Distributed Database System Providing Data and Space Management Methodology

• US 20080172429A1
• Filed: 03/25/2008
• Published: 07/17/2008
• Est. Priority Date: 11/01/2004
• Status: Active Grant

• Current Assignee: Sybase Incorporated (SAP SE)
• Original Assignee: Sybase Incorporated (SAP SE)
• Inventors: Zhou, Fei, Sampath, Srikanth, Ramachandran, Satya N., Francis, Joe, Lin, Mei-Lin Linda, Varakur, Gangavara Prasad
• Granted Patent: US 9,152,666 B2
• Time in Patent Office: Days
• US Class Current: 707/205
• CPC Class Codes: G06F 16/2343 Locking methods, e.g. distributed locking or locking implementation details
• CPC Class Codes: Y10S 707/99938 Concurrency, e.g. lock management in shared database

Abstract

A distributed database system providing data and space management methodology. In one embodiment a system for allocating resources amongst a plurality of database servers sharing resources comprises: an input module for receiving user input for allocating resources shared amongst a plurality of database servers and establishing thresholds for utilization of resources at each database server; a monitoring module at each database server for monitoring local resource utilization at each database server and sending a request for balancing resources to a second database server when local resource utilization reaches an established threshold at a first database server; and a load balancing module for receiving the request for balancing resources and determining whether to adjust resources allocated to the first database server and the second database server in response to the request.

Claims

1. A system for allocating resources amongst a plurality of database servers sharing resources, the system comprising:

an input module for receiving user input for allocating resources shared amongst a plurality of database servers and establishing thresholds for utilization of resources at each database server;

a monitoring module at each database server for monitoring local resource utilization at each database server and sending a request for balancing resources to a second database server when local resource utilization reaches an established threshold at a first database server; and

a load balancing module for receiving the request for balancing resources and determining whether to adjust resources allocated to the first database server and the second database server in response to the request.

2. The system of claim 1, wherein the resources include data pages allocated amongst the plurality of database servers.

3. The system of claim 2, wherein the input module receives user input specifying a threshold based on number of data pages remaining free at a database server.

4. The system of claim 1, wherein the load balancing module provides available resources allocated to the second database server to the first database server in response to the request, so as to adjust resources between them.

5. The system of claim 4, wherein the load balancing module allocates free data pages available at the second database server to the first database server in response to the request.

6. The system of claim 4, wherein the load balancing module at the second database server forwards the request to a third database server if resources allocated to the first database server and second database server cannot be adjusted within thresholds established at the first database server and the second database server.

7. The system of claim 6, wherein the load balancing module at the second database server includes information about resources available at the second database server with the request forwarded to the third database server.

8. The system of claim 6, further comprising:

a module at the third database server for adjusting resources allocated to the first database server, the second database server, and the third database server in response to the request forwarded to the third database server.

9. The system of claim 8, wherein the module at the third database server adjusts free data pages allocated to the first database server, the second database server, and the third database server in response to the forwarded request.

10. The system of claim 1, wherein each of the plurality of database servers has an assigned database server for sending requests for balancing resources.

11. The system of claim 1, wherein a load balancing module at a database server sends a notification to a user when resource utilization at all database servers reaches an established threshold.

12. The system of claim 1, wherein the module for tracking suspends a process running at the first database server which is attempting to utilize resources when resource utilization reaches an established threshold applicable to the first database server.

13. In a distributed database system comprising a plurality of database servers sharing resources, a method for allocating resources amongst the plurality of database servers, the method comprising:

receiving user input specifying allocation of shared resources amongst a plurality of database servers including established thresholds for utilization of resources at each of said plurality of database servers;

during operation of the distributed database system, monitoring local resource utilization at each database server;

when local resource utilization reaches an established threshold at a first database server, sending a request for balancing resources to a second database server; and

when the request for balancing resources is received at the second database server, providing available resources allocated to the second database server to the first database server in response to the request, so as to adjust resources between them.

