/*
* gistindex_keytest() -- does this index tuple satisfy the scan key(s)?
*
* The index tuple might represent either a heap tuple or a lower index page,
* depending on whether the containing page is a leaf page or not.
*
* On success return for a heap tuple, *recheck_p is set to indicate
* whether recheck is needed. We recheck if any of the consistent() functions
* request it. recheck is not interesting when examining a non-leaf entry,
* since we must visit the lower index page if there's any doubt.
*
* If we are doing an ordered scan, so->distances[] is filled with distance
* data from the distance() functions before returning success.
*
* We must decompress the key in the IndexTuple before passing it to the
* sk_funcs (which actually are the opclass Consistent or Distance methods).
*
* 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 or Distance methods.
*/
static bool
gistindex_keytest(IndexScanDesc scan,
IndexTuple tuple,
Page page,
OffsetNumber offset,
bool *recheck_p)
{
GISTScanOpaque so = (GISTScanOpaque) scan->opaque;
GISTSTATE *giststate = so->giststate;
ScanKey key = scan->keyData;
int keySize = scan->numberOfKeys;
double *distance_p;
Relation r = scan->indexRelation;
*recheck_p = false;
/*
* If it's a leftover invalid tuple from pre-9.1, treat it as a match with
* minimum possible distances. This means we'll always follow it to the
* referenced page.
*
* GPDB: the virtual TIDs created for AO tables use the full range of
* offset numbers from 0 to 65535. So a tuple on leaf page that looks like
* an invalid tuple, is actually ok.
*/
if (!GistPageIsLeaf(page) && GistTupleIsInvalid(tuple))
{
int i;
for (i = 0; i < scan->numberOfOrderBys; i++)
so->distances[i] = -get_float8_infinity();
return true;
}
/* Check whether it matches according to the Consistent functions */
while (keySize > 0)
{
Datum datum;
bool isNull;
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: union (VAL, NULL) is VAL.
* But if on non-leaf page key IS NULL, then all children are
* NULL.
*/
if (key->sk_flags & SK_SEARCHNULL)
{
if (GistPageIsLeaf(page) && !isNull)
return false;
}
else
{
Assert(key->sk_flags & SK_SEARCHNOTNULL);
if (isNull)
return false;
}
}
else if (isNull)
{
return false;
}
else
{
Datum test;
bool recheck;
GISTENTRY de;
gistdentryinit(giststate, key->sk_attno - 1, &de,
datum, r, page, offset,
FALSE, isNull);
/*
* Call the Consistent function to evaluate the test. The
* arguments are the index datum (as a GISTENTRY*), the comparison
* datum, the comparison operator's strategy number and subtype
* from pg_amop, and the recheck flag.
*
* (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.)
*
* We initialize the recheck flag to true (the safest assumption)
* in case the Consistent function forgets to set it.
*/
recheck = true;
test = FunctionCall5Coll(&key->sk_func,
key->sk_collation,
PointerGetDatum(&de),
key->sk_argument,
Int32GetDatum(key->sk_strategy),
ObjectIdGetDatum(key->sk_subtype),
PointerGetDatum(&recheck));
if (!DatumGetBool(test))
return false;
*recheck_p |= recheck;
}
key++;
keySize--;
}
/* OK, it passes --- now let's compute the distances */
key = scan->orderByData;
distance_p = so->distances;
keySize = scan->numberOfOrderBys;
while (keySize > 0)
{
Datum datum;
bool isNull;
datum = index_getattr(tuple,
key->sk_attno,
giststate->tupdesc,
&isNull);
if ((key->sk_flags & SK_ISNULL) || isNull)
{
/* Assume distance computes as null and sorts to the end */
*distance_p = get_float8_infinity();
}
else
{
Datum dist;
GISTENTRY de;
gistdentryinit(giststate, key->sk_attno - 1, &de,
datum, r, page, offset,
FALSE, isNull);
/*
* Call the Distance function to evaluate the distance. The
* arguments are the index datum (as a GISTENTRY*), the comparison
* datum, and the ordering 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.)
*
* Note that Distance functions don't get a recheck argument. We
* can't tolerate lossy distance calculations on leaf tuples;
* there is no opportunity to re-sort the tuples afterwards.
*/
dist = FunctionCall4Coll(&key->sk_func,
key->sk_collation,
PointerGetDatum(&de),
key->sk_argument,
Int32GetDatum(key->sk_strategy),
ObjectIdGetDatum(key->sk_subtype));
*distance_p = DatumGetFloat8(dist);
}
key++;
distance_p++;
keySize--;
}
return true;
}
/*
* gistindex_keytest() -- does this index tuple satisfy the scan key(s)?
*
* The index tuple might represent either a heap tuple or a lower index page,
* depending on whether the containing page is a leaf page or not.
