SYNCHRONIZING HISTORICAL ARCHIVE DATA BETWEEN PRIMARY AND SECONDARY HISTORIAN SYSTEMS

• US 20090006499A1
• Filed: 06/29/2007
• Published: 01/01/2009
• Est. Priority Date: 06/29/2007
• Status: Active Grant

• Current Assignee: Air Liquide Large Industries U.S. LP (L'Air Liquide SA)
• Original Assignee: Air Liquide Large Industries U.S. LP (L'Air Liquide SA)
• Inventors: Momin, Emtiaz A., Vinta, Prabhakara R., Mukhi, Sultan Q.
• Granted Patent: US 7,853,569 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 11/1662 the resynchronized component or unit being a persistent storage device re-synchronization of failed mirror storage G06F11/2082; rebuild or reconstruction of parity RAID storage G06F11/1008
• CPC Class Codes: G06F 16/275 Synchronous replication

Abstract

Techniques for operating an archival database, referred to as a historian, are disclosed. Embodiments of the invention provide techniques for synchronizing historical archive files and/or archival data between a primary and a secondary historian used to archive data values from a real-time database. The real-time database may be used to monitor the current operational state of a large industrial system, such as a pipeline. In turn, the historian may be used to archive the data stored by the real-time database. In the event that either the primary or the secondary system (or both) goes down and then comes back online at a later time, embodiments of the invention may be used to synchronize data between the primary and secondary historian systems.

Claims

1. A computer-implemented method of archiving data values from a real-time database in a first historian system and in a second historian system, wherein each of the first and second historian systems includes a short-term repository and a long-term archive, comprising:

identifying one or more data values in the short-term repository of the first historian system, wherein each of the data values are stored in the respective short term-repositories of the first and second historian systems as a tag that includes a timestamp, a tag ID identifying a monitored parameter in the real-time database, and a value for the monitored parameter;

copying the tags storing the one or more identified data values from the short-term repository of the first historian system to the long-term archive of the first historian system;

upon determining that the long-term archive of the second historian system is available, copying the tags storing the one or more identified data values from the short-term repository of the first historian system to the long-term archive of the second historian system; and

upon determining that the long-term archive of the second historian system is not available, setting a flag in a mask file for each tag ID present in the tags storing the one or more identified data values.

2. The method of claim 1, wherein the short-term repositories of the first and second historian systems are each a memory-mapped database.

3. The method of claim 1, wherein the long-term archives of the first and second historian systems are a disk-based database.

4. The method of claim 1, further comprising:

after a period of time where the second historian system is unavailable, restoring the second historian system;

accessing, by the second historian system, the mask file of the first historian system,

identifying a tag ID associated with the flag in the mask file of the first historian system;

determining a timestamp for the most recent tag having the identified tag ID stored in the long-term archive of the second historian;

identifying one or more tags in the first historian system which have the identified tag ID and have a timestamp greater than the determined timestamp of the most recent tag in the second historian system; and

copying the identified one or more tags from the long-term archive of the first historian system to the long-term archive of the second historian system.

5. The method of claim 1, wherein the real-time status database is a supervisory control and data acquisition (SCADA) system configured to monitor operational status of a pipeline.

6. The method of claim 1, wherein copying the tags storing the one or more identified data values from the short-term repository of the first historian system to the long-term archive of the first historian system comprises copying the tags to one of a plurality of archive files, wherein each archive file has a pre-determined maximum size, and wherein each archive file is associated with a given tag ID.

7. The method of claim 6, wherein copying the tags storing the one or more identified data values from the short-term repository of the first historian system to the long-term archive of the first historian system further comprises:

determining that a first archive file associated with the given tag ID has reached the pre-determined maximum size;

closing the first archive file; and

opening a second archive associated with the given tag ID file in the long-term archive of the first historian system.

8. The method of claim 6, wherein each archive file includes a header indicating a timestamp of a most recent tag in that archive file and a timestamp of an oldest tag in that archive file.

9. The method of claim 7, further comprising, aggregating two or more archive files associated with the given tag ID into a single link file.

10. The method of claim 9, wherein the link file includes a header indicating a timestamp of a most recent tag and a timestamp of an oldest tag for each archive file aggregated in the link file.

11. A computer-readable storage medium containing a program for archiving data values from a real-time database in a first historian system and in a second historian system, wherein each of the first and second historian systems includes a short-term repository and a long-term archive, the program including instructions for performing an operation, comprising:

identifying one or more data values in the short-term repository of the first historian system, wherein each of the data values are stored in the respective short term-repositories of the first and second historian systems as a tag that includes a timestamp, a tag ID identifying a monitored parameter in the real-time database, and a value for the monitored parameter;

copying the tags storing the one or more identified data values from the short-term repository of the first historian system to the long-term archive of the first historian system;

upon determining that the long-term archive of the second historian system is available, copying the tags storing the one or more identified data values from the short-term repository of the first historian system to the long-term archive of the second historian system; and

upon determining that the long-term archive of the second historian system is not available, setting a flag in a mask file for each tag ID present in the tags storing the one or more identified data values.

12. The computer-readable storage medium of claim 11, wherein the short-term repositories of the first and second historian systems are each a memory-mapped database.

13. The computer-readable storage medium of claim 11, wherein the long-term archives of the first and second historian systems are a disk-based database.

