*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/catalog/heap.c,v 1.232.2.1 2002/12/16 18:39:56 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/catalog/heap.c,v 1.232.2.2 2003/05/12 00:17:33 tgl Exp $
*
*
* INTERFACE ROUTINES
static void StoreRelCheck(Relation rel, char *ccname, char *ccbin);
static void StoreConstraints(Relation rel, TupleDesc tupdesc);
static void SetRelationNumChecks(Relation rel, int numchecks);
-static void RemoveStatistics(Relation rel);
+static void RemoveStatistics(Relation rel, AttrNumber attnum);
/* ----------------------------------------------------------------
* RemoveAttributeById
*
* This is the guts of ALTER TABLE DROP COLUMN: actually mark the attribute
- * deleted in pg_attribute. (Everything else needed, such as getting rid
- * of any pg_attrdef entry, is handled by dependency.c.)
+ * deleted in pg_attribute. We also remove pg_statistic entries for it.
+ * (Everything else needed, such as getting rid of any pg_attrdef entry,
+ * is handled by dependency.c.)
*/
void
RemoveAttributeById(Oid relid, AttrNumber attnum)
/* Mark the attribute as dropped */
attStruct->attisdropped = true;
+ /*
+ * Set the type OID to invalid. A dropped attribute's type link cannot
+ * be relied on (once the attribute is dropped, the type might be too).
+ * Fortunately we do not need the type row --- the only really essential
+ * information is the type's typlen and typalign, which are preserved in
+ * the attribute's attlen and attalign. We set atttypid to zero here
+ * as a means of catching code that incorrectly expects it to be valid.
+ */
+ attStruct->atttypid = InvalidOid;
+
/* Remove any NOT NULL constraint the column may have */
attStruct->attnotnull = false;
heap_close(attr_rel, RowExclusiveLock);
+ RemoveStatistics(rel, attnum);
+
relation_close(rel, NoLock);
}
/*
* delete statistics
*/
- RemoveStatistics(rel);
+ RemoveStatistics(rel, 0);
/*
* delete attribute tuples
}
+/*
+ * RemoveStatistics --- remove entries in pg_statistic for a rel or column
+ *
+ * If attnum is zero, remove all entries for rel; else remove only the one
+ * for that column.
+ */
static void
-RemoveStatistics(Relation rel)
+RemoveStatistics(Relation rel, AttrNumber attnum)
{
Relation pgstatistic;
SysScanDesc scan;
- ScanKeyData key;
+ ScanKeyData key[2];
+ int nkeys;
HeapTuple tuple;
pgstatistic = heap_openr(StatisticRelationName, RowExclusiveLock);
- ScanKeyEntryInitialize(&key, 0x0,
+ ScanKeyEntryInitialize(&key[0], 0x0,
Anum_pg_statistic_starelid, F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(rel)));
+ if (attnum == 0)
+ nkeys = 1;
+ else
+ {
+ ScanKeyEntryInitialize(&key[1], 0x0,
+ Anum_pg_statistic_staattnum, F_INT2EQ,
+ Int16GetDatum(attnum));
+ nkeys = 2;
+ }
+
scan = systable_beginscan(pgstatistic, StatisticRelidAttnumIndex, true,
- SnapshotNow, 1, &key);
+ SnapshotNow, nkeys, key);
while (HeapTupleIsValid(tuple = systable_getnext(scan)))
simple_heap_delete(pgstatistic, &tuple->t_self);
systable_endscan(scan);
+
heap_close(pgstatistic, RowExclusiveLock);
}
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/optimizer/prep/preptlist.c,v 1.57 2002/09/18 21:35:21 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/optimizer/prep/preptlist.c,v 1.57.2.1 2003/05/12 00:17:34 tgl Exp $
*
*-------------------------------------------------------------------------
*/
* the attribute, so that it gets copied to the new tuple. But
* generate a NULL for dropped columns (we want to drop any
* old values).
+ *
+ * When generating a NULL constant for a dropped column, we label
+ * it INT4 (any other guaranteed-to-exist datatype would do as
+ * well). We can't label it with the dropped column's datatype
+ * since that might not exist anymore. It does not really
+ * matter what we claim the type is, since NULL is NULL --- its
+ * representation is datatype-independent. This could perhaps
+ * confuse code comparing the finished plan to the target
+ * relation, however.
*/
Oid atttype = att_tup->atttypid;
int32 atttypmod = att_tup->atttypmod;
switch (command_type)
{
case CMD_INSERT:
- new_expr = (Node *) makeConst(atttype,
- att_tup->attlen,
- (Datum) 0,
- true, /* isnull */
- att_tup->attbyval,
- false, /* not a set */
- false);
if (!att_tup->attisdropped)
- new_expr = coerce_type_constraints(new_expr,
- atttype,
- COERCE_IMPLICIT_CAST);
- break;
- case CMD_UPDATE:
- /* Insert NULLs for dropped columns */
- if (att_tup->attisdropped)
+ {
new_expr = (Node *) makeConst(atttype,
att_tup->attlen,
(Datum) 0,
- true, /* isnull */
+ true, /* isnull */
att_tup->attbyval,
false, /* not a set */
false);
+ new_expr = coerce_type_constraints(new_expr,
+ atttype,
+ COERCE_IMPLICIT_CAST);
+ }
else
+ {
+ /* Insert NULL for dropped column */
+ new_expr = (Node *) makeConst(INT4OID,
+ sizeof(int32),
+ (Datum) 0,
+ true, /* isnull */
+ true, /* byval */
+ false, /* not a set */
+ false);
+ /* label resdom with INT4, too */
+ atttype = INT4OID;
+ atttypmod = -1;
+ }
+ break;
+ case CMD_UPDATE:
+ if (!att_tup->attisdropped)
+ {
new_expr = (Node *) makeVar(result_relation,
attrno,
atttype,
atttypmod,
0);
+ }
+ else
+ {
+ /* Insert NULL for dropped column */
+ new_expr = (Node *) makeConst(INT4OID,
+ sizeof(int32),
+ (Datum) 0,
+ true, /* isnull */
+ true, /* byval */
+ false, /* not a set */
+ false);
+ /* label resdom with INT4, too */
+ atttype = INT4OID;
+ atttypmod = -1;
+ }
break;
default:
elog(ERROR, "expand_targetlist: unexpected command_type");
drop table p1, p2 cascade;
NOTICE: Drop cascades to table c1
NOTICE: Drop cascades to table gc1
+-- test that operations with a dropped column do not try to reference
+-- its datatype
+create domain mytype as text;
+create temp table foo (f1 text, f2 mytype, f3 text);
+insert into foo values('aa','bb','cc');
+select * from foo;
+ f1 | f2 | f3
+----+----+----
+ aa | bb | cc
+(1 row)
+
+drop domain mytype cascade;
+NOTICE: Drop cascades to table foo column f2
+select * from foo;
+ f1 | f3
+----+----
+ aa | cc
+(1 row)
+
+insert into foo values('qq','rr');
+select * from foo;
+ f1 | f3
+----+----
+ aa | cc
+ qq | rr
+(2 rows)
+
+update foo set f3 = 'zz';
+select * from foo;
+ f1 | f3
+----+----
+ aa | zz
+ qq | zz
+(2 rows)
+
+select f3,max(f1) from foo group by f3;
+ f3 | max
+----+-----
+ zz | qq
+(1 row)
+
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