(Oid indexId, bool concurrent)
* proceeding until we commit and send out a shared-cache-inval notice
* that will make them update their index lists.
*
- * In the concurrent case we make sure that nobody can be looking at the
- * indexes by dropping the index in multiple steps, so we don't need a full
- * AccessExclusiveLock yet.
- *
- * All predicate locks on the index are about to be made invalid. Promote
- * them to relation locks on the heap. For correctness the index must not
- * be seen with indisvalid = true during query planning after the move
- * starts, so that the index will not be used for a scan after the
- * predicate lock move, as this could create new predicate locks on the
- * index which would not ensure a heap relation lock. Also, the index must
- * not be seen during execution of a heap tuple insert with indisready =
- * false before the move is complete, since the conflict with the
- * predicate lock on the index gap could be missed before the lock on the
- * heap relation is in place to detect a conflict based on the heap tuple
- * insert.
+ * In the concurrent case we avoid this requirement by disabling index use
+ * in multiple steps and waiting out any transactions that might be using
+ * the index, so we don't need exclusive lock on the parent table. Instead
+ * we take ShareUpdateExclusiveLock, to ensure that two sessions aren't
+ * doing CREATE/DROP INDEX CONCURRENTLY on the same index. (We will get
+ * AccessExclusiveLock on the index below, once we're sure nobody else is
+ * using it.)
*/
heapId = IndexGetRelation(indexId, false);
- if (concurrent)
- {
- userHeapRelation = heap_open(heapId, ShareUpdateExclusiveLock);
- userIndexRelation = index_open(indexId, ShareUpdateExclusiveLock);
- }
- else
- {
- userHeapRelation = heap_open(heapId, AccessExclusiveLock);
- userIndexRelation = index_open(indexId, AccessExclusiveLock);
- }
+ lockmode = concurrent ? ShareUpdateExclusiveLock : AccessExclusiveLock;
+ userHeapRelation = heap_open(heapId, lockmode);
+ userIndexRelation = index_open(indexId, lockmode);
/*
- * We might still have open queries using it in our own session.
+ * We might still have open queries using it in our own session, which the
+ * above locking won't prevent, so test explicitly.
*/
CheckTableNotInUse(userIndexRelation, "DROP INDEX");
/*
- * Drop Index concurrently is similar in many ways to creating an index
- * concurrently, so some actions are similar to DefineIndex() just in the
- * reverse order.
+ * Drop Index Concurrently is more or less the reverse process of Create
+ * Index Concurrently.
*
* First we unset indisvalid so queries starting afterwards don't use the
- * index to answer queries anymore. We have to keep indisready = true
- * so transactions that are still scanning the index can continue to
- * see valid index contents. E.g. when they are using READ COMMITTED mode,
- * and another transactions that started later commits makes changes and
- * commits, they need to see those new tuples in the index.
+ * index to answer queries anymore. We have to keep indisready = true so
+ * transactions that are still scanning the index can continue to see
+ * valid index contents. For instance, if they are using READ COMMITTED
+ * mode, and another transaction makes changes and commits, they need to
+ * see those new tuples in the index.
*
- * After all transactions that could possibly have used it for queries
- * ended we can unset indisready and wait till nobody could be updating it
- * anymore.
+ * After all transactions that could possibly have used the index for
+ * queries end, we can unset indisready and set indisvalid, then wait till
+ * nobody could be touching it anymore. (Note: we use this illogical
+ * combination because this state must be distinct from the initial state
+ * during CREATE INDEX CONCURRENTLY, which has indisready and indisvalid
+ * both false. That's because in that state, transactions must examine
+ * the index for HOT-safety decisions, while in this state we don't want
+ * them to open it at all.)
+ *
+ * Since all predicate locks on the index are about to be made invalid, we
+ * must promote them to predicate locks on the heap. In the
+ * non-concurrent case we can just do that now. In the concurrent case
+ * it's a bit trickier. The predicate locks must be moved when there are
+ * no index scans in progress on the index and no more can subsequently
+ * start, so that no new predicate locks can be made on the index. Also,
+ * they must be moved before heap inserts stop maintaining the index, else
+ * the conflict with the predicate lock on the index gap could be missed
+ * before the lock on the heap relation is in place to detect a conflict
+ * based on the heap tuple insert.
*/
if (concurrent)
{
/*
- * Mark index invalid by updating its pg_index entry
- *
- * Don't Assert(indexForm->indisvalid) because we may be trying to
- * clear up after an error when trying to create an index which left
- * the index invalid
+ * We must commit our transaction in order to make the first pg_index
+ * state update visible to other sessions. If the DROP machinery has
+ * already performed any other actions (removal of other objects,
+ * pg_depend entries, etc), the commit would make those actions
+ * permanent, which would leave us with inconsistent catalog state if
+ * we fail partway through the following sequence. Since DROP INDEX
+ * CONCURRENTLY is restricted to dropping just one index that has no
+ * dependencies, we should get here before anything's been done ---
+ * but let's check that to be sure. We can verify that the current
+ * transaction has not executed any transactional updates by checking
+ * that no XID has been assigned.
