Method generateRetrieval

src/jrd/optimizer/Optimizer.cpp:3011–3200

//

RecordSource* Optimizer::generateRetrieval(StreamType stream,
										   SortNode** sortClause,
										   bool outerFlag,
										   bool innerFlag,
										   BoolExprNode** returnBoolean)
{
	const auto tail = &csb->csb_rpt[stream];
	const auto relation = tail->csb_relation;
	fb_assert(relation);

	const string alias = makeAlias(stream);
	tail->activate();

	// Time to find inversions. For each index on the relation
	// match all unused booleans against the index looking for upper
	// and lower bounds that can be computed by the index. When
	// all unused conjunctions are exhausted, see if there is enough
	// information for an index retrieval. If so, build up an
	// inversion component of the boolean.

	RecordSource* rsb = nullptr;
	InversionNode* inversion = nullptr;
	BoolExprNode* condition = nullptr;
	Array<DbKeyRangeNode*> dbkeyRanges;
	double scanSelectivity = MAXIMUM_SELECTIVITY;

	if (relation->rel_file)
	{
		// External table
		rsb = FB_NEW_POOL(getPool()) ExternalTableScan(csb, alias, stream, relation);
	}
	else if (relation->isVirtual())
	{
		// Virtual table: monitoring or security
		switch (relation->rel_id)
		{
		case rel_global_auth_mapping:
			rsb = FB_NEW_POOL(getPool()) GlobalMappingScan(csb, alias, stream, relation);
			break;

		case rel_sec_users:
		case rel_sec_user_attributes:
			rsb = FB_NEW_POOL(getPool()) UsersTableScan(csb, alias, stream, relation);
			break;

		case rel_sec_db_creators:
			rsb = FB_NEW_POOL(getPool()) DbCreatorsScan(csb, alias, stream, relation);
			break;

		case rel_time_zones:
			rsb = FB_NEW_POOL(getPool()) TimeZonesTableScan(csb, alias, stream, relation);
			break;

		case rel_config:
			rsb = FB_NEW_POOL(getPool()) ConfigTableScan(csb, alias, stream, relation);
			break;

		case rel_keywords: