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Commitd97c9b3

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committed
Apply fixes for problems with dropped columns whose types have also been
dropped. The simplest fix for INSERT/UPDATE cases turns out to be forpreptlist.c to insert NULLs of a known-good type (I used INT4) ratherthan making them match the deleted column's type. Since the representationof NULL is actually datatype-independent, this should work fine.I also re-reverted the patch to disable the use_physical_tlist optimizationin the presence of dropped columns. It still doesn't look worth thetrouble to be smarter, if there are no other bugs to fix.Added a regression test to catch future problems in this area.
1 parenta7c50cd commitd97c9b3

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6 files changed

+167
-27
lines changed

6 files changed

+167
-27
lines changed

‎src/backend/catalog/heap.c

Lines changed: 40 additions & 9 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $Header: /cvsroot/pgsql/src/backend/catalog/heap.c,v 1.243 2003/05/08 22:19:56 tgl Exp $
11+
* $Header: /cvsroot/pgsql/src/backend/catalog/heap.c,v 1.244 2003/05/12 00:17:02 tgl Exp $
1212
*
1313
*
1414
* INTERFACE ROUTINES
@@ -76,7 +76,7 @@ static void StoreAttrDefault(Relation rel, AttrNumber attnum, char *adbin);
7676
staticvoidStoreRelCheck(Relationrel,char*ccname,char*ccbin);
7777
staticvoidStoreConstraints(Relationrel,TupleDesctupdesc);
7878
staticvoidSetRelationNumChecks(Relationrel,intnumchecks);
79-
staticvoidRemoveStatistics(Relationrel);
79+
staticvoidRemoveStatistics(Relationrel,AttrNumberattnum);
8080

8181

8282
/* ----------------------------------------------------------------
@@ -925,8 +925,9 @@ DeleteAttributeTuples(Oid relid)
925925
*RemoveAttributeById
926926
*
927927
* This is the guts of ALTER TABLE DROP COLUMN: actually mark the attribute
928-
* deleted in pg_attribute. (Everything else needed, such as getting rid
929-
* of any pg_attrdef entry, is handled by dependency.c.)
928+
* deleted in pg_attribute. We also remove pg_statistic entries for it.
929+
* (Everything else needed, such as getting rid of any pg_attrdef entry,
930+
* is handled by dependency.c.)
930931
*/
931932
void
932933
RemoveAttributeById(Oidrelid,AttrNumberattnum)
@@ -960,6 +961,16 @@ RemoveAttributeById(Oid relid, AttrNumber attnum)
960961
/* Mark the attribute as dropped */
961962
attStruct->attisdropped= true;
962963

964+
/*
965+
* Set the type OID to invalid. A dropped attribute's type link cannot
966+
* be relied on (once the attribute is dropped, the type might be too).
967+
* Fortunately we do not need the type row --- the only really essential
968+
* information is the type's typlen and typalign, which are preserved in
969+
* the attribute's attlen and attalign. We set atttypid to zero here
970+
* as a means of catching code that incorrectly expects it to be valid.
971+
*/
972+
attStruct->atttypid=InvalidOid;
973+
963974
/* Remove any NOT NULL constraint the column may have */
964975
attStruct->attnotnull= false;
965976

@@ -984,6 +995,8 @@ RemoveAttributeById(Oid relid, AttrNumber attnum)
984995

985996
heap_close(attr_rel,RowExclusiveLock);
986997

998+
RemoveStatistics(rel,attnum);
999+
9871000
relation_close(rel,NoLock);
9881001
}
9891002

@@ -1158,7 +1171,7 @@ heap_drop_with_catalog(Oid rid)
11581171
/*
11591172
* delete statistics
11601173
*/
1161-
RemoveStatistics(rel);
1174+
RemoveStatistics(rel,0);
11621175

11631176
/*
11641177
* delete attribute tuples
@@ -1819,27 +1832,45 @@ RemoveRelConstraints(Relation rel, const char *constrName,
18191832
}
18201833

18211834

1835+
/*
1836+
* RemoveStatistics --- remove entries in pg_statistic for a rel or column
1837+
*
1838+
* If attnum is zero, remove all entries for rel; else remove only the one
1839+
* for that column.
1840+
*/
18221841
staticvoid
1823-
RemoveStatistics(Relationrel)
1842+
RemoveStatistics(Relationrel,AttrNumberattnum)
18241843
{
18251844
Relationpgstatistic;
18261845
SysScanDescscan;
1827-
ScanKeyDatakey;
1846+
ScanKeyDatakey[2];
1847+
intnkeys;
18281848
HeapTupletuple;
18291849

18301850
pgstatistic=heap_openr(StatisticRelationName,RowExclusiveLock);
18311851

1832-
ScanKeyEntryInitialize(&key,0x0,
1852+
ScanKeyEntryInitialize(&key[0],0x0,
18331853
Anum_pg_statistic_starelid,F_OIDEQ,
18341854
ObjectIdGetDatum(RelationGetRelid(rel)));
18351855