*/
- indexRelation = heap_open(IndexRelationId, RowExclusiveLock);
-
- tuple = SearchSysCacheCopy1(INDEXRELID,
- ObjectIdGetDatum(indexId));
- if (!HeapTupleIsValid(tuple))
- elog(ERROR, "cache lookup failed for index %u", indexId);
- indexForm = (Form_pg_index) GETSTRUCT(tuple);
+ if (GetTopTransactionIdIfAny() != InvalidTransactionId)
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("DROP INDEX CONCURRENTLY must be first action in transaction")));
/*
- * If indisready == true we leave it set so the index still gets
- * maintained by pre-existing transactions. We only need to ensure
- * that indisvalid is false.
+ * Mark index invalid by updating its pg_index entry
*/
- if (indexForm->indisvalid)
- {
- indexForm->indisvalid = false; /* make unusable for new queries */
+ index_set_state_flags(indexId, INDEX_DROP_CLEAR_VALID);
- simple_heap_update(indexRelation, &tuple->t_self, tuple);
- CatalogUpdateIndexes(indexRelation, tuple);
- }
-
- heap_close(indexRelation, RowExclusiveLock);
+ /*
+ * Invalidate the relcache for the table, so that after this commit
+ * all sessions will refresh any cached plans that might reference the
+ * index.
+ */
+ CacheInvalidateRelcache(userHeapRelation);
/* save lockrelid and locktag for below, then close but keep locks */
heaprelid = userHeapRelation->rd_lockInfo.lockRelId;
SET_LOCKTAG_RELATION(heaplocktag, heaprelid.dbId, heaprelid.relId);
- heap_close(userHeapRelation, NoLock);
-
indexrelid = userIndexRelation->rd_lockInfo.lockRelId;
+
+ heap_close(userHeapRelation, NoLock);
index_close(userIndexRelation, NoLock);
/*
- * For a concurrent drop, it's important to make the catalog entries
- * visible to other transactions before we drop the index. The index
- * will be marked not indisvalid, so that no one else tries to use it
- * for queries.
- *
- * We must commit our current transaction so that the index update
- * becomes visible; then start another. Note that all the data
- * structures we just built are lost in the commit. The only data we
- * keep past here are the relation IDs.
+ * We must commit our current transaction so that the indisvalid
+ * update becomes visible to other transactions; then start another.
+ * Note that any previously-built data structures are lost in the
+ * commit. The only data we keep past here are the relation IDs.
*
* Before committing, get a session-level lock on the table, to ensure
* that neither it nor the index can be dropped before we finish. This
@@ -1432,13 +1433,13 @@ index_drop(Oid indexId, bool concurrent)
StartTransactionCommand();
/*
- * Now we must wait until no running transaction could have the table
- * open with the old list of indexes. To do this, inquire which xacts
- * currently would conflict with AccessExclusiveLock on the table --
- * ie, which ones have a lock of any kind on the table. Then wait for
- * each of these xacts to commit or abort. Note we do not need to
- * worry about xacts that open the table for writing after this point;
- * they will see the index as invalid when they open the relation.
+ * Now we must wait until no running transaction could be using the
+ * index for a query. To do this, inquire which xacts currently would
+ * conflict with AccessExclusiveLock on the table -- ie, which ones
+ * have a lock of any kind on the table. Then wait for each of these
+ * xacts to commit or abort. Note we do not need to worry about xacts
+ * that open the table for reading after this point; they will see the
+ * index as invalid when they open the relation.
*
* Note: the reason we use actual lock acquisition here, rather than
* just checking the ProcArray and sleeping, is that deadlock is
@@ -1469,28 +1470,19 @@ index_drop(Oid indexId, bool concurrent)
TransferPredicateLocksToHeapRelation(userIndexRelation);
/*
- * Now we are sure that nobody uses the index for queries, they just
- * might have it opened for updating it. So now we can unset
- * indisready and wait till nobody could update the index anymore.
+ * Now we are sure that nobody uses the index for queries; they just
+ * might have it open for updating it. So now we can unset indisready
+ * and set indisvalid, then wait till nobody could be using it at all
+ * anymore.
*/
- indexRelation = heap_open(IndexRelationId, RowExclusiveLock);
+ index_set_state_flags(indexId, INDEX_DROP_SET_DEAD);
- tuple = SearchSysCacheCopy1(INDEXRELID,
- ObjectIdGetDatum(indexId));
- if (!HeapTupleIsValid(tuple))
- elog(ERROR, "cache lookup failed for index %u", indexId);
- indexForm = (Form_pg_index) GETSTRUCT(tuple);
-
- Assert(indexForm->indisvalid == false);
- if (indexForm->indisready)
- {
- indexForm->indisready = false; /* don't update index anymore */
-
- simple_heap_update(indexRelation, &tuple->t_self, tuple);
- CatalogUpdateIndexes(indexRelation, tuple);
- }
-
- heap_close(indexRelation, RowExclusiveLock);
+ /*
+ * Invalidate the relcache for the table, so that after this commit
+ * all sessions will refresh the table's index list. Forgetting just
+ * the index's relcache entry is not enough.
+ */
+ CacheInvalidateRelcache(userHeapRelation);
/*
* Close the relations again, though still holding session lock.
@@ -1499,23 +1491,15 @@ index_drop(Oid indexId, bool concurrent)
index_close(userIndexRelation, NoLock);
/*
- * Invalidate the relcache for the table, so that after this
- * transaction we will refresh the index list. Forgetting just the
- * index is not enough.
