Balancing database workloads through migration

• US 9,020,901 B2
• Filed: 04/03/2013
• Issued: 04/28/2015
• Est. Priority Date: 04/16/2012
• Status: Expired due to Fees

• Current Assignee: NEC Corporation
• Original Assignee: NEC Laboratories America Inc (NEC Corporation)
• Inventors: Chi, Yun, Hacigumus, Vahit Hakan
• Primary Examiner(s): Beausoliel, Jr., Robert
• Assistant Examiner(s): BROMELL, ALEXANDRIA Y
• Application Number:
  US13/855,765
• Publication Number:
  US 20130275382A1
• Time in Patent Office: 755 Days
• Field of Search: 707/654, 707/602, 718/105, 709/208, 709/226
• US Class Current: 707/654
• CPC Class Codes: B01L 2300/0654 Lenses; Optical fibres
• CPC Class Codes: B01L 2300/168 Specific optical properties, e.g. reflective coatings
• CPC Class Codes: B01L 3/502715 characterised by interfacing components, e.g. fluidic, electrical, optical or mechanical interfaces
• CPC Class Codes: C12Q 1/6874 involving nucleic acid arrays, e.g. sequencing by hybridisation
• CPC Class Codes: G01N 15/1404 Handling flow, e.g. hydrodynamic focusing
• CPC Class Codes: G01N 15/1434 Optical arrangements
• CPC Class Codes: G01N 21/6486 Measuring fluorescence of biological material, e.g. DNA, RNA, cells G01N21/6428 takes precedence
• CPC Class Codes: G01N 33/6875 Nucleoproteins
• CPC Class Codes: G06F 16/214 Database migration support

Abstract

A method for balancing database workloads among a plurality of database servers includes when a new server is available, selecting a set of master and slave databases to be migrated to the new server; and migrating the selected databases to result in a balanced new workload among all servers while minimizing migration cost; and during operation, if workload unbalance is detected in real time from a workload change in a certain database, iteratively selecting one database at a time to migrate to a different server to balance the workload.

Claims

1. A method for balancing database workloads among a plurality of database servers, the method comprising:

when a new server is available, selecting a set of master and slave databases to be migrated to the new server and migrating the selected databases to result in a balanced new workload among all servers while minimizing migration cost;

during operation, if a workload unbalance is detected in real-time from a workload change, iteratively selecting one database at a time to migrate to a different server to balance the workload; and

determining a metric for a given database configuration including a mean and a variance, wherein the variance is determined as;

σ

²=c_mem·

σ

_memCap²+c_cpuσ

_cpuCap,

where c_mem and c_cpu are parameters for calibrating different units between memory and a CPU.

2. The method of claim 1, comprising applying a metric to measure a goodness of a given database configuration.

3. The method of claim 2, wherein the metric comprises system resources including processor (CPU) usage and memory usage.

4. The method of claim 2, wherein the metric comprises different factors in a unified way through a weighting strategy and a vector norm.

5. The method of claim 1, wherein the selecting a set of master databases and slave databases for migration further comprises considering one or more factors including (a) the expect cost reduction after the migration, (b) the master-to-slave ratio at each of the server after migration, and (c) the migration cost that is related to the size of each database.

6. The method of claim 1, comprising choosing an optimal order of migration to minimize impact on the system during migration.

7. The method of claim 1, comprising iteratively selecting a next database to migrate and a corresponding target database server to eliminate a hot spot.

8. The method of claim 1, comprising iteratively migrating one database at a time until all hot spots are eliminated.

9. The method of claim 1, comprising setting

10. A system for balancing database workloads among a plurality of database servers, the system comprising:

a processor;

code executable by the processor when a new server is available, including instructions for selecting a set of master and slave databases to be migrated to the new server; and

migrating the selected databases to result in a balanced new workload among all servers while minimizing migration cost; and

code executable by the processor during operation, including instructions for detecting if workload unbalance is detected in real time and iteratively selecting one database at a time to migrate to a different server to balance the workload; and

code for determining a metric for a given database configuration including a mean and a variance, wherein the variance is determined as;

σ

²=c_mem·

σ

_memCap²+c_cpu·

σ

_cpuCap²,

where c_mem and c_cpu are parameters for calibrating different units between memory and a CPU.

11. The system of claim 10, comprising code for applying a metric to measure a goodness of a given database configuration.

12. The system of claim 11, wherein the metric comprises system resources including processor (CPU) usage and memory usage.

13. The system of claim 10, wherein the metric combines different factors in a unified way through a weighting strategy and a vector norm.

14. The system of claim 10, wherein the code for selecting a set of master databases and slave databases for migration further comprises considering one or more factors including (a) the expect cost reduction after the migration, (b) the master-to-slave ratio at each of the server after migration, and (c) the migration cost that is related to the size of each database.

15. The system of claim 10, comprising code for choosing an optimal order of migration to minimize impact on the system during migration.

16. The system of claim 10, comprising code for iteratively selecting a next database to migrate and a corresponding target database server to eliminate a hot spot.

17. The system of claim 10, comprising code for iteratively migrating one database at a time until all hot spots are eliminated.

18. The system of claim 10, comprising code for setting