/*
* btmarkpos() -- save current scan position
*/
void
btmarkpos(IndexScanDesc scan)
{
BTScanOpaque so = (BTScanOpaque) scan->opaque;
/* There may be an old mark with a pin (but no lock). */
BTScanPosUnpinIfPinned(so->markPos);
/*
* Just record the current itemIndex. If we later step to next page
* before releasing the marked position, _bt_steppage makes a full copy of
* the currPos struct in markPos. If (as often happens) the mark is moved
* before we leave the page, we don't have to do that work.
*/
if (BTScanPosIsValid(so->currPos))
so->markItemIndex = so->currPos.itemIndex;
else
{
BTScanPosInvalidate(so->markPos);
so->markItemIndex = -1;
}
/* Also record the current positions of any array keys */
if (so->numArrayKeys)
_bt_mark_array_keys(scan);
}
/*
* btmarkpos() -- save current scan position
*/
Datum
btmarkpos(PG_FUNCTION_ARGS)
{
IndexScanDesc scan = (IndexScanDesc) PG_GETARG_POINTER(0);
BTScanOpaque so = (BTScanOpaque) scan->opaque;
/* we aren't holding any read locks, but gotta drop the pin */
if (BTScanPosIsValid(so->markPos))
{
ReleaseBuffer(so->markPos.buf);
so->markPos.buf = InvalidBuffer;
}
/*
* Just record the current itemIndex. If we later step to next page
* before releasing the marked position, _bt_steppage makes a full copy of
* the currPos struct in markPos. If (as often happens) the mark is moved
* before we leave the page, we don't have to do that work.
*/
if (BTScanPosIsValid(so->currPos))
so->markItemIndex = so->currPos.itemIndex;
else
so->markItemIndex = -1;
/* Also record the current positions of any array keys */
if (so->numArrayKeys)
_bt_mark_array_keys(scan);
PG_RETURN_VOID();
}