- */
- CacheInvalidateRelcache(userHeapRelation);
-
- /*
- * Just as with indisvalid = false we need to make sure indisready
- * is false is visible for everyone.
+ * Again, commit the transaction to make the pg_index update visible
+ * to other sessions.
*/
CommitTransactionCommand();
StartTransactionCommand();
/*
- * Wait till everyone that saw indisready = true finished so we can
- * finally really remove the index. The logic here is the same as
- * above.
+ * Wait till every transaction that saw the old index state has
+ * finished. The logic here is the same as above.
*/
old_lockholders = GetLockConflicts(&heaplocktag, AccessExclusiveLock);
@@ -1536,7 +1520,10 @@ index_drop(Oid indexId, bool concurrent)
userIndexRelation = index_open(indexId, AccessExclusiveLock);
}
else
+ {
+ /* Not concurrent, so just transfer predicate locks and we're good */
TransferPredicateLocksToHeapRelation(userIndexRelation);
+ }
/*
* Schedule physical removal of the files
@@ -1590,7 +1577,8 @@ index_drop(Oid indexId, bool concurrent)
* of relhasindex (the next VACUUM will fix it if necessary). So there is
* no need to update the pg_class tuple for the owning relation. But we
* must send out a shared-cache-inval notice on the owning relation to
- * ensure other backends update their relcache lists of indexes.
+ * ensure other backends update their relcache lists of indexes. (In the
+ * concurrent case, this is redundant but harmless.)
*/
CacheInvalidateRelcache(userHeapRelation);
@@ -1666,7 +1654,7 @@ BuildIndexInfo(Relation index)
/* other info */
ii->ii_Unique = indexStruct->indisunique;
- ii->ii_ReadyForInserts = indexStruct->indisready;
+ ii->ii_ReadyForInserts = IndexIsReady(indexStruct);
/* initialize index-build state to default */
ii->ii_Concurrent = false;
@@ -2024,8 +2012,20 @@ index_build(Relation heapRelation,
* index's usability horizon. Moreover, we *must not* try to change the
* index's pg_index entry while reindexing pg_index itself, and this
* optimization nicely prevents that.
+ *
+ * We also need not set indcheckxmin during a concurrent index build,
+ * because we won't set indisvalid true until all transactions that care
+ * about the broken HOT chains are gone.
+ *
+ * Therefore, this code path can only be taken during non-concurrent
+ * CREATE INDEX. Thus the fact that heap_update will set the pg_index
+ * tuple's xmin doesn't matter, because that tuple was created in the
+ * current transaction anyway. That also means we don't need to worry
+ * about any concurrent readers of the tuple; no other transaction can see
+ * it yet.
*/
- if (indexInfo->ii_BrokenHotChain && !isreindex)
+ if (indexInfo->ii_BrokenHotChain && !isreindex &&
+ !indexInfo->ii_Concurrent)
{
Oid indexId = RelationGetRelid(indexRelation);
Relation pg_index;
@@ -2988,6 +2988,95 @@ validate_index_heapscan(Relation heapRelation,
}
+/*
+ * index_set_state_flags - adjust pg_index state flags
+ *
+ * This is used during CREATE/DROP INDEX CONCURRENTLY to adjust the pg_index
+ * flags that denote the index's state. We must use an in-place update of
+ * the pg_index tuple, because we do not have exclusive lock on the parent
+ * table and so other sessions might concurrently be doing SnapshotNow scans
+ * of pg_index to identify the table's indexes. A transactional update would
+ * risk somebody not seeing the index at all. Because the update is not
+ * transactional and will not roll back on error, this must only be used as
+ * the last step in a transaction that has not made any transactional catalog
+ * updates!
+ *
+ * Note that heap_inplace_update does send a cache inval message for the
+ * tuple, so other sessions will hear about the update as soon as we commit.
+ */
+void
+index_set_state_flags(Oid indexId, IndexStateFlagsAction action)
+{
+ Relation pg_index;
+ HeapTuple indexTuple;
+ Form_pg_index indexForm;
+
+ /* Assert that current xact hasn't done any transactional updates */
+ Assert(GetTopTransactionIdIfAny() == InvalidTransactionId);
+
+ /* Open pg_index and fetch a writable copy of the index's tuple */
+ pg_index = heap_open(IndexRelationId, RowExclusiveLock);
+
+ indexTuple = SearchSysCacheCopy1(INDEXRELID,
+ ObjectIdGetDatum(indexId));
+ if (!HeapTupleIsValid(indexTuple))
+ elog(ERROR, "cache lookup failed for index %u", indexId);
+ indexForm = (Form_pg_index) GETSTRUCT(indexTuple);
+
+ /* Perform the requested state change on the copy */
+ switch (action)
+ {
+ case INDEX_CREATE_SET_READY:
+ /* Set indisready during a CREATE INDEX CONCURRENTLY sequence */
+ Assert(!indexForm->indisready);
+ Assert(!indexForm->indisvalid);
+ indexForm->indisready = true;
+ break;
+ case INDEX_CREATE_SET_VALID:
+ /* Set indisvalid during a CREATE INDEX CONCURRENTLY sequence */
+ Assert(indexForm->indisready);
+ Assert(!indexForm->indisvalid);
+ indexForm->indisvalid = true;
+ break;
+ case INDEX_DROP_CLEAR_VALID:
+
+ /*
+ * Clear indisvalid during a DROP INDEX CONCURRENTLY sequence
+ *
+ * If indisready == true we leave it set so the index still gets
+ * maintained by active transactions. We only need to ensure that
+ * indisvalid is false. (We don't assert that either is initially
+ * true, though, since we want to be able to retry a DROP INDEX
+ * CONCURRENTLY that failed partway through.)
