Method for dynamic validation of a distributed database segment which yields a suitable successor

• US 6,578,035 B1
• Filed: 01/14/2000
• Issued: 06/10/2003
• Est. Priority Date: 01/14/2000
• Status: Expired due to Term

• Current Assignee: Micro Focus Software, Inc. (Open Text Corporation)
• Original Assignee: Novell Incorporated (Open Text Corporation)
• Inventors: Barker, Kent D.
• Primary Examiner(s): Corrielus, Jean M.
• Assistant Examiner(s): Liang, Gwen
• Application Number:
  US09/483,131
• Time in Patent Office: 1,243 Days
• Field of Search: 707/201, 707/202, 707/10, 707/9, 707/103.R, 707/203, 709/201, 709/223, 709/224, 713/201
• US Class Current: 707/610
• CPC Class Codes: G06F 16/219 Managing data history or versioning querying versioned data G06F16/2474; querying temporal data G06F16/2477
• CPC Class Codes: G06F 16/27 Replication, distribution or synchronisation of data between databases or within a distributed database system; Distributed database system architectures therefor
• CPC Class Codes: G06F 16/275 Synchronous replication
• CPC Class Codes: Y10S 707/99952 Coherency, e.g. same view to multiple users
• CPC Class Codes: Y10S 707/99953 Recoverability

Abstract

A method and system for ensuring an current and valid copy of a distributed database is re-installed for a file server that has failed and been restored or otherwise has been offline and is then brought online. This invention can include validating the database each time the database is opened. The method can include placing a signature in the database indicating that the database was closed normally. The method can also include indicating the time the database was last used. The method can also check the partition placement and structure with other servers that hold replicas to insure that the partition structure is correct. The method can also include comparing the synchronization state of replicas with the other servers that hold replicas of the database to see if they agree on the synchronized/time/state of the replicas of the restored server. The method can also check to see that the database belongs to this server. The method can then notify the operator/administrator if the database is determined to be old or foreign. The operator/administrator can then produce a more suitable database if possible.

Claims

1. A method for dynamic validation of a distributed database segment on a database on a server in a system, the method comprising:

creating a signature for the database indicating whether the last usage of the database had been completed successfully and the database was closed and tagged appropriately;

comparing a time signature on the database of a last time the database was used in relation to a time signature known by other databases in the system;

comparing a partition configuration of the database with the configuration from other servers'"'"' databases to determine that the correct replica distribution has been maintained;

checking a plurality of synchronization properties of the database with other databases in the system to validate that the instance of the database is time specific;

comparing an ownership property of the database with information known to belong to the server which may be retrieved from other databases;

determining whether the database is a correct copy to be introduced into the system; and

notifying an operator whether the database is correct or not.

2. The method of claim 1 further including allowing the operator an option of providing the correct database for the server when it has been determined that the current database is not correct.

3. The method of claim 1 further including determining whether better copies of the database exist and if not, re-using an old database.

4. The method of claim 3 further including synchronizing objects to ensure other databases are aware of the reuse of the old database and re-activate the old database.

5. The method of claim 1 wherein the automatic identification of the current database'"'"'s status is made.

6. The method of claim 5 further including operator status reporting, or an automated method by which another suitable database is produced or the decision to re-use the current database is made.

7. The method of claim 5 further including an automated determination by which another suitable database is produced.

8. The method of claim 5 further including re-using the current database if it determined that a better copy does not exist.

9. The method of claim 1 further including refurbishment of an old database to provide a suitable successor.

10. A computer program for dynamic validation of a distributed database with a database segment, the computer program comprising:

instructions for creating a signature for the database segment indicating whether the database segment was previously closed correctly;

instructions for comparing a time signature on the database of a last time the database in use;

instructions for comparing a partition configuration of the database;

instructions for checking a plurality of synchronization properties of the database;

instructions for comparing an ownership property of the database to a server that the database resides on;

instructions for determining whether the database is a correct copy to re-install; and

instructions for notifying an operator whether the database is acceptable.

11. The computer program of claim 10 further including instructions for an automated response if an operator is not available to perform the task.

12. The computer program of claim 10 wherein the computer program resides on a general purpose microprocessor based computer.

13. The computer program of claim 10 wherein the computer program resides on a general purpose multi-process based computer.

14. A method for continued operation when a database has been replaced inadvertently, the method comprising:

copying information from a synchronization engine to replace out of date data;

replacing a plurality of objects that have been moved and where status can not be verified by the pointers to the objects;

modifying a plurality of internal data structures for use wherein the plurality of internal data structures includes at least one from a group consisting of;

naming properties, network addresses, and encryption keys; and

re-using an old database, when a correct database cannot be produced, by generating a suitable successor from data available in the old databases.