KR101430239B1 - Method and Apparatus for Synchronizing Data in Active-Active Database Server System - Google Patents

Abstract

The present invention relates to an apparatus and method for synchronizing data in an active-active database server system.

The present invention provides a method of synchronizing data synchronization between two database nodes using an application program when a failure occurs in one database node in an active-active database server system in which two storages exist.

The present invention can provide an effect of ensuring data synchronization between database servers while ensuring performance in a database server system having a plurality of storages.

Transaction, Data Synchronization, Active-Active Database System

Description

[0001] The present invention relates to an apparatus and method for synchronizing data in an active-active database server system,

The present invention relates to a data synchronization apparatus and method, and more particularly, to an apparatus and method for synchronizing data in an active-active database server system.

In the information technology field, a disk-based database management system (DBMS) is mainly utilized. In recent years, main memory DBMS has been used in applications.

Commercial DBMS provides replication function and synchronization function in the engine itself to provide data availability, reliability, and consistency.

However, in commercial DBMS, there are many cases where the performance is not satisfied when the actual database server is constructed or the functions required by the user are not satisfied. Therefore, the application program is separately developed to perform replication and data synchronization.

In particular, in an active-active database server environment that has redundant storage as well as DBMS servers, if one database node fails, another database node continues to serve, ensuring data synchronization between the two database nodes after recovery of the failed server Is very important.

When 2PC (2 Phase Commit) is used as a conventional technology in commercial DBMS, transaction consistency can be guaranteed, but it is not suitable for commercial DBMS service due to its slow processing speed.

In order to solve such problems, the present invention provides a data synchronization apparatus and method for synchronizing data synchronization between two database nodes by using an application program when a failure occurs in one database node in an active-active database server system.

According to an aspect of the present invention, there is provided a data synchronization method comprising the steps of: (a) checking a failure state of a database server in which a failure occurs and, when a failure recovery signal is received from the database server, - each application server including middleware with a log recorder - translating the first log received from the application server into a query message and requesting the database server for transaction processing; (b) upon completion of the transaction processing, generating and transmitting a transaction processing completion signal to the one or more application servers; And (c) during the transaction processing in step (a), converting the second log received from the one or more application servers into a query and requesting the database server to process the remaining transaction, do.

A data synchronization apparatus according to an embodiment of the present invention includes a failure confirmation unit for controlling at least one database server in cooperation with a polling method to determine whether a server has failed; A log receiver for receiving and storing a first log from one or more application servers that perform transactions, each application server including middleware with a logger; And a first transaction processing unit that requests the first database server to process the first transaction if the failure log is received from the database server in which the failure occurs, And a transaction processor for converting a second log received during the first transaction process into a query and requesting the database server that has generated the failure to perform a second transaction process.

According to the above-described configuration, it is possible to guarantee data synchronization between database servers while ensuring performance in a database server system having a plurality of storages.

The present invention can be expected to achieve data synchronization in an active-active database server system without causing transaction leaks between two servers by using an application program when a failure occurs in one database node.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention in the drawings, parts not related to the description are omitted, and like parts are denoted by similar reference numerals throughout the specification.

Throughout the specification, when a component is referred to as "comprising ", it means that it can include other components as well, without excluding other components unless specifically stated otherwise. Also, the terms " part, "" module," " module, "and " block" refer to units that process at least one function or operation, Lt; / RTI >

FIG. 1 is a diagram illustrating a normal state in an active-active redundant database server system according to an embodiment of the present invention. FIG. 2 is a block diagram illustrating an active-active redundant database server system according to an embodiment of the present invention. 130) in which a failure has occurred.

The first application server 100, the second application server 110, the disk-based first DBMS server 120, the disk-based second DBMS server 130, and the data synchronization device 140 are included in the embodiment of the present invention do.

The first application server 100 and the second application server 110 each have middleware 1 102 and middleware 2 112 installed as application programs.

The transaction data processed by the middleware 1 102 of the first application server 100 and the middleware 2 112 of the second application server 110 are stored in the storage 1 124 of the disk- Based second DBMS server 130 in the storage 2 134 of the second DBMS server 130. [

The disk-based first DBMS server 120 includes a first DBMS server 122 and a storage 1 124. The disk-based second DBMS server 130 includes a second DBMS server 132 and a storage 2 134, .

The middleware 1 102 of the first application server 100 and the middleware 2 112 of the second application server 110 are connected to the disk based first DBMS server 120 and the disk based second DBMS server 130, You can read and write.

For example, when the middleware 1 102 generates and writes transaction data, the same transaction data is transmitted to the disk-based first DBMS server 120 and the disk-based second DBMS server 130. Therefore, the disk-based first DBMS server 120 and the disk-based second DBMS server 130 store the same transaction data.

The middleware 1 102 of the first application server 100 and the middleware 2 112 of the second application server 110 fail in the disk based first DBMS server 120 or the disk based second DBMS server 130 , The transactions performed in the disk-based first DBMS server 120 and the disk-based second DBMS server 130 transmit logs to the data synchronizer 140 while maintaining the order.

