JP2003242014A - Database system and duplicating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable the update for a plurality of databases of DB at a remote location to synchronize with global transaction. <P>SOLUTION: A client terminal, not shown in the figure, in a DB system conducts business with a server machine 1, and, if any trouble occurs in the server machine 1, requests a server machine 14 to process the business. According to the business request from a client terminal, DB 5 managed by DBMS 15 and DB 6 managed by DBMS 16 in the global transaction 3 are updated. DBMS 15 and DBMS 16 updates the contents of their corresponding DB 8 and DB 10 for duplication, by their duplication function, to the contents of DB 5 and DB 6 respectively via a network 7. TM 2 then transfers the management information 13 of the transaction to acquire synchronization between DB 8 and DB 10, to TM 12 at a remote location. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a database (D
B) The present invention relates to a system and a duplication method, and more particularly, to a DB system and a duplication method capable of processing a plurality of DBs as one global transaction and synchronizing the state of a remote DB with the result of this global transaction.

[0002]

2. Description of the Related Art Generally, an RM that manages a DB.
(A resource manager, specifically, a DBMS or the like.
(Hereinafter, referred to as DBMS) has its own DB duplication function, and by using this, it is possible to synchronize with the contents of a database at a remote place.

FIG. 5 is a block diagram showing the structure of a DB system for explaining DB duplication according to the prior art. In FIG. 5, 1 and 14 are servers, and 35 and 36 are D.
BMS, 43 is a user application (UAP), 4
Reference numerals 4 and 45 are DBs, 46 is a network, and 47 is a communication means.

In the DB system shown in FIG. 5, two server machines 1 and 14 constituting a DB device are connected to a network 4
It is configured to be connected via 6. Then, in the server machine 1 in which a DB device as a production system is configured, a UAP 43, a DB 44 updated by this UAP 43, and a DBMS 35 that manages the DB 44 are configured. In addition, a DB 45 and a DBMS that manages the DB 45 are configured in the server machine 14 that configures a DB device as a backup system installed in a remote place.

The DBMS 35 on the server machine 1 is a DB
The DB 44 updated by the UAP 43 managed by the MS 35 is managed, and the DB of the server machine 14 at a remote location is managed through the network 46 using the unique communication means 47.
Transfer information for update to MS 36. The DBMS 36 that has received this information is
It is possible to update the database 45 managed by, that is, to synchronize the contents of the DBs in the server machines 1 and 14 with each other.

[0006]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
Even if there is a delay in updating, it is possible to update the database of the remote system. However, the above-mentioned conventional technique is capable of updating the contents between the single DB devices, and this updating is performed by the function unique to the DBMS. Therefore, DB and DB
When a conventional system as described above is applied to a large-scale system that has a plurality of DB devices configured by MS and processes these plurality of DBs as one global transaction, It would be impossible to synchronize the state with the outcome of the global transaction described above.

A global transaction is a unit that can control a plurality of transactions (these are called transaction branches) in a bundle. A plurality of DB devices can be included in this global transaction, and in this case, a function of controlling the settlement of a plurality of DBMSs and a plurality of transaction branches is required. This function is the basic function of a program called TM (transaction manager). TM is
It controls information for multiple settlements and controls multiple transaction branches as one global transaction. The update result of the DB in the transaction branch under the control of one global transaction is uniquely determined according to the settlement of the global transaction controlled by TM.

FIG. 4 is a block diagram showing the configuration of the DB system for explaining the DB update by the global transaction. In FIG. 4, 22 and 27 are TM,
23 and 30 are UAPs, 26 are communication means, 31 and 32 are D
B, 33, and 34 are DBMS. In the system shown in FIG. 4, each DB system including TM22 and 27 is
It is supposed to operate as a production system and a backup system.

In FIG. 4, a link function 28 called an XA link function defined by X / OPEN is provided between each TM and each DBMS, and TM has this link function 2
8 for transaction control to the DBMS. The UAP 23 uses the DB update function 24, that is, S
It has a function of updating the database 31 by using QL, and can make a processing request to another UAP 30 by using the communication means 29 provided by the TM 22. At this time, the UAP 30 becomes a transaction branch for the UAP 23 transaction. Then, the update of the database 32 by the DB update function 24 of the UAP 30 is performed as one global transaction including the transaction of the UAP 23 as TM2.
2, managed by TM27.

The UAP 23 can call the transaction control function 25 of the TM 22 to settle the transaction. At this time, the TM 22 uses the contact means 26 to instruct the TM 27 to settle the transaction so that the transaction of the UAP 30 managed by the TM 27 is also settled.

As described above, U within the global transaction managed by TM22 and TM27.
Update of DB31 by AP23 and D by UAP30
Since it is performed in synchronization with the update of B32, one of D
Only B is not updated. That is, the result of a plurality of transaction branches in the global transaction is kept unique under the control of TM.

