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+ NULLs handling

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Actually required by multi-column indices support.
	We still don't use btree for 'A is (not) null', but
	now btree keep items with NULL attrs using single rule
	for placing/finding items on pages:
	NULLs greater NOT_NULLs and NULL = NULL.
+ Bulkload code (nbtsort.c) support for multi-column indices
	building and NULLs.
+ Fix for btendscan()->pfree(scanopaque) from Chris Dunlop.
This commit is contained in:
Vadim B. Mikheev
1997-03-24 08:48:16 +00:00
parent 427a87911d
commit 14f6b387b1
5 changed files with 434 additions and 109 deletions
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120
src/backend/access/nbtree/nbtinsert.c
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@@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtinsert.c,v 1.10 1997/01/25 21:08:09 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtinsert.c,v 1.11 1997/03/24 08:48:09 vadim Exp $
*
*-------------------------------------------------------------------------
*/
@@ -19,6 +19,7 @@
#include <access/nbtree.h>
#include <access/heapam.h>
#include <storage/bufmgr.h>
#include <fmgr.h>
#ifndef HAVE_MEMMOVE
# include <regex/utils.h>
@@ -33,6 +34,7 @@ static void _bt_newroot(Relation rel, Buffer lbuf, Buffer rbuf);
static OffsetNumber _bt_pgaddtup(Relation rel, Buffer buf, int keysz, ScanKey itup_scankey, Size itemsize, BTItem btitem, BTItem afteritem);
static bool _bt_goesonpg(Relation rel, Buffer buf, Size keysz, ScanKey scankey, BTItem afteritem);
static void _bt_updateitem(Relation rel, Size keysz, Buffer buf, Oid bti_oid, BTItem newItem);
static bool _bt_isequal (TupleDesc itupdesc, Page page, OffsetNumber offnum, int keysz, ScanKey scankey);
/*
* _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
itupdesc = RelationGetTupleDescriptor(rel);
nbuf = InvalidBuffer;
opaque = (BTPageOpaque) PageGetSpecialPointer(page);
/*
* _bt_compare returns 0 for (1,NULL) and (1,NULL) -
* this's how we handling NULLs - and so we must not use
* _bt_compare in real comparison, but only for
* ordering/finding items on pages. - vadim 03/24/97
while ( !_bt_compare (rel, itupdesc, page,
natts, itup_scankey, offset) )
*/
while ( _bt_isequal (itupdesc, page, offset, natts, itup_scankey) )
{ /* they're equal */
btitem = (BTItem) PageGetItem(page, PageGetItemId(page, offset));
itup = &(btitem->bti_itup);
@@ -123,8 +133,8 @@ _bt_doinsert(Relation rel, BTItem btitem, bool index_is_unique, Relation heapRel
{ /* move right ? */
if ( P_RIGHTMOST (opaque) )
break;
if ( _bt_compare (rel, itupdesc, page,
natts, itup_scankey, P_HIKEY) )
if ( !_bt_isequal (itupdesc, page, P_HIKEY,
natts, itup_scankey) )
break;
/*
* min key of the right page is the same,
@@ -939,18 +949,70 @@ _bt_itemcmp(Relation rel,
IndexTuple indexTuple1, indexTuple2;
Datum attrDatum1, attrDatum2;
int i;
bool isNull;
bool isFirstNull, isSecondNull;
bool compare;
bool useEqual = false;
if ( strat == BTLessEqualStrategyNumber )
{
useEqual = true;
strat = BTLessStrategyNumber;
}
else if ( strat == BTGreaterEqualStrategyNumber )
{
useEqual = true;
strat = BTGreaterStrategyNumber;
}
tupDes = RelationGetTupleDescriptor(rel);
indexTuple1 = &(item1->bti_itup);
indexTuple2 = &(item2->bti_itup);
for (i = 1; i <= keysz; i++) {
attrDatum1 = index_getattr(indexTuple1, i, tupDes, &isNull);
attrDatum2 = index_getattr(indexTuple2, i, tupDes, &isNull);
compare = _bt_invokestrat(rel, i, strat, attrDatum1, attrDatum2);
if (!compare) {
attrDatum1 = index_getattr(indexTuple1, i, tupDes, &isFirstNull);
attrDatum2 = index_getattr(indexTuple2, i, tupDes, &isSecondNull);
/* see comments about NULLs handling in btbuild */
if ( isFirstNull ) /* attr in item1 is NULL */
{
if ( isSecondNull ) /* attr in item2 is NULL too */
compare = ( strat == BTEqualStrategyNumber ) ? true : false;
else
compare = ( strat == BTGreaterStrategyNumber ) ? true : false;
}
else if ( isSecondNull ) /* attr in item1 is NOT_NULL and */
{ /* and attr in item2 is NULL */
compare = ( strat == BTLessStrategyNumber ) ? true : false;
}
else
{
compare = _bt_invokestrat(rel, i, strat, attrDatum1, attrDatum2);
}
if ( compare ) /* true for one of ">, <, =" */
{
if ( strat != BTEqualStrategyNumber )
return (true);
}
else /* false for one of ">, <, =" */
{
if ( strat == BTEqualStrategyNumber )
return (false);
/*
* if original strat was "<=, >=" OR
* "<, >" but some attribute(s) left
* - need to test for Equality
*/
if ( useEqual || i < keysz )
{
if ( isFirstNull || isSecondNull )
compare = ( isFirstNull && isSecondNull ) ? true : false;
else
compare = _bt_invokestrat(rel, i, BTEqualStrategyNumber,
attrDatum1, attrDatum2);
if ( compare ) /* item1' and item2' attributes are equal */
continue; /* - try to compare next attributes */
}
return (false);
}
}
@@ -1015,3 +1077,45 @@ _bt_updateitem(Relation rel,
ItemPointerCopy(&itemPtrData, &(oldIndexTuple->t_tid));
}
/*
* _bt_isequal - used in _bt_doinsert in check for duplicates.
*
* Rule is simple: NOT_NULL not equal NULL, NULL not_equal NULL too.
*/
static bool
_bt_isequal (TupleDesc itupdesc, Page page, OffsetNumber offnum,
int keysz, ScanKey scankey)
{
Datum datum;
BTItem btitem;
IndexTuple itup;
ScanKey entry;
AttrNumber attno;
long result;
int i;
bool null;
btitem = (BTItem) PageGetItem(page, PageGetItemId(page, offnum));
itup = &(btitem->bti_itup);
for (i = 1; i <= keysz; i++)
{
entry = &scankey[i - 1];
attno = entry->sk_attno;
Assert (attno == i);
datum = index_getattr(itup, attno, itupdesc, &null);
/* NULLs are not equal */
if ( entry->sk_flags & SK_ISNULL || null )
return (false);
result = (long) FMGR_PTR2(entry->sk_func, entry->sk_procedure,
entry->sk_argument, datum);
if (result != 0)
return (false);
}
/* by here, the keys are equal */
return (true);
}