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Commit14f6b38

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committed
+ NULLs handling
Actually required by multi-column indices support.We still don't use btree for 'A is (not) null', butnow btree keep items with NULL attrs using single rulefor placing/finding items on pages:NULLs greater NOT_NULLs and NULL = NULL.+ Bulkload code (nbtsort.c) support for multi-column indicesbuilding and NULLs.+ Fix for btendscan()->pfree(scanopaque) from Chris Dunlop.
1 parent427a879 commit14f6b38

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5 files changed

+432
-107
lines changed

5 files changed

+432
-107
lines changed

‎src/backend/access/nbtree/nbtinsert.c

Lines changed: 112 additions & 8 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/nbtinsert.c,v 1.10 1997/01/25 21:08:09momjian Exp $
10+
* $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtinsert.c,v 1.11 1997/03/2408:48:09vadim Exp $
1111
*
1212
*-------------------------------------------------------------------------
1313
*/
@@ -19,6 +19,7 @@
1919
#include<access/nbtree.h>
2020
#include<access/heapam.h>
2121
#include<storage/bufmgr.h>
22+
#include<fmgr.h>
2223

2324
#ifndefHAVE_MEMMOVE
2425
# include<regex/utils.h>
@@ -33,6 +34,7 @@ static void _bt_newroot(Relation rel, Buffer lbuf, Buffer rbuf);
3334
staticOffsetNumber_bt_pgaddtup(Relationrel,Bufferbuf,intkeysz,ScanKeyitup_scankey,Sizeitemsize,BTItembtitem,BTItemafteritem);
3435
staticbool_bt_goesonpg(Relationrel,Bufferbuf,Sizekeysz,ScanKeyscankey,BTItemafteritem);
3536
staticvoid_bt_updateitem(Relationrel,Sizekeysz,Bufferbuf,Oidbti_oid,BTItemnewItem);
37+
staticbool_bt_isequal (TupleDescitupdesc,Pagepage,OffsetNumberoffnum,intkeysz,ScanKeyscankey);
3638

3739
/*
3840
* _bt_doinsert() -- Handle insertion of a single btitem in the tree.
@@ -104,8 +106,16 @@ _bt_doinsert(Relation rel, BTItem btitem, bool index_is_unique, Relation heapRel
104106
itupdesc=RelationGetTupleDescriptor(rel);
105107
nbuf=InvalidBuffer;
106108
opaque= (BTPageOpaque)PageGetSpecialPointer(page);
109+
/*
110+
* _bt_compare returns 0 for (1,NULL) and (1,NULL) -
111+
* this's how we handling NULLs - and so we must not use
112+
* _bt_compare in real comparison, but only for
113+
* ordering/finding items on pages.- vadim 03/24/97
114+
107115
while ( !_bt_compare (rel, itupdesc, page,
108116
natts, itup_scankey, offset) )
117+
*/
118+
while (_bt_isequal (itupdesc,page,offset,natts,itup_scankey) )
109119
{/* they're equal */
110120
btitem= (BTItem)PageGetItem(page,PageGetItemId(page,offset));
111121
itup=&(btitem->bti_itup);
@@ -123,8 +133,8 @@ _bt_doinsert(Relation rel, BTItem btitem, bool index_is_unique, Relation heapRel
123133
{/* move right ? */
124134
if (P_RIGHTMOST (opaque) )
125135
break;
126-
if (_bt_compare (rel,itupdesc,page,
127-
natts,itup_scankey,P_HIKEY) )
136+
if (!_bt_isequal (itupdesc,page,P_HIKEY,
137+
natts,itup_scankey) )
128138
break;
129139
/*
130140
* min key of the right page is the same,
@@ -939,18 +949,70 @@ _bt_itemcmp(Relation rel,
939949
IndexTupleindexTuple1,indexTuple2;
940950
DatumattrDatum1,attrDatum2;
941951
inti;
942-
boolisNull;
952+
boolisFirstNull,isSecondNull;
943953
boolcompare;
954+
booluseEqual= false;
955+
956+
if (strat==BTLessEqualStrategyNumber )
957+
{
958+
useEqual= true;
959+
strat=BTLessStrategyNumber;
960+
}
961+
elseif (strat==BTGreaterEqualStrategyNumber )
962+
{
963+
useEqual= true;
964+
strat=BTGreaterStrategyNumber;
965+
}
944966

