Query routing of federated information systems for fast response time, load balance, availability, and reliability
First Claim
1. A system for optimizing query processing in a federated information system, said system comprising:
- a calibrator in communication with said federated information system and adapted to intercept queries to said federated information system;
a simulator in communication with said calibrator and adapted to derive alternative query plans for each of said queries,wherein each of said query plans comprises a plurality of query fragment plans associated with at least one data source,wherein said simulator is further adapted to determine first query fragment cost estimates for each of said query fragment plans,wherein said calibrator is further adapted to calibrate source-specific cost factors for each data source in said federated information system based on workload associated with said each data source by dividing an actual query fragment cost associated with processing a query fragment at a specific data source by a first query fragment cost estimate for processing said query fragment,wherein said calibrator comprises a memory adapted to store said source-specific cost factors, andwherein said simulator is further adapted to calculate second query fragment cost estimates by multiplying each of said first query fragment cost estimates times a corresponding one of said source-specific cost factors.
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Abstract
Disclosed are embodiments of a system for optimizing query processing in a federated information system. The system may be used to identify alternative query plans in a simulated environment and to calculate cost estimates associated with the alternative query plans, based not only on database statistics and query statements, but also based on workload and processing latencies associated with specific data source and with the federated information system as a whole. In addition the calculated cost estimates may also factor in data source availability and reliability. The system may use the alternative query plans and the associated cost estimates to influence query processing in a federated information system by feeding to the federated information system query plans that allow for cost-efficient query plan-level load distribution, cost-efficient query fragment plan-level load distribution, and load distribution based upon quality of service cost constraints.
80 Citations
17 Claims
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1. A system for optimizing query processing in a federated information system, said system comprising:
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a calibrator in communication with said federated information system and adapted to intercept queries to said federated information system; a simulator in communication with said calibrator and adapted to derive alternative query plans for each of said queries, wherein each of said query plans comprises a plurality of query fragment plans associated with at least one data source, wherein said simulator is further adapted to determine first query fragment cost estimates for each of said query fragment plans, wherein said calibrator is further adapted to calibrate source-specific cost factors for each data source in said federated information system based on workload associated with said each data source by dividing an actual query fragment cost associated with processing a query fragment at a specific data source by a first query fragment cost estimate for processing said query fragment, wherein said calibrator comprises a memory adapted to store said source-specific cost factors, and wherein said simulator is further adapted to calculate second query fragment cost estimates by multiplying each of said first query fragment cost estimates times a corresponding one of said source-specific cost factors. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A system for optimizing query processing in a federated information system, said system comprising:
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a calibrator in communication with said federated information system and adapted to intercept queries to said federated information system; and a simulator 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 by dividing a sum of actual query costs associated with processing a plurality of different queries in said federated information system by a sum of corresponding first query cost estimates, wherein said calibrator comprises a memory adapted to store said system cost factor, 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. - View Dependent Claims (10, 11, 12)
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13. A system for optimizing query processing in a federated information system, said system comprising:
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a calibrator in communication with said federated information system and adapted to intercept queries to said federated information system; and a simulator 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 by dividing an actual query fragment cost associated with a specific data source, when said specific data source processes a query fragment, by a first query fragment cost estimate for processing said query fragment, wherein said calibrator comprises a memory adapted to store said source-specific cost factors, 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. - View Dependent Claims (14, 15, 16, 17)
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Specification