*
* On success return for a heap tuple, *recheck_p is set to indicate whether
* the quals need to be rechecked. We recheck if any of the consistent()
* functions request it. recheck is not interesting when examining a non-leaf
* entry, since we must visit the lower index page if there's any doubt.
* Similarly, *recheck_distances_p is set to indicate whether the distances
* need to be rechecked, and it is also ignored for non-leaf entries.
*
* If we are doing an ordered scan, so->distances[] is filled with distance
* data from the distance() functions before returning success.
*
* We must decompress the key in the IndexTuple before passing it to the
* sk_funcs (which actually are the opclass Consistent or Distance methods).
*
* 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 or Distance methods.
*/
static bool
gistindex_keytest(IndexScanDesc scan,
IndexTuple tuple,
Page page,
OffsetNumber offset,
bool *recheck_p,
bool *recheck_distances_p)
{
GISTScanOpaque so = (GISTScanOpaque) scan->opaque;
GISTSTATE *giststate = so->giststate;
ScanKey key = scan->keyData;
int keySize = scan->numberOfKeys;
double *distance_p;
Relation r = scan->indexRelation;
*recheck_p = false;
*recheck_distances_p = false;
/*
* If it's a leftover invalid tuple from pre-9.1, treat it as a match with
* minimum possible distances. This means we'll always follow it to the
* referenced page.
*/
if (GistTupleIsInvalid(tuple))
{
int i;
if (GistPageIsLeaf(page)) /* shouldn't happen */
elog(ERROR, "invalid GiST tuple found on leaf page");
for (i = 0; i < scan->numberOfOrderBys; i++)
so->distances[i] = -get_float8_infinity();
return true;
}
/* Check whether it matches according to the Consistent functions */
while (keySize > 0)
{
Datum datum;
bool isNull;
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: union (VAL, NULL) is VAL.
* But if on non-leaf page key IS NULL, then all children are
* NULL.
*/
if (key->sk_flags & SK_SEARCHNULL)
{
if (GistPageIsLeaf(page) && !isNull)
return false;
}
else
{
Assert(key->sk_flags & SK_SEARCHNOTNULL);
if (isNull)
return false;
}
}
else if (isNull)
{
return false;
}
else
{
Datum test;
bool recheck;
GISTENTRY de;
gistdentryinit(giststate, key->sk_attno - 1, &de,
datum, r, page, offset,
false, isNull);
/*
* Call the Consistent function to evaluate the test. The
* arguments are the index datum (as a GISTENTRY*), the comparison
* datum, the comparison operator's strategy number and subtype
* from pg_amop, and the recheck flag.
*
* (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.)
*
* We initialize the recheck flag to true (the safest assumption)
* in case the Consistent function forgets to set it.
*/
recheck = true;
test = FunctionCall5Coll(&key->sk_func,
key->sk_collation,
PointerGetDatum(&de),
key->sk_argument,
Int16GetDatum(key->sk_strategy),
ObjectIdGetDatum(key->sk_subtype),
PointerGetDatum(&recheck));
if (!DatumGetBool(test))
return false;
*recheck_p |= recheck;
}
key++;
keySize--;
}
/* OK, it passes --- now let's compute the distances */
key = scan->orderByData;
distance_p = so->distances;
keySize = scan->numberOfOrderBys;
while (keySize > 0)
{
Datum datum;
bool isNull;
datum = index_getattr(tuple,
key->sk_attno,
giststate->tupdesc,
&isNull);
if ((key->sk_flags & SK_ISNULL) || isNull)
{
/* Assume distance computes as null and sorts to the end */
*distance_p = get_float8_infinity();
}
else
{
Datum dist;
bool recheck;
GISTENTRY de;
gistdentryinit(giststate, key->sk_attno - 1, &de,
datum, r, page, offset,
false, isNull);
/*
* Call the Distance function to evaluate the distance. The
* arguments are the index datum (as a GISTENTRY*), the comparison
* datum, the ordering operator's strategy number and subtype from
* pg_amop, and the recheck flag.
*
* (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.)
*
* If the function sets the recheck flag, the returned distance is
* a lower bound on the true distance and needs to be rechecked.
* We initialize the flag to 'false'. This flag was added in
* version 9.5; distance functions written before that won't know
* about the flag, but are expected to never be lossy.
*/
recheck = false;
dist = FunctionCall5Coll(&key->sk_func,
key->sk_collation,
PointerGetDatum(&de),
key->sk_argument,
Int16GetDatum(key->sk_strategy),
ObjectIdGetDatum(key->sk_subtype),
PointerGetDatum(&recheck));
*recheck_distances_p |= recheck;
*distance_p = DatumGetFloat8(dist);
}
key++;
distance_p++;
keySize--;
}
return true;
}
