Systems and methods for processing queries

• US 20050044064A1
• Filed: 06/17/2003
• Published: 02/24/2005
• Est. Priority Date: 06/17/2002
• Status: Active Grant

• Current Assignee: Kenneth Haase
• Original Assignee: Kenneth Haase
• Inventors: Haase, Kenneth
• Granted Patent: US 7,966,311 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 16/24534 Query rewriting; Transformation
• CPC Class Codes: G06F 16/24552 Database cache management
• CPC Class Codes: G06F 16/2471 Distributed queries

Abstract

The present invention relates to systems and methods for processing queries. One embodiment of the invention provides a system for executing complex procedural queries across a plurality of databases. The system includes: a query processor capable of partial execution of procedural queries; a set of database adaptors capable of optimizing or and referring collections of queries to external databases; and a query cache component in communication with the query processor and the set of database adaptors. The query cache component stores the results of external database queries in a query cache and notes when a query has not been stored and records the same query.

Claims

1. A system for executing complex procedural queries across a plurality of databases, the system comprising:

a query processor capable of partial execution of procedural queries;

a set of database adaptors capable of optimizing and referring collections of queries to external databases; and

a query cache component in communication with the query processor and the set of database adaptors, the query cache component capable of storing results of external database queries in a query cache and of noting when a query'"'"'s results have not been stored.

2. The system of claim 1 wherein results in the query cache persist between queries.

3. The system of claim 2 wherein the query cache component is operative to provide a two-level cache, where a query-specific query cache refers to a global persistent query cache.

4. The system of claim 1 wherein the query processor comprises:

a query buffer for maintaining a top-level query;

a query execution unit in communication with the query buffer and operative to execute a query and its sub-queries; and

a device in communication with the QEU and with the query buffer, the device operative to indicate to the query buffer when at least one of query execution and sub-query execution results in a soft failure;

such that the system continually executes independent sub-queries when a given sub-query results in a soft failure; and

failed queries are referred to the database adapters when the partial execution of the top-level query finishes.

5. A method for query execution, the method comprising:

a. partially executing a query and, if a soft failure occurs, noting data which the query needs but does not have;

b. referring unresolved data needs to at least one database adapter;

c. storing resulting responses in a query cache for a future execution; and

iteratively repeating (a), (b), and (c) until no more soft failures occur.

6. The method of claim 5 wherein partially executing a query comprises identifying sub queries to be executed separately.

7. The method of claim 6 wherein the query includes a query procedure and wherein the method further comprises identifying the query procedure by an object and by an argument of the procedure.

8. The method of claim 5 wherein the method further comprises using query langauge that is a subset of a general purpose programming language to express the query.

9. The method of claim 5 wherein the query language is functional and repetitively innocous.

10. The method of claim 9 wherein the query language is maximally severable.

11. A system for processing queries, the system comprising:

a query buffer for receiving a particular query expression, including a plurality of sub-queries, for iterated partial execution;

an external memory for storing non-persistent program data and procedures that can be routinely accessed in the course of query execution;

a query execution unit (QEU) in communication with the query buffer and the external memory;

the QEU operative to iteratively execute a query by executing the query'"'"'s sub-queries and combining results of the sub-queries such that incomplete execution of one sub-query does not rule out execution of other independent sub-queries;

a device in communication with the QEU, the device operative to signal and respond to soft failures, which may terminate one sub-query of a query while allowing independent sub-queries to proceed;

a query cache in communication with the QEU, the query cache operative to store known query results for immediate retrieval without recourse to at least one external database, to return known query results, and to return a soft failure when results are not known without recourse to at least one external database; and

a plurality of external database adaptors in communication with the query cache, the database adaptors operative to optimize a set of independent queries bundled together into a single package.

12. The system of claim 11 wherein the device is operative to signal a requesting application that the query execution is complete when a query execution completes without any software failures.

13. The system of claim 12 wherein the QEU is operative to forward the results of the query execution to a requesting application when a query execution completes without any software failures.

14. The system of claim 11 wherein the system further comprises:

a query rewriter in communication with the query buffer, the query rewriter operative to receive a query and to convert certain query language constructs into a form that the QEU can execute.