mirror of https://github.com/postgres/postgres
More btree fixes from Massimo Dal Zotto <dz@cs.unitn.it>
Fixes: I found another bug in btree index. Looking at the code it seems that NULL keys are never used to build or scan a btree index (see the explain commands in the example). However this is not the case when a null key is retrieved in 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.
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@ -7,7 +7,7 @@
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/access/common/Attic/heapvalid.c,v 1.1.1.1 1996/07/09 06:21:09 scrappy Exp $
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* $Header: /cvsroot/pgsql/src/backend/access/common/Attic/heapvalid.c,v 1.1.1.1.2.1 1996/10/30 06:06:36 scrappy Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -54,6 +54,10 @@ heap_keytest(HeapTuple t,
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/* XXX eventually should check if SK_ISNULL */
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return false;
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if (keys->sk_flags & SK_ISNULL) {
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return (false);
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}
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if (keys->sk_flags & SK_COMMUTE)
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test = (long) FMGR_PTR2(keys->sk_func, keys->sk_procedure,
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keys->sk_argument, atp);
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@ -7,7 +7,7 @@
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/access/common/Attic/indexvalid.c,v 1.1.1.1 1996/07/09 06:21:09 scrappy Exp $
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* $Header: /cvsroot/pgsql/src/backend/access/common/Attic/indexvalid.c,v 1.1.1.1.2.1 1996/10/30 06:06:34 scrappy Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -61,6 +61,10 @@ index_keytest(IndexTuple tuple,
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return (false);
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}
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if (key[0].sk_flags & SK_ISNULL) {
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return (false);
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}
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if (key[0].sk_flags & SK_COMMUTE) {
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test = (int) (*(key[0].sk_func))
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(DatumGetPointer(key[0].sk_argument),
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@ -7,7 +7,7 @@
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtsearch.c,v 1.2 1996/07/30 07:56:02 scrappy Exp $
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* $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtsearch.c,v 1.2.2.1 1996/10/30 06:06:40 scrappy Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -248,6 +248,18 @@ _bt_skeycmp(Relation rel,
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&isNull);
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keyDatum = entry->sk_argument;
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/*
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* This may happen in a nested loop if an attribute used
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* as scan key is null. DZ 29-10-1996
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*/
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if ((entry->sk_flags & SK_ISNULL) || (isNull)) {
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if ((entry->sk_flags & SK_ISNULL) && (isNull)) {
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return (true);
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} else {
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return (false);
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}
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}
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compare = _bt_invokestrat(rel, i, strat, keyDatum, attrDatum);
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if (!compare)
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return (false);
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@ -490,6 +502,19 @@ _bt_compare(Relation rel,
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entry = &scankey[i - 1];
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attno = entry->sk_attno;
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datum = index_getattr(itup, attno, itupdesc, &null);
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/*
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* This may happen in a nested loop if an attribute used
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* as scan key is null. DZ 29-10-1996
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*/
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if ((entry->sk_flags & SK_ISNULL) || (null)) {
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if ((entry->sk_flags & SK_ISNULL) && (null)) {
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return (0);
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} else {
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return (null ? +1 : -1);
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}
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}
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tmpres = (long) FMGR_PTR2(entry->sk_func, entry->sk_procedure,
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entry->sk_argument, datum);
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result = tmpres;
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@ -630,7 +655,7 @@ _bt_first(IndexScanDesc scan, ScanDirection dir)
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* hardwired attno == 1.
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*/
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proc = index_getprocid(rel, 1, BTORDER_PROC);
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ScanKeyEntryInitialize(&skdata, 0x0, 1, proc,
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ScanKeyEntryInitialize(&skdata, so->keyData[0].sk_flags, 1, proc,
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so->keyData[0].sk_argument);
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stack = _bt_search(rel, 1, &skdata, &buf);
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@ -7,7 +7,7 @@
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/executor/nodeIndexscan.c,v 1.1.1.1 1996/07/09 06:21:26 scrappy Exp $
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* $Header: /cvsroot/pgsql/src/backend/executor/nodeIndexscan.c,v 1.1.1.1.2.1 1996/10/30 06:06:50 scrappy Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -273,6 +273,11 @@ ExecIndexReScan(IndexScan *node, ExprContext *exprCtxt, Plan* parent)
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scanvalue = (Datum)
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ExecEvalExpr(scanexpr, exprCtxt, &isNull, &isDone);
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scan_keys[j].sk_argument = scanvalue;
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if (isNull) {
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scan_keys[j].sk_flags |= SK_ISNULL;
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} else {
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scan_keys[j].sk_flags &= ~SK_ISNULL;
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}
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}
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}
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}
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