+ *
+ * Note: the CLUSTER logic assumes that indisclustered cannot be
+ * set on any invalid index, so clear that flag too.
+ */
+ indexForm->indisvalid = false;
+ indexForm->indisclustered = false;
+ break;
+ case INDEX_DROP_SET_DEAD:
+
+ /*
+ * Clear indisready during DROP INDEX CONCURRENTLY
+ *
+ * We clear indisready and set indisvalid, because we not only
+ * want to stop updates, we want to prevent sessions from touching
+ * the index at all. See README.HOT.
+ */
+ Assert(!indexForm->indisvalid);
+ indexForm->indisready = false;
+ indexForm->indisvalid = true;
+ break;
+ }
+
+ /* ... and write it back in-place */
+ heap_inplace_update(pg_index, indexTuple);
+
+ heap_close(pg_index, RowExclusiveLock);
+}
+
+
/*
* IndexGetRelation: given an index's relation OID, get the OID of the
* relation it is an index on. Uses the system cache.
@@ -3021,12 +3110,9 @@ void
reindex_index(Oid indexId, bool skip_constraint_checks)
{
Relation iRel,
- heapRelation,
- pg_index;
+ heapRelation;
Oid heapId;
IndexInfo *indexInfo;
- HeapTuple indexTuple;
- Form_pg_index indexForm;
volatile bool skipped_constraint = false;
/*
@@ -3099,32 +3185,48 @@ reindex_index(Oid indexId, bool skip_constraint_checks)
ResetReindexProcessing();
/*
- * If the index is marked invalid or not ready (ie, it's from a failed
- * CREATE INDEX CONCURRENTLY), and we didn't skip a uniqueness check, we
- * can now mark it valid. This allows REINDEX to be used to clean up in
- * such cases.
+ * If the index is marked invalid/not-ready/dead (ie, it's from a failed
+ * CREATE INDEX CONCURRENTLY, or a DROP INDEX CONCURRENTLY failed midway),
+ * and we didn't skip a uniqueness check, we can now mark it valid. This
+ * allows REINDEX to be used to clean up in such cases.
*
* We can also reset indcheckxmin, because we have now done a
* non-concurrent index build, *except* in the case where index_build
- * found some still-broken HOT chains. If it did, we normally leave
- * indcheckxmin alone (note that index_build won't have changed it,
- * because this is a reindex). But if the index was invalid or not ready
- * and there were broken HOT chains, it seems best to force indcheckxmin
- * true, because the normal argument that the HOT chains couldn't conflict
- * with the index is suspect for an invalid index.
+ * found some still-broken HOT chains. If it did, and we don't have to
+ * change any of the other flags, we just leave indcheckxmin alone (note
+ * that index_build won't have changed it, because this is a reindex).
+ * This is okay and desirable because not updating the tuple leaves the
+ * index's usability horizon (recorded as the tuple's xmin value) the same
+ * as it was.
*
- * Note that it is important to not update the pg_index entry if we don't
- * have to, because updating it will move the index's usability horizon
- * (recorded as the tuple's xmin value) if indcheckxmin is true. We don't
- * really want REINDEX to move the usability horizon forward ever, but we
- * have no choice if we are to fix indisvalid or indisready. Of course,
- * clearing indcheckxmin eliminates the issue, so we're happy to do that
- * if we can. Another reason for caution here is that while reindexing
- * pg_index itself, we must not try to update it. We assume that
- * pg_index's indexes will always have these flags in their clean state.
+ * But, if the index was invalid/not-ready/dead and there were broken HOT
+ * chains, we had better force indcheckxmin true, because the normal
+ * argument that the HOT chains couldn't conflict with the index is
+ * suspect for an invalid index. (A conflict is definitely possible if
+ * the index was dead. It probably shouldn't happen otherwise, but let's
+ * be conservative.) In this case advancing the usability horizon is
+ * appropriate.
+ *
+ * Note that if we have to update the tuple, there is a risk of concurrent
+ * transactions not seeing it during their SnapshotNow scans of pg_index.
+ * While not especially desirable, this is safe because no such
+ * transaction could be trying to update the table (since we have
+ * ShareLock on it). The worst case is that someone might transiently
+ * fail to use the index for a query --- but it was probably unusable
+ * before anyway, if we are updating the tuple.
+ *
+ * Another reason for avoiding unnecessary updates here is that while
+ * reindexing pg_index itself, we must not try to update tuples in it.
+ * pg_index's indexes should always have these flags in their clean state,
+ * so that won't happen.
