Movatterモバイル変換

[0]ホーム
URL:

Skip to content

Navigation Menu

Sign in
Appearance settings

Search code, repositories, users, issues, pull requests...

Provide feedback

We read every piece of feedback, and take your input very seriously.

Saved searches

Use saved searches to filter your results more quickly

 Sign up
Appearance settings

Commit6d0d15c

Browse files
committed
Make the world at least somewhat safe for zero-column tables, and
remove the special case in ALTER DROP COLUMN to prohibit dropping atable's last column.
1 parent23616b4 commit6d0d15c

File tree

6 files changed

+64
-81
lines changed

6 files changed

+64
-81
lines changed

‎src/backend/access/common/tupdesc.c

Lines changed: 39 additions & 26 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $Header: /cvsroot/pgsql/src/backend/access/common/tupdesc.c,v 1.90 2002/09/22 19:42:50 tgl Exp $
11+
* $Header: /cvsroot/pgsql/src/backend/access/common/tupdesc.c,v 1.91 2002/09/28 20:00:18 tgl Exp $
1212
*
1313
* NOTES
1414
* some of the executor utility code such as "ExecTypeFromTL" should be
@@ -39,28 +39,34 @@
3939
TupleDesc
4040
CreateTemplateTupleDesc(intnatts,boolhasoid)
4141
{
42-
uint32size;
4342
TupleDescdesc;
4443

4544
/*
4645
* sanity checks
4746
*/
48-
AssertArg(natts >=1);
47+
AssertArg(natts >=0);
4948

5049
/*
5150
* allocate enough memory for the tuple descriptor and zero it as
5251
* TupleDescInitEntry assumes that the descriptor is filled with NULL
5352
* pointers.
5453
*/
55-
size=natts*sizeof(Form_pg_attribute);
5654
desc= (TupleDesc)palloc(sizeof(structtupleDesc));
57-
desc->attrs= (Form_pg_attribute*)palloc(size);
58-
desc->constr=NULL;
59-
MemSet(desc->attrs,0,size);
6055

6156
desc->natts=natts;
6257
desc->tdhasoid=hasoid;
6358

59+
if (natts>0)
60+
{
61+
uint32size=natts*sizeof(Form_pg_attribute);
62+
63+
desc->attrs= (Form_pg_attribute*)palloc(size);
64+
MemSet(desc->attrs,0,size);
65+
}
66+
else
67+
desc->attrs=NULL;
68+
desc->constr=NULL;
69+
6470
returndesc;
6571
}
6672

@@ -79,7 +85,7 @@ CreateTupleDesc(int natts, bool hasoid, Form_pg_attribute *attrs)
7985
/*
8086
* sanity checks
8187
*/
82-
AssertArg(natts >=1);
88+
AssertArg(natts >=0);
8389

8490
desc= (TupleDesc)palloc(sizeof(structtupleDesc));
8591
desc->attrs=attrs;
@@ -108,17 +114,20 @@ CreateTupleDescCopy(TupleDesc tupdesc)
108114

109115
desc= (TupleDesc)palloc(sizeof(structtupleDesc));
110116
desc->natts=tupdesc->natts;
111-
size=desc->natts*sizeof(Form_pg_attribute);
112-
desc->attrs= (Form_pg_attribute*)palloc(size);
113-
for (i=0;i<desc->natts;i++)
117+
if (desc->natts>0)
114118
{
115-
desc->attrs[i]= (Form_pg_attribute)palloc(ATTRIBUTE_TUPLE_SIZE);
116-
memcpy(desc->attrs[i],
117-
tupdesc->attrs[i],
118-
ATTRIBUTE_TUPLE_SIZE);
119-
desc->attrs[i]->attnotnull= false;
120-
desc->attrs[i]->atthasdef= false;
119+
size=desc->natts*sizeof(Form_pg_attribute);
120+
desc->attrs= (Form_pg_attribute*)palloc(size);
121+
for (i=0;i<desc->natts;i++)
122+
{
123+
desc->attrs[i]= (Form_pg_attribute)palloc(ATTRIBUTE_TUPLE_SIZE);
124+
memcpy(desc->attrs[i],tupdesc->attrs[i],ATTRIBUTE_TUPLE_SIZE);
125+
desc->attrs[i]->attnotnull= false;
126+
desc->attrs[i]->atthasdef= false;
127+
}
121128
}
129+
else
130+
desc->attrs=NULL;
122131
desc->constr=NULL;
123132
desc->tdhasoid=tupdesc->tdhasoid;
124133

