Reliable database administration arrangement

• US 5,136,707 A
• Filed: 10/28/1988
• Issued: 08/04/1992
• Est. Priority Date: 10/28/1988
• Status: Expired due to Fees

• Current Assignee: American Telephone & Telegraph Company (AT&T, Inc.), AT&T Information Systems Inc. (AT&T, Inc.)
• Original Assignee: AT&T, Inc.
• Inventors: Block, Frederick P., Chan, Norman C.
• Primary Examiner(s): Fleming, Michael R.
• Assistant Examiner(s): Chun, Debra A.
• Application Number:
  US07/264,283
• Time in Patent Office: 1,376 Days
• Field of Search: 364/300, 364/200 MS File, 364/900 MS File, 395/600, 371/21.6
• US Class Current: 711/121
• CPC Class Codes: G06F 16/27 Replication, distribution or synchronisation of data between databases or within a distributed database system; Distributed database system architectures therefor
• CPC Class Codes: H04Q 2213/1305 Software aspects
• CPC Class Codes: H04Q 2213/13109 Initializing, personal profile
• CPC Class Codes: H04Q 2213/13376 Information service, downloading of information, 0800/0900 services
• CPC Class Codes: H04Q 3/54516 Initialization, software or data downloading G06F9/445 takes precedence
• CPC Class Codes: Y10S 707/99952 Coherency, e.g. same view to multiple users

Abstract

In a distributed system, such as a PBX (FIG. 1), which uses a database for its operation, a master copy (22) of the database having a first format is stored at a central node (10) and cache copies (32) of database portions (24) but having a different format are stored at peripheral nodes (11-12). A change to the database is made to the master copy, is recorded in a change table (26) corresponding to the affected database portion, and is sent to affected peripheral nodes. At initialization, a boot copy (25) is made of each database portion by translating the database portion from the master database format to the cache copy format. Periodically thereafter, each boot copy is replaced with a new boot copy that reflects changes presently recorded in the corresponding change table. When the new boot copy is generated, the present change table contents are erased. When a peripheral node calls for a new cache copy (e.g., upon reboot), it is sent the corresponding boot copy and any changes presently recorded in the corresponding change table.

Claims

1. An apparatus comprising:

means for modifying a database having a plurality of modifiable portions, the portions having a first format;

means for storing records of modifications made to the database portions;

means for generating boot copies of the database portions, the boot copies having a second format; and

means responsive to a request from a requester for a database portion, for sending to the requester the boot copy of the requested portion and the presently-stored records of modifications made to the requested portion.

2. The apparatus of claim 1 further comprising:

means for occasionally generating a new boot copy of a database portion based on then-present contents of that portion and for deleting previously-stored records of modifications made to that portion.

3. The apparatus of claim 1 wherein

the means for generating boot copies include

means for translating the database portions from the first format to the second format.

4. An apparatus comprising:

a database having a plurality of modifiable portions having a first format;

a plurality of storage means connected to the database, each corresponding with a different one of the database portions, each for storing records of modifications made to the corresponding database portion;

memory means connected to the database for storing a plurality of boot copies of the database portions, each boot copy corresponding with a different one of the database portions and having a second format different from the first format;

means connected to the plurality of storage means and responsive to modification of a database portion, for making a record of the modification in the storage means corresponding to the modified database portion; and

means connected to the plurality of storage means and to the memory means, responsive to a request from a requester for a cache copy of a database portion, for sending to the requester the boot copy of the requested portion and the modifications presently recorded in the storage means corresponding to the requested portion.

5. The apparatus of claim 4 further comprising:

means for occasionally generating a new boot copy of a database portion, the new boot copy reflecting modifications presently recorded in the storage means corresponding to that database portion, and for deleting from the storage means corresponding to a database portion the records of the modifications reflected in the boot copy of that database portion.

6. The apparatus of claim 5 wherein a boot copy initially comprises an up-to-date copy of the corresponding database portion.

7. The apparatus of claim 5 wherein

the boot copy generating means include means for translating the database portions from the first format to the second format.

8. The apparatus of claim 4 further comprising:

cache copies of the database portions each maintained by a requester, the cache copies having the second format; and

means responsive to a modification of a database portion, for notifying of the modification the cache copy of the database portion.

9. A distributed system comprising:

a plurality of system portions interconnected for communications;

a database having a plurality of portions and stored in a first system portion, the database portions having a first format;

cache copies of the database portions stored in a plurality of the system portions, the cache copies having a second format;

means connected to the database in the first system portion for making changes in the database portions;

a plurality of storage means in the first system portion each corresponding with a different one of the database portions, each for storing records of changes made to the corresponding database portion;

a plurality of boot copies of the database portions stored in the first system portion, each corresponding with a different one of the database portions, the boot copies having the second format;

means connected to the plurality of storage means in the first system portion and responsive to the change making means, for making a record of a change in a database portion in the storage means corresponding to the modified database portion, and for notifying of the change the system portion at which a cache copy of the database portion is located;

means connected to the plurality of boot copies in the first system portion, for occasionally regenerating a boot copy to reflect in the boot copy changes that are presently recorded in the storage means corresponding to a same database portion as the boot copy, and for deleting from that storage means the records of the changes that were reflected in the regenerated boot copy; and

means located at the first system portion and responsive to a request from a system portion for a new cache copy of a database portion, for sending to the requesting system portion the boot copy of the requested portion and the changes presently recorded in the storage means corresponding to the requested portion.

