Replication of objects having non-primitive fields, especially addresses

• US 8,015,236 B2
• Filed: 10/18/2006
• Issued: 09/06/2011
• Est. Priority Date: 10/25/2005
• Status: Active Grant

• Current Assignee: Waratek Limited (Waratek Holdings Ltd.)
• Original Assignee: Waratek Pty Limited
• Inventors: Holt, John Matthew
• Primary Examiner(s): Hamza; Faruk
• Assistant Examiner(s): MARTINEZ, MICHAEL T
• Application Number:
  US11/583,948
• Publication Number:
  US 20070126750A1
• Time in Patent Office: 1,784 Days
• Field of Search: 709/220, 709/320, 709/248, 709212-217, 707/10, 707/100, 707/103, 707/202, 707626-628, 717/103, 717/108, 717/140, 717/143, 711/134, 711/154, 712/20
• US Class Current: 709/201
• CPC Class Codes: G06F 9/5066 Algorithms for mapping a plurality of inter-dependent sub-tasks onto a plurality of physical CPUs mappping at compile time, see G06F8/451

Abstract

The updating of only some memory locations in a multiple computer environment in which at least one applications program (50) executes simultaneously on a plurality of computers M1, M2 . . . Mn each of which has a local memory, is disclosed. Objects A and B in each local memory are disclosed which each include primitive fields (11). However, the simultaneous operation of the application program (50) can result in a “non-primitive” reference field (10) in one machine which must then be replicated in all other machines. However, the reference field (10) references another object (H) in the one machine'"'"'s local memory so corresponding objects (T, K) must be created in the local memory of each other machine and be referenced by the corresponding non-primitive field (10).

Claims

1. A method of replicating non-primitive fields of objects in a multiple java virtual machine computer environment in which different portions of at least one application program execute simultaneously on different ones of multiple computers interconnected via a communications network, said method of replicating non-primitive fields of objects comprising:

(i) in each of said multiple computers, providing a local independent memory which is not able to be accessed by any other one of said multiple computers, wherein all read requests of each said computer are satisfied by reading the independent local memory of a requesting computer without reading a memory of any other computer in the multiple computer environment,

(ii) in each of said multiple computers, creating one or more objects each having a primitive field,

(iii) in at least some of said multiple computers, creating at least one to be replicated object each having a non-primitive field with a local address pointer to a corresponding local memory object,

(iv) replicating said to be replicated objects with non-primitive fields in associated local independent memories in each of said multiple computers, such that the replicated non-primitive fields constitute address pointers to associated local memory which have different addresses from the to be replicated objects,

(v) creating a concordance table and, for each to be replicated object with a non-primitive field present in any one of said multiple computers, making the entries in said concordance table correspond to each reference to said to be replicated object,

(vi) replicating said concordance table in each computer or allowing each computer to access a corresponding portion of a single concordance table for all machines present in a server computer, each said entry in said concordance table for each said non-primitive field containing a local pointer to the local memory object with a non-primitive field referenced by the non-primitive field of a corresponding machine, and

(vii) having each machine, other than said corresponding machine, designate an equivalent non-primitive field and local object, and entering the designated equivalent non-primitive field and local object for that machine in said table or tables.

2. The method as claimed in claim 1 including the further step of:

(viii) utilizing a global name in said table(s) corresponding to all local pointers of corresponding non-primitive fields or corresponding objects.

3. The method as claimed in claim 1 including the further step of:

(ix) where processing of one of said application program portions dictates the creation of a second or subsequent referenced non-primitive field in one of said machines, creating a corresponding second or subsequent referenced non-primitive field in each of the other ones of said machines.

4. The method as defined in claim 3 including the further steps of:

(x) executing said different portions of said application program utilizing one of multiple threads within each said computer, and

(xi) having the thread which dictates the creation of said second or subsequent referenced non-primitive field, instruct each of said other ones of said computers to create said corresponding second or subsequent referenced non-primitive field.

5. The method as defined in claim 3, further comprising:

(xii) executing said different portions of said application program utilizing one of multiple threads within each said computer, and

(xiii) providing a thread which dictates the creation of said second or subsequent referenced non-primitive field, and providing one of said multiple threads other than the thread which dictates the creation of said second or subsequent referenced non-primitive field, instruct each of said other ones of said computers to create said corresponding second or subsequent referenced non-primitive field.

11. A plurality of computers interconnected via a communications network and operable to ensure carrying out of the method as claimed in claim 1.

12. A computer program product comprising a non-transitory computer readable storage medium containing a set of program instructions stored therein which, when executed by a processor, permit a plurality of computers to carry out the method of claim 1.

13. A single computer arranged to cooperate with at least one other computer in order to carry out the method as claimed in claim 1 wherein the single computer carries out the steps of:

(i) providing a local independent memory which is not able to be accessed by any other one of said multiple computers, wherein all read requests of said single computer are satisfied by reading the independent local memory of said single computer without reading a memory of any other computer in the multiple computer environment,

(ii) creating one or more objects each having a primitive field,

(iii) creating at least one to be replicated object each having a non-primitive field with a local address pointer to a corresponding local memory object,

(iv) replicating said to be replicated objects with non-primitive fields in the corresponding local memory such that the replicated non-primitive fields constitute address pointers to corresponding local memory which have different addresses from the to be replicated objects,

(v) creating a concordance table and, for each to be replicated object with a non-primitive field present in said single computer, making the entries in said concordance table correspond to each reference to said to be replicated object,

(vi) replicating said concordance table in said single computer or allowing said single computer to access a corresponding portion of a single concordance table for all machines present in a server computer, each said entry in said concordance table for each said non-primitive field containing a local pointer to the local memory object with a non-primitive field referenced by the non-primitive field of the single computer.

