1. A two-tier information retrieval system for distributing a first client service request from a client to query servers, the system comprising: a web server, the web server invoking a gateway upon receiving the first client service request; a dispatcher in a first tier and in communication with the web server, a plurality of query servers suitable for fulfilling the first client service request, the plurality of query servers forming a second tier and receiving information from the gateway, the gateway being an interface between the web server and the plurality of query servers; the gateway determining a presence of a server identification parameter in the first client service request, the server identification parameter identifying a first query server among the plurality of query servers, the first query server having handled a previous service request from the client; the gateway distributing the first client service request directly to the first query server; and the dispatcher receiving status information from the plurality of query servers, forwarding a second client service request to an available query server of the plurality of query servers in the absence of the server identification parameter; and including a queue for the second client service request.