System for parallel processing of complex read-only database queries using master and slave central processor complexes

• US 5,495,606 A
• Filed: 11/04/1993
• Issued: 02/27/1996
• Est. Priority Date: 11/04/1993
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Rathi, Bharat D., Kelley, William K., Narang, Iderpal S., Borden, Terry L., Wisneski, David J.
• Primary Examiner(s): Black, Thomas G.
• Assistant Examiner(s): Choules, Jack M.
• Application Number:
  US08/148,091
• Time in Patent Office: 845 Days
• Field of Search: 395/600, 395/650, 395/200, 364/228.1, 364/228.5, 364/228.7, 364/229.4, 364/230.4, 364/230.5, 364/282.4
• US Class Current: 1/1
• CPC Class Codes: G06F 15/17375 One dimensional, e.g. linear array, ring
• CPC Class Codes: G06F 16/24532 of parallel queries
• CPC Class Codes: Y10S 707/99933 Query processing, i.e. searching

Abstract

A parallel query processing system comprises a front end processor, a query processing complex attached to the front end processor, and a database on a data repository attached by a first path to the front end processor, and by one or more additional paths to one or more slave processors within the query processing complex. An external operations command processor within the front end processor quiesces database managers in the slave processors to permit maintenance operations by the front end processor, and restarts the slave processors in read-only mode after maintenance operation completion. A splitter/scheduler function in a master processor within the query processor complex receives complex read-only queries from the front end processor, splits them into query elements, schedules the query elements for execution on the slave processors and recombines the execution results to be sent back to the front end processor.

Claims

1. A method for processing complex read-only queries in parallel, said method comprising the steps of:

a) Sending an end_-- update command to an external operations command processor in a front end processor to cause one or more slave central processors complexes (CPCs) in a query processor complex to operate in read-only mode;

b) initiating a complex read-only query on said front end processor;

c) routing said complex read-only query to a master CPC in said query processor complex;

d) splitting said complex read-only into two or more query elements and scheduling each of said two or more query elements for execution by one of the one or more slave CPCs, each one of said slave CPCs independently executing a database management system, each one of said CPCs comprising each of said one or more slave CPCs being capable of accessing any part of a database using a slave channel means;

e) forwarding a set of results of said two or more query element executions back to said master CPC reassembling the set of results into a combined final result and forwarding the combined final result back to said front-end processor.

2. The method of claim 1 further comprising the steps of

a) sending a begin_-- update command to said external operations command processor in said front end processor to cause said one or more slave CPCs in said query processor complex to cease query processing;

b) initiating an import/update function on said database by said front end processor, using a maintenance channel path.

3. A system for parallel processing of complex read-only queries comprising:

a) a front-end processor comprising;

i) an interface means for identifying said complex read-only queries and routing them to a query processor complex, said interface means routing queries not identified as complex read-only queries to a local database manager means;

ii) said local database manager means for processing database queries and updating a database, said local database manager means comprising import/update function processor means for performing database import/update functions on said database non-concurrently with complex read-only queries of said database by said query processor complex;

iii) at least two connection paths;

a first path for transporting, to said query processor complex, said read-only complex queries identified by said interface means, and a second path for communication with said database by said import/update function means;

iv) external operations command processor means for ensuring the integrity of said read-only complex queries in response to a command procedure issued by a system operator, wherein said command processor ensures the integrity of said read-only complex queries by disabling their execution by a query processor database manager means prior to enabling said database import/update functions;

b) said query processor complex comprising;

i) a multi-CPU processor (MP), connected to said front-end processor by said first path and connected to said database by a channel means;

ii) splitter means, executable on said MP, for splitting one of said read-only complex queries into two or more query elements, said splitter means further comprising a reassembly means for reassembling a set of results of said two or more query elements into a combined final result;

iii) scheduler means, executable on said MP, for scheduling each of said two or more query elements for processing by said MP;

iv) said query processor database manager means, executable on said MP, for processing any of said two or more query elements;

c) a data repository means for storing said database, said data repository means being connected to said MP by said channel means, and connected to said front-end processor by said second path.

4. The system of claim 3 in which said query processor complex further comprises internal command processor means, executable on said MP, responsive to said external operations command processor means, for receiving a disable request from said front-end processor and transmitting a related request to said slave processor database manager means.

5. A system for parallel processing of complex read-only queries comprising:

a) a front-end processor comprising;

i) an interface means for identifying said complex read-only queries and routing them to a query processor complex, said interface means routing queries not identified as complex read-only queries to a local database manager means;

ii) said local database manager means for processing database queries and updating a database, said local database manager means comprising import/update function processor means for performing database import/update functions on said database non-concurrently with complex read-only queries of said database by said query processor complex;

iii) a first path for transporting, to a master central processor complex (CPC), said read-only complex queries identified by said interface means, and a second path for communicating with said database by said import/update function means;

iv) external operations command processor means for ensuring the integrity of said read-only complex queries in response to a command procedure issued by a system operator, wherein said command processor ensures the integrity of said read-only complex queries by disabling their execution by a slave processor database manager means prior to enabling said database import/update functions;

b) said query processor complex comprising;

i) said master CPC, controlled by an operating system and executing a database management system, said master CPC connected to said front-end processor by said first path, connected to one or more slave CPC'"'"'s by a first master channel means, and connected to said database by a second master channel means;

ii) splitter means executable on said master CPC for splitting one of said read only complex queries into two or more query elements, said splitter means further comprising a reassembly means for reassembling a set of results of said two or more query elements into a combined final result;

iii) scheduler means, for scheduling each of said two or more query elements for processing by said one of one or more slave CPCs;

iv) said one or more of said slave CPCs, each one of said slave CPCs controlled by an operating system and each one of said slave CPCs comprising first slave channel means for communicating with said master CPC, and second slave channel means for accessing any portion of said database;

v) said slave processor database manager means, executable on each of said one or more of said slave CPCs, for processing any of said two or more query elements;

c) a data repository means for storing said database, said data repository means being connected to said master CPC by said second master channel means, connected to said slave CPCs by said second slave channel means, and connected to said front-end processor by said second path.

6. The system of claim 5 in which said scheduler means is executable on said master CPC.

7. The system of claim 5 in which said scheduler means is executable on any of said one or more slave CPCs.

8. The system of claim 5 in which said query processor complex further comprises server means, executable on each of said one or more slave CPCs, for receiving said query elements from said master processor and assigning them to said slave processor database manager means.

9. The system of claim 5 in which said query processor complex further comprises internal command processor means, executable on said master CPC and responsive to said external operations command processor means, for receiving a disable request from said front-end processor and transmitting a related request to said slave CPC.

10. The system of claim 5 in which one of said one or more slave CPCs, termed an alternate master CPC, further comprises third slave channel means for communicating with said front-end processor.