Multi-processor system for database management

• US 6,351,744 B1
• Filed: 05/28/1999
• Issued: 02/26/2002
• Est. Priority Date: 05/28/1999
• Status: Expired due to Term

• Current Assignee: Unisys Corporation
• Original Assignee: Unisys Corporation
• Inventors: Landresse, P. J.
• Primary Examiner(s): Breene, John
• Assistant Examiner(s): Le, Debbie M
• Application Number:
  US09/322,535
• Time in Patent Office: 1,005 Days
• Field of Search: 707/200, 707/8, 707/1, 707/10, 709/103, 709/107, 714/11-12, 710/20, 710/33, 710/51-52
• US Class Current: 1/1
• CPC Class Codes: G06F 16/273 Asynchronous replication or reconciliation
• CPC Class Codes: G06F 9/544 Buffers; Shared memory; Pipes
• CPC Class Codes: Y10S 707/99931 Database or file accessing
• CPC Class Codes: Y10S 707/99938 Concurrency, e.g. lock management in shared database

Abstract

A multi processor system is interconnected through a memory means to multiple numbers of database engines on which there can operate multiple numbers of user programs in order to select buffers which have been modified so that the data in the buffers can be written or copied to a storage medium holding database file structures. The user programs operate in parallel so that multiple concurrent update operations can be continuously completed.

Claims

1. In a multi-processor system for reading and writing data buffers from and to a storage medium whereby multiple processors and multiple user programs utilize a common memory working in conjunction with a master control program and database engines for availability to each processor, a system for providing concurrent operations which flush multiple buffers which are being operated upon from concurrently operating user programs which participate in buffer I/O activity, said system comprising:

(a) multiple processor means connected to a commonly shared memory means, said processor means utilizing a stack architecture permitting an accessroutines program to run on top of each user application;

(b) master control program means providing multiple user application programs which include;

(b1) a plurality of database engines for providing multiple access routines to modified buffers in a buffer pool enabling parallel concurrent tasks from said user application programs to function concurrently;

(b2) buffer pool means having multiple buffers for holding modified data to be copied to a plurality of database file structures;

(c) storage structure means including database files which communicate with said data buffer pool and said database engine.

2. The system of claim 1 which includes:

(d) said commonly shared memory means providing multiple access paths connecting each one of said multiple processors means to each one of said plurality of database engines;

(e) said buffer pool means providing multiple buffer units for each database file structure.

3. The multiple processor system of claim 1 wherein said multiple access routines of said database engine include:

(b1a) means for building a list of buffer units and file structures;

(b1b) means for setting a series of address pointers for said list of buffers units and structures;

(b1c) means for writing modified buffer data from said buffer units into the database file structures on a concurrent basis working in parallel until all write operations to the appropriate database file structures are completed.

4. The system of claim 1 wherein said database engine includes:

(i) means to concurrently build a list of buffer units and file structures;

(ii) means to organize said buffer units for flushing tasks in logical groups so that each logical group can be processed in a single transaction;

(iii) means for setting a series of address pointers for pointing to said list of buffer units and structures;

(iv) means for writing the modified data from said buffers into said database file structures in a parallel fashion concurrently until all the buffer unit transfer tasks have been exhausted and written to said database file structures.

5. In a multi-processor system for reading and writing data buffers to modular units of a storage medium means wherein multiple processors work with multiple user application program means utilizing a common memory for communication with a master control program which provides multiple database engines available to each and any of the multiple processors, a system for concurrently flushing multiple buffers operated upon from concurrently operating user programs and concurrently operating processors for writing modified buffer data to selected database file structures, said system comprising:

(a) multiple processor means having user application programs linked with buffer access routine programs and connected to a commonly shared memory means;

(b) said commonly shared memory means providing multiple access paths connecting each or any of said multiple processors to each of the modular units of said storage medium means;

(c) master control program means providing multiple user application programs which include;

(c1) a database engine for providing said multiple access routines to modified buffers in a buffer pool means;

(c2) buffer pool means having multiple buffers for some of which are selected holding modified data to be copied to a series of database file structures;

(d) said storage medium means including database file structures which communicate with said data buffer pool and said database engine.

6. The system of claim 5 wherein said buffer pool means includes:

(c2a) a plurality of buffer units, wherein each said buffer unit is addressably linked with a particular database file structure.

7. The system of claim 5 wherein said Master Control Program means includes:

(c3) means for distributing and controlling the workload of the system, including that of buffer flushing, over a number of different process operations including that of Read operations for supplying data to a requesting user application.

8. The system of claim 6 wherein said multiple user application program means includes:

(c4) means to logically group the flushing of buffers and updating the database file structures so as to orient each group according to the specific file structure involved with a specific modular unit of said storage medium means thus enabling each logical group to be processed in a single transaction.

9. The system of claim 8 wherein said multiple user application programs means includes:

(c5) means to verify the completion of each buffer unit flushed to its particular database file structure.

10. The system of claim 6 wherein said multiple user application program means includes:

(i) means to flush various logical groups of buffer units in parallel to selected file structures in said database file structure;

(ii) means to verify the completion of each flushing of the buffers to each logical group database file structure in parallel concurrently with the verification of the flushing of buffers to their other logical database file structures.