Systems and methods for synchronization of items without snapshots

• US 20060136418A1
• Filed: 12/20/2004
• Published: 06/22/2006
• Est. Priority Date: 12/20/2004
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Novik, Lev, Agarwal, Sameet H., Hudis, Irena, Jhaveri, Vivek Jawahir, Rao, Rajesh M.
• Granted Patent: US 7,457,826 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 16/256 in federated or virtual databases
• CPC Class Codes: G06F 16/275 Synchronous replication
• CPC Class Codes: Y10S 707/99931 Database or file accessing
• CPC Class Codes: Y10S 707/99943 Generating database or data structure, e.g. via user interface

Abstract

Various embodiments of the present invention are directed to systems and methods for synchronizing mixed elements (MEs) comprising structure data and unstructured filestreams between peer computer systems in a hardware/software interface system environment that does not permit snapshotting of large unstructured ME filestreams during synchronization. For several such embodiments, the method comprises synchronizing the ME in two steps, one for snapshotting the structured data component of the ME (as well as the cv of the filestream but not the filestream itself) and one for locking and transmitting the filestream to the receiving sync peer if and only if, after being locked, it is determined that the filestream is unchanged from the time of the ME data component snapshot.

Claims

1. A method for synchronizing a mixed element comprising a structured data component and an unstructured filestream in a hardware software interface system that does not permit snapshotting of filestreams, said method comprising:

snapshotting the structured data component;

locking the unstructured filestream;

determining if the filestream changed during the time between when the structured data component was snapshotted and the unstructured filestream was locked; and

if the filestream did not change during the time between when the structured data component was snapshotted and the unstructured filestream was locked, then copying said unstructured filestream to the synchronization peer and, once completed, unlocking said unstructured filestream.

2. The method of claim 1 wherein said step of determining if the filestream changed during the time between when the structured data component was snapshotted and the unstructured filestream was locked comprises:

determining a first change value of said unstructured filestream at the time said structured data component was snapshotted;

determining a second change value of said unstructured filestream after it is locked; and

comparing the second change value to the first change value to ascertain if changes were made to the unstructured filestream during the time the structured data component was snapshotted and the unstructured filestream was locked.

3. The method of claim 1 further comprising:

if the filestream did change during the time between when the structured data component was snapshotted and the unstructured filestream was locked, then raising an exception to a synchronization peer and unlocking said unstructured filestream.

4. The method of claim 1 wherein said element of snapshotting the structured data component comprises:

preventing changes to said structured data component while it is being copied to a synchronization peer;

making a first copy of said structured data component for a process that would make changes to said structured data during said copying of said structured data to a synchronization peer, and enabling said process to make changes to said first copy instead of to said structured data;

once said structured data is copied to said synchronization peer, updating said structured data with said first copy.

5. The method of claim 1 wherein step of locking said unstructured filestream is achieved by a transactional read operation.

6. The method of claim 1 wherein, if said unstructured filestream cannot be locked during the element of locking the unstructured filestream, then raising an exception to a synchronization peer and not performing the elements of (a) determining a second change value of said unstructured filestream after it is locked;

and (b) if the second change value compared to the first change value indicates that no changes to the unstructured filestream occurred between the time the structured data component was snapshotted and the unstructured filestream was locked, then copying said unstructured filestream to the synchronization peer and, once completed, unlocking said unstructured filestream.

7. The method of claim 1 implemented by a hardware control device, said hardware control device comprising means for implementing each element of said method.

8. A computer-readable medium comprising computer-readable instructions for synchronizing a mixed element comprising a structured data component and an unstructured filestream in a hardware software interface system that does not permit snapshotting of filestreams, said computer-readable instructions comprising instructions for:

snapshotting the structured data component;

locking the unstructured filestream;

determining if the filestream changed during the time between when the structured data component was snapshotted and the unstructured filestream was locked; and

if the filestream did not change during the time between when the structured data component was snapshotted and the unstructured filestream was locked, then copying said unstructured filestream to the synchronization peer and, once completed, unlocking said unstructured filestream.

9. The computer-readable medium of claim 8 further comprising instructions whereby said step of determining if the filestream changed during the time between when the structured data component was snapshotted and the unstructured filestream was locked comprises instructions for:

determining a first change value of said unstructured filestream at the time said structured data component was snapshotted;

determining a second change value of said unstructured filestream after it is locked; and

comparing the second change value to the first change value to ascertain if changes were made to the unstructured filestream during the time the structured data component was snapshotted and the unstructured filestream was locked.

10. The computer-readable medium of claim 8 further comprising instructions for:

if the filestream did change during the time between when the structured data component was snapshotted and the unstructured filestream was locked, then raising an exception to a synchronization peer and unlocking said unstructured filestream.

11. The computer-readable medium of claim 8 further comprising instructions whereby said element of snapshotting the structured data component comprises:

preventing changes to said structured data component while it is being copied to a synchronization peer;

making a first copy of said structured data component for a process that would make changes to said structured data during said copying of said structured data to a synchronization peer, and enabling said process to make changes to said first copy instead of to said structured data;

once said structured data is copied to said synchronization peer, updating said structured data with said first copy.

12. The computer-readable medium of claim 8 further comprising instructions whereby step of locking said unstructured filestream is achieved by a transactional read operation.

13. The computer-readable medium of claim 8 further comprising instructions whereby, if said unstructured filestream cannot be locked during the element of locking the unstructured filestream, then raising an exception to a synchronization peer and not performing the elements of (a) determining a second change value of said unstructured filestream after it is locked;

and (b) if the second change value compared to the first change value indicates that no changes to the unstructured filestream occurred between the time the structured data component was snapshotted and the unstructured filestream was locked, then copying said unstructured filestream to the synchronization peer and, once completed, unlocking said unstructured filestream.

14. The computer-readable medium of claim 8 wherein said computer-readable medium is an electromagnetic carrier signal that is capable of being transmitted through a communications medium.

15. A system for synchronizing a mixed element comprising a structured data component and an unstructured filestream in a hardware software interface system that does not permit snapshotting of filestreams, said system comprising at least one subsystem for:

snapshotting the structured data component;

locking the unstructured filestream;

determining if the filestream changed during the time between when the structured data component was snapshotted and the unstructured filestream was locked; and

if the filestream did not change during the time between when the structured data component was snapshotted and the unstructured filestream was locked, then copying said unstructured filestream to the synchronization peer and, once completed, unlocking said unstructured filestream.

16. The system of claim 15 further comprising a subsystem whereby said step of determining if the filestream changed during the time between when the structured data component was snapshotted and the unstructured filestream was locked comprises said subsystem:

determining a first change value of said unstructured filestream at the time said structured data component was snapshotted;

determining a second change value of said unstructured filestream after it is locked; and

comparing the second change value to the first change value to ascertain if changes were made to the unstructured filestream during the time the structured data component was snapshotted and the unstructured filestream was locked.

17. The system of claim 15 further comprising at least one subsystem for:

if the filestream did change during the time between when the structured data component was snapshotted and the unstructured filestream was locked, then raising an exception to a synchronization peer and unlocking said unstructured filestream.

18. The system of claim 15 wherein, for said element of snapshotting the structured data component, said system further comprises at least one subsystem for:

preventing changes to said structured data component while it is being copied to a synchronization peer;

making a first copy of said structured data component for a process that would make changes to said structured data during said copying of said structured data to a synchronization peer, and enabling said process to make changes to said first copy instead of to said structured data;

once said structured data is copied to said synchronization peer, updating said structured data with said first copy.

19. The system of claim 15 further comprising at least one subsystem whereby said step of locking said unstructured filestream is achieved by a transactional read operation.

20. The system of claim 15 further comprising at least one subsystem whereby, if said unstructured filestream cannot be locked during the element of locking the unstructured filestream, then raising an exception to a synchronization peer and not performing the elements of (a) determining a second change value of said unstructured filestream after it is locked;

and (b) if the second change value compared to the first change value indicates that no changes to the unstructured filestream occurred between the time the structured data component was snapshotted and the unstructured filestream was locked, then copying said unstructured filestream to the synchronization peer and, once completed, unlocking said unstructured filestream.