Added preserves_order flag to SQL mapping table #585
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A long time ago, the
preserves_mappingattribute was added as performance improvement to enable bulk-id-mappings. Bulk-id-mappings was disabled before as some mappers could not guarantee that the order of incoming ids == order of outgoing ids. Read more about it here: phovea/phovea_server#141This PR sets this flag in the sql-mapping table, as this mapper guarantees a preserved order.
The performance increase is huge when testing with many items, as previously a query was sent to the database for every single id. As a test with human genes, ~60k queries were sent... Now, a single query with a large where is sent instead.
I added a comment to the line which ensures a preserved order.