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 5790f872fe67cfb1f3a6bcda4a654842cd84292d..7b64a7af446cab229375297249d96cc5574e8c0b 100644 (file)
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -2529,26 +2529,29 @@ 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;
@@ -2604,7 +2607,7 @@ 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);
@@ -2625,11 +2628,11 @@ 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)
@@ -2657,10 +2660,12 @@ 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 19c3cf9674cfe5a76e1b0070fcaa55a600493655..59a439413e1be4e3dd2ad384b93835470294c1b6 100644 (file)
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -565,7 +565,7 @@ 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);
 }
 
 
@@ -1362,10 +1362,12 @@ 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 */
@@ -1395,7 +1397,10 @@ 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 f809a26369e37ed48032d69c01adb3804a4fd61b..7a6a4c33adcdda9f9f339a8062be630746bcf72d 100644 (file)
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -1629,7 +1629,7 @@ 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)));
@@ -1742,7 +1742,7 @@ 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 f3bd565b986f4b0df9eeed93fc98c083f52a9800..a9bb8351bc13202f2fbbe7e3b84a16ffec85d8e4 100644 (file)
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -1076,7 +1076,7 @@ ExecuteTruncate(TruncateStmt *stmt)
            /*
             * Reconstruct the indexes to match, and we're done.
             */
-           reindex_relation(heap_relid, true, false);
+           reindex_relation(heap_relid, true, 0);
        }
    }
 
@@ -3236,13 +3236,14 @@ ATRewriteTables(List **wqueue, LOCKMODE lockmode)
 
            /*
             * 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 2804c6338ea514705a5e74cfc5529bf45b5ae8c2..29c471703c286d009afaf86093c345a4654ffde3 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 427d802a0b351ae73dc70436f4bbaef8bcfb4e5d..518e8969c9dcce448be3bea12fa6ce02fcb06d8b 100644 (file)
--- a/src/include/commands/cluster.h
+++ b/src/include/commands/cluster.h
@@ -29,6 +29,7 @@ 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 3d126bbf30835409f430fbf3670c75baff7f5084..3280065f75b80dbb9a65b3ffaa3e17181deb3361 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 4895768d7feacb960d764c67752bb148e3f1e455..cfbfbb6b4381420bcccb1fa15fed99ff728b7888 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