Method makeIndexScanNode

src/jrd/optimizer/Retrieval.cpp:1126–1297

//

InversionNode* Retrieval::makeIndexScanNode(IndexScratch* indexScratch) const
{
	if (!createIndexScanNodes)
		return nullptr;

	const auto idx = indexScratch->index;
	auto& segments = indexScratch->segments;

	// Check whether this is during a compile or during a SET INDEX operation
	if (csb)
		CMP_post_resource(&csb->csb_resources, relation, Resource::rsc_index, idx->idx_id);
	else
	{
		CMP_post_resource(&tdbb->getRequest()->getStatement()->resources, relation,
			Resource::rsc_index, idx->idx_id);
	}

	// For external requests, determine index name (to be reported in plans)
	MetaName indexName;
	if (!(csb->csb_g_flags & csb_internal))
		MET_lookup_index(tdbb, indexName, relation->rel_name, idx->idx_id + 1);

	const auto retrieval =
		FB_NEW_POOL(getPool()) IndexRetrieval(getPool(), relation, idx, indexName);

	// Pick up lower bound segment values
	ValueExprNode** lower = retrieval->irb_value;
	ValueExprNode** upper = retrieval->irb_value + idx->idx_count;
	retrieval->irb_lower_count = indexScratch->lowerCount;
	retrieval->irb_upper_count = indexScratch->upperCount;

	if (idx->idx_flags & idx_descending)
	{
		// switch upper/lower information
		upper = retrieval->irb_value;
		lower = retrieval->irb_value + idx->idx_count;
		retrieval->irb_lower_count = indexScratch->upperCount;
		retrieval->irb_upper_count = indexScratch->lowerCount;
		retrieval->irb_generic |= irb_descending;
	}

	if (const auto count = MAX(indexScratch->lowerCount, indexScratch->upperCount))
	{
		bool ignoreNullsOnScan = true;

		for (unsigned i = 0; i < count; i++)
		{
			if (segments[i].scanType == segmentScanMissing)
			{
				*lower++ = *upper++ = NullNode::instance();
				ignoreNullsOnScan = false;
			}
			else
			{
				if (i < indexScratch->lowerCount)
					*lower++ = segments[i].lowerValue;

				if (i < indexScratch->upperCount)