Make ALTER TABLE revalidate uniqueness and exclusion constraints.

Failure to do so can lead to constraint violations.  This was broken by
commit 1ddc2703a936d03953657f43345460b9242bbed1 on 2010-02-07, so
back-patch to 9.0.

Noah Misch.  Regression test by me.

diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index a3ac44c..8af382b 100644 (file)
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -2508,26 +2508,29 @@ reindex_index(Oid indexId, bool skip_constraint_checks)
  * reindex_relation - This routine is used to recreate all indexes
  * of a relation (and optionally its toast relation too, if any).
  *
- * If heap_rebuilt is true, then the relation was just completely rebuilt by
- * an operation such as VACUUM FULL or CLUSTER, and therefore its indexes are
- * inconsistent with it.  This makes things tricky if the relation is a system
- * catalog that we might consult during the reindexing.  To deal with that
- * case, we mark all of the indexes as pending rebuild so that they won't be
- * trusted until rebuilt.  The caller is required to call us *without* having
- * made the rebuilt versions visible by doing CommandCounterIncrement; we'll
- * do CCI after having collected the index list.  (This way we can still use
- * catalog indexes while collecting the list.)
+ * "flags" can include REINDEX_SUPPRESS_INDEX_USE and REINDEX_CHECK_CONSTRAINTS.
  *
- * We also skip rechecking uniqueness/exclusion constraint properties if
- * heap_rebuilt is true.  This avoids likely deadlock conditions when doing
- * VACUUM FULL or CLUSTER on system catalogs.  REINDEX should be used to
- * rebuild an index if constraint inconsistency is suspected.
+ * If flags has REINDEX_SUPPRESS_INDEX_USE, the relation was just completely
+ * rebuilt by an operation such as VACUUM FULL or CLUSTER, and therefore its
+ * indexes are inconsistent with it.  This makes things tricky if the relation
+ * is a system catalog that we might consult during the reindexing.  To deal
+ * with that case, we mark all of the indexes as pending rebuild so that they
+ * won't be trusted until rebuilt.  The caller is required to call us *without*
+ * having made the rebuilt versions visible by doing CommandCounterIncrement;
+ * we'll do CCI after having collected the index list.  (This way we can still
+ * use catalog indexes while collecting the list.)
+ *
+ * To avoid deadlocks, VACUUM FULL or CLUSTER on a system catalog must omit the
+ * REINDEX_CHECK_CONSTRAINTS flag.  REINDEX should be used to rebuild an index
+ * if constraint inconsistency is suspected.  For optimal performance, other
+ * callers should include the flag only after transforming the data in a manner
+ * that risks a change in constraint validity.
  *
  * Returns true if any indexes were rebuilt.  Note that a
  * CommandCounterIncrement will occur after each index rebuild.
  */
 bool
-reindex_relation(Oid relid, bool toast_too, bool heap_rebuilt)
+reindex_relation(Oid relid, bool toast_too, int flags)
 {
        Relation        rel;
        Oid                     toast_relid;
@@ -2583,7 +2586,7 @@ reindex_relation(Oid relid, bool toast_too, bool heap_rebuilt)
                List       *doneIndexes;
                ListCell   *indexId;
 
-               if (heap_rebuilt)
+               if (flags & REINDEX_SUPPRESS_INDEX_USE)
                {
                        /* Suppress use of all the indexes until they are rebuilt */
                        SetReindexPending(indexIds);
@@ -2604,11 +2607,11 @@ reindex_relation(Oid relid, bool toast_too, bool heap_rebuilt)
                        if (is_pg_class)
                                RelationSetIndexList(rel, doneIndexes, InvalidOid);
 
-                       reindex_index(indexOid, heap_rebuilt);
+                       reindex_index(indexOid, !(flags & REINDEX_CHECK_CONSTRAINTS));
 
                        CommandCounterIncrement();
 
-                       if (heap_rebuilt)
+                       if (flags & REINDEX_SUPPRESS_INDEX_USE)
                                RemoveReindexPending(indexOid);
 
                        if (is_pg_class)
@@ -2636,10 +2639,12 @@ reindex_relation(Oid relid, bool toast_too, bool heap_rebuilt)
 
        /*
         * If the relation has a secondary toast rel, reindex that too while we
-        * still hold the lock on the master table.
+        * still hold the lock on the master table.  There's never a reason to
+        * reindex the toast table right after rebuilding the heap.
         */
+       Assert(!(toast_too && (flags & REINDEX_SUPPRESS_INDEX_USE)));
        if (toast_too && OidIsValid(toast_relid))
-               result |= reindex_relation(toast_relid, false, false);
+               result |= reindex_relation(toast_relid, false, flags);
 
        return result;
 }

diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index 7a1b8e8..61020dc 100644 (file)
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -607,7 +607,7 @@ rebuild_relation(Relation OldHeap, Oid indexOid,
         * rebuild the target's indexes and throw away the transient table.
         */
        finish_heap_swap(tableOid, OIDNewHeap, is_system_catalog,
-                                        swap_toast_by_content, frozenXid);
+                                        swap_toast_by_content, false, frozenXid);
 }
 
 
@@ -1326,10 +1326,12 @@ void
 finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
                                 bool is_system_catalog,
                                 bool swap_toast_by_content,
+                                bool check_constraints,
                                 TransactionId frozenXid)
 {
        ObjectAddress object;
        Oid                     mapped_tables[4];
+       int                     reindex_flags;
        int                     i;
 