10. The system of claim 9 wherein the boot copy regenerating means include means for translating the database portion from the first format to the second format.

11. The system of claim 9 wherein the regenerating means comprise means for occasionally making changes that are presently recorded in the storage means corresponding to a database portion in the boot copy of that database portion.

12. The system of claim 9 wherein the regenerating means comprise means for replacing a boot copy of a database portion with a new boot copy that is formed from the corresponding database portion as modified by the change making means.

13. A method of administering a database by a database manager means, the database having plurality of modifiable portions, the portions having a first format, comprising the steps of:

generating boot copies of the database portions, the boot copies having a second format;

modifying a database portion;

storing a record of the modification; and

sending to a requester the boot copy of a requested portion and the presently-stored records of modifications made to the requested portion, in response to a request from the requester for the database portion.

14. The method of claim 13 further comprising the step of:

occasionally generating a new boot copy of a database portion based on then-present contents of that portion; and

deleting previously-stored records of modifications made to that portion.

15. The method of claim 13 wherein

the step of generating boot copies includes the step of

translating the database portion from the first format to the second format.

16. A method of administering a database by a database manager means, the database having a plurality of modifiable portions, comprising the steps of:

(A) making a boot copy of each of the database portions, the database portions having a first format and the boot copies having a second format different from the first format;

(B) modifying a database portion;

(C) making a record of the modification in a storage means corresponding to the modified database portion;

(D) repeating steps B and C; and

(E) in response to a request from a requester for a database portion, sending to the requester the boot copy of the requested portion and the modifications presently recorded in the storage means corresponding to the requested portion.

17. The method of claim 16 further comprising the steps of:

(F) occasionally generating a new boot copy of a database portion to reflect in the new boot copy modifications presently recorded in the storage means corresponding to that database portion; and

(G) deleting from the storage means corresponding to a database portion the records of the modifications reflected in the boot copy of that database portion.

18. The method of claim 16 wherein step (A) includes the step of:

translating each of the database portions from the first format into the second format.

19. The method of claim 16 in an apparatus having a first node including the database and a plurality of other nodes including cache copies of the database portions, the method further comprising the step of:

in response to modifying a database portion, notifying the node at which a cache copy of the database portion is located of the modification.

20. The method of claim 16 in an apparatus having a first node including the database and a plurality of other nodes, the method further comprising the steps of:

initially sending cache copies of the database portions to the other nodes for storage at the other nodes; and

in response to modifying a database portion, notifying the node at which a cache copy of the database portion is located of the modification.

21. The method of claim 17 wherein the step (F) comprises the step of occasionally modifying the boot copy of a database portion with modifications presently recorded in the storage means corresponding to that database portion.

22. The method of claim 17 wherein the step (F) comprises the step of replacing a boot copy of a database portion with a new boot copy that is formed from the corresponding database portion as modified by any preceding step (B).

23. The method of claim 17 wherein the step (F) comprises the step of

translating the database portion from the first format into the second format.

24. An apparatus comprising:

means for modifying a database having a plurality of modifiable portions;

means for storing records of modifications made to the database portions;

means for occasionally generating and storing boot copies of the database portions; and

means responsive to a request from a requester for a database portion, for sending to the requester the stored boot copy of the requested database portion and the stored records of modifications that have been made to the requested database portion since the stored boot copy was generated.

25. The apparatus of claim 24 further comprising:

means for occasionally generating a new boot copy of a database portion based on then-present contents of that database portion and for deleting previously-stored records of modifications made to that database portion.

26. The apparatus of claim 24 wherein

the means for generating boot copies include

means for translating the database portions from a format of the database to a different format.

27. A method of administering a database by a database manager means, the database having a plurality of modifiable portions, comprising the steps of:

occasionally generating and storing boot copies of the database portions;

modifying a database portion;

storing a record of the modification; and

sending to a requester the stored boot copy of a requester database portion and the stored records of modifications that have been made to the requested database portion since the stored boot copy was generated, in response to a request from the requester for the database portion.

28. The method of claim 27 further comprising the step of:

occasionally generating a new boot copy of a database portion based on then-present contents of that database portion; and

deleting previously-stored records of modifications made to that database portion.

29. The method of claim 27 wherein

the step of generating boot copies includes the step of

translating the database portion from a format of the database to a different format.