Replicated object identification in a partitioned hierarchy

• US 5,832,487 A
• Filed: 12/14/1996
• Issued: 11/03/1998
• Est. Priority Date: 12/15/1994
• Status: Expired due to Term

• Current Assignee: Oracle International Corporation (Oracle Corporation)
• Original Assignee: Novell Incorporated (Open Text Corporation)
• Inventors: Prasad, Ranjan, Olds, Dale R., Izatt, Layne
• Primary Examiner(s): Black, Thomas G.
• Assistant Examiner(s): Alam, Hosain T.
• Application Number:
  US08/764,236
• Time in Patent Office: 689 Days
• Field of Search: 707/10, 707/8, 707/201, 707/202, 707/203, 395/200.3, 395/200.31
• US Class Current: 1/1
• 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

Methods and systems for managing replicated objects in a partitioned hierarchical database are disclosed. One method combines partition-wide object identifiers in order according to ancestry to form a database-wide object identifier that identifies a target object relative to all other objects in the database. Each partition-wide object identifier includes a replica identifier and at least one integer value. Suitable integer values include timestamp values, event counter values, random values, and GUID values. Other methods use the identifiers to access objects after a single object or a subtree of objects has been renamed or moved.

Claims

1. A method for managing replicated objects in a partitioned hierarchical database which includes a root object, comprising the steps of:

(a) obtaining a replica identifier which identifies a replica in the database relative to other replicas in the database;

(b) obtaining an integer value;

(c) adjoining the replica identifier and the integer value to form a partition-wide object identifier which identifies a target object in a partition of the database relative to all other objects in that partition;

(d) repeating the steps (a)-(c) for each object in the replica which is on a path containing the root object and the target object, thereby creating at least one additional partition-wide object identifier; and

(e) combining the partition-wide object identifier of the target object with the partition-wide object identifiers of the objects on the path to form a database-wide object identifier which identifies the target object relative to all other objects in the database.

2. The method of claim 1, wherein the combining step comprises placing the partition-wide object identifiers adjacent one another in order according to ancestry as components in the database-wide object identifier.

3. The method of claim 1, wherein the step of obtaining an integer value comprises obtaining a timestamp value.

4. The method of claim 1, wherein the step of obtaining an integer value comprises obtaining an event counter value.

5. The method of claim 1, wherein the step of obtaining an integer value comprises obtaining a random value.

6. The method of claim 1, wherein the step of obtaining an integer value comprises obtaining a GUID value.

7. A method for managing replicated objects in a partitioned hierarchical database having a plurality of writable replicas, comprising the steps of:

(a) obtaining a replica number which identifies a particular writable replica in the database relative to other replicas in the database;

(b) obtaining an event counter;

(c) adjoining the replica number and the event counter to form a tuned name component which identifies a target object in a partition of the database relative to all other objects in that partition;

(d) repeating the steps (a)-(c) for each object in the particular replica which is an ancestor of the target object, thereby creating at least one additional tuned name component; and

(e) adjoining the tuned name components created by steps (a)-(d) in order according to ancestry, thereby forming a tuned name which identifies the target object relative to all other objects in the database.

8. The method of claim 7, wherein the target object is identified by a distinguished name in addition to being identified by the tuned name.

9. The method of claim 8, wherein the method further comprises renaming the target object by changing the distinguished name, and the same tuned name identifies the object before and after the renaming is complete.

10. The method of claim 7, wherein the steps (a)-(e) provide a first tuned name, and the method further comprises comparing the first tuned name with a second tuned name by comparing tuned name components one-by-one in order according to ancestry.

11. The method of claim 7, wherein the steps (a)-(e) provide a first tuned name, and the method further comprises moving the target object to a different location in the database and then repeating the steps (a)-(e) to create a second tuned name which identifies the target object at the different location.

12. The method of claim 11, wherein each replica is stored on a server computer and the method further comprises notifying each server computer of the second tuned name and then deleting the first tuned name from the database.

13. The method of claim 7, wherein the steps (a)-(e) provide a first tuned name which identifies the target object at a first location in the database, the target object has at least one descendant object in the database, and the method further comprises moving the target object and all its descendant objects from a first set of locations to a second set of locations in the database and then repeating the steps (a)-(e) to create a second tuned name which identifies the target object at its second location.

14. The method of claim 13, wherein the method further comprises the steps of:

attempting to access a descendant object of the target object at its first location using a first tuned name of the descendant object;

detecting that the descendant object has been moved; and

then

accessing the descendant object at its second location by replacing a first tuned name component in the first tuned name of the descendant object by a tuned name component in the second tuned name of the descendant object, the first tuned name component identifying the target object at its first location and the second tuned name component identifying the target object at its second location.

15. A system for managing objects, the system comprising:

at least one server computer having an addressable storage medium configured by containing at least one replica of a partitioned hierarchical database of objects, the server storage medium being further configured by containing a server program capable of responding to requests for access to the database;

at least one client computer in communication with the server computer through a network connection, the client computer having an addressable storage medium configured by containing an application program capable of making requests for access to the database;

means for adjoining replica identifiers and integer values to form a sequence of relative object identifiers;

wherein at least one object in the partitioned hierarchical database is identified to the server program by the sequence of relative object identifiers, the sequence corresponds to the object and its ancestor objects, and each relative object identifier identifies an object relative to its sibling objects within the replica of the database on the server.

16. The system of claim 15, wherein each relative object identifier comprises a replica number and an integer value that is an event counter value or a random value.

17. The system of claim 15, wherein each relative object identifier comprises a replica number, an event counter value, and a timestamp value.

18. The system of claim 15, wherein each relative object identifier comprises a replica number and a GUID value.

19. The system of claim 15, further comprising means for accessing an object using a sequence of relative object identifiers after the object has been moved to a different location in the database.

20. The system of claim 15, further comprising means for accessing an object using a sequence of relative object identifiers after the object and at least one ancestor of the object have been moved together to a different location in the database.

21. A computer-readable storage medium having a configuration that represents data and instructions which cause a computer system to perform method steps for managing replicated objects in a partitioned hierarchical database, the method steps comprising the following:

(a) obtaining a replica identifier which identifies a replica in the database relative to other replicas in the database;

(b) obtaining an integer value;

(c) adjoining the replica identifier and the integer value to form a partition-wide object identifier which identifies a target object in a partition of the database relative to all other objects in that partition;

(d) repeating the steps (a)-(c) for each object in the replica which is an ancestor of the target object, thereby creating at least one additional partition-wide object identifier; and

(e) combining the partition-wide object identifier of the target object with the partition-wide object identifiers of the ancestors of the target object to form a database-wide object identifier which identifies the target object relative to all other objects in the database.

22. The storage medium of claim 21, wherein the combining step comprises placing the partition-wide object identifiers adjacent one another in order according to ancestry as components in the database-wide object identifier.

23. The storage medium of claim 21, wherein the step of obtaining an integer value comprises obtaining a timestamp value.

24. The storage medium of claim 21, wherein the step of obtaining an integer value comprises obtaining an event counter value.

25. The storage medium of claim 21, wherein the step of obtaining an integer value comprises obtaining a GUID value.

26. The storage medium of claim 21, wherein each partition-wide object identifier comprises a replica number, an event counter value, and a timestamp value.

27. The storage medium of claim 21, wherein the method further comprises accessing an object using a partition-wide object identifier after the object has been moved to a different location in the database.