The current DBMS duplicate function is
For example, referring to the example described with reference to FIG.
And the DBMS 32 update the DB managed by the remote DBMS at a timing independent of each other. Therefore, the result of the UAP23 updating the DB31 is reflected in the DB32 at the remote location, but the UAP30 updates the DB31.
There may be a timing at which the result of updating 32 is not yet reflected in the DB 31.

Therefore, it is a large-scale system that needs to update a plurality of databases in a global transaction, and is a DB in a remote place such as a disaster countermeasure system.
In the system where it is necessary to reflect the update result in, it was necessary to devise a means for synchronizing by devising the user himself. For example, do not depend on multiple DBs,
Parallel processing can be performed by a business application by restricting the configuration of the business application such as not creating a transaction branch, or by using a means of transferring the original data that generated the transaction and generating a similar transaction. Had to come true.

An object of the present invention is to provide a means for synchronizing and updating a plurality of DBs at a remote location by using TM that manages global transactions while avoiding the above need.
It is an object of the present invention to provide a DB system and a duplication method capable of synchronizing database updates of a plurality of DBs at remote locations with a global transaction.

[0015]

According to the present invention, the object is to provide a database system comprising a plurality of databases, each database system having at least two transaction managers connected by communication means. , The transaction manager of one database system includes transaction management information including transaction settlement information for reflecting the update results of the multiple databases updated in the global transaction of the own database system to the database in the other database system, A means for transferring to the transaction manager of the other database system is provided, and the transaction manager of the other database system is based on the received transaction management information. There are, is achieved by providing a means for updating the database in its own system.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a global transaction control system and control method according to the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a DB system that uses global transaction control according to an embodiment of the present invention, and FIG. 2 is a diagram showing a remote side DB system for explaining recovery processing in the remote side DB system. FIG. 3 is a block diagram showing the configuration, and FIG. 3 is a diagram for explaining the transaction management information 13. 1 to 3, 2, 12
Is TM, 3 is global transaction, 4 is UA
P, 5, 6, 8, 10 is DB, 9 and 11 is recovery information, 1
3 is transaction management information, 15, 16, 37, 3
Reference numeral 8 is a DBMS, and other reference numerals are the same as those in FIG.

The DB system shown in FIG. 1 is constructed by connecting two server machines 1 and 14 constituting the DB system via a network 46. Then, in the server machine 1 in which the DB system as the production system is configured, TM2, UAP4, DB5 updated by this UAP4 and DBMS1 for managing DB5
DB device by 5 and DB6 updated by UAP4
And a DB device by the DBMS 16 that manages the DB 6. And UAP4 and the above two D
A global transaction is constituted by the B device.

In addition, TM12, DB8, and DB8 are installed in the server machine 14 in which a DB system as a backup system for disaster countermeasures, which is installed in a remote place, is formed.
A DB device by the DBMS 37 that manages the DB and a DB device by the DBMS 38 that manages the DB 10 and the DB 10 are configured, and the transaction management information 13 that manages the transaction transferred from the TM 2 is stored.

Normally, the client terminal (not shown) of the DB system shown in FIG. 1 is performing business with the server machine 1 as a partner, but some failure occurs in the area where the server machine 1 exists and the server machine 1 When the business becomes difficult to continue, the server machine 14 is requested to process the business. Now, it is assumed that a certain task from the client is the global transaction 3. Normally, a transaction is not generated from the client terminal. Therefore, the operation in the server machine will be described below.

In response to a business request from the client terminal, the DB 5 managed by the DBMS 15 and the DB 6 managed by the DBMS 16 are updated in the global transaction 3, and the global transaction 3 is committed.
Since DB5 and DB6 update the contents of the database in synchronization with the function of TM2, DB5 and DB6
The update contents of and are synchronized correctly. Various work requests are input from the client to the illustrated system, and the results are reflected in DB5 and DB6.

Each of the DBMS 15 and the DBMS 16 has a conventional database duplication function.
DBMS that is a replication DB corresponding to each remote location
DB8 managed by 37 and DB1 managed by DBMS38
0 can be updated to the contents of DB5 and DB6 through the network 7. In this case, the transfer process is DBMS
15 and 16, the transfer interval is D
The BMS 15 and the DBMS 16 are not synchronized. The embodiment of the present invention, in addition to the replication to the remote DB by the duplicate function of the DBMS as described above,
The transaction management information 13 for synchronizing between B8 and DB10 is to be transferred to the remote TM12 using the function 17 for transferring the transaction management information by TM2.

The transaction management information 13 is shown in FIG.
As shown in FIG. 5, it is configured to include a plurality of transaction information 42. One piece of transaction information 42 includes a transaction identifier 39, settlement information 40 such as transaction commit / rollback, and information on the DBMS 41 participating in this transaction.

Next, the recovery process in the server machine 14 on the remote side will be described with reference to FIG.

The updated contents of DB5 and DB6 transferred by the DBMS15 and DBMS16 are respectively
DBMS 37 and D as the recovery information 9 and 11 shown in FIG.
It is once held in the BMS38. On the other hand, the TM 12 in the server machine 14 installed in the remote place sends the transaction information to the DBMS 37 and the DBMS 38 by the information 41 of the participating DBMS based on the transaction management information 13 of the transferred transfer source TM 2. D using the function 20 for issuing a transaction settlement preparation instruction according to the transaction information in the settlement information 40
A transaction settlement preparation instruction is issued to the BMS 37, 38. The transaction identifier 39 is used for this instruction.

