Recursive lock-and-propagate operation

• US 20080195615A1
• Filed: 02/13/2007
• Published: 08/14/2008
• Est. Priority Date: 02/13/2007
• Status: Active Grant

• Current Assignee: Red Hat, Inc. (International Business Machines Corporation)
• Original Assignee: Red Hat, Inc. (International Business Machines Corporation)
• Inventors: Rowley, Peter A.
• Granted Patent: US 8,996,484 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 16/1837 Management specially adapted to peer-to-peer storage networks topology management mechanisms of peer-to-peer networks H04L67/1042
• CPC Class Codes: G06F 16/2343 Locking methods, e.g. distributed locking or locking implementation details

Abstract

A distributed database server receives an operation request including a flag to cause recursive lock-and-propagate operation, acquires a local lock, tests the operation locally and propagates the recursive request to a peer database server. Specific implementations within a Lightweight Directory Access Protocol (“LDAP”) server are described.

Claims

1. A method comprising:

receiving a recursive operation request;

acquiring a local lock;

testing the requested operation locally; and

propagating the recursive operation request to a peer while the local lock is held.

2. The method of claim 1, further comprising:

preparing a response containing a result of the recursive operation request and a list of peers visited;

releasing the local lock; and

transmitting the response to an entity from which the recursive operation request was received.

3. The method of claim 1 wherein the recursive operation request includes a list of already-visited peers, and

propagating the recursive operation request to a peer comprises iteratively propagating the recursive operation request to all directly-connected peers that are not on the list of already-visited peers.

4. The method of claim 1 wherein the recursive operation request is a Lightweight Directory Access Protocol (“

LDAP”

) operation request containing a control to trigger recursive lock-and-propagate operation.

5. The method of claim 4 wherein propagating the recursive operation request to a peer comprises issuing an LDAP operation request containing the control to trigger recursive lock-and-propagate operation at the peer.

6. The method of claim 1 wherein the local lock is a non-blocking lock.

7. The method of claim 1 wherein the local lock is a mutex or a semaphore.

8. The method of claim 1 wherein the recursive operation request is associated with a modification request, the method further comprising:

collecting data for a consolidated response to the recursive operation request; and

performing the modification request only if the consolidated response indicates success.

9. A computer-readable medium containing data and instructions to cause a programmable processor to perform operations comprising:

receiving an operation request including a flag to trigger a recursive lock and propagate algorithm;

executing the recursive lock and propagate algorithm; and

returning a result of the recursive lock and propagate algorithm.

10. The computer-readable medium of claim 9, containing additional data and instructions to cause the programmable processor to implement the recursive lock and propagate algorithm as:

acquiring a local lock;

testing the operation request to determine whether the request would succeed against a local database; and

propagating the operation request to a directly-connected peer server if the request would succeed against the local database.

11. The computer-readable medium of claim 9 wherein the operation request is a Lightweight Directory Access Protocol (“

LDAP”

) request and the flag is an LDAP control associated with the LDAP request.

12. The computer-readable medium of claim 11, containing additional data and instructions to cause the programmable processor to perform operations comprising:

receiving an LDAP modify request associated with the LDAP request; and

executing the LDAP modify request if the result of the recursive lock and propagate algorithm is success.

13. The computer-readable medium of claim 9, containing additional data and instructions to cause the programmable processor to perform operations comprising:

propagating data corresponding the operation request to a peer server if the result of the recursive lock and propagate algorithm is failure.

14. The computer-readable medium of claim 9 wherein the operation request comprises a list of already-visited peer servers.

15. The computer-readable medium of claim 9 wherein the operation request comprises a list of to-be-visited peer servers.

16. A system comprising:

database logic to maintain a local copy of a distributed database;

Lightweight Directory Access Protocol (“

LDAP”

) logic coupled to the database logic to receive LDAP requests and transmit LDAP responses; and

recursive lock and propagate logic coupled to the LDAP logic to test an operation against the local copy of the distributed database and propagate the operation to a connected LDAP server.

17. The system of claim 16, further comprising:

replication logic coupled to the recursive lock and propagate logic to propagate a data value in the local copy of the distributed database if the data value is associated with a recursive search failure.

18. The system of claim 16 wherein the distributed database contains a plurality of computer user entries, each entry including a unique user identification (“

UID”

) attribute.

19. The system of claim 16 wherein a lock used by the recursive lock and propagate logic is a mutex or a semaphore.

20. The system of claim 16 wherein a lock used by the recursive lock and propagate logic is associated with a data value that is a target of the operation.