945967
tupDes=RelationGetTupleDescriptor(rel);
946968
indexTuple1=&(item1->bti_itup);
947969
indexTuple2=&(item2->bti_itup);
948970

949971
for (i=1;i <=keysz;i++) {
950-
attrDatum1=index_getattr(indexTuple1,i,tupDes,&isNull);
951-
attrDatum2=index_getattr(indexTuple2,i,tupDes,&isNull);
952-
compare=_bt_invokestrat(rel,i,strat,attrDatum1,attrDatum2);
953-
if (!compare) {
972+
attrDatum1=index_getattr(indexTuple1,i,tupDes,&isFirstNull);
973+
attrDatum2=index_getattr(indexTuple2,i,tupDes,&isSecondNull);
974+
975+
/* see comments about NULLs handling in btbuild */
976+
if (isFirstNull )/* attr in item1 is NULL */
977+
{
978+
if (isSecondNull )/* attr in item2 is NULL too */
979+
compare= (strat==BTEqualStrategyNumber ) ? true : false;
980+
else
981+
compare= (strat==BTGreaterStrategyNumber ) ? true : false;
982+
}
983+
elseif (isSecondNull )/* attr in item1 is NOT_NULL and */
984+
{/* and attr in item2 is NULL */
985+
compare= (strat==BTLessStrategyNumber ) ? true : false;
986+
}
987+
else
988+
{
989+
compare=_bt_invokestrat(rel,i,strat,attrDatum1,attrDatum2);
990+
}
991+
992+
if (compare )/* true for one of ">, <, =" */
993+
{
994+
if (strat!=BTEqualStrategyNumber )
995+
return (true);
996+
}
997+
else/* false for one of ">, <, =" */
998+
{
999+
if (strat==BTEqualStrategyNumber )
1000+
return (false);
1001+
/*
1002+
* if original strat was "<=, >=" OR
1003+
* "<, >" but some attribute(s) left
1004+
* - need to test for Equality
1005+
*/
1006+
if (useEqual||i<keysz )
1007+
{
1008+
if (isFirstNull||isSecondNull )
1009+
compare= (isFirstNull&&isSecondNull ) ? true : false;
1010+
else
1011+
compare=_bt_invokestrat(rel,i,BTEqualStrategyNumber,
1012+
attrDatum1,attrDatum2);
1013+
if (compare )/* item1' and item2' attributes are equal */
1014+
continue;/* - try to compare next attributes */
1015+
}
9541016
return (false);
9551017
}
9561018
}
@@ -1015,3 +1077,45 @@ _bt_updateitem(Relation rel,
10151077
ItemPointerCopy(&itemPtrData,&(oldIndexTuple->t_tid));
10161078

10171079
}
1080+
1081+
/*
1082+
* _bt_isequal - used in _bt_doinsert in check for duplicates.
1083+
*
1084+
* Rule is simple: NOT_NULL not equal NULL, NULL not_equal NULL too.
1085+
*/
1086+
staticbool
1087+
_bt_isequal (TupleDescitupdesc,Pagepage,OffsetNumberoffnum,
1088+
intkeysz,ScanKeyscankey)
1089+
{
1090+
Datumdatum;
1091+
BTItembtitem;
1092+
IndexTupleitup;
1093+
ScanKeyentry;
1094+
AttrNumberattno;
1095+
longresult;
1096+
inti;
1097+
boolnull;
1098+
1099+
btitem= (BTItem)PageGetItem(page,PageGetItemId(page,offnum));
1100+
itup=&(btitem->bti_itup);
1101+
1102+
for (i=1;i <=keysz;i++)
1103+
{
1104+
entry=&scankey[i-1];
1105+
attno=entry->sk_attno;
1106+
Assert (attno==i);
1107+
datum=index_getattr(itup,attno,itupdesc,&null);
1108+
1109+
/* NULLs are not equal */
1110+
if (entry->sk_flags&SK_ISNULL||null )
1111+
return (false);
1112+
1113+
result= (long)FMGR_PTR2(entry->sk_func,entry->sk_procedure,
1114+
entry->sk_argument,datum);
1115+
if (result!=0)
1116+
return (false);
1117+
}
1118+
1119+
/* by here, the keys are equal */
1120+
return (true);
1121+
}

