Apparatus and method for securing preliminary information about database fragments for utilization in mapreduce processing

A method of processing a query in a distributed database implemented across a set of nodes includes receiving a query. The query is divided into split characterization queries. The split characterization queries are distributed to worker nodes. Each worker node stores a partition of the distributed database with encoded textual objects and pre-defined indices characterizing encoded textual object fragments. The split characterization queries are executed at the worker nodes to obtain preliminary information about query results. Executing the split characterization queries includes matching query fragments associated with the split characterization queries with encoded textual object fragments of the pre-defined indices to produce fragment matches representative of the size of the query results. For each split characterization query the preliminary information about query results includes a fragment count, a database partition identification, and a database host name.