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Commit69c7f25

Browse files
committed
Fixes:
I found another bug in btree index. Looking at the code it seems that NULLkeys are never used to build or scan a btree index (see the explain commandsin the example). However this is not the case when a null key is retrievedin an outer loop of a join select and used in an index scan of an inner loop.This bug causes at least three kinds of problems:1) the backend crashes when it tries to compare a text string with a null.2) it is not possible to find tuples with null keys in a join.3) null is considered equal to 0 when the datum is passed by value, see the last query.Submitted by: Massimo Dal Zotto <dz@cs.unitn.it>
1 parent6ada9df commit69c7f25

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4 files changed

+43
-5
lines changed

4 files changed

+43
-5
lines changed

‎src/backend/access/common/heapvalid.c

Lines changed: 5 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,7 @@
77
*
88
*
99
* IDENTIFICATION
10-
* $Header: /cvsroot/pgsql/src/backend/access/common/Attic/heapvalid.c,v 1.6 1996/10/21 11:49:36 scrappy Exp $
10+
* $Header: /cvsroot/pgsql/src/backend/access/common/Attic/heapvalid.c,v 1.7 1996/10/30 06:07:56 scrappy Exp $
1111
*
1212
*-------------------------------------------------------------------------
1313
*/
@@ -71,6 +71,10 @@ heap_keytest(HeapTuple t,
7171
/* XXX eventually should check if SK_ISNULL */
7272
return false;
7373

74+
if (keys->sk_flags&SK_ISNULL) {
75+
return (false);
76+
}
77+
7478
if (keys->sk_flags&SK_COMMUTE)
7579
test= (long)FMGR_PTR2(keys->sk_func,keys->sk_procedure,
7680
keys->sk_argument,atp);

‎src/backend/access/common/indexvalid.c

Lines changed: 5 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,7 @@
77
*
88
*
99
* IDENTIFICATION
10-
* $Header: /cvsroot/pgsql/src/backend/access/common/Attic/indexvalid.c,v 1.6 1996/10/21 11:49:38 scrappy Exp $
10+
* $Header: /cvsroot/pgsql/src/backend/access/common/Attic/indexvalid.c,v 1.7 1996/10/30 06:07:55 scrappy Exp $
1111
*
1212
*-------------------------------------------------------------------------
1313
*/
@@ -68,6 +68,10 @@ index_keytest(IndexTuple tuple,
6868
return (false);
6969
}
7070

71+
if (key[0].sk_flags&SK_ISNULL) {
72+
return (false);
73+
}
74+
7175
if (key[0].sk_flags&SK_COMMUTE) {
7276
test= (int) (*(key[0].sk_func))
7377
(DatumGetPointer(key[0].sk_argument),

‎src/backend/access/nbtree/nbtsearch.c

Lines changed: 27 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,7 @@
77
*
88
*
99
* IDENTIFICATION
10-
* $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtsearch.c,v 1.4 1996/10/23 07:39:10 scrappy Exp $
10+
* $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtsearch.c,v 1.5 1996/10/30 06:08:01 scrappy Exp $
1111
*
1212
*-------------------------------------------------------------------------
1313
*/
@@ -269,6 +269,18 @@ _bt_skeycmp(Relation rel,
269269
&isNull);
270270
keyDatum=entry->sk_argument;
271271

272+
/*
273+
* This may happen in a nested loop if an attribute used
274+
* as scan key is null.DZ 29-10-1996
275+
*/
276+
if ((entry->sk_flags&SK_ISNULL)|| (isNull)) {
277+
if ((entry->sk_flags&SK_ISNULL)&& (isNull)) {
278+
return (true);
279+
}else {
280+
return (false);
281+
}
282+
}
283+
272284
compare=_bt_invokestrat(rel,i,strat,keyDatum,attrDatum);
273285
if (!compare)
274286
return (false);
@@ -501,6 +513,19 @@ _bt_compare(Relation rel,
501513
entry=&scankey[i-1];
502514
attno=entry->sk_attno;
503515
datum=index_getattr(itup,attno,itupdesc,&null);
516+
517+
/*
518+
* This may happen in a nested loop if an attribute used
519+
* as scan key is null.DZ 29-10-1996
520+
*/
521+
if ((entry->sk_flags&SK_ISNULL)|| (null)) {
522+
if ((entry->sk_flags&SK_ISNULL)&& (null)) {
523+
return (0);
524+
}else {
525+
return (null ?+1 :-1);
526+
}
527+
}
528+
504529
tmpres= (long)FMGR_PTR2(entry->sk_func,entry->sk_procedure,
505530
entry->sk_argument,datum);
506531
result=tmpres;
@@ -641,7 +666,7 @@ _bt_first(IndexScanDesc scan, ScanDirection dir)
641666
* hardwired attno == 1.
642667
*/
643668
proc=index_getprocid(rel,1,BTORDER_PROC);
644-
ScanKeyEntryInitialize(&skdata,0x0,1,proc,
669+
ScanKeyEntryInitialize(&skdata,so->keyData[0].sk_flags,1,proc,
645670
so->keyData[0].sk_argument);
646671

647672
stack=_bt_search(rel,1,&skdata,&buf);

‎src/backend/executor/nodeIndexscan.c

Lines changed: 6 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,7 @@
77
*
88
*
99
* IDENTIFICATION
10-
* $Header: /cvsroot/pgsql/src/backend/executor/nodeIndexscan.c,v 1.1.1.1 1996/07/09 06:21:26 scrappy Exp $
10+
* $Header: /cvsroot/pgsql/src/backend/executor/nodeIndexscan.c,v 1.2 1996/10/30 06:08:10 scrappy Exp $
1111
*
1212
*-------------------------------------------------------------------------
1313
*/
@@ -273,6 +273,11 @@ ExecIndexReScan(IndexScan *node, ExprContext *exprCtxt, Plan* parent)
273273
scanvalue= (Datum)
274274
ExecEvalExpr(scanexpr,exprCtxt,&isNull,&isDone);
275275
scan_keys[j].sk_argument=scanvalue;
276+
if (isNull) {
277+
scan_keys[j].sk_flags |=SK_ISNULL;
278+
}else {
279+
scan_keys[j].sk_flags &= ~SK_ISNULL;
280+
}
276281
}
277282
}
278283
}

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