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Apply fixes for problems with dropped columns whose types have also been

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dropped.  The simplest fix for INSERT/UPDATE cases turns out to be for
preptlist.c to insert NULLs of a known-good type (I used INT4) rather
than making them match the deleted column's type.  Since the representation
of NULL is actually datatype-independent, this should work fine.
I also re-reverted the patch to disable the use_physical_tlist optimization
in the presence of dropped columns.  It still doesn't look worth the
trouble to be smarter, if there are no other bugs to fix.
Added a regression test to catch future problems in this area.
This commit is contained in:
Tom Lane 2003-05-12 00:17:03 +00:00
parent a7c50cd92b
commit d97c9b3662
6 changed files with 167 additions and 27 deletions
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49
src/backend/catalog/heap.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/catalog/heap.c,v 1.243 2003/05/08 22:19:56 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/catalog/heap.c,v 1.244 2003/05/12 00:17:02 tgl Exp $
*
*
* INTERFACE ROUTINES
@ -76,7 +76,7 @@ static void StoreAttrDefault(Relation rel, AttrNumber attnum, char *adbin);
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);
/* ----------------------------------------------------------------
@ -925,8 +925,9 @@ DeleteAttributeTuples(Oid relid)
* 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)
@ -960,6 +961,16 @@ 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;
@ -984,6 +995,8 @@ RemoveAttributeById(Oid relid, AttrNumber attnum)
heap_close(attr_rel, RowExclusiveLock);
RemoveStatistics(rel, attnum);
relation_close(rel, NoLock);
}
@ -1158,7 +1171,7 @@ heap_drop_with_catalog(Oid rid)
/*
* delete statistics
*/
RemoveStatistics(rel);
RemoveStatistics(rel, 0);
/*
* delete attribute tuples
@ -1819,27 +1832,45 @@ RemoveRelConstraints(Relation rel, const char *constrName,
}
/*
* 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);
}

8
src/backend/optimizer/plan/createplan.c
View File

@ -10,7 +10,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/optimizer/plan/createplan.c,v 1.141 2003/05/11 20:25:50 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/optimizer/plan/createplan.c,v 1.142 2003/05/12 00:17:03 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -295,6 +295,12 @@ use_physical_tlist(RelOptInfo *rel)
*/
if (rel->reloptkind != RELOPT_BASEREL)
return false;
/*
* Can't do it if relation contains dropped columns. This is detected
* in plancat.c, see notes there.
*/
if (rel->varlist == NIL)
return false;
/*
* Can't do it if any system columns are requested, either. (This could
* possibly be fixed but would take some fragile assumptions in setrefs.c,

50
src/backend/optimizer/prep/preptlist.c
View File

@ -15,7 +15,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/optimizer/prep/preptlist.c,v 1.60 2003/02/03 21:15:44 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/optimizer/prep/preptlist.c,v 1.61 2003/05/12 00:17:03 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -171,6 +171,15 @@ expand_targetlist(List *tlist, int command_type,
* 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;
@ -179,31 +188,52 @@ expand_targetlist(List *tlist, int command_type,
switch (command_type)
{
case CMD_INSERT:
if (!att_tup->attisdropped)
{
new_expr = (Node *) makeConst(atttype,
att_tup->attlen,
(Datum) 0,
true, /* isnull */
att_tup->attbyval);
if (!att_tup->attisdropped)
new_expr = coerce_to_domain(new_expr,
InvalidOid,
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,
}
else
{
/* Insert NULL for dropped column */
new_expr = (Node *) makeConst(INT4OID,
sizeof(int32),
(Datum) 0,
true, /* isnull */
att_tup->attbyval);
else
true /* byval */);
/* 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 */);
/* label resdom with INT4, too */
atttype = INT4OID;
atttypmod = -1;
}
break;
default:
elog(ERROR, "expand_targetlist: unexpected command_type");

20
src/backend/optimizer/util/plancat.c
View File

@ -9,7 +9,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/optimizer/util/plancat.c,v 1.81 2003/05/11 20:25:50 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/optimizer/util/plancat.c,v 1.82 2003/05/12 00:17:03 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -62,8 +62,15 @@ get_relation_info(Oid relationObjectId, RelOptInfo *rel)
relation = heap_open(relationObjectId, AccessShareLock);
/*
* Make list of physical Vars. Note we do NOT ignore dropped columns;
* the intent is to model the physical tuples of the relation.
* Make list of physical Vars. But if there are any dropped columns,
* punt and set varlist to NIL. (XXX Ideally we would like to include
* dropped columns so that the varlist models the physical tuples
* of the relation. However this creates problems for ExecTypeFromTL,
* which may be asked to build a tupdesc for a tlist that includes vars
* of no-longer-existent types. In theory we could dig out the required
* info from the pg_attribute entries of the relation, but that data is
* not readily available to ExecTypeFromTL. For now, punt and don't
* apply the physical-tlist optimization when there are dropped cols.)
*/
numattrs = RelationGetNumberOfAttributes(relation);
@ -71,6 +78,13 @@ get_relation_info(Oid relationObjectId, RelOptInfo *rel)
{
Form_pg_attribute att_tup = relation->rd_att->attrs[attrno - 1];
if (att_tup->attisdropped)
{
/* found a dropped col, so punt */
varlist = NIL;
break;
}
varlist = lappend(varlist,
makeVar(varno,
attrno,

41
src/test/regress/expected/alter_table.out
View File

@ -1253,3 +1253,44 @@ select * from p1;
drop table p1 cascade;
NOTICE: Drop cascades to table c1
NOTICE: Drop cascades to constraint p1_a1 on table c1
-- 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)

18
src/test/regress/sql/alter_table.sql
View File

@ -895,3 +895,21 @@ update p1 set a1 = a1 + 1, f2 = upper(f2);
select * from p1;
drop table p1 cascade;
-- 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;
drop domain mytype cascade;
select * from foo;
insert into foo values('qq','rr');
select * from foo;
update foo set f3 = 'zz';
select * from foo;
select f3,max(f1) from foo group by f3;