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When converting a table to a view, remove its system columns.

2012年10月24日 17:39:37 +0000 (13:39 -0400)

Views should not have any pg_attribute entries for system columns.
However, we forgot to remove such entries when converting a table to a
view. This could lead to crashes later on, if someone attempted to
reference such a column, as reported by Kohei KaiGai.

Patch in HEAD only. This bug has been there forever, but in the back
branches we will have to defend against existing mis-converted views,
so it doesn't seem worthwhile to change the conversion code too.

src/backend/catalog/heap.c patch | blob | blame | history

src/backend/rewrite/rewriteDefine.c patch | blob | blame | history

src/include/catalog/heap.h patch | blob | blame | history

src/test/regress/expected/rules.out patch | blob | blame | history

src/test/regress/sql/rules.sql patch | blob | blame | history

diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c

index 6edd11fb98679be7ddf138e224dbd43a8e63275d..8818b680c8b62a8d5e9bbd2841a8b6a57ad9eeb9 100644 (file)

--- a/src/backend/catalog/heap.c

+++ b/src/backend/catalog/heap.c

@@ -1434,6 +1434,47 @@ DeleteAttributeTuples(Oid relid)

heap_close(attrel, RowExclusiveLock);

}

+/*

+ * DeleteSystemAttributeTuples

+ *

+ * Remove pg_attribute rows for system columns of the given relid.

+ *

+ * Note: this is only used when converting a table to a view. Views don't

+ * have system columns, so we should remove them from pg_attribute.

+ */

+void

+DeleteSystemAttributeTuples(Oid relid)

+ Relation attrel;

+ SysScanDesc scan;

+ ScanKeyData key[2];

+ HeapTuple atttup;

+ /* Grab an appropriate lock on the pg_attribute relation */

+ attrel = heap_open(AttributeRelationId, RowExclusiveLock);

+ /* Use the index to scan only system attributes of the target relation */

+ ScanKeyInit(&key[0],

+ Anum_pg_attribute_attrelid,

+ BTEqualStrategyNumber, F_OIDEQ,

+ ObjectIdGetDatum(relid));

+ ScanKeyInit(&key[1],

+ Anum_pg_attribute_attnum,

+ BTLessEqualStrategyNumber, F_INT2LE,

+ Int16GetDatum(0));

+ scan = systable_beginscan(attrel, AttributeRelidNumIndexId, true,

+ SnapshotNow, 2, key);

+ /* Delete all the matching tuples */

+ while ((atttup = systable_getnext(scan)) != NULL)

+ simple_heap_delete(attrel, &atttup->t_self);

+ /* Clean up after the scan */

+ systable_endscan(scan);

+ heap_close(attrel, RowExclusiveLock);

* RemoveAttributeById

diff --git a/src/backend/rewrite/rewriteDefine.c b/src/backend/rewrite/rewriteDefine.c

index 8efc9fc9d521b6f72f620d8429a17f7b60036378..55b0fed5f79c8e28fd51ef921fd2a799682cade0 100644 (file)

--- a/src/backend/rewrite/rewriteDefine.c

+++ b/src/backend/rewrite/rewriteDefine.c

@@ -18,6 +18,7 @@

#include "access/htup_details.h"

#include "catalog/catalog.h"

#include "catalog/dependency.h"

+#include "catalog/heap.h"

#include "catalog/indexing.h"

#include "catalog/namespace.h"

#include "catalog/objectaccess.h"

@@ -510,13 +511,19 @@ DefineQueryRewrite(char *rulename,

}

- * IF the relation is becoming a view, delete the storage files associated

- * with it. NB: we had better have AccessExclusiveLock to do this ...

+ * If the relation is becoming a view, delete the storage files associated

+ * with it. Also, get rid of any system attribute entries in pg_attribute,

+ * because a view shouldn't have any of those.

+ *

+ * NB: we had better have AccessExclusiveLock to do this ...

* XXX what about getting rid of its TOAST table? For now, we don't.

if (RelisBecomingView)

+ {

RelationDropStorage(event_relation);

+ DeleteSystemAttributeTuples(event_relid);

+ }

/* Close rel, but keep lock till commit... */

heap_close(event_relation, NoLock);

diff --git a/src/include/catalog/heap.h b/src/include/catalog/heap.h

index 1465456cc7d1498d824745d5d500f1f4fac1c17d..a35829bb7b98e733c90d6774c3912295d03e57df 100644 (file)

--- a/src/include/catalog/heap.h

+++ b/src/include/catalog/heap.h

@@ -107,6 +107,7 @@ extern Node *cookDefault(ParseState *pstate,

extern void DeleteRelationTuple(Oid relid);

extern void DeleteAttributeTuples(Oid relid);

+extern void DeleteSystemAttributeTuples(Oid relid);

extern void RemoveAttributeById(Oid relid, AttrNumber attnum);

extern void RemoveAttrDefault(Oid relid, AttrNumber attnum,

DropBehavior behavior, bool complain, bool internal);

diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out

index ad1591be598405c34085d258a40aeb88d98c827c..a235571b3dff00aa0732e62d6caac04a5e28bb71 100644 (file)

--- a/src/test/regress/expected/rules.out

+++ b/src/test/regress/expected/rules.out

@@ -1457,6 +1457,28 @@ ERROR: cannot drop rule _RETURN on view fooview because view fooview requires i

HINT: You can drop view fooview instead.

drop view fooview;

+-- test conversion of table to view (needed to load some pg_dump files)

+--

+create table fooview (x int, y text);

+select xmin, * from fooview;

+ xmin | x | y

+------+---+---

+(0 rows)

+create rule "_RETURN" as on select to fooview do instead

+ select 1 as x, 'aaa'::text as y;

+select * from fooview;

+ x | y

+---+-----

+ 1 | aaa

+(1 row)

+select xmin, * from fooview; -- fail, views don't have such a column

+ERROR: column "xmin" does not exist

+LINE 1: select xmin, * from fooview;

+ ^

+drop view fooview;

+--

-- check for planner problems with complex inherited UPDATES

create table id (id serial primary key, name text);

diff --git a/src/test/regress/sql/rules.sql b/src/test/regress/sql/rules.sql

index 1de5b0b68533daf131f65cc16559c9fa895231ad..458c2f026c0fbce861c7c4dc5898b2749b71af55 100644 (file)

--- a/src/test/regress/sql/rules.sql

+++ b/src/test/regress/sql/rules.sql

@@ -859,6 +859,21 @@ create view fooview as select 'foo'::text;

drop rule "_RETURN" on fooview;