*/
if (!skipped_constraint)
{
+ Relation pg_index;
+ HeapTuple indexTuple;
+ Form_pg_index indexForm;
+ bool index_bad;
+
pg_index = heap_open(IndexRelationId, RowExclusiveLock);
indexTuple = SearchSysCacheCopy1(INDEXRELID,
@@ -3133,17 +3235,28 @@ reindex_index(Oid indexId, bool skip_constraint_checks)
elog(ERROR, "cache lookup failed for index %u", indexId);
indexForm = (Form_pg_index) GETSTRUCT(indexTuple);
- if (!indexForm->indisvalid || !indexForm->indisready ||
+ index_bad = (!indexForm->indisvalid ||
+ !indexForm->indisready);
+ if (index_bad ||
(indexForm->indcheckxmin && !indexInfo->ii_BrokenHotChain))
{
if (!indexInfo->ii_BrokenHotChain)
indexForm->indcheckxmin = false;
- else if (!indexForm->indisvalid || !indexForm->indisready)
+ else if (index_bad)
indexForm->indcheckxmin = true;
indexForm->indisvalid = true;
indexForm->indisready = true;
simple_heap_update(pg_index, &indexTuple->t_self, indexTuple);
CatalogUpdateIndexes(pg_index, indexTuple);
+
+ /*
+ * Invalidate the relcache for the table, so that after we commit
+ * all sessions will refresh the table's index list. This ensures
+ * that if anyone misses seeing the pg_index row during this
+ * update, they'll refresh their list before attempting any update
+ * on the table.
+ */
+ CacheInvalidateRelcache(heapRelation);
}
heap_close(pg_index, RowExclusiveLock);
diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index a72b0ad5ff2..98534cceb93 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -444,7 +444,7 @@ check_index_is_clusterable(Relation OldHeap, Oid indexOid, bool recheck, LOCKMOD
* might put recently-dead tuples out-of-order in the new table, and there
* is little harm in that.)
*/
- if (!OldIndex->rd_index->indisvalid)
+ if (!IndexIsValid(OldIndex->rd_index))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot cluster on invalid index \"%s\"",
@@ -458,6 +458,11 @@ check_index_is_clusterable(Relation OldHeap, Oid indexOid, bool recheck, LOCKMOD
* mark_index_clustered: mark the specified index as the one clustered on
*
* With indexOid == InvalidOid, will mark all indexes of rel not-clustered.
+ *
+ * Note: we do transactional updates of the pg_index rows, which are unsafe
+ * against concurrent SnapshotNow scans of pg_index. Therefore this is unsafe
+ * to execute with less than full exclusive lock on the parent table;
+ * otherwise concurrent executions of RelationGetIndexList could miss indexes.
*/
void
mark_index_clustered(Relation rel, Oid indexOid)
@@ -513,6 +518,9 @@ mark_index_clustered(Relation rel, Oid indexOid)
}
else if (thisIndexOid == indexOid)
{
+ /* this was checked earlier, but let's be real sure */
+ if (!IndexIsValid(indexForm))
+ elog(ERROR, "cannot cluster on invalid index %u", indexOid);
indexForm->indisclustered = true;
simple_heap_update(pg_index, &indexTuple->t_self, indexTuple);
CatalogUpdateIndexes(pg_index, indexTuple);
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index d32839fd6dc..5848305a351 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -123,6 +123,7 @@ CheckIndexCompatible(Oid oldId,
Oid accessMethodId;
Oid relationId;
HeapTuple tuple;
+ Form_pg_index indexForm;
Form_pg_am accessMethodForm;
bool amcanorder;
int16 *coloptions;
@@ -192,17 +193,22 @@ CheckIndexCompatible(Oid oldId,
tuple = SearchSysCache1(INDEXRELID, ObjectIdGetDatum(oldId));
if (!HeapTupleIsValid(tuple))
elog(ERROR, "cache lookup failed for index %u", oldId);
+ indexForm = (Form_pg_index) GETSTRUCT(tuple);
- /* We don't assess expressions or predicates; assume incompatibility. */
+ /*
+ * We don't assess expressions or predicates; assume incompatibility.
+ * Also, if the index is invalid for any reason, treat it as incompatible.
+ */
if (!(heap_attisnull(tuple, Anum_pg_index_indpred) &&
- heap_attisnull(tuple, Anum_pg_index_indexprs)))
+ heap_attisnull(tuple, Anum_pg_index_indexprs) &&
+ IndexIsValid(indexForm)))
{
ReleaseSysCache(tuple);
return false;
}
/* Any change in operator class or collation breaks compatibility. */
- old_natts = ((Form_pg_index) GETSTRUCT(tuple))->indnatts;
+ old_natts = indexForm->indnatts;
Assert(old_natts == numberOfAttributes);
d = SysCacheGetAttr(INDEXRELID, tuple, Anum_pg_index_indcollation, &isnull);
@@ -319,9 +325,6 @@ DefineIndex(IndexStmt *stmt,
LockRelId heaprelid;
LOCKTAG heaplocktag;
Snapshot snapshot;
- Relation pg_index;
- HeapTuple indexTuple;
- Form_pg_index indexForm;
int i;
/*
@@ -718,23 +721,7 @@ DefineIndex(IndexStmt *stmt,
* commit this transaction, any new transactions that open the table must
* insert new entries into the index for insertions and non-HOT updates.