The data synchronization apparatus 140 receives the log from the middleware 1 102 of the first application server 100 and the middleware 2 112 of the second application server 110, And requests the DBMS server 120 or the disk-based second DBMS server 130 for transaction processing.

The middleware 1 102 and the middleware 2 112 described above include a log recorder (application program) for parsing a structured query language (SQL) and storing a log for each operation.

The type of log to be stored in the data synchronization apparatus 140 is as follows.

Log schema = (serial number, execution time, call service, operation name, table name, column name, value, condition)

Here, the serial number is the sequence of the structured query language executed, the execution time is the time at which the log is recorded, the call service is the service of the middleware that called the log record, and the operation name is the type of the write-only DML (Data Manipulation Language) , DELETE), the table name is the table name, the column name is the column name to be processed, the value is the value to be reflected in the column, and the condition is the condition of the row to execute the write DML.

For example, suppose you have the following schema:

create table AAA (a integer, b varchar (20));

create table BBB (a integer, b varchar (20), c varchar (20));

create table CCC (x integer, y varchar (10));

The middleware 1 102 of the first application server 100 and the middleware 2 112 of the second application server 110 simultaneously execute the following transaction on the disk-based first DBMS server 120 while invoking the log recorder And stores the log in the data synchronization apparatus 140 as well.

Trans_begin

insert into AAA values (1, 'aaa');

update AAA set a = 'bbb' where a = 'aaa';

insert into BBB values (2, 'bbb', 'ccc');

delete from CCC where x = 1 and y <> 'zzz';

Trans_end

Next, the internal configuration of the data synchronization apparatus 140 in the active-active duplication database server system will be described in detail with reference to FIG.

3 is a block diagram schematically illustrating an internal structure of a data synchronization apparatus 140 in an active-active duplication database server system according to an embodiment of the present invention.

The data synchronization apparatus 140 according to the embodiment of the present invention includes a failure confirmation unit 142, a log reception unit 144, a transaction processing unit 146, and a signal processing unit 148.

The failure checking unit 142 controls the disk-based first DBMS server 120 and the disk-based second DBMS server 130 in a polling manner to check whether the server has failed.

The log receiving unit 144 receives logs from the log recorder 1 104 of the first application server 100 and the log recorder 2 114 of the second application server 110 and stores them in a log format.

The transaction processing unit 146 may be configured such that when the failure state is recovered in the failed disk based first DBMS server 120 or the disk based second DBMS server 130 The second DB server 130 converts the log received from the log recorder 1 104 of the first application server 110 and the log recorder 2 114 of the second application server 110 into a query message and requests transaction processing to the disk- In addition, the transaction processing unit 146 queries the remaining log received from the log recorder 1 104 of the first application server 100 and the log recorder 2 114 of the second application server 110 during the transaction processing as a query And requests transaction processing to the disk-based second DBMS server 130.

When the transaction processing unit 146 completes the transaction processing for the log, the signal processing unit 148 generates a transaction processing completion signal and transmits the transaction processing completion signal to the middleware 1 102 of the first application server 100 and the middleware of the second application server 110 2 (112). When all the logs for data synchronization have been processed, the signal processing unit 148 generates a normal duplication completion signal and transmits the normal duplication completion signal to the middleware 1 102 of the first application server 100 and the middleware 2 of the second application server 110 (112).

Next, a data synchronization method in an active-active duplication database server system will be described in detail with reference to FIG.

4 is a diagram for explaining a data synchronization method in an active-active duplication database server system according to an embodiment of the present invention.

As shown in FIG. 4, in the active-active redundant database server system, a method of adjusting data synchronization when a failure occurs in the disk-based second DBMS server 130 and then the failure recovers normally.

The middleware 1 102 of the first application server 100 and the middleware 2 112 of the second application server 110 are connected to the disk based first DBMS server 120 and the disk based second DBMS server 130, And periodically checks for a failure (S100).

The middleware 2 112 of the second application server 110 determines that a failure occurs in the disk-based second DBMS server 130, instead of connecting to the disk-based second DBMS server 130, To the data synchronization apparatus 140 (S102).

The log recorder 1 104 of the first application server 100 and the log recorder 2 114 of the second application server 110 are connected to the first application server 100 and the second application server 110, And transmits the first log to the data synchronization apparatus 140 while maintaining the order of the data (S104).

The data synchronization apparatus 140 stores the first log received from the first application server 100 and the second application server 110 in a log format.

The fault checking unit 142 continuously polls the interoperable disk-based first DBMS server 120 and the disk-based second DBMS server 130 (S106). If the disk-based second DBMS server 130 determines that the disk-based second DBMS server 130 has recovered from a failure (that is, a failure recovery signal is received), the transaction processing unit 146 converts the first stored log into a query And requests the disk-based second DBMS server 130 for transaction processing (S108).

The disk-based second DBMS server 130 sequentially executes the transactions accumulated in the first log received from the data synchronization apparatus 140.