1856+
if (attnum==0)
1857+
nkeys=1;
1858+
else
1859+
{
1860+
ScanKeyEntryInitialize(&key[1],0x0,
1861+
Anum_pg_statistic_staattnum,F_INT2EQ,
1862+
Int16GetDatum(attnum));
1863+
nkeys=2;
1864+
}
1865+
18361866
scan=systable_beginscan(pgstatistic,StatisticRelidAttnumIndex, true,
1837-
SnapshotNow,1,&key);
1867+
SnapshotNow,nkeys,key);
18381868

18391869
while (HeapTupleIsValid(tuple=systable_getnext(scan)))
18401870
simple_heap_delete(pgstatistic,&tuple->t_self);
18411871

18421872
systable_endscan(scan);
1873+
18431874
heap_close(pgstatistic,RowExclusiveLock);
18441875
}
18451876

‎src/backend/optimizer/plan/createplan.c

Lines changed: 7 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -10,7 +10,7 @@
1010
*
1111
*
1212
* IDENTIFICATION
13-
* $Header: /cvsroot/pgsql/src/backend/optimizer/plan/createplan.c,v 1.141 2003/05/11 20:25:50 tgl Exp $
13+
* $Header: /cvsroot/pgsql/src/backend/optimizer/plan/createplan.c,v 1.142 2003/05/12 00:17:03 tgl Exp $
1414
*
1515
*-------------------------------------------------------------------------
1616
*/
@@ -295,6 +295,12 @@ use_physical_tlist(RelOptInfo *rel)
295295
*/
296296
if (rel->reloptkind!=RELOPT_BASEREL)
297297
return false;
298+
/*
299+
* Can't do it if relation contains dropped columns. This is detected
300+
* in plancat.c, see notes there.
301+
*/
302+
if (rel->varlist==NIL)
303+
return false;
298304
/*
299305
* Can't do it if any system columns are requested, either. (This could
300306
* possibly be fixed but would take some fragile assumptions in setrefs.c,

‎src/backend/optimizer/prep/preptlist.c

Lines changed: 44 additions & 14 deletions
Original file line numberDiff line numberDiff line change
@@ -15,7 +15,7 @@
1515
* Portions Copyright (c) 1994, Regents of the University of California
1616
*
1717
* IDENTIFICATION
18-
* $Header: /cvsroot/pgsql/src/backend/optimizer/prep/preptlist.c,v 1.60 2003/02/03 21:15:44 tgl Exp $
18+
* $Header: /cvsroot/pgsql/src/backend/optimizer/prep/preptlist.c,v 1.61 2003/05/12 00:17:03 tgl Exp $
1919
*
2020
*-------------------------------------------------------------------------
2121
*/
@@ -171,6 +171,15 @@ expand_targetlist(List *tlist, int command_type,
171171
* the attribute, so that it gets copied to the new tuple. But
172172
* generate a NULL for dropped columns (we want to drop any
173173
* old values).
174+
*
175+
* When generating a NULL constant for a dropped column, we label
176+
* it INT4 (any other guaranteed-to-exist datatype would do as
177+
* well). We can't label it with the dropped column's datatype
178+
* since that might not exist anymore. It does not really
179+
* matter what we claim the type is, since NULL is NULL --- its
180+
* representation is datatype-independent. This could perhaps
181+
* confuse code comparing the finished plan to the target
182+
* relation, however.
174183
*/
175184
Oidatttype=att_tup->atttypid;
176185
int32atttypmod=att_tup->atttypmod;
@@ -179,31 +188,52 @@ expand_targetlist(List *tlist, int command_type,
179188
switch (command_type)
180189
{
181190
caseCMD_INSERT:
182-
new_expr= (Node*)makeConst(atttype,
183-
att_tup->attlen,
184-
(Datum)0,
185-
true,/* isnull */
186-
att_tup->attbyval);
187191
if (!att_tup->attisdropped)
192+
{
193+
new_expr= (Node*)makeConst(atttype,
194+
att_tup->attlen,
195+
(Datum)0,
196+
true,/* isnull */
197+
att_tup->attbyval);
188198
new_expr=coerce_to_domain(new_expr,
189199
InvalidOid,
190200
atttype,
191201
COERCE_IMPLICIT_CAST);
202+
}
203+
else
204+
{
205+
/* Insert NULL for dropped column */
206+
new_expr= (Node*)makeConst(INT4OID,
207+
sizeof(int32),
208+
(Datum)0,
209+
true,/* isnull */
210+
true/* byval */);
211+
/* label resdom with INT4, too */
212+
atttype=INT4OID;
213+
atttypmod=-1;
214+
}
192215
break;
193216
caseCMD_UPDATE:
194-
/* Insert NULLs for dropped columns */
195-
if (att_tup->attisdropped)
196-
new_expr= (Node*)makeConst(atttype,
197-
att_tup->attlen,
198-
(Datum)0,
199-
true,/* isnull */
200-
att_tup->attbyval);
201-
else
217+
if (!att_tup->attisdropped)
218+
{
202219
new_expr= (Node*)makeVar(result_relation,
203220
attrno,
204221
atttype,
205222
atttypmod,
206223
0);
224+
}
225+
else
226+
{
227+
/* Insert NULL for dropped column */
228+
new_expr= (Node*)makeConst(INT4OID,
229+
sizeof(int32),
230+
(Datum)0,
231+
true,/* isnull */
232+
true/* byval */);
233+
/* label resdom with INT4, too */
234+
atttype=INT4OID;
235+
atttypmod=-1;
236+
}
207237
break;
208238
default:
209239
elog(ERROR,"expand_targetlist: unexpected command_type");

