Pipelined database processing circuit and method

A query processing system, comprising:

• a first memory arrangement configured and arranged for storage of documents;
• a first-stage circuit of a pipelined processing circuit configured and arranged to receive a data access request and determine hash values from keys in a query in the data access request;
• a second memory arrangement configured and arranged for storage of document addresses associated with a plurality of hash values;
• a second-stage circuit of the pipelined processing circuit coupled to the second memory arrangement and coupled to receive the determined hash values from the first-stage circuit and configured and arranged to determine from the second memory arrangement, ones of the document addresses associated with the determined hash values;
• a third-stage circuit of the pipelined processing circuit coupled to receive the ones of the document addresses from the second-stage circuit and configured and arranged to read data of respective documents at the ones of the document addresses from the first memory arrangement;
• a fourth-stage circuit of the pipelined processing circuit coupled to receive the data of the respective documents read from the first memory arrangement and configured and arranged to select a subset of the data of the respective documents according to the query, wherein the query specifies search criteria, and the subset of the data is selected in response to satisfaction of the search criteria by data of the respective documents;
• and
• a fifth-stage circuit of the pipelined processing circuit coupled to receive the subset of the data and configured and arranged to merge the subset of the data of the respective documents into response data.