/*
* _hash_checkqual -- does the index tuple satisfy the scan conditions?
*/
bool
_hash_checkqual(IndexScanDesc scan, IndexTuple itup)
{
TupleDesc tupdesc = RelationGetDescr(scan->indexRelation);
ScanKey key = scan->keyData;
int scanKeySize = scan->numberOfKeys;
IncrIndexProcessed();
while (scanKeySize > 0)
{
Datum datum;
bool isNull;
Datum test;
datum = index_getattr(itup,
key->sk_attno,
tupdesc,
&isNull);
/* assume sk_func is strict */
if (isNull)
return false;
if (key->sk_flags & SK_ISNULL)
return false;
test = FunctionCall2(&key->sk_func, datum, key->sk_argument);
if (!DatumGetBool(test))
return false;
key++;
scanKeySize--;
}
return true;
}
/*
* Test whether an indextuple satisfies all the scankey conditions.
*
* If so, copy its TID into scan->xs_ctup.t_self, and return TRUE.
* If not, return FALSE (xs_ctup is not changed).
*
* If the tuple fails to pass the qual, we also determine whether there's
* any need to continue the scan beyond this tuple, and set *continuescan
* accordingly. See comments for _bt_preprocess_keys(), above, about how
* this is done.
*
* scan: index scan descriptor (containing a search-type scankey)
* page: buffer page containing index tuple
* offnum: offset number of index tuple (must be a valid item!)
* dir: direction we are scanning in
* continuescan: output parameter (will be set correctly in all cases)
*/
bool
_bt_checkkeys(IndexScanDesc scan,
Page page, OffsetNumber offnum,
ScanDirection dir, bool *continuescan)
{
ItemId iid = PageGetItemId(page, offnum);
bool tuple_valid;
IndexTuple tuple;
TupleDesc tupdesc;
BTScanOpaque so;
int keysz;
int ikey;
ScanKey key;
*continuescan = true; /* default assumption */
/*
* If the scan specifies not to return killed tuples, then we treat a
* killed tuple as not passing the qual. Most of the time, it's a win to
* not bother examining the tuple's index keys, but just return
* immediately with continuescan = true to proceed to the next tuple.
* However, if this is the last tuple on the page, we should check the
* index keys to prevent uselessly advancing to the next page.
*/
if (scan->ignore_killed_tuples && ItemIdIsDead(iid))
{
/* return immediately if there are more tuples on the page */
if (ScanDirectionIsForward(dir))
{
if (offnum < PageGetMaxOffsetNumber(page))
return false;
}
else
{
BTPageOpaque opaque = (BTPageOpaque) PageGetSpecialPointer(page);
if (offnum > P_FIRSTDATAKEY(opaque))
return false;
}
/*
* OK, we want to check the keys, but we'll return FALSE even if the
* tuple passes the key tests.
*/
tuple_valid = false;
}
else
tuple_valid = true;
tuple = (IndexTuple) PageGetItem(page, iid);
IncrIndexProcessed();
tupdesc = RelationGetDescr(scan->indexRelation);
so = (BTScanOpaque) scan->opaque;
keysz = so->numberOfKeys;
for (key = so->keyData, ikey = 0; ikey < keysz; key++, ikey++)
{
Datum datum;
bool isNull;
Datum test;
/* row-comparison keys need special processing */
if (key->sk_flags & SK_ROW_HEADER)
{
if (_bt_check_rowcompare(key, tuple, tupdesc, dir, continuescan))
continue;
return false;
}
datum = index_getattr(tuple,
key->sk_attno,
tupdesc,
&isNull);
if (key->sk_flags & SK_ISNULL)
{
/* Handle IS NULL tests */
Assert(key->sk_flags & SK_SEARCHNULL);
if (isNull)
continue; /* tuple satisfies this qual */
/*
* Tuple fails this qual. If it's a required qual for the current
* scan direction, then we can conclude no further tuples will
* pass, either.
*/
if ((key->sk_flags & SK_BT_REQFWD) &&
ScanDirectionIsForward(dir))
*continuescan = false;
else if ((key->sk_flags & SK_BT_REQBKWD) &&
ScanDirectionIsBackward(dir))
*continuescan = false;
/*
* In any case, this indextuple doesn't match the qual.
