Synchronizing recovery log having time stamp to a remote site for disaster recovery of a primary database having related hierarchial and relational databases

• US 6,065,018 A
• Filed: 03/04/1998
• Issued: 05/16/2000
• Est. Priority Date: 03/04/1998
• Status: Expired due to Term

• Current Assignee: GlobalFoundries, Inc.
• Original Assignee: International Business Machines Corporation
• Inventors: Kern, Robert Frederic, Moore, David Wayne, Beier, Harley Al, Watts, Vern Lee, Ranson, Karen Alicia
• Primary Examiner(s): Fetting, Anton W.
• Assistant Examiner(s): CHANNAVAJJALA, SRIRAMA T
• Application Number:
  US09/034,867
• Time in Patent Office: 804 Days
• Field of Search: 707/1-5, 707/8, 707/10, 707/200-205, 707/100-104, 714/1, 714/6, 714/12-13, 714/20, 714/731, 714/744, 714/775, 714/16-18, 711/113, 711/117-118, 711/130, 711/147, 711/153, 711/161, 711/162, 711/167-168, 709/101, 709/201, 709/203, 709/212-215, 709/217, 709/232, 709/248
• US Class Current: 707/610
• CPC Class Codes: G06F 11/1402 Saving, restoring, recovering or retrying
• CPC Class Codes: Y10S 707/954 Relational
• CPC Class Codes: Y10S 707/956 Hierarchical
• CPC Class Codes: Y10S 707/99952 Coherency, e.g. same view to multiple users
• CPC Class Codes: Y10S 707/99953 Recoverability

Abstract

A method and apparatus to synchronize recovery logs transmitted to a remote site for recovering related databases having different logical structuring. In one embodiment, the related databases are a hierarchial structured database such as IMS and a relational structured database such as DB2.

Claims

1. A method for synchronizing a recovery log to a remote site for disaster recovery of a primary database having related hierarchial and relational databases, comprising:

processing hierarchial records and relational records of the recovery logs wherein a time stamp of each hierarchial record is ≦

to a time stamp for a last entered relational record, and wherein a time stamp is used to mark a point in time and a hierarchial record reflects hierarchial database data and a relational record reflects relational database data.

2. The method recited in claim 1, further comprising transmitting the hierarchial records to the remote site independent from the transmission of the relational database.

3. The method recited in claim 2, further comprising maintaining a hierarchial database in real time at the remote site that shadows the primary site hierarchial database.

4. The method recited in claim 3, further comprising:

(a) continually comparing, in sequence by time stamp, the time stamp for each hierarchial record to a last entered time stamp for a relational record; and

(b) processing recovery log records;

(1) if the time stamp for the hierarchial record is ≦

to the last entered time stamp for the relational record, processing the hierarchial record and selecting a next hierarchial record for comparison;

(2) if the time stamp for the hierarchial record is not ≦

to the last entered time stamp for the relational record, requesting a new last entered time stamp for a relational record;

(i) if the time stamp for the hierarchial record is ≦

the new last entered time stamp for the relational record, processing the hierarchial record and selecting a next hierarchial record;

(ii) if no new time stamp is received within a specified period of time, periodically requesting a new last entered time stamp for a relational record until a new last entered time stamp for a relational record is obtained; and

(iii) suspending hierarchial record processing until a new last entered time stamp for a relational record is obtained.

5. The method recited in claim 4, further comprising truncating a recovery log when a primary site disaster occurs at a point in time substantially coinciding with the last time stamp used for processing recovery log records.

6. The method recited in claim 5, further comprising:

truncating first the hierarchial records at the point in time;

reporting a truncation time; and

then

truncating the relational records at the truncation time.

7. The method recited in claim 6, further comprising processing the hierarchial and the relational records entered into the recovery logs and having an earlier time stamp than the truncation time.

8. The method recited in claim 7, further comprising maintaining a primary site, the primary site including a database and logs, the logs comprising updated records to be transferred to the database, the database including related hierarchial and relational databases, the remote site including recovery logs and a recovery database, the recovery database including related hierarchial and relational databases, the recovery logs comprising updated records to be transferred to the recovery database, the recovery site used to take over the database functions of the primary site if a disaster occurs at the primary site.

9. A signal-bearing medium tangibly embodying a program of machine-readable instructions executable by a digital processing apparatus to perform a method for synchronizing update recovery logs transmitted to a remote site for disaster recovery of a primary database having related hierarchial and relational databases, said method comprising:

processing hierarchial records and relational records of the recovery logs wherein a time stamp of each hierarchial record is ≦

to a time stamp for a last entered relational record, and wherein a time stamp is used to mark a point in time and a hierarchial record reflects hierarchial database data and a relational record reflects relational database data.

10. The medium recited in claim 9, the method further comprising transmitting the hierarchial records to the remote site independent from the transmission of the relational records.

11. The medium recited in claim 10, the method further comprising maintaining a hierarchial database in real time at the remote site that shadows the primary site hierarchial database.

12. The medium recited in claim 11, the method further comprising:

(a) continually comparing, in sequence by time stamp, the time stamp for each hierarchial record to a last entered time stamp for a relational record; and

(b) processing recovery log records;

(1) if the time stamp for the hierarchial record is ≦

to the last entered time stamp for the relational record, processing the hierarchial record and selecting a next hierarchial record for comparison;

(2) if the time stamp for the hierarchial record is not ≦

to the last entered time stamp for the relational record, requesting a new last entered time stamp for a relational record;

(i) if the time stamp for the hierarchial record is ≦

the new last entered time stamp for the relational record, processing the hierarchial record and selecting a next hierarchial record;

(ii) if no new time stamp is received within a specified period of time, periodically requesting a new last entered time stamp for a relational record until a new last entered time stamp for a relational record is obtained; and

(iii) suspending hierarchial record processing until a new last entered time stamp for a relational record is obtained.

