Field:smw hash

The "smw_hash" field to the "smw_objects_ids" table now contains a SHA-1 hash which is composed of title, namespace, interwiki prefix and the subobject identifier to help with "warm up"of the ID cache. The objective is to reduce queries required to match IDs for entities during a webrequest by collecting the SHA-1 hash and run a collective  query before any access happens to find an ID. This warm up reduces the amount of queries necessary for finding entity IDs and may improve the lookup performance.CiteRef::gh:smw:3080