Method internalOpen

src/jrd/recsrc/FullTableScan.cpp:51–112

}

void FullTableScan::internalOpen(thread_db* tdbb) const
{
	Database* const dbb = tdbb->getDatabase();
	Attachment* const attachment = tdbb->getAttachment();
	Request* const request = tdbb->getRequest();
	Impure* const impure = request->getImpure<Impure>(m_impure);

	impure->irsb_flags = irsb_open;

	RLCK_reserve_relation(tdbb, request->req_transaction, m_relation, false);

	record_param* const rpb = &request->req_rpb[m_stream];
	rpb->getWindow(tdbb).win_flags = 0;

	// Unless this is the only attachment, limit the cache flushing
	// effect of large sequential scans on the page working sets of
	// other attachments

	if (attachment && (attachment != dbb->dbb_attachments || attachment->att_next))
	{
		// If the relation has more data pages than the number of
		// pages in the buffer cache then mark the input window
		// block as a large scan so that a data page is released
		// to the LRU tail after its last record is fetched.
		//
		// A database backup treats everything as a large scan
		// because the cumulative effect of scanning all relations
		// is equal to that of a single large relation.

		BufferControl* const bcb = dbb->dbb_bcb;

		if (attachment->isGbak() || DPM_data_pages(tdbb, m_relation) > bcb->bcb_count)
		{
			rpb->getWindow(tdbb).win_flags = WIN_large_scan;
			rpb->rpb_org_scans = m_relation->rel_scan_count++;
		}
	}

	rpb->rpb_number.setValue(BOF_NUMBER);

	if (m_dbkeyRanges.hasData())
	{
		impure->irsb_lower.setValid(false);
		impure->irsb_upper.setValid(false);

		EVL_dbkey_bounds(tdbb, m_dbkeyRanges, rpb->rpb_relation,
			impure->irsb_lower, impure->irsb_upper);

		if (impure->irsb_lower.isValid())
		{
			auto number = impure->irsb_lower.getValue();

			const auto ppages = rpb->rpb_relation->getPages(tdbb)->rel_pages;
			const auto maxRecno = (SINT64) ppages->count() *
				dbb->dbb_dp_per_pp * dbb->dbb_max_records - 1;
			if (number > maxRecno)
				number = maxRecno;