*/
- pg_index = heap_open(IndexRelationId, RowExclusiveLock);
-
- indexTuple = SearchSysCacheCopy1(INDEXRELID,
- ObjectIdGetDatum(indexRelationId));
- if (!HeapTupleIsValid(indexTuple))
- elog(ERROR, "cache lookup failed for index %u", indexRelationId);
- indexForm = (Form_pg_index) GETSTRUCT(indexTuple);
-
- Assert(!indexForm->indisready);
- Assert(!indexForm->indisvalid);
-
- indexForm->indisready = true;
-
- simple_heap_update(pg_index, &indexTuple->t_self, indexTuple);
- CatalogUpdateIndexes(pg_index, indexTuple);
-
- heap_close(pg_index, RowExclusiveLock);
+ index_set_state_flags(indexRelationId, INDEX_CREATE_SET_READY);
/* we can do away with our snapshot */
PopActiveSnapshot();
@@ -858,23 +845,7 @@ DefineIndex(IndexStmt *stmt,
/*
* Index can now be marked valid -- update its pg_index entry
*/
- pg_index = heap_open(IndexRelationId, RowExclusiveLock);
-
- indexTuple = SearchSysCacheCopy1(INDEXRELID,
- ObjectIdGetDatum(indexRelationId));
- if (!HeapTupleIsValid(indexTuple))
- elog(ERROR, "cache lookup failed for index %u", indexRelationId);
- indexForm = (Form_pg_index) GETSTRUCT(indexTuple);
-
- Assert(indexForm->indisready);
- Assert(!indexForm->indisvalid);
-
- indexForm->indisvalid = true;
-
- simple_heap_update(pg_index, &indexTuple->t_self, indexTuple);
- CatalogUpdateIndexes(pg_index, indexTuple);
-
- heap_close(pg_index, RowExclusiveLock);
+ index_set_state_flags(indexRelationId, INDEX_CREATE_SET_VALID);
/*
* The pg_index update will cause backends (including this one) to update
@@ -882,7 +853,7 @@ DefineIndex(IndexStmt *stmt,
* relcache inval on the parent table to force replanning of cached plans.
* Otherwise existing sessions might fail to use the new index where it
* would be useful. (Note that our earlier commits did not create reasons
- * to replan; relcache flush on the index itself was sufficient.)
+ * to replan; so relcache flush on the index itself was sufficient.)
*/
CacheInvalidateRelcacheByRelid(heaprelid.relId);
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index d88e3dee3fa..ab5ab940ade 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -743,10 +743,13 @@ RemoveRelations(DropStmt *drop)
int flags = 0;
LOCKMODE lockmode = AccessExclusiveLock;
+ /* DROP CONCURRENTLY uses a weaker lock, and has some restrictions */
if (drop->concurrent)
{
+ flags |= PERFORM_DELETION_CONCURRENTLY;
lockmode = ShareUpdateExclusiveLock;
- if (list_length(drop->objects) > 1)
+ Assert(drop->removeType == OBJECT_INDEX);
+ if (list_length(drop->objects) != 1)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("DROP INDEX CONCURRENTLY does not support dropping multiple objects")));
@@ -838,19 +841,6 @@ RemoveRelations(DropStmt *drop)
add_exact_object_address(&obj, objects);
}
- /*
- * Set options and check further requirements for concurrent drop
- */
- if (drop->concurrent)
- {
- /*
- * Confirm that concurrent behaviour is restricted in grammar.
- */
- Assert(drop->removeType == OBJECT_INDEX);
-
- flags |= PERFORM_DELETION_CONCURRENTLY;
- }
-
performMultipleDeletions(objects, drop->behavior, flags);
free_object_addresses(objects);
@@ -917,7 +907,7 @@ RangeVarCallbackForDropRelation(const RangeVar *rel, Oid relOid, Oid oldRelOid,
* locking the index. index_drop() will need this anyway, and since
* regular queries lock tables before their indexes, we risk deadlock if
* we do it the other way around. No error if we don't find a pg_index
- * entry, though --- the relation may have been droppd.
+ * entry, though --- the relation may have been dropped.
*/
if (relkind == RELKIND_INDEX && relOid != oldRelOid)
{
@@ -4783,6 +4773,8 @@ ATExecDropNotNull(Relation rel, const char *colName, LOCKMODE lockmode)
/*
* Check that the attribute is not in a primary key
+ *
+ * Note: we'll throw error even if the pkey index is not valid.
*/
/* Loop over all indexes on the relation */
@@ -6317,7 +6309,7 @@ transformFkeyGetPrimaryKey(Relation pkrel, Oid *indexOid,
/*
* Get the list of index OIDs for the table from the relcache, and look up
* each one in the pg_index syscache until we find one marked primary key
- * (hopefully there isn't more than one such).
+ * (hopefully there isn't more than one such). Insist it's valid, too.
*/
*indexOid = InvalidOid;
@@ -6331,7 +6323,7 @@ transformFkeyGetPrimaryKey(Relation pkrel, Oid *indexOid,
if (!HeapTupleIsValid(indexTuple))
elog(ERROR, "cache lookup failed for index %u", indexoid);
indexStruct = (Form_pg_index) GETSTRUCT(indexTuple);
- if (indexStruct->indisprimary)
+ if (indexStruct->indisprimary && IndexIsValid(indexStruct))
{
/*
* Refuse to use a deferrable primary key. This is per SQL spec,
@@ -6429,10 +6421,12 @@ transformFkeyCheckAttrs(Relation pkrel,
/*
* Must have the right number of columns; must be unique and not a
- * partial index; forget it if there are any expressions, too
+ * partial index; forget it if there are any expressions, too. Invalid
+ * indexes are out as well.
