Naming service implementation in a clustered environment

• US 20050278332A1
• Filed: 05/27/2004
• Published: 12/15/2005
• Est. Priority Date: 05/27/2004
• Status: Active Grant

• Current Assignee: SAP SE
• Original Assignee: SAP AG (SAP SE)
• Inventors: Petev, Petio, Pancheva, Elitsa
• Granted Patent: US 8,028,002 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 16/10 File systems; File servers

Abstract

A method and system for providing naming operations. Contexts are created and organized hierarchically under an initial context. The hierarchy is retained in a non-persistent storage medium. The objects and contexts created as a result of various naming operations are removed from the naming system responsive to a reboot of a server. In one embodiment, the entire naming hierarchy is represented in nested hash tables with a nesting level of only two.

Claims

1. An apparatus comprising:

a server node;

a non-persistent storage unit accessible by the server node; and

a hierarchical naming structure retained within the non-persistent storage unit to be removed if the server is rebooted.

2. The apparatus of claim 1 wherein the hierarchical naming structure comprises:

a plurality of hash tables with two levels of nesting.

3. The apparatus of claim 1 wherein the hierarchical naming structure comprises:

a plurality of contexts each context including a basic object linked to a container object.

4. The apparatus of claim 3 wherein the container object comprises:

a hash table of objects to names.

5. The apparatus of claim 3 wherein the container object comprises:

a hash table of objects to identifiers.

6. The apparatus of claim 2 wherein the hash tables with two levels of nesting comprise:

a plurality of associations of names with containers and wherein each container comprises at least one of a hash table of a first type of object against names and a hash table of a first type of object against identifiers, for objects in the container.

7. The apparatus of claim 3 wherein the basic object comprises:

a name string;

a byte array; and

a link identifier.

8. The apparatus of claim 7 wherein the link identifier has a value equal to a container identifier of exactly one container in the naming structure and wherein that link identifier is unique within the naming structure.

9. A system comprising:

a plurality of virtual machines (VM) each having a server node resident therein;

a non-persistent memory implementation within each VM; and

a naming service within each of the plurality of VM, the naming service to store a hierarchical representation of objects bound within each respective VM in the non-persistent memory implementation of the respective VM.

10. The system of claim 9 wherein the naming service comprises:

a naming cache, including a hash table of cached objects as a byte array and a name; and

a hash table of cached objects as an object instance and a name.

11. The system of claim 10 wherein the naming cache further comprises:

a cache communicator to provide communication between naming services running on different server nodes a cluster.

12. The system of claim 9 wherein the hierarchical representation comprises:

two levels of nested hash tables, the first level being containers against container names and the second level being objects within a container against one of an object name and an object identifier.

13. A method comprising:

providing an abstraction as an initial context;

creating a context instance to be hierarchically organized within the abstraction;

storing the context instance in non-persistent storage; and

removing the context instance responsive to a reboot of a server.

14. The method of claim 13 wherein storing comprises:

placing the context instance within a container instance in a memory implementation of a virtual machine.

15. The method of claim 13 wherein creating comprises:

receiving a serialized directory object instance in a server context implementation;

generating a basic object instance from the serialized directory object instance to be placed in a first container;

creating a new container instance; and

linking the basic object instance to the new container instance.

16. The method of claim 13 further comprising:

organizing a plurality of objects as a hash table of containers; and

retaining within each container a hash table of objects in the container.

17. An apparatus comprising:

means for hierarchically organizing a plurality of contexts in a naming system as two level nested hash tables; and

means for non-persistently storing the nested hash tables.

18. The apparatus of claim 17 further comprising:

means for linking a first object type to a container object type to form a sub-context.

19. The apparatus of claim 18 wherein the means for linking insure that no more than one object of the first object type is linked to a single object of the container object type.

20. A machine-accessible medium containing instructions that, when executed, cause a machine to:

provide an abstraction as an initial context;

create a context instance to be hierarchically organized within the abstraction;

store the context instance in non-persistent storage; and

remove the context instance responsive to a reboot of a server.

21. The machine accessible median of claim 20 wherein instructions causing the machine to store comprise instructions to cause the machine to:

place the context instance within a container instance in a memory implementation of a virtual machine.

22. The machine accessible median of claim 20 wherein instructions causing the machine to store comprise instructions to cause the machine to:

receive a serialized directory object instance in a server context implementation;

generate a new directory object instance from the serialized directory object instance to be placed in a first container; and

create a new container instance and linking the new directory object instance to the new container instance.

23. The machine accessible median of claim 20 wherein instructions causing the machine to store comprise instructions to cause the machine to:

organize a plurality of objects as a hash table of containers; and

retain within each container a hash table of objects in the container.