Function VIO_get

src/jrd/vio.cpp:2923–2985

bool VIO_get(thread_db* tdbb, record_param* rpb, jrd_tra* transaction, MemoryPool* pool)
{
/**************************************
 *
 *	V I O _ g e t
 *
 **************************************
 *
 * Functional description
 *	Get a specific record from a relation.
 *
 **************************************/
	SET_TDBB(tdbb);

#ifdef VIO_DEBUG
	jrd_rel* relation = rpb->rpb_relation;
	VIO_trace(DEBUG_READS,
		"VIO_get (rel_id %u, record_param %" QUADFORMAT"d, transaction %" SQUADFORMAT", pool %p)\n",
		relation->rel_id, rpb->rpb_number.getValue(), transaction ? transaction->tra_number : 0,
		(void*) pool);
#endif

	// Fetch data page from a modify/erase input stream with a write
	// lock. This saves an upward conversion to a write lock when
	// refetching the page in the context of the output stream.

	const USHORT lock_type = (rpb->rpb_stream_flags & RPB_s_update) ? LCK_write : LCK_read;

	if (!DPM_get(tdbb, rpb, lock_type) ||
		!VIO_chase_record_version(tdbb, rpb, transaction, pool, false, false))
	{
		return false;
	}

#ifdef VIO_DEBUG
	VIO_trace(DEBUG_READS_INFO,
		"   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

	if (rpb->rpb_runtime_flags & RPB_undo_data)
		fb_assert(rpb->getWindow(tdbb).win_bdb == NULL);
	else
		fb_assert(rpb->getWindow(tdbb).win_bdb != NULL);

	if (pool && !(rpb->rpb_runtime_flags & RPB_undo_data))
	{
		if (rpb->rpb_stream_flags & RPB_s_no_data)
		{
			CCH_RELEASE(tdbb, &rpb->getWindow(tdbb));
			rpb->rpb_address = NULL;
			rpb->rpb_length = 0;
		}
		else
			VIO_data(tdbb, rpb, pool);