13. The medium recited in claim 12, the method further comprising truncating a recovery log when a primary site disaster occurs at a point in time substantially coinciding with the last time stamp used for processing recovery log records.

14. The medium recited in claim 13, the method further comprising:

truncating first the hierarchial records at the point in time;

reporting a truncation time; and

then

truncating the relational records at the truncation time.

15. The medium recited in claim 14, the method further comprising processing the hierarchial and the relational records entered into the recovery logs and having an earlier time stamp than the truncation time.

16. The medium recited in claim 15, the method further comprising maintaining a primary site, the primary site including a database and logs, the logs comprising updated records to be transferred to the database, the database including related hierarchial and relational databases, the remote site including recovery logs and a recovery database, the recovery database including related hierarchial and relational databases, the recovery logs comprising updated records to be transferred to the recovery database, the recovery site used to take over the database functions of the primary site if a disaster occurs at the primary site.

17. An apparatus used to synchronize recovery logs transmitted to a remote site for disaster recovery of a primary database, the apparatus comprising:

a primary site including primary data storage, the primary storage used for storing the primary database, the primary storage including at least one log comprising updated records for transfer to the primary database, the primary database including a hierarchial database and a relational database;

a remote site including remote site data storage, the remote site storage used for maintaining the remote database and including at least one recovery log;

a link communicatively coupling the primary site with the remote site;

a processor communicatively linked to the primary site and the remote site, the processor executing a series of commands to synchronize recovery logs transmitted from the primary site to the remote site by;

processing hierarchial records and relational records of the recovery logs wherein a time stamp of each hierarchial record is ≦

to a time stamp for a last entered relational record, and wherein a time stamp is used to mark a point in time and a hierarchial record reflects hierarchial database data and a relational record reflects relational database data.

18. The apparatus recited in claim 17, the processor further executing commands for transmitting the hierarchial records to the remote site independent from the transmission of the relational records.

19. The apparatus recited in claim 18, the processor further executing commands for maintaining a hierarchial database in real time at the remote site that shadows the primary site hierarchial database.

20. The apparatus recited in claim 19, the processor further executing commands for:

(a) continually comparing, in sequence by time stamp, the time stamp for each hierarchial record to a last entered time stamp for a relational record; and

(b) processing recovery log records;

(1) if the time stamp for the hierarchial record is ≦

to the last entered time stamp for the relational record, processing the hierarchial record and selecting a next hierarchial record for comparison;

(2) if the time stamp for the hierarchial record is not ≦

to the last entered time stamp for the relational record, requesting a new last entered time stamp for a relational record;

(i) if the time stamp for the hierarchial record is ≦

the new last entered time stamp for the relational record, processing the hierarchial record and selecting a next hierarchial record;

(ii) if no new time stamp is received within a specified period of time, periodically requesting a new last entered time stamp for a relational record until a new last entered time stamp for a relational record is obtained; and

(iii) suspending hierarchial record processing until a new last entered time stamp for a relational record is obtained.

21. The apparatus recited in claim 20, the processor further executing commands for truncating a recovery log when a primary site disaster occurs at a point in time substantially coinciding with the last time stamp used for processing recovery log records.

22. The apparatus recited in claim 21, the processor further executing commands for:

truncating first the hierarchial records at the point in time;

reporting a truncation time; and

then

truncating the relational records at the truncation time.

23. The apparatus recited in claim 22, the processor further executing commands for processing the hierarchial and the relational records entered into the recovery logs and having an earlier time stamp than the truncation time.

24. An apparatus for synchronizing update recovery logs at a remote site for recovery of related hierarchial and relational databases, the apparatus comprising:

a means for processing hierarchial records and relational records of the recovery logs wherein a time stamp of each hierarchial record is ≦

to a time stamp for a last entered relational record, and wherein a time stamp is used to mark a point in time and a hierarchial record reflects hierarchial database data and a relational record reflects relational database data;

means for maintaining a hierarchial database in real time at the remote site that shadows the primary site hierarchial database; and

means for transmitting the hierarchial records to the remote site independent from the transmission of the relational records.

25. The apparatus recited in claim 24, including:

(a) continually comparing, in sequence by time stamp, the time stamp for each hierarchial record to a last entered time stamp for a relational record; and

(b) processing recovery log records;

(1) if the time stamp for the hierarchial record is ≦

to the last entered time stamp for the relational record, processing the hierarchial record and selecting a next hierarchial record for comparison;

(2) if the time stamp for the hierarchial record is not ≦

to the last entered time stamp for the relational record, requesting a new last entered time stamp for a relational record;

(i) if the time stamp for the hierarchial record is ≦

the new last entered time stamp for the relational record, processing the hierarchial record and selecting a next hierarchial record;

(ii) if no new time stamp is received within a specified period of time, periodically requesting a new last entered time stamp for a relational record until a new last entered time stamp for a relational record is obtained; and

(iii) suspending hierarchial record processing until a new last entered time stamp for a relational record is obtained; and

truncating a recovery log when a primary site disaster occurs at a point in time substantially coinciding with the last time stamp used for processing recovery log records.

26. The apparatus recited in claim 25 wherein the truncation means truncating first the hierarchial records at the point in time, reporting a truncation time, and then truncating the relational records at the truncation time.

27. The apparatus recited in claim 26, including a means for processing the hierarchial and the relational records entered into the recovery logs and having an earlier time stamp than the truncation time.