Function delete_tail

src/jrd/vio.cpp:4984–5040

static UCHAR* delete_tail(thread_db* tdbb,
						  record_param* rpb,
						  ULONG prior_page,
						  UCHAR* tail,
						  const UCHAR* tail_end)
{
/**************************************
 *
 *	d e l e t e _ t a i l
 *
 **************************************
 *
 * Functional description
 *	Delete the tail of a record.  If no tail, don't do nuttin'.
 *	If the address of a record tail has been passed, fetch data.
 *
 **************************************/
	SET_TDBB(tdbb);

#ifdef VIO_DEBUG
	jrd_rel* relation = rpb->rpb_relation;
	VIO_trace(DEBUG_WRITES,
		"delete_tail (rel_id %u, record_param %" QUADFORMAT"d, prior_page %" SLONGFORMAT", tail %p, length %u)\n",
		relation->rel_id, rpb->rpb_number.getValue(), prior_page, tail, tail_end - tail);

	VIO_trace(DEBUG_WRITES_INFO,
		"   tail of record  %" SLONGFORMAT":%d, rpb_trans %" SQUADFORMAT
		", flags %d, back %" SLONGFORMAT":%d, fragment %" SLONGFORMAT":%d\n",
		rpb->rpb_page, rpb->rpb_line, rpb->rpb_transaction_nr,
		rpb->rpb_flags, rpb->rpb_b_page, rpb->rpb_b_line,
		rpb->rpb_f_page, rpb->rpb_f_line);
#endif

	RuntimeStatistics::Accumulator fragments(tdbb, rpb->rpb_relation,
		RuntimeStatistics::RECORD_FRAGMENT_READS);

	while (rpb->rpb_flags & rpb_incomplete)
	{
		rpb->rpb_page = rpb->rpb_f_page;
		rpb->rpb_line = rpb->rpb_f_line;

		// Since the callers are modifying this record, it should not be garbage collected.

		if (!DPM_fetch(tdbb, rpb, LCK_write))
			BUGCHECK(248);		// msg 248 cannot find record fragment

		if (tail)
			tail = unpack(rpb, tail_end - tail, tail);

		DPM_delete(tdbb, rpb, prior_page);
		prior_page = rpb->rpb_page;

		++fragments;
	}

	return tail;
}