‎src/backend/access/nbtree/nbtree.c

Lines changed: 20 additions & 8 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtree.c,v 1.16 1997/03/18 18:38:35 scrappy Exp $
11+
* $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtree.c,v 1.17 1997/03/24 08:48:11 vadim Exp $
1212
*
1313
* NOTES
1414
* This file contains only the public interface routines.
@@ -219,11 +219,21 @@ btbuild(Relation heap,
219219
* artifact of the strategy map architecture chosen in 1986, not
220220
* of the way nulls are handled here.
221221
*/
222-
222+
/*
223+
* New comments: NULLs handling.
224+
* While we can't do NULL comparison, we can follow simple
225+
* rule for ordering items on btree pages - NULLs greater
226+
* NOT_NULLs and NULL = NULL is TRUE. Sure, it's just rule
227+
* for placing/finding items and no more - keytest'll return
228+
* FALSE for a = 5 for items having 'a' isNULL.
229+
* Look at _bt_skeycmp, _bt_compare and _bt_itemcmp for
230+
* how it works.- vadim 03/23/97
231+
223232
if (itup->t_info & INDEX_NULL_MASK) {
224233
pfree(itup);
225234
continue;
226235
}
236+
*/
227237

228238
itup->t_tid=htup->t_ctid;
229239
btitem=_bt_formitem(itup);
@@ -328,8 +338,12 @@ btinsert(Relation rel, Datum *datum, char *nulls, ItemPointer ht_ctid, Relation
328338
itup=index_formtuple(RelationGetTupleDescriptor(rel),datum,nulls);
329339
itup->t_tid=*ht_ctid;
330340

341+
/*
342+
* See comments in btbuild.
343+
331344
if (itup->t_info & INDEX_NULL_MASK)
332345
return ((InsertIndexResult) NULL);
346+
*/
333347

334348
btitem=_bt_formitem(itup);
335349

@@ -423,7 +437,7 @@ btrescan(IndexScanDesc scan, bool fromEnd, ScanKey scankey)
423437

424438
/* reset the scan key */
425439
so->numberOfKeys=scan->numberOfKeys;
426-
so->numberOfFirstKeys=0;
440+
so->numberOfFirstKeys=0;/* may be changed by _bt_orderkeys */
427441
so->qual_ok=1;/* may be changed by _bt_orderkeys */
428442
if (scan->numberOfKeys>0) {
429443
memmove(scan->keyData,
@@ -433,10 +447,7 @@ btrescan(IndexScanDesc scan, bool fromEnd, ScanKey scankey)
433447
scankey,
434448
so->numberOfKeys*sizeof(ScanKeyData));
435449
/* order the keys in the qualification */
436-
if (so->numberOfKeys>1)
437-
_bt_orderkeys(scan->relation,so);
438-
else
439-
so->numberOfFirstKeys=1;
450+
_bt_orderkeys(scan->relation,so);
440451
}
441452

442453
/* finally, be sure that the scan exploits the tree order */
@@ -499,9 +510,10 @@ btendscan(IndexScanDesc scan)
499510
ItemPointerSetInvalid(iptr);
500511
}
501512

502-
pfree (scan->opaque);
503513
if (so->keyData!= (ScanKey)NULL )
504514
pfree (so->keyData);
515+
pfree (so);
516+
505517
_bt_dropscan(scan);
506518
}
507519

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