*/
return false;
}
if (isNull)
{
if (key->sk_flags & SK_BT_NULLS_FIRST)
{
/*
* Since NULLs are sorted before non-NULLs, we know we have
* reached the lower limit of the range of values for this
* index attr. On a backward scan, we can stop if this qual
* is one of the "must match" subset. On a forward scan,
* however, we should keep going.
*/
if ((key->sk_flags & SK_BT_REQBKWD) &&
ScanDirectionIsBackward(dir))
*continuescan = false;
}
else
{
/*
* Since NULLs are sorted after non-NULLs, we know we have
* reached the upper limit of the range of values for this
* index attr. On a forward scan, we can stop if this qual is
* one of the "must match" subset. On a backward scan,
* however, we should keep going.
*/
if ((key->sk_flags & SK_BT_REQFWD) &&
ScanDirectionIsForward(dir))
*continuescan = false;
}
/*
* In any case, this indextuple doesn't match the qual.
*/
return false;
}
test = FunctionCall2(&key->sk_func, datum, key->sk_argument);
if (!DatumGetBool(test))
{
/*
* Tuple fails this qual. If it's a required qual for the current
* scan direction, then we can conclude no further tuples will
* pass, either.
*
* Note: because we stop the scan as soon as any required equality
* qual fails, it is critical that equality quals be used for the
* initial positioning in _bt_first() when they are available. See
* comments in _bt_first().
*/
if ((key->sk_flags & SK_BT_REQFWD) &&
ScanDirectionIsForward(dir))
*continuescan = false;
else if ((key->sk_flags & SK_BT_REQBKWD) &&
ScanDirectionIsBackward(dir))
*continuescan = false;
/*
* In any case, this indextuple doesn't match the qual.
*/
return false;
}
}
/* If we get here, the tuple passes all index quals. */
if (tuple_valid)
scan->xs_ctup.t_self = tuple->t_tid;
return tuple_valid;
}
/*
* gistindex_keytest() -- does this index tuple satisfy the scan key(s)?
*
* We must decompress the key in the IndexTuple before passing it to the
* sk_func (and we have previously overwritten the sk_func to use the
* user-defined Consistent method, so we actually are invoking that).
*
* Note that this function is always invoked in a short-lived memory context,
* so we don't need to worry about cleaning up allocated memory, either here
* or in the implementation of any Consistent methods.
*/
static bool
gistindex_keytest(IndexTuple tuple,
IndexScanDesc scan,
OffsetNumber offset)
{
int keySize = scan->numberOfKeys;
ScanKey key = scan->keyData;
Relation r = scan->indexRelation;
GISTScanOpaque so;
Page p;
GISTSTATE *giststate;
so = (GISTScanOpaque) scan->opaque;
giststate = so->giststate;
p = BufferGetPage(so->curbuf);
IncrIndexProcessed();
/*
* Tuple doesn't restore after crash recovery because of incomplete insert
*/
if (!GistPageIsLeaf(p) && GistTupleIsInvalid(tuple))
return true;
while (keySize > 0)
{
Datum datum;
bool isNull;
Datum test;
GISTENTRY de;
datum = index_getattr(tuple,
key->sk_attno,
giststate->tupdesc,
&isNull);
if (key->sk_flags & SK_ISNULL)
{
/*
* On non-leaf page we can't conclude that child hasn't NULL
* values because of assumption in GiST: uinon (VAL, NULL) is VAL
* But if on non-leaf page key IS NULL then all childs has NULL.
*/
Assert(key->sk_flags & SK_SEARCHNULL);
if (GistPageIsLeaf(p) && !isNull)
return false;
}
else if (isNull)
{
return false;
}
else
{
gistdentryinit(giststate, key->sk_attno - 1, &de,
datum, r, p, offset,
FALSE, isNull);
/*
* Call the Consistent function to evaluate the test. The
* arguments are the index datum (as a GISTENTRY*), the comparison
* datum, and the comparison operator's strategy number and
* subtype from pg_amop.
*
* (Presently there's no need to pass the subtype since it'll
* always be zero, but might as well pass it for possible future
* use.)
*/
test = FunctionCall4(&key->sk_func,
PointerGetDatum(&de),
key->sk_argument,
Int32GetDatum(key->sk_strategy),
ObjectIdGetDatum(key->sk_subtype));
if (!DatumGetBool(test))
return false;
}
keySize--;
key++;
}
return true;
}
