Method, apparatus and computer program for retrieving data

A system for retrieving a data item, the system comprising:

• a data store;
• a partial index, which partially indexes the data store;
• a partiality definition store being a pointer that distinguishes between a part of the data store that is indexed and a part of the data store that is not indexed;
• means for receiving a request for a data item from the data store;
• means for searching the partial index;
• and
• means for searching an unindexed part of the data store by using the partiality definition store to avoid searching a part of the data store which is known to be indexed in response to determining that the requested data item is not referenced by the partial index.

A computer program product for retrieving a data item from a data store in a data processing system, the computer program product comprising a computer readable storage medium having stored therein computer readable program code, the computer readable program code comprising:

• computer readable program code configured to receive a request for a data item from the data store;
• computer readable program code configured to search a partial index that at least partially indexes the data store;
• and
• computer readable program code configured to search an unindexed part of the data store using a partiality definition store in response to determining that the requested data item is not referenced by the partial index, wherein the partiality definition store is a pointer that distinguishes between a part of the data store that is indexed and a part of the data store that is not indexed.