        /* Zero out possible results from swapped_relation_files */
@@ -1359,7 +1361,10 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
         * so no chance to reclaim disk space before commit.  We do not need a
         * final CommandCounterIncrement() because reindex_relation does it.
         */
-       reindex_relation(OIDOldHeap, false, true);
+       reindex_flags = REINDEX_SUPPRESS_INDEX_USE;
+       if (check_constraints)
+               reindex_flags |= REINDEX_CHECK_CONSTRAINTS;
+       reindex_relation(OIDOldHeap, false, reindex_flags);
 
        /* Destroy new heap with old filenode */
        object.classId = RelationRelationId;

diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 780dbc2..a129511 100644 (file)
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -1634,7 +1634,7 @@ ReindexTable(RangeVar *relation)
 
        ReleaseSysCache(tuple);
 
-       if (!reindex_relation(heapOid, true, false))
+       if (!reindex_relation(heapOid, true, 0))
                ereport(NOTICE,
                                (errmsg("table \"%s\" has no indexes",
                                                relation->relname)));
@@ -1747,7 +1747,7 @@ ReindexDatabase(const char *databaseName, bool do_system, bool do_user)
                StartTransactionCommand();
                /* functions in indexes may want a snapshot set */
                PushActiveSnapshot(GetTransactionSnapshot());
-               if (reindex_relation(relid, true, false))
+               if (reindex_relation(relid, true, 0))
                        ereport(NOTICE,
                                        (errmsg("table \"%s.%s\" was reindexed",
                                                        get_namespace_name(get_rel_namespace(relid)),

diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index ab9c6a5..6a1804b 100644 (file)
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -1032,7 +1032,7 @@ ExecuteTruncate(TruncateStmt *stmt)
                        /*
                         * Reconstruct the indexes to match, and we're done.
                         */
-                       reindex_relation(heap_relid, true, false);
+                       reindex_relation(heap_relid, true, 0);
                }
        }
 
@@ -2941,13 +2941,14 @@ ATRewriteTables(List **wqueue)
 
                        /*
                         * Swap the physical files of the old and new heaps, then rebuild
-                        * indexes and discard the new heap.  We can use RecentXmin for
+                        * indexes and discard the old heap.  We can use RecentXmin for
                         * the table's new relfrozenxid because we rewrote all the tuples
                         * in ATRewriteTable, so no older Xid remains in the table.  Also,
                         * we never try to swap toast tables by content, since we have no
                         * interest in letting this code work on system catalogs.
                         */
-                       finish_heap_swap(tab->relid, OIDNewHeap, false, false, RecentXmin);
+                       finish_heap_swap(tab->relid, OIDNewHeap,
+                                                        false, false, true, RecentXmin);
                }
                else
                {

diff --git a/src/include/catalog/index.h b/src/include/catalog/index.h
index 6b5f3c4..18f1703 100644 (file)
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@@ -71,7 +71,10 @@ extern double IndexBuildHeapScan(Relation heapRelation,
 extern void validate_index(Oid heapId, Oid indexId, Snapshot snapshot);
 
 extern void reindex_index(Oid indexId, bool skip_constraint_checks);
-extern bool reindex_relation(Oid relid, bool toast_too, bool heap_rebuilt);
+
+#define REINDEX_CHECK_CONSTRAINTS      0x1
+#define REINDEX_SUPPRESS_INDEX_USE     0x2
+extern bool reindex_relation(Oid relid, bool toast_too, int flags);
 
 extern bool ReindexIsProcessingHeap(Oid heapOid);
 extern bool ReindexIsProcessingIndex(Oid indexOid);

diff --git a/src/include/commands/cluster.h b/src/include/commands/cluster.h
index ed3853a..a5aeb1a 100644 (file)
--- a/src/include/commands/cluster.h
+++ b/src/include/commands/cluster.h
@@ -28,6 +28,7 @@ extern Oid    make_new_heap(Oid OIDOldHeap, Oid NewTableSpace);
 extern void finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
                                 bool is_system_catalog,
                                 bool swap_toast_by_content,
+                                bool check_constraints,
                                 TransactionId frozenXid);
 
 #endif   /* CLUSTER_H */

diff --git a/src/test/regress/expected/alter_table.out b/src/test/regress/expected/alter_table.out
index 5aff44f..40a907d 100644 (file)
--- a/src/test/regress/expected/alter_table.out
+++ b/src/test/regress/expected/alter_table.out
@@ -413,6 +413,10 @@ insert into atacc1 (test) values (4);
 -- try adding a unique oid constraint
 alter table atacc1 add constraint atacc_oid1 unique(oid);
 NOTICE:  ALTER TABLE / ADD UNIQUE will create implicit index "atacc_oid1" for table "atacc1"
+-- try to create duplicates via alter table using - should fail
+alter table atacc1 alter column test type integer using 0;
+ERROR:  could not create unique index "atacc_test1"
+DETAIL:  Key (test)=(0) is duplicated.
 drop table atacc1;
 -- let's do one where the unique constraint fails when added
 create table atacc1 ( test int );

diff --git a/src/test/regress/sql/alter_table.sql b/src/test/regress/sql/alter_table.sql
index 82c2e4e..2b01238 100644 (file)
--- a/src/test/regress/sql/alter_table.sql
+++ b/src/test/regress/sql/alter_table.sql
@@ -419,6 +419,8 @@ insert into atacc1 (test) values (2);
 insert into atacc1 (test) values (4);
 -- try adding a unique oid constraint
 alter table atacc1 add constraint atacc_oid1 unique(oid);
+-- try to create duplicates via alter table using - should fail
+alter table atacc1 alter column test type integer using 0;
 drop table atacc1;
 
 -- let's do one where the unique constraint fails when added