Method lookupKey

src/jrd/replication/Applier.cpp:1010–1070

}

bool Applier::lookupKey(thread_db* tdbb, jrd_rel* relation, index_desc& key)
{
	RelationPages* const relPages = relation->getPages(tdbb);
	auto page = relPages->rel_index_root;
	if (!page)
	{
		DPM_scan_pages(tdbb);
		page = relPages->rel_index_root;
	}

	const PageNumber root_page(relPages->rel_pg_space_id, page);
	win window(root_page);
	const auto root = (index_root_page*) CCH_FETCH(tdbb, &window, LCK_read, pag_root);

	index_desc idx;
	idx.idx_id = key.idx_id = idx_invalid;

	for (USHORT i = 0; i < root->irt_count; i++)
	{
		if (BTR_description(tdbb, relation, root, &idx, i))
		{
			if (idx.idx_flags & idx_primary)
			{
				key = idx;
				break;
			}

			if (idx.idx_flags & idx_unique)
			{
				if (key.idx_id == idx_invalid)
					key = idx;
				else if (relation->isSystem())
				{
					// For unique system indices, prefer ones using metanames rather than IDs
					USHORT metakeys1 = 0, metakeys2 = 0;

					for (USHORT id = 0; id < idx.idx_count; id++)
					{
						if (idx.idx_rpt[id].idx_itype == idx_metadata)
							metakeys1++;
					}

					for (USHORT id = 0; id < key.idx_count; id++)
					{
						if (key.idx_rpt[id].idx_itype == idx_metadata)
							metakeys2++;
					}

					if (metakeys1 > metakeys2)
						key = idx;
				}
				else if (idx.idx_count < key.idx_count)
					key = idx;
			}
		}
	}

	CCH_RELEASE(tdbb, &window);