Method and system for controlling accesses to a database

• US 8,176,076 B2
• Filed: 12/05/2008
• Issued: 05/08/2012
• Est. Priority Date: 12/07/2007
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Iwamoto, Yuhko
• Primary Examiner(s): Quader, Fazlul
• Application Number:
  US12/316,567
• Publication Number:
  US 20090193025A1
• Time in Patent Office: 1,250 Days
• Field of Search: 707/781
• US Class Current: 707/781
• CPC Class Codes: G06F 16/2471 Distributed queries

Abstract

The frequency of occurrences of an exclusion process is reduced so as to enhance the efficiency of handling accesses to a database. A system is provided for controlling accesses to a database. The system includes a database identifying section that identifies a database corresponding to an input of a first access command, an access judging section that judges whether a series of accesses to the identified database initiated by a second access command still continue, a frequency determining section that determines how often accesses to the identified database occur with reference to a history of accesses. The system further comprises an access control section that checks the accesses made by the first access command to the identified database when the series of accesses to the identified database initiated by the second access command still continue and the frequency of accesses to the identified database determined by the frequency determining section is higher than or equal to a predetermined value.

Claims

1. A method for controlling accesses to a database, comprising:

identifying a database by an input of a first access command;

determining whether a series of accesses to the identified database initiated by a second access command still continue;

determining how often accesses to the identified database occurs with reference to a history of accesses; and

checking the access made by the first access command to the identified database under the condition that the series of accesses to the identified database initiated by the second access command still continue and the frequency of accesses to the identified database determined by the frequency determining section is higher than or equal to a predetermined value.

2. A method for controlling accesses to a database, comprising:

identifying a database from a first command received from a first computer that initiated the first command as a first series of accesses to a database;

after said identifying the database and while the first command has not been performed, ascertaining that a second series of accesses to the database, initiated by a second command from a second computer, is currently being performed;

determining an access frequency at which accesses to the database have occurred;

after said determining the access frequency and in response to said ascertaining, determining, by a processor of a computer, that each condition of at least one condition is satisfied, said at least one condition including a condition of the access frequency not being less than a predetermined reference frequency; and

in response to having determined that the at least one condition is satisfied, performing an exclusion process that comprises blocking and suspending execution of the first command.

3. The method of claim 2, wherein the at least one condition includes a condition of the second computer differing from the first computer.

4. The method of claim 2, wherein the at least one condition includes a condition of the first command being a command to create a new record or update an existing record in the database.

5. The method of claim 2, wherein the method further comprises:

prior to having determined that the condition of the access frequency not being less than the predetermined reference frequency is satisfied, computing the reference frequency as equal to (1−

r)/(α

β

), wherein r is a fraction of previous time during which the processor has been utilized, wherein α

is a number of message transmissions to and from the processor to perform one cycle of the exclusion process, and wherein β

is a measure of an amount of time for performing each message transmission.

6. The method of claim 2, wherein the method further comprises:

after said identifying the database and while the first command has not been performed, creating in a data storage device a data record associated with the first command, said creating comprising storing in the record;

an identification of the first computer, an identification of the database, an identifier of a type of access in the first command, and a start time at which a first access of the first series of accesses is to be initiated; and

after said determining the access frequency, recording in the data record the access frequency.

7. The method of claim 6, wherein the method further comprises:

after said blocking and suspending execution of the first command, determining that the second series of accesses to the database have been completed and that at least one access of the first series of accesses have been performed, followed by committing the at least one access and recording in the data record a time of said committing.

8. A computer program product, comprising a computer readable physically tangible storage device having a computer readable instructions stored therein, said instructions configured to be executed by a processor of a computer to implement a method for controlling accesses to a database, said method comprising:

identifying a database from a first command received from a first computer that initiated the first command as a first series of accesses to a database;

after said identifying the database and while the first command has not been performed, ascertaining that a second series of accesses to the database, initiated by a second command from a second computer, is currently being performed;

determining an access frequency at which accesses to the database have occurred;

after said determining the access frequency and in response to said ascertaining, determining that each condition of at least one condition is satisfied, said at least one condition including a condition of the access frequency not being less than a predetermined reference frequency; and

in response to having determined that the at least one condition is satisfied, performing an exclusion process that comprises blocking and suspending execution of the first command.

9. The computer program product of claim 8, wherein the at least one condition includes a condition of the second computer differing from the first computer.

10. The computer program product of claim 8, wherein the at least one condition includes a condition of the first command being a command to create a new record or update an existing record in the database.

11. The computer program product of claim 8, wherein the method further comprises:

prior to having determined that the condition of the access frequency not being less than the predetermined reference frequency is satisfied, computing the reference frequency as equal to (1−

r)/(α

β

), wherein r is a fraction of previous time during which the processor has been utilized, wherein α

is a number of message transmissions to and from the processor to perform one cycle of the exclusion process, and wherein β

is a measure of an amount of time for performing each message transmission.

12. The computer program product of claim 8, wherein the method further comprises:

after said identifying the database and while the first command has not been performed, creating in a data storage device a data record associated with the first command, said creating comprising storing in the record;

an identification of the first computer, an identification of the database, an identifier of a type of access in the first command, and a start time at which a first access of the first series of accesses is to be initiated; and

after said determining the access frequency, recording in the data record the access frequency.

13. The computer program product of claim 12, wherein the method further comprises:

after said blocking and suspending execution of the first command, determining that the second series of accesses to the database have been completed and that at least one access of the first series of accesses have been performed, followed by committing the at least one access and recording in the data record a time of said committing.

14. A system comprising a computer, said computer comprising a processor and a computer readable memory unit coupled to the processor, said memory unit containing instructions configured to be executed by the processor to implement a method for controlling accesses to a database, said method comprising:

identifying a database from a first command received from a first computer that initiated the first command as a first series of accesses to a database;

after said identifying the database and while the first command has not been performed, ascertaining that a second series of accesses to the database, initiated by a second command from a second computer, is currently being performed;

determining an access frequency at which accesses to the database have occurred;

after said determining the access frequency and in response to said ascertaining, determining that each condition of at least one condition is satisfied, said at least one condition including a condition of the access frequency not being less than a predetermined reference frequency; and

in response to having determined that the at least one condition is satisfied, performing an exclusion process that comprises blocking and suspending execution of the first command.

15. The system of claim 14, wherein the at least one condition includes a condition of the second computer differing from the first computer.

16. The system of claim 14, wherein the at least one condition includes a condition of the first command being a command to create a new record or update an existing record in the database.

17. The system of claim 14, wherein the method further comprises:

prior to having determined that the condition of the access frequency not being less than the predetermined reference frequency is satisfied, computing the reference frequency as equal to (1−

r)/(α

β

), wherein r is a fraction of previous time during which the processor has been utilized, wherein α

is a number of message transmissions to and from the processor to perform one cycle of the exclusion process, and wherein β

is a measure of an amount of time for performing each message transmission.

18. The system of claim 14, wherein the method further comprises:

after said identifying the database and while the first command has not been performed, creating in a data storage device a data record associated with the first command, said creating comprising storing in the record;

an identification of the first computer, an identification of the database, an identifier of a type of access in the first command, and a start time at which a first access of the first series of accesses is to be initiated; and

after said determining the access frequency, recording in the data record the access frequency.

19. The system of claim 18, wherein the method further comprises:

after said blocking and suspending execution of the first command, determining that the second series of accesses to the database have been completed and that at least one access of the first series of accesses have been performed, followed by committing the at least one access and recording in the data record a time of said committing.