The signal processing unit 148 generates a transaction processing completion signal to process the middleware 1 102 of the first application server 100 and the middleware 2 112 of the second application server 110 (S110). The middleware 1 102 of the first application server 100 and the middleware 2 112 of the second application server 110 receive the transaction processing completion signal and do not process the transaction for the preset time, (Sleep Time) (S112).

The transaction processor 146 converts the second log into a query message during the sleep time described above and requests the disk-based second DBMS server 130 to process the remaining transaction (S114).

Here, the second log means a log received from the log recorder 1 104 of the first application server 100 and the log recorder 2 114 of the second application server 110 during transaction processing in step S108.

More specifically, the second log is processed in step S108, and a transaction process completion signal is received by the middleware 1 102 of the first application server 100 and the middleware 2 112 of the second application server 110 Means a log received from the log recorder 1 104 of the first application server 100 and the log recorder 2 114 of the second application server 110 until the second application server 110 receives the log.

The reason for requesting the residual transaction processing is that after the disk-based second DBMS server 130 recovers from the failure, the transaction processing is performed based on the first log stored in step S108. At this time, the middleware 1 102 and the middleware 2 112 continues to generate a transaction to leave a log in the data synchronization device 140.

Upon receiving the remaining transaction processing completion signal from the disk-based second DBMS server 130, the signal processing unit 148 generates a normal replication completion signal indicating that all the logs have been processed and transmits the normal replication completion signal to the middleware 1 ( 102 and the middleware 2 112 of the second application server 110 (S116). Subsequently, the data synchronization apparatus 140 deletes the log that has been normally recovered (S118).

The embodiments of the present invention described above are not implemented only by the apparatus and / or method, but may be implemented through a program for realizing functions corresponding to the configuration of the embodiment of the present invention, a recording medium on which the program is recorded And such an embodiment can be easily implemented by those skilled in the art from the description of the embodiments described above.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It belongs to the scope of right.

1 illustrates a steady state in an active-active redundancy database server system according to an embodiment of the present invention.

2 is a diagram illustrating a case where a failure occurs in a disk-based second DBMS server in an active-active duplication database server system according to an embodiment of the present invention.

3 is a block diagram schematically illustrating an internal configuration of a data synchronization apparatus in an active-active duplication database server system according to an embodiment of the present invention.

4 is a diagram for explaining a data synchronization method in an active-active duplication database server system according to an embodiment of the present invention.

Claims (6)

(a) when a failure occurs in one of the plurality of database servers that duplicate and store the transaction data performed by one or more application servers, the one or more application servers execute the first Forwarding the log to a data synchronization device; (b) The data synchronization device checks the failure status of the failed database server and, when receiving a failure recovery signal from the failed database server, converts the first log into a query message, ; (c) when the transaction processing according to the first log is completed by the database server in which the failure occurs, the data synchronization device generates and transmits a transaction processing completion signal to the one or more application servers; And (d) the data synchronization apparatus, which has received the second log in which the transactions performed in the one or more application servers are logged while the transaction processing according to the first log is performed by the database server in which the failure occurs, To a query message, and requesting the database server in which the failure occurred to process the remaining transaction, thereby matching data synchronization, Wherein the one or more application servers do not perform transaction processing for a predetermined period of time such that the failed database server processes a transaction according to the second log The data synchronization method comprising: The method according to claim 1, After the step (d) When the remaining transaction processing is completed by the failed database server, generating a normal replication completion signal indicating that all logs for data synchronization have been processed and transmitting the signal to the one or more application servers; And Wherein the one or more application servers delete the processed log for data synchronization Further comprising the steps of: A fault checking unit for controlling a plurality of database servers, which duplicate and store transaction data performed by one or more application servers, in a polling manner to determine a fault; A log receiving unit for receiving and storing a first log of a transaction performed by the at least one application server from each application server when it is determined by the failure check unit that one of the plurality of database servers has failed; And Wherein when a failure recovery signal is received from the database server in which the failure occurs, the first log stored in the log receiving unit is converted into a query message to request a first transaction processing to the failed database server, When the first transaction processing is completed, a second log, which is a log of a transaction performed by the one or more application servers during the first transaction processing, is received from each application server, converted into a query statement, And a transaction processing unit for requesting a second transaction processing, Wherein the one or more application servers do not perform transaction processing for a predetermined time so that the failed database server processes the second transaction The data synchronization device comprising: The method of claim 3, Generating a transaction completion signal by transmitting a transaction completion signal to the one or more application servers when the first transaction process is completed and generating a normal replication completion signal indicating that all logs for data synchronization have been processed when the second transaction process is completed, A signal processor for transmitting to one or more application servers Further comprising: The method according to claim 3 or 4, Wherein the first log means a log received from the one or more application servers until receiving the failure recovery signal from the failed database server. 5. The method of claim 4, Wherein the second log means a log received from the one or more application servers until the first transaction processing is performed and the transaction processing completion signal is received by the one or more application servers.

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