*/
if (indexStruct->indnatts == numattrs &&
indexStruct->indisunique &&
+ IndexIsValid(indexStruct) &&
heap_attisnull(indexTuple, Anum_pg_index_indpred) &&
heap_attisnull(indexTuple, Anum_pg_index_indexprs))
{
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index 710c2afc9f3..9b5b79fdcc5 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -1096,9 +1096,16 @@ vacuum_rel(Oid relid, VacuumStmt *vacstmt, bool do_toast, bool for_wraparound)
/*
- * Open all the indexes of the given relation, obtaining the specified kind
- * of lock on each. Return an array of Relation pointers for the indexes
- * into *Irel, and the number of indexes into *nindexes.
+ * Open all the vacuumable indexes of the given relation, obtaining the
+ * specified kind of lock on each. Return an array of Relation pointers for
+ * the indexes into *Irel, and the number of indexes into *nindexes.
+ *
+ * We consider an index vacuumable if it is marked insertable (IndexIsReady).
+ * If it isn't, probably a CREATE INDEX CONCURRENTLY command failed early in
+ * execution, and what we have is too corrupt to be processable. We will
+ * vacuum even if the index isn't indisvalid; this is important because in a
+ * unique index, uniqueness checks will be performed anyway and had better not
+ * hit dangling index pointers.
*/
void
vac_open_indexes(Relation relation, LOCKMODE lockmode,
@@ -1112,21 +1119,30 @@ vac_open_indexes(Relation relation, LOCKMODE lockmode,
indexoidlist = RelationGetIndexList(relation);
- *nindexes = list_length(indexoidlist);
+ /* allocate enough memory for all indexes */
+ i = list_length(indexoidlist);
- if (*nindexes > 0)
- *Irel = (Relation *) palloc(*nindexes * sizeof(Relation));
+ if (i > 0)
+ *Irel = (Relation *) palloc(i * sizeof(Relation));
else
*Irel = NULL;
+ /* collect just the ready indexes */
i = 0;
foreach(indexoidscan, indexoidlist)
{
Oid indexoid = lfirst_oid(indexoidscan);
+ Relation indrel;
- (*Irel)[i++] = index_open(indexoid, lockmode);
+ indrel = index_open(indexoid, lockmode);
+ if (IndexIsReady(indrel->rd_index))
+ (*Irel)[i++] = indrel;
+ else
+ index_close(indrel, lockmode);
}
+ *nindexes = i;
+
list_free(indexoidlist);
}
diff --git a/src/backend/executor/execUtils.c b/src/backend/executor/execUtils.c
index 0bbd0d46402..d6cf06c6fdf 100644
--- a/src/backend/executor/execUtils.c
+++ b/src/backend/executor/execUtils.c
@@ -906,6 +906,9 @@ ExecOpenIndices(ResultRelInfo *resultRelInfo)
/*
* For each index, open the index relation and save pg_index info. We
* acquire RowExclusiveLock, signifying we will update the index.
+ *
+ * Note: we do this even if the index is not IndexIsReady; it's not worth
+ * the trouble to optimize for the case where it isn't.
*/
i = 0;
foreach(l, indexoidlist)
diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c
index 85315ed4bb9..d6056e55a71 100644
--- a/src/backend/optimizer/util/plancat.c
+++ b/src/backend/optimizer/util/plancat.c
@@ -168,9 +168,10 @@ get_relation_info(PlannerInfo *root, Oid relationObjectId, bool inhparent,
* Ignore invalid indexes, since they can't safely be used for
* queries. Note that this is OK because the data structure we
* are constructing is only used by the planner --- the executor
- * still needs to insert into "invalid" indexes!
+ * still needs to insert into "invalid" indexes, if they're marked
+ * IndexIsReady.
*/
- if (!index->indisvalid)
+ if (!IndexIsValid(index))
{
index_close(indexRelation, NoLock);
continue;
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index f70e2df58fe..e3f9c62b2a6 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -1532,18 +1532,12 @@ transformIndexConstraint(Constraint *constraint, CreateStmtContext *cxt)
index_name, RelationGetRelationName(heap_rel)),
parser_errposition(cxt->pstate, constraint->location)));
- if (!index_form->indisvalid)
+ if (!IndexIsValid(index_form))
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("index \"%s\" is not valid", index_name),
parser_errposition(cxt->pstate, constraint->location)));
- if (!index_form->indisready)
- ereport(ERROR,
- (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
- errmsg("index \"%s\" is not ready", index_name),
- parser_errposition(cxt->pstate, constraint->location)));
-
if (!index_form->indisunique)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index 2b0b604636d..a64d739cebc 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -1730,9 +1730,22 @@ RelationReloadIndexInfo(Relation relation)
RelationGetRelid(relation));
index = (Form_pg_index) GETSTRUCT(tuple);
+ /*
+ * Basically, let's just copy all the bool fields. There are one or
+ * two of these that can't actually change in the current code, but
+ * it's not worth it to track exactly which ones they are. None of
+ * the array fields are allowed to change, though.