The DBMS 37 and the DBMS 38 that have received the transaction settlement preparation instruction check whether or not the information for updating the database corresponding to the instructed transaction identifier 39 exists in the recovery information 9 and the recovery information 11, respectively. If so, then reply that it is ready. TM12 is DBMS37, DBM
When it is possible to determine that the state is updatable in response to the response from S38, the function to issue a transaction settlement instruction 21 is used to instruct the DBMS 37 and the DBMS 38 to perform the update. D who received the update instruction
The BMS 37 and the DBMS 38 have recovery information 9 and
Database 8 and database 1 using recovery information 11
Update 0.

FIG. 6 is a flow chart for explaining the operation of the recovery process in the above-mentioned remote side DB system. Next, this will be explained.

(1) The transaction management information 13 is read out, and if there is transaction management information, the transaction identifier, the settlement information such as whether the transaction is committed or rolled back, and the DB that has participated.
The MS information is acquired (step 100).

(2) Based on the information obtained in step 100, first, a settlement preparation instruction may be issued to one DBMS participating in the transaction in the information, and the answer to the instruction may be settled. Is checked (steps 101 and 102).

(3) In step 102, if the answer is that the decision may be made, the next DB, that is, D
Confirm whether BMS exists and check whether there is another DB. If there is another DB, step 101
Returning to the processing from, the settlement preparation instruction is given to the other DBMS (step 104, step 105).

(4) If the answer at step 102 is that the decision may not be made, then after holding for a certain period of time, the process returns to step 101 and is executed again (step 103).

(5) When there is no other DB in the check in step 105, that is, when all the DBMSs reply that they are ready, the DBMSs participating in all the transactions are And an instruction for settlement is given (step 106).

(6) After that, it is checked whether or not transaction information still exists, and if it exists, the process returns to step 100, and then the transaction is processed based on that information. If there is no transaction information, it waits for the information to be transferred (steps 107 and 108).

Each processing according to the above-described embodiment of the present invention can be configured as a processing program, and the processing program is HD, DAT, FD, MO, DVD-.
It can be provided by being stored in a recording medium such as a ROM or a CD-ROM.

According to the above-described embodiment of the present invention, the updated contents of DB5 and DB6 updated as the global transaction 3 in the transfer source server machine 1 are transferred to DB15 and DB16 in the remote server machine 14, respectively. It is possible to update them synchronously and correctly, and it is possible to build a redundant system such as a disaster countermeasure system in a remote place to realize high reliability of a DB system prepared for a disaster.

[0036]

As described above, according to the present invention, in a large-scale system for updating a plurality of databases by a global transaction, it is possible to reflect the update information in a remote place in a correct synchronization. . As a result, it is possible to improve the reliability of the disaster countermeasure system in which a redundant system is constructed in a remote place.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a DB system using global transaction control according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a remote side DB system for explaining recovery processing in the remote side DB system.

FIG. 3 is a diagram illustrating transaction management information 13.

FIG. 4 is a block diagram showing a configuration of a DB system for explaining DB updating by a global transaction.

FIG. 5 is a block diagram showing a configuration of a DB system for explaining DB duplication according to a conventional technique.

FIG. 6 is a flowchart illustrating an operation of a recovery process in the DB system on the remote side.

[Explanation of symbols]

1, 14 Server machine 2, 12, 22, 27 TM 3 Global transaction 4, 23, 30, 43 User application (UA
P) 5, 6, 8, 10, 31, 32, 44, 45 DB 9, 10 Recovery information 13 Transaction management information 15, 16, 33-38 DBMS 26 Contact means 46 Network 47 Communication means

Claims (5)

[Claims] 1. A database system having a plurality of databases, each of which is provided with a transaction manager and is configured by connecting at least two database systems by communication means, wherein the transaction manager of one database system is its own database system. Database that includes transaction management information for reflecting the update results of a plurality of databases updated in the other global transaction to the database in the other database system to the transaction manager of the other database system. system. 2. The database system according to claim 1, wherein the transaction manager of the other database system comprises means for updating the database in the own system based on the received transaction management information. 3. A duplication method in a database system having a plurality of databases, each of which is provided with a transaction manager and is connected by communication means, wherein the transaction manager of one database system comprises: Duplicate characterized by transferring transaction management information for reflecting the update results of multiple databases updated in the global transaction of the own database system to the database in the other database system to the transaction manager of the other database system Method. 4. The duplicate method according to claim 3, wherein the transaction manager of the other database system updates the database in its own system based on the received transaction management information. 5. A processing program for realizing the duplicate method according to claim 3, wherein the transaction is for reflecting the update results of a plurality of databases updated in the global transaction of the database system in the database in the other database system. A processing program that transfers management information to the transaction manager of the other database system.