Method and apparatus for affinity of users to application servers
View Patent ↗A method and apparatus route hypertext protocol requests to one of a plurality of application servers, which share a database through a backend database management system. The application servers store session data in the database. Hence, if a subsequent request is routed to a different application server, the session data is available through the backend database management system. One or more web servers perform routing of requests to the application server. When a request is received that is accompanied by a session ID, routing is performed by utilizing a hash function on the session ID. The resulting hash value is mapped to an application server. A hash function on a session ID will always result in the same hash value; therefore, the request will always be routed to the same application server. However, if an application server is non-functional, a new hash based on the previous hash is computed until a functional application server is selected.
1. An apparatus for routing a request to one of a number of servers, comprising:
a processor; and
a memory electrically connected to the processor, the memory having stored therein a program to be executed on the processor for performing:
receiving a request including a session identification;
performing a hash function on the session identification to form a first hash value;
performing a modulus function on the first hash value to form a first integer;
routing the request to a first server based on the first integer in response to the first server being functional;
performing a hash function on the first hash value to form a second hash value in response to the first server being non-functional;
performing a modulus function on the second hash value to form a second integer; and
routing the request to a second server based on the second integer.
2. The apparatus of claim 1 , wherein the integer is between zero and the number of servers minus one.
3. The apparatus of claim 1 , wherein the step of routing the request comprises looking up the server in a look-up table using the integer.
4. A computer program product stored in a computer readable storage medium for routing a request to one of a number of servers, which has a processor comprising:
instructions for receiving a request including a session identification; instructions for performing a hash function on the session identification to form a first hash value;
instructions for performing a modulus function on the first hash value to form a first integer;
instructions for routing the request to number of a first server based on the first integer in response to the first server being functional;
instructions for performing a hash function on the first hash value to form a second hash value in response to the first server being non-functional;
instructions for performing a modulus function on the second hash value to form a second integer; and
instructions for routing the request to a second server based on the second integer.