+ */
+ relation->rd_index->indisunique = index->indisunique;
+ relation->rd_index->indisprimary = index->indisprimary;
+ relation->rd_index->indisexclusion = index->indisexclusion;
+ relation->rd_index->indimmediate = index->indimmediate;
+ relation->rd_index->indisclustered = index->indisclustered;
relation->rd_index->indisvalid = index->indisvalid;
relation->rd_index->indcheckxmin = index->indcheckxmin;
relation->rd_index->indisready = index->indisready;
+
+ /* Copy xmin too, as that is needed to make sense of indcheckxmin */
HeapTupleHeaderSetXmin(relation->rd_indextuple->t_data,
HeapTupleHeaderGetXmin(tuple->t_data));
@@ -3297,6 +3310,10 @@ CheckConstraintFetch(Relation relation)
* so that we must recompute the index list on next request. This handles
* creation or deletion of an index.
*
+ * Indexes that are marked not IndexIsLive are omitted from the returned list.
+ * Such indexes are expected to be dropped momentarily, and should not be
+ * touched at all by any caller of this function.
+ *
* The returned list is guaranteed to be sorted in order by OID. This is
* needed by the executor, since for index types that we obtain exclusive
* locks on when updating the index, all backends must lock the indexes in
@@ -3356,9 +3373,12 @@ RelationGetIndexList(Relation relation)
bool isnull;
/*
- * Ignore any indexes that are currently being dropped
+ * Ignore any indexes that are currently being dropped. This will
+ * prevent them from being searched, inserted into, or considered in
+ * HOT-safety decisions. It's unsafe to touch such an index at all
+ * since its catalog entries could disappear at any instant.
*/
- if (!index->indisvalid && !index->indisready)
+ if (!IndexIsLive(index))
continue;
/* Add index's OID to result list in the proper order */
@@ -3377,7 +3397,8 @@ RelationGetIndexList(Relation relation)
indclass = (oidvector *) DatumGetPointer(indclassDatum);
/* Check to see if it is a unique, non-partial btree index on OID */
- if (index->indnatts == 1 &&
+ if (IndexIsValid(index) &&
+ index->indnatts == 1 &&
index->indisunique && index->indimmediate &&
index->indkey.values[0] == ObjectIdAttributeNumber &&
indclass->values[0] == OID_BTREE_OPS_OID &&
@@ -3672,6 +3693,13 @@ RelationGetIndexAttrBitmap(Relation relation)
/*
* For each index, add referenced attributes to indexattrs.
+ *
+ * Note: we consider all indexes returned by RelationGetIndexList, even if
+ * they are not indisready or indisvalid. This is important because an
+ * index for which CREATE INDEX CONCURRENTLY has just started must be
+ * included in HOT-safety decisions (see README.HOT). If a DROP INDEX
+ * CONCURRENTLY is far enough along that we should ignore the index, it
+ * won't be returned at all by RelationGetIndexList.
*/
indexattrs = NULL;
foreach(l, indexoidlist)
diff --git a/src/include/catalog/index.h b/src/include/catalog/index.h
index eb417cecb74..45efe8ece6c 100644
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@@ -27,6 +27,15 @@ typedef void (*IndexBuildCallback) (Relation index,
bool tupleIsAlive,
void *state);
+/* Action code for index_set_state_flags */
+typedef enum
+{
+ INDEX_CREATE_SET_READY,
+ INDEX_CREATE_SET_VALID,
+ INDEX_DROP_CLEAR_VALID,
+ INDEX_DROP_SET_DEAD
+} IndexStateFlagsAction;
+
extern void index_check_primary_key(Relation heapRel,
IndexInfo *indexInfo,
@@ -89,6 +98,8 @@ extern double IndexBuildHeapScan(Relation heapRelation,
extern void validate_index(Oid heapId, Oid indexId, Snapshot snapshot);
+extern void index_set_state_flags(Oid indexId, IndexStateFlagsAction action);
+
extern void reindex_index(Oid indexId, bool skip_constraint_checks);
/* Flag bits for reindex_relation(): */
diff --git a/src/include/catalog/pg_index.h b/src/include/catalog/pg_index.h
index 9a86121cf9e..2ba355820ce 100644
--- a/src/include/catalog/pg_index.h
+++ b/src/include/catalog/pg_index.h
@@ -95,4 +95,13 @@ typedef FormData_pg_index *Form_pg_index;
#define INDOPTION_DESC 0x0001 /* values are in reverse order */
#define INDOPTION_NULLS_FIRST 0x0002 /* NULLs are first instead of last */
+/*
+ * Use of these macros is recommended over direct examination of the state
+ * flag columns where possible; this allows source code compatibility with
+ * the less ugly representation used after 9.2.
+ */
+#define IndexIsValid(indexForm) ((indexForm)->indisvalid && (indexForm)->indisready)
+#define IndexIsReady(indexForm) ((indexForm)->indisready)
+#define IndexIsLive(indexForm) ((indexForm)->indisready || !(indexForm)->indisvalid)
+
#endif /* PG_INDEX_H */