@@ -142,15 +151,18 @@ CreateTupleDescCopyConstr(TupleDesc tupdesc)
142151

143152
desc= (TupleDesc)palloc(sizeof(structtupleDesc));
144153
desc->natts=tupdesc->natts;
145-
size=desc->natts*sizeof(Form_pg_attribute);
146-
desc->attrs= (Form_pg_attribute*)palloc(size);
147-
for (i=0;i<desc->natts;i++)
154+
if (desc->natts>0)
148155
{
149-
desc->attrs[i]= (Form_pg_attribute)palloc(ATTRIBUTE_TUPLE_SIZE);
150-
memcpy(desc->attrs[i],
151-
tupdesc->attrs[i],
152-
ATTRIBUTE_TUPLE_SIZE);
156+
size=desc->natts*sizeof(Form_pg_attribute);
157+
desc->attrs= (Form_pg_attribute*)palloc(size);
158+
for (i=0;i<desc->natts;i++)
159+
{
160+
desc->attrs[i]= (Form_pg_attribute)palloc(ATTRIBUTE_TUPLE_SIZE);
161+
memcpy(desc->attrs[i],tupdesc->attrs[i],ATTRIBUTE_TUPLE_SIZE);
162+
}
153163
}
164+
else
165+
desc->attrs=NULL;
154166
if (constr)
155167
{
156168
TupleConstr*cpy= (TupleConstr*)palloc(sizeof(TupleConstr));
@@ -197,7 +209,8 @@ FreeTupleDesc(TupleDesc tupdesc)
197209

198210
for (i=0;i<tupdesc->natts;i++)
199211
pfree(tupdesc->attrs[i]);
200-
pfree(tupdesc->attrs);
212+
if (tupdesc->attrs)
213+
pfree(tupdesc->attrs);
201214
if (tupdesc->constr)
202215
{
203216
if (tupdesc->constr->num_defval>0)
@@ -228,7 +241,6 @@ FreeTupleDesc(TupleDesc tupdesc)
228241
}
229242

230243
pfree(tupdesc);
231-
232244
}
233245

234246
/*
@@ -361,6 +373,7 @@ TupleDescInitEntry(TupleDesc desc,
361373
*/
362374
AssertArg(PointerIsValid(desc));
363375
AssertArg(attributeNumber >=1);
376+
AssertArg(attributeNumber <=desc->natts);
364377

365378
/*
366379
* attributeName's are sometimes NULL, from resdom's. I don't know

‎src/backend/commands/tablecmds.c

Lines changed: 3 additions & 26 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $Header: /cvsroot/pgsql/src/backend/commands/tablecmds.c,v 1.44 2002/09/23 20:43:40 tgl Exp $
11+
* $Header: /cvsroot/pgsql/src/backend/commands/tablecmds.c,v 1.45 2002/09/28 20:00:19 tgl Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -2331,9 +2331,7 @@ AlterTableDropColumn(Oid myrelid, bool recurse, bool recursing,
23312331
{
23322332
Relationrel;
23332333
AttrNumberattnum;
2334-
AttrNumbern;
23352334
TupleDesctupleDesc;
2336-
boolsuccess;
23372335
ObjectAddressobject;
23382336

23392337
rel=heap_open(myrelid,AccessExclusiveLock);
@@ -2359,34 +2357,13 @@ AlterTableDropColumn(Oid myrelid, bool recurse, bool recursing,
23592357
RelationGetRelationName(rel),colName);
23602358

23612359
/* Can't drop a system attribute */
2360+
/* XXX perhaps someday allow dropping OID? */
23622361
if (attnum<0)
23632362
elog(ERROR,"ALTER TABLE: Cannot drop system attribute \"%s\"",
23642363
colName);
23652364

2366-
/*
2367-
* Make sure there will be at least one user column left in the
2368-
* relation after we drop this one. Zero-length tuples tend to
2369-
* confuse us.
2370-
*/
2371-
tupleDesc=RelationGetDescr(rel);
2372-
2373-
success= false;
2374-
for (n=1;n <=tupleDesc->natts;n++)
2375-
{
2376-
Form_pg_attributeattribute=tupleDesc->attrs[n-1];
2377-
2378-
if (!attribute->attisdropped&&n!=attnum)
2379-
{
2380-
success= true;
2381-
break;
2382-
}
2383-
}
2384-
2385-
if (!success)
2386-
elog(ERROR,"ALTER TABLE: Cannot drop last column from table \"%s\"",
2387-
RelationGetRelationName(rel));
2388-
23892365
/* Don't drop inherited columns */
2366+
tupleDesc=RelationGetDescr(rel);
23902367
if (tupleDesc->attrs[attnum-1]->attinhcount>0&& !recursing)
23912368
elog(ERROR,"ALTER TABLE: Cannot drop inherited column \"%s\"",
23922369
colName);

‎src/backend/executor/execTuples.c

Lines changed: 5 additions & 12 deletions
Original file line numberDiff line numberDiff line change
@@ -15,7 +15,7 @@
1515
*
1616
*
1717
* IDENTIFICATION
18-
* $Header: /cvsroot/pgsql/src/backend/executor/execTuples.c,v 1.59 2002/09/04 20:31:17 momjian Exp $
18+
* $Header: /cvsroot/pgsql/src/backend/executor/execTuples.c,v 1.60 2002/09/28 20:00:19 tgl Exp $
1919
*
2020
*-------------------------------------------------------------------------
2121
*/
@@ -560,23 +560,14 @@ ExecInitNullTupleSlot(EState *estate, TupleDesc tupType)
560560
TupleDesc
561561
ExecTypeFromTL(List*targetList,boolhasoid)
562562
{
563-
List*tlitem;
564563
TupleDesctypeInfo;
565-
Resdom*resdom;
566-
Oidrestype;
564+
List*tlitem;
567565
intlen;
568566