‎src/backend/optimizer/util/plancat.c

Lines changed: 17 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -9,7 +9,7 @@
99
*
1010
*
1111
* IDENTIFICATION
12-
* $Header: /cvsroot/pgsql/src/backend/optimizer/util/plancat.c,v 1.81 2003/05/11 20:25:50 tgl Exp $
12+
* $Header: /cvsroot/pgsql/src/backend/optimizer/util/plancat.c,v 1.82 2003/05/12 00:17:03 tgl Exp $
1313
*
1414
*-------------------------------------------------------------------------
1515
*/
@@ -62,15 +62,29 @@ get_relation_info(Oid relationObjectId, RelOptInfo *rel)
6262
relation=heap_open(relationObjectId,AccessShareLock);
6363

6464
/*
65-
* Make list of physical Vars. Note we do NOT ignore dropped columns;
66-
* the intent is to model the physical tuples of the relation.
65+
* Make list of physical Vars. But if there are any dropped columns,
66+
* punt and set varlist to NIL. (XXX Ideally we would like to include
67+
* dropped columns so that the varlist models the physical tuples
68+
* of the relation. However this creates problems for ExecTypeFromTL,
69+
* which may be asked to build a tupdesc for a tlist that includes vars
70+
* of no-longer-existent types. In theory we could dig out the required
71+
* info from the pg_attribute entries of the relation, but that data is
72+
* not readily available to ExecTypeFromTL. For now, punt and don't
73+
* apply the physical-tlist optimization when there are dropped cols.)
6774
*/
6875
numattrs=RelationGetNumberOfAttributes(relation);
6976

7077
for (attrno=1;attrno <=numattrs;attrno++)
7178
{
7279
Form_pg_attributeatt_tup=relation->rd_att->attrs[attrno-1];
7380

81+
if (att_tup->attisdropped)
82+
{
83+
/* found a dropped col, so punt */
84+
varlist=NIL;
85+
break;
86+
}
87+
7488
varlist=lappend(varlist,
7589
makeVar(varno,
7690
attrno,

‎src/test/regress/expected/alter_table.out

Lines changed: 41 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -1253,3 +1253,44 @@ select * from p1;
12531253
drop table p1 cascade;
12541254
NOTICE: Drop cascades to table c1
12551255
NOTICE: Drop cascades to constraint p1_a1 on table c1
1256+
-- test that operations with a dropped column do not try to reference
1257+
-- its datatype
1258+
create domain mytype as text;
1259+
create temp table foo (f1 text, f2 mytype, f3 text);
1260+
insert into foo values('aa','bb','cc');
1261+
select * from foo;
1262+
f1 | f2 | f3
1263+
----+----+----
1264+
aa | bb | cc
1265+
(1 row)
1266+
1267+
drop domain mytype cascade;
1268+
NOTICE: Drop cascades to table foo column f2
1269+
select * from foo;
1270+
f1 | f3
1271+
----+----
1272+
aa | cc
1273+
(1 row)
1274+
1275+
insert into foo values('qq','rr');
1276+
select * from foo;
1277+
f1 | f3
1278+
----+----
1279+
aa | cc
1280+
qq | rr
1281+
(2 rows)
1282+
1283+
update foo set f3 = 'zz';
1284+
select * from foo;
1285+
f1 | f3
1286+
----+----
1287+
aa | zz
1288+
qq | zz
1289+
(2 rows)
1290+
1291+
select f3,max(f1) from foo group by f3;
1292+
f3 | max
1293+
----+-----
1294+
zz | qq
1295+
(1 row)
1296+

‎src/test/regress/sql/alter_table.sql

Lines changed: 18 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -895,3 +895,21 @@ update p1 set a1 = a1 + 1, f2 = upper(f2);
895895
select*from p1;
896896

897897
droptable p1 cascade;
898+
899+
-- test that operations with a dropped column do not try to reference
900+
-- its datatype
901+
902+
createdomainmytypeastext;
903+
create temp table foo (f1text, f2 mytype, f3text);
904+
905+
insert into foovalues('aa','bb','cc');
906+
select*from foo;
907+
908+
dropdomain mytype cascade;
909+
910+
select*from foo;
911+
insert into foovalues('qq','rr');
912+
select*from foo;
913+
update fooset f3='zz';
914+
select*from foo;
915+
select f3,max(f1)from foogroup by f3;

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