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Fix sloppiness about alignment requirements in findsplitloc() space

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calculation, also make it stop when it has a 'good enough' split instead
of exhaustively trying all split points.
This commit is contained in:
Tom Lane
2000-07-21 19:21:00 +00:00
parent 2f011a9c72
commit 1ea912e16d
2 changed files with 101 additions and 38 deletions
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72
src/backend/access/nbtree/nbtutils.c
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@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtutils.c,v 1.38 2000/07/21 06:42:33 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtutils.c,v 1.39 2000/07/21 19:21:00 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -103,6 +103,9 @@ _bt_freeskey(ScanKey skey)
pfree(skey);
}
/*
* free a retracement stack made by _bt_search.
*/
void
_bt_freestack(BTStack stack)
{
@@ -116,12 +119,38 @@ _bt_freestack(BTStack stack)
}
}
/*
* Construct a BTItem from a plain IndexTuple.
*
* This is now useless code, since a BTItem *is* an index tuple with
* no extra stuff. We hang onto it for the moment to preserve the
* notational distinction, in case we want to add some extra stuff
* again someday.
*/
BTItem
_bt_formitem(IndexTuple itup)
{
int nbytes_btitem;
BTItem btitem;
Size tuplen;
extern Oid newoid();
/* make a copy of the index tuple with room for extra stuff */
tuplen = IndexTupleSize(itup);
nbytes_btitem = tuplen + (sizeof(BTItemData) - sizeof(IndexTupleData));
btitem = (BTItem) palloc(nbytes_btitem);
memcpy((char *) &(btitem->bti_itup), (char *) itup, tuplen);
return btitem;
}
/*
* _bt_orderkeys() -- Put keys in a sensible order for conjunctive quals.
*
* The order of the keys in the qual match the ordering imposed by
* the index. This routine only needs to be called if there are
* more than one qual clauses using this index.
* the index. This routine only needs to be called if there is
* more than one qual clause using this index.
*/
void
_bt_orderkeys(Relation relation, BTScanOpaque so)
@@ -189,7 +218,8 @@ _bt_orderkeys(Relation relation, BTScanOpaque so)
if (i == numberOfKeys || cur->sk_attno != attno)
{
if (cur->sk_attno != attno + 1 && i < numberOfKeys)
elog(ERROR, "_bt_orderkeys: key(s) for attribute %d missed", attno + 1);
elog(ERROR, "_bt_orderkeys: key(s) for attribute %d missed",
attno + 1);
underEqualStrategy = (!equalStrategyEnd);
@@ -320,24 +350,18 @@ _bt_orderkeys(Relation relation, BTScanOpaque so)
pfree(xform);
}
BTItem
_bt_formitem(IndexTuple itup)
{
int nbytes_btitem;
BTItem btitem;
Size tuplen;
extern Oid newoid();
/* make a copy of the index tuple with room for the sequence number */
tuplen = IndexTupleSize(itup);
nbytes_btitem = tuplen + (sizeof(BTItemData) - sizeof(IndexTupleData));
btitem = (BTItem) palloc(nbytes_btitem);
memcpy((char *) &(btitem->bti_itup), (char *) itup, tuplen);
return btitem;
}
/*
* Test whether an indextuple satisfies all the scankey conditions
*
* If not ("false" return), the number of conditions satisfied is
* returned in *keysok. Given proper ordering of the scankey conditions,
* we can use this to determine whether it's worth continuing the scan.
* See _bt_orderkeys().
*
* HACK: *keysok == (Size) -1 means we stopped evaluating because we found
* a NULL value in the index tuple. It's not quite clear to me why this
* case has to be treated specially --- tgl 7/00.
*/
bool
_bt_checkkeys(IndexScanDesc scan, IndexTuple tuple, Size *keysok)
{
@@ -389,9 +413,9 @@ _bt_checkkeys(IndexScanDesc scan, IndexTuple tuple, Size *keysok)
if (DatumGetBool(test) == !!(key[0].sk_flags & SK_NEGATE))
return false;
keysz -= 1;
key++;
(*keysok)++;
key++;
keysz--;
}
return true;