KR101989074B1 - Migration based on replication log in database sharding environment - Google Patents

Abstract

Provides replication log-based migration technology in database sharding environment. The migration method according to an exemplary embodiment of the present invention classifies shardkeys of sharded data and processes database migration using group identifiers and a transaction log of each of a predetermined number of groups .

Description

MIGRATION BASED ON REPLICATION LOG IN DATABASE SHARDING ENVIRONMENT In the database sharding environment,

The discussion below relates to a replication log-based migration technique in a database sharding environment.

There are techniques for data migration between databases. For example, Korean Patent No. 10-1748912 discloses a technique for migrating data from a source repository to a target repository.

At this time, a transaction may occur even while data is being copied from the first database to the second database. In the prior art, the transaction is first reflected in the first database, which is the source database, and then the transaction log is transferred to the second database. The second database sequentially reflects the transactions in accordance with the transaction log so that the first database and the second database Can be synchronized.

However, in the second database, after the completion of the data migration, the transactions according to the transaction log sequentially proceed according to the order of the transactions, so that the replication delay may occur and the access blocking time to the data for migration may become longer .

The transaction reflected in the first database during the data migration between the first database and the second database is concurrently reflected in the second database using the transaction log so that the replication delay time can be reduced and the access to the migrated data can be prevented A computer program for performing a data migration method and a data migration method capable of reducing time and a computer program stored in a computer readable recording medium for causing a computer to execute a data migration method according to embodiments of the present invention, And provides the recording medium.

A data migration method and a data migration method capable of minimizing access blocking time to migrated data by changing group identifiers managed in the first database and the second database at the time when data migration is terminated while simultaneously reflecting transactions And a computer program stored in a computer-readable recording medium for causing a computer to execute a data migration method according to embodiments of the present invention, and a recording medium therefor.

A data migration method comprising the steps of: associating group identifiers of a first database with group identifiers of respective groups of a predetermined number of groups generated by sorting shardkeys of sharded data; Managing a group identifier of a second database; Identifying shard keys for data to be replicated from the first database to the second database; Migrating data corresponding to the identified shard keys from the first database to the second database; Simultaneously reflecting the transaction reflected in the first database in the second database using the transaction log during the migration; And changing the group identifiers managed in the first database and the second database in accordance with the migration of the data.

And a computer program for causing the computer to execute the data migration method is recorded.

There is provided a computer program stored in a computer-readable recording medium for causing a computer to execute the data migration method in combination with a computer.

CLAIMS What is claimed is: 1. A computer device comprising: at least one processor implemented to execute computer-readable instructions, the at least one processor being configured to classify shardkeys of sharded data, Managing a group identifier of a first database and a group identifier of a second database in association with the group identifiers of the plurality of groups of the plurality of groups and managing shard keys for data to be copied from the first database to the second database Migrate data corresponding to the identified shard keys from the first database to the second database, and transfer, during the migration, transactions reflected in the first database to the second database And the data of the above data Depending on the computer and provides the data and wherein changing the first database and the group identifiers that are managed by the second database, respectively.

The transaction reflected in the first database during the data migration between the first database and the second database is concurrently reflected in the second database using the transaction log so that the replication delay time can be reduced and the access to the migrated data can be prevented Time can be reduced.

The access blocking time to the migrated data can be minimized by changing the group identifiers managed in the first database and the second database at the time when the migration of the data is ended while simultaneously reflecting the transactions.

1 is a diagram showing an example of data stored in a database in an embodiment of the present invention.
2 is a diagram showing an example of shading of data in an embodiment of the present invention.
3 is a diagram illustrating an example of a process of data migration in an embodiment of the present invention.
4 is a diagram illustrating an example of utilization of a group identifier in an embodiment of the present invention.
5 is a block diagram for explaining an internal configuration of a computer apparatus according to an embodiment of the present invention.
6 is a flowchart showing an example of a data migration method in an embodiment of the present invention.
FIG. 7 and FIG. 8 are views illustrating an example of a process of applying the data migration method according to an embodiment of the present invention.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings.

A data migration method according to embodiments of the present invention can be performed by a computer apparatus. In one example, a computer program may be installed and run on a computer device for controlling a computer device to perform a data migration method, the computer program being coupled to the computer device to cause the computer device to execute a data migration method, Can be stored in the medium.

FIG. 1 is a diagram illustrating an example of data stored in a database according to an embodiment of the present invention. FIG. 2 is a diagram illustrating an example of data sharding in an embodiment of the present invention. 1 and 2 show an example in which data is distributed to n shard nodes 210, 220 and 230 by database sharding of data stored in the database 110. [ For example, in FIG. 1 and FIG. 2, records of the same shard key are collected by using the identifiers 'id1', 'id2', 'id3', and 'id4' Shards 210, 220, and 230, respectively. In this case, the data in units of the shard key may mean data identified through the same shard key. For example, in FIG. 2, the data identified through the shard key 'id2' is indicated by a thick solid line 240.

The data of the shard key unit has a relatively small capacity and QPS (Query Per Second), but the number of the shard key is very large, and as a result, the database overall capacity and the QPS are very large. Further, the relation between the data identified through the shard key is meaningful, but the relationship between the data identified through the different shard keys is meaningless. In other words, the data identified through one shard key has no dependency on the data identified by the other shard keys, and it is possible to process independent individual operations (transactions) on a shard key basis.

Each of the n shard nodes 210,220 and 230 may include data corresponding to one shard key, as shown through the first shard node 210, As shown, it may include data corresponding to a plurality of shard keys.

At this time, in the embodiments of the present invention, the shard keys are classified into a plurality of groups of a predetermined number in relation to the data of the shard key described above, and the consistency check of the data is performed through the group identifiers of the plurality of groups have. At this time, each of the database servers can manage the group identifiers of the group in which the shard key managed by the database servers is classified.

3 is a diagram illustrating an example of a process of data migration in an embodiment of the present invention. FIG. 3 shows an example of migrating (330) the data of the