15. The method as claimed in claim 1 wherein:

the non-primitive fields comprise a reference field that stores a pointer to another memory location or another object.

16. The method as claimed in claim 15 wherein:

the primitive fields only store alphanumeric data content.

6. A multiple java virtual machine computer system in which different portions of at least one application program execute simultaneously on different ones of the multiple computers which are interconnected via a communications network, wherein:

each of said multiple computers has a local independent memory which is not able to be accessed by another one of said multiple computers so that all read requests of each said computer are satisfied by reading only the independent local memory of the requesting computer without reading a local memory of any other of the multiple computers,

each of said multiple computers has one or more objects each having a primitive field,

at least some of said multiple computers have at least one to be replicated object each having a non-primitive field with a local address pointer to a corresponding local memory object,

said to be replicated objects with non-primitive fields are replicated in said computers, for each said non-primitive field created in any one of said computers there is a corresponding entry in a concordance table accessible by all said computers or replicated in each said computer, said table entry containing a local pointer to the local memory object referenced by said non-primitive field of said one computer, and

wherein each said computer other than said one computer designates an equivalent non-primitive field and local object and the equivalent local pointer of the equivalent local memory object are entered in said concordance table or tables such that the replicated non-primitive fields constitute address pointers to associated local memory which have different addresses from the to be replicated object.

7. The system as claimed in claim 6 wherein said table or tables utilize a global name corresponding to all local pointers of corresponding non-primitive fields or corresponding objects.

8. The system as claimed in claim 6 wherein for each second or subsequent referenced non-primitive field in one of said computers, a corresponding second or subsequent referenced non-primitive field is created in each of the other ones of said computers.

9. The system as claimed in claim 8 in which multiple thread processing is utilized in each said computer to execute a different portion of said application program, and the thread which dictates the creation of said second or subsequent referenced non-primitive field, instructs each of the other ones of said computers to create said second or subsequent referenced non-primitive field.

10. The system as claimed in claim 8 in which multiple thread processing is utilized in each said computer to execute a different portion of said application program, and a different thread from that thread which dictates the creation of said second or subsequent referenced non-primitive field, instructs each of the other ones of said computers to create said second or subsequent referenced non-primitive field.

14. A single computer arranged to cooperate with at least one other computer in order to form the computer system as claimed in claim 6, wherein:

the single computer has a independent local memory which is not able to be accessed by another one of said multiple computers so that all read requests of said single computer are satisfied by reading only the independent local memory without reading a local memory of any other of the multiple computers,

said single computer has one or more objects each having a primitive field,

said single computer has at least one to be replicated object each having a non-primitive field with a local address pointer to a corresponding local memory object, and said to be replicated objects with non-primitive fields are replicated in said single computer, for each said non-primitive field created in any one of said computers there is a corresponding entry in a concordance table accessible by said single computer or replicated in said single computer, said table entry containing a local pointer to the local memory object referenced by said non-primitive field of said single computer.

17. The system as claimed in claim 6 wherein:

the non-primitive fields comprise a reference field that stores a pointer to another memory location or another object.

18. The system as claimed in claim 17 wherein:

the primitive fields only store alphanumeric data content.

19. A single computer arranged to cooperate with at least one other computer in a multiple java virtual machine computer environment in order to carry out a method of replicating non-primitive fields of duplicated objects in said multiple computer environment in which different portions of at least one application program execute simultaneously on different ones of multiple computers interconnected via a communications network, said single computer comprising:

(i) a local independent memory which is not able to be accessed by any other one of said multiple computers, wherein all read requests of each said computer are satisfied by reading an associated independent local memory of a requesting computer without reading any other memory;

(ii) means for creating one or more objects each having a primitive field,

(iii) means for creating at least one to be replicated object each having a non-primitive field with a local pointer to a corresponding local memory object;

(iv) means for replicating said to be replicated objects and non-primitive fields in said multiple computers,

(v) a concordance table in which, for each to be replicated object present in any one of said multiple computers, entries in said concordance table are made to correspond to each reference to said to be replicated object;

(vi) means for replicating said concordance table in each said computer or allowing each computer to access a corresponding portion of a single concordance table for all computers present in a server computer, each said entry in said concordance table for each said non-primitive field containing a local pointer to the local memory object referenced by the non-primitive field of the corresponding computer, and

(vii) means for each computer, other than said corresponding computer, to designate an equivalent non-primitive field and local object, and means for entering said equivalent non-primitive field and local object for that computer in said table or tables such that the replicated non-primitive fields constitute address pointers to associated local memory which have different addresses from the to be replicated objects.

20. The single computer as claimed in claim 19 wherein:

the non-primitive fields comprise a reference field that stores a pointer to another memory location or another object.

21. The single computer as claimed in claim 20 wherein:

the primitive fields only store alphanumeric data content.