14. The method of claim 13, wherein the resources include data pages allocated amongst the plurality of database servers.

15. The method of claim 14, wherein the established threshold is based on number of data pages remaining free at a database server.

16. The method of claim 13, wherein said providing step includes allocating free data pages available at the second database server to the first database server in response to the request.

17. The method of claim 13, wherein said providing step includes determining whether free data pages are available at the second database server that can be allocated for use at the first database server.

18. The method of claim 17, further comprising:

if free data pages are not available at the second database server for allocation to the first database server, forwarding the request for balancing resources to a third database server.

19. The method of claim 18, wherein the request for balancing resources is forwarded to the third database server if the resources allocated to the first database server and second database server cannot be adjusted within thresholds established at the first database server and the second database server.

20. The method of claim 18, wherein the second database server includes information about free data pages available at the second database server with the request for balancing resources forwarded to the third database server.

21. The method of claim 18, further comprising:

in response to the forwarded request for balancing resources received at the third database server, adjusting free data pages allocated to the first database server, the second database server.

22. The method of claim 13, wherein a designated database server to which requests for balancing resources are to be sent is assigned for each of the plurality of database servers.

23. The method of claim 13, further comprising:

when resource utilization at all of said plurality of database servers reaches an established threshold, sending a notification to a user.

24. The method of claim 13, further comprising:

suspending a process running at the first database server which is attempting to utilize resources when resource utilization reaches an established threshold applicable to the first database server.

25. A computer-readable medium having processor-executable instructions for performing the method of claim 13.

26. In a distributed database system comprising a plurality of database servers sharing access to data, a method for allocating free data pages amongst the plurality of database servers, the method comprising:

assigning a quantity of free data pages for use at each of the plurality of database servers;

establishing thresholds at each of said plurality of database servers based on number of free data pages available at each database server;

during operation, when the number of free data pages remaining available reaches an established threshold at a first database server, issuing a request for additional free data pages to a second database server; and

providing free data pages assigned to the second database server to the first database server in response to the request, while the number of free data pages available at the second database server remains above an established threshold applicable to the second database server.

27. The method of claim 26, wherein said step of providing free data pages includes determining a quantity of free data pages that can be provided to the first database server in response to the request.

28. The method of claim 27, wherein said step of determining a quantity of free data pages that can be provided includes providing half the free data pages then remaining available at the second database to the first database server in response to the request.

29. The method of claim 26, wherein said wherein said step of providing free data pages includes determining whether the number of free data pages available at the second database server more than a specified number of pages above an established threshold.

30. The method of claim 26, wherein said step of establishing thresholds includes specifying a buffer zone of free data pages corresponding to each established threshold and said step of providing free data pages includes providing free data pages available at the second server while the number of free data pages available at the second database server remains above the buffer zone applicable at the second database server.

31. The method of claim 30, wherein the buffer zone comprises a user specified number of free data pages.

32. The method of claim 26, further comprising:

forwarding the request from the second database server to a third database server if a sufficient number of free data pages are not available at the second database server.

33. The method of claim 32, wherein said forwarding step includes indicating the number of free data pages available at the first database server and the second database server.

34. The method of claim 32, further comprising:

if sufficient free data pages are available at the third database server, providing a quantity of free data pages to the first database server and the second database server.

35. The method of claim 26, wherein said step of assigning a quantity of free data pages includes assigning a quantity based on total number of free data pages and number of database servers in the distributed database system.

36. The method of claim 26, wherein said step of establishing thresholds includes establishing at least two thresholds at each of the plurality of database servers.

37. The method of claim 36, wherein said step of issuing a request includes issuing the request when the number of free data pages reaches a first threshold at the first database server.

38. The method of claim 37, further comprising:

freezing use of additional free data pages at the first database server when the number of free data pages reaches a second threshold at the first database server.

39. A computer-readable medium having processor-executable instructions for performing the method of claim 26.