569-
/*
570-
* examine targetlist - if empty then return NULL
571-
*/
572-
len=ExecTargetListLength(targetList);
573-
574-
if (len==0)
575-
returnNULL;
576-
577567
/*
578568
* allocate a new typeInfo
579569
*/
570+
len=ExecTargetListLength(targetList);
580571
typeInfo=CreateTemplateTupleDesc(len,hasoid);
581572

582573
/*
@@ -585,6 +576,8 @@ ExecTypeFromTL(List *targetList, bool hasoid)
585576
foreach(tlitem,targetList)
586577
{
587578
TargetEntry*tle=lfirst(tlitem);
579+
Resdom*resdom;
580+
Oidrestype;
588581

589582
if (tle->resdom!=NULL)
590583
{

‎src/backend/executor/nodeAgg.c

Lines changed: 11 additions & 11 deletions
Original file line numberDiff line numberDiff line change
@@ -46,7 +46,7 @@
4646
* Portions Copyright (c) 1994, Regents of the University of California
4747
*
4848
* IDENTIFICATION
49-
* $Header: /cvsroot/pgsql/src/backend/executor/nodeAgg.c,v 1.87 2002/09/18 21:35:20 tgl Exp $
49+
* $Header: /cvsroot/pgsql/src/backend/executor/nodeAgg.c,v 1.88 2002/09/28 20:00:19 tgl Exp $
5050
*
5151
*-------------------------------------------------------------------------
5252
*/
@@ -658,20 +658,20 @@ ExecAgg(Agg *node)
658658
if (inputTuple==NULL)
659659
{
660660
TupleDesctupType;
661-
Datum*tupValue;
662-
char*null_array;
663-
AttrNumberattnum;
661+
Datum*dvalues;
662+
char*dnulls;
664663

665664
tupType=aggstate->csstate.css_ScanTupleSlot->ttc_tupleDescriptor;
666-
tupValue=projInfo->pi_tupValue;
667665
/* watch out for null input tuples, though... */
668-
if (tupType&&tupValue)
666+
if (tupType&&tupType->natts>0)
669667
{
670-
null_array= (char*)palloc(sizeof(char)*tupType->natts);
671-
for (attnum=0;attnum<tupType->natts;attnum++)
672-
null_array[attnum]='n';
673-
inputTuple=heap_formtuple(tupType,tupValue,null_array);
674-
pfree(null_array);
668+
dvalues= (Datum*)palloc(sizeof(Datum)*tupType->natts);
669+
dnulls= (char*)palloc(sizeof(char)*tupType->natts);
670+
MemSet(dvalues,0,sizeof(Datum)*tupType->natts);
671+
MemSet(dnulls,'n',sizeof(char)*tupType->natts);
672+
inputTuple=heap_formtuple(tupType,dvalues,dnulls);
673+
pfree(dvalues);
674+
pfree(dnulls);
675675
}
676676
}
677677
}

‎src/backend/parser/parse_target.c

Lines changed: 4 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $Header: /cvsroot/pgsql/src/backend/parser/parse_target.c,v 1.90 2002/09/18 21:35:22 tgl Exp $
11+
* $Header: /cvsroot/pgsql/src/backend/parser/parse_target.c,v 1.91 2002/09/28 20:00:19 tgl Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -386,6 +386,7 @@ static List *
386386
ExpandAllTables(ParseState*pstate)
387387
{
388388
List*target=NIL;
389+
boolfound_table= false;
389390
List*ns;
390391

391392
foreach(ns,pstate->p_namespace)
@@ -413,11 +414,12 @@ ExpandAllTables(ParseState *pstate)
413414
if (!rte->inFromCl)
414415
continue;
415416

417+
found_table= true;
416418
target=nconc(target,expandRelAttrs(pstate,rte));
417419
}
418420

419421
/* Check for SELECT *; */
420-
if (target==NIL)
422+
if (!found_table)
421423
elog(ERROR,"Wildcard with no tables specified not allowed");
422424

423425
returntarget;

‎src/test/regress/expected/alter_table.out

Lines changed: 2 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -939,11 +939,9 @@ drop table test2;
939939
alter table atacc1 drop c;
940940
alter table atacc1 drop d;
941941
alter table atacc1 drop b;
942-
ERROR: ALTER TABLE: Cannot drop last column from table "atacc1"
943942
select * from atacc1;
944-
b
945-
----
946-
21
943+
944+
--
947945
(1 row)
948946

949947
drop table atacc1;

0 commit comments

Comments
 (0)
[8]ページ先頭
©2009-2025 Movatter.jp