Query routing of federated information systems for fast response time, load balance, availability, and reliability

A system for optimizing query processing in a federated information system, said system comprising:

• a processor;
• memory elements comprising a computer readable medium operatively connected to said processor;
• a calibrator, operating through said processor and memory elements, in communication with said federated information system and adapted to intercept queries to said federated information system;
• and
• a simulator, operating through said processor and memory elements, in communication with said calibrator and adapted to derive alternative query plans for each of said queries and to determine a first query cost estimate for each of said query plans,
• wherein said calibrator is adapted to calibrate a system cost factor for said federated information system based on workload associated with said federated information system, and
• wherein said simulator is further adapted to calculate second query cost estimates for each of said query plans by multiplying each of said first query cost estimate times said system cost factor and to balance workload distribution by select a plurality of query plans based on said second query cost estimates, and each time said query is requested, submitting any one of said plurality of query plans to said federated information system.

A system for optimizing query processing in a federated information system, said system comprising:

• a processor;
• memory elements comprising a computer readable medium operatively connected to said processor;
• a calibrator, operating through said processor and memory elements, in communication with said federated information system and adapted to intercept queries to said federated information system;
• and
• a simulator, operating through said processor and memory elements, in communication with said calibrator and adapted to derive alternative query plans for each of said queries and to determine first query fragment cost estimates for each query fragment plan within each of said query plans;
• wherein said calibrator is further adapted to calibrate source-specific cost factors for each data source associated with each of said query fragment plans based on workload,
• wherein said simulator is further adapted to calculate second query fragment cost estimates for each of said query fragment plans by multiplying each of said first query fragment cost estimates times a corresponding one of said source-specific cost factors, and
• wherein said simulator is further adapted to balance workload distribution by selecting one of said query plans for submission to said federated information system each time said query is requested and each time said one query plan is submitted to said federated information system interchanging at least one query fragment plan within said one query plan with other identical query fragment plans based on said second query fragment costs.