14. The computer-readable storage medium of claim 11, wherein the operations further comprise:

after a period of time where the second historian system is unavailable, restoring the second historian system;

accessing, by the second historian system, the mask file of the first historian system,

identifying a tag ID associated with the flag in the mask file of the first historian system;

determining a timestamp for the most recent tag having the identified tag ID stored in the long-term archive of the second historian;

identifying one or more tags in the first historian system which have the identified tag ID and have a timestamp greater than the determined timestamp of the most recent tag in the second historian system; and

copying the identified one or more tags from the long-term archive of the first historian system to the long-term archive of the second historian system.

15. The computer-readable storage medium of claim 11, wherein the real-time status database is a supervisory control and data acquisition (SCADA) system configured to monitor operational status of a pipeline.

16. The computer-readable storage medium of claim 11, wherein copying the tags storing the one or more identified data values from the short-term repository of the first historian system to the long-term archive of the first historian system comprises copying the tags to one of a plurality of archive files, wherein each archive file has a pre-determined maximum size, and wherein each archive file is associated with a given tag ID.

17. The computer-readable storage medium of claim 16, wherein copying the tags storing the one or more identified data values from the short-term repository of the first historian system to the long-term archive of the first historian system further comprises:

determining that a first archive file associated with the given tag ID has reached the pre-determined maximum size;

closing the first archive file; and

opening a second archive associated with the given tag ID file in the long-term archive of the first historian system.

18. The computer-readable storage medium of claim 16, wherein each archive file includes a header indicating a timestamp of a most recent tag in that archive file and a timestamp of an oldest tag in that archive file.

19. The computer-readable storage medium of claim 17, wherein the operations further comprise aggregating two or more archive files associated with the given tag ID into a single link file.

20. The computer-readable storage medium of claim 19, wherein the link file includes a header indicating a timestamp of a most recent tag and a timestamp of an oldest tag for each archive file aggregated in the link file.

21. A system, comprising at least one processor and further comprising:

a real-time database, wherein the real-time database is configured to store a current value for the plurality of monitored data values, and wherein each of the plurality of data values correspond to information reflecting an operational parameter of one or more monitored devices; and

a first and second historian systems, wherein the first and second historian systems each includes a respective short-term repository and long term archive, and wherein the first historian system is configured to;

identify one or more data values in the short-term repository of the first historian system, wherein each of the data values are stored in the respective short term-repositories of the first and second historian systems as a tag that includes a timestamp, a tag ID identifying a monitored parameter in the real-time database, and a value for the monitored parameter,

copy the tags storing the one or more identified data values from the short-term repository of the first historian system to the long-term archive of the first historian system,

upon determining that the long-term archive of the second historian system is available, copy the tags storing the one or more identified data values from the short-term repository of the first historian system to the long-term archive of the second historian system, and

upon determining that the long-term archive of the second historian system is not available, set a flag in a mask file for each tag ID present in the tags storing the one or more identified data values.

22. The system of claim 21, wherein the short-term repositories of the first and second historian systems are each a memory-mapped database.

23. The system of claim 21, wherein the long-term archives of the first and second historian systems are a disk-based database.

24. The system of claim 21, wherein the second historian system is configured to:

after a period of time where the second historian system was unavailable,

access the mask file of the first historian system,

identify a tag ID associated with the flag in the mask file of the first historian system;

determine a timestamp for the most recent tag having the identified tag ID stored in the long-term archive of the second historian;

identify one or more tags in the first historian system which have the identified tag ID and have a timestamp greater than the determined timestamp of the most recent tag in the second historian system; and

copy the identified one or more tags from the long-term archive of the first historian system to the long-term archive of the second historian system.

25. The system of claim 21, wherein the real-time status database is a supervisory control and data acquisition (SCADA) system configured to monitor operational status of a pipeline.

26. The system of claim 21, wherein the fist historian system is configured to copy the tags storing the one or more identified data values from the short-term repository of the first historian system to the long-term archive of the first historian system by copying the tags to one of a plurality of archive files, wherein each archive file has a pre-determined maximum size, and wherein each archive file is associated with a given tag ID.

27. The system of claim 26, wherein the fist historian system is further configured to copy the tags storing the one or more identified data values from the short-term repository of the first historian system to the long-term archive of the first historian system by:

determining that a first archive file associated with the given tag ID has reached the pre-determined maximum size;

closing the first archive file; and

opening a second archive associated with the given tag ID file in the long-term archive of the first historian system.

28. The system of claim 26, wherein each archive file includes a header indicating a timestamp of a most recent tag in that archive file and a timestamp of an oldest tag in that archive file.

29. The system of claim 27, further comprising, aggregating two or more archive files associated with the given tag ID into a single link file.

30. The system of claim 29, wherein the link file includes a header indicating a timestamp of a most recent tag and a timestamp of an oldest tag for each archive file aggregated in the link file.

31. A computer-implemented method for synchronizing a second historian system with a first historian system after a period of after a period of time where the second historian system was unavailable, wherein each of the first and second historian systems includes a short-term repository and a long-term archive, comprising:

accessing, by the second historian system, a mask file of the first historian system,

identifying a tag ID associated with a flag in the mask file of the first historian system, wherein each data value stored in the short term-repositories of the first and second historian systems are stored as a tag that includes a timestamp, a tag ID identifying a monitored parameter in the real-time database, and a value for the monitored parameter;

determining a timestamp for a most recent tag having the identified tag ID stored in the long-term archive of the second historian;

identifying one or more tags in the first historian system which have the identified tag ID and also have a timestamp greater than the determined timestamp of the most recent tag in the second historian system;

copying the identified one or more tags from the long-term archive of the first historian system to the long-term archive of the second historian system; and

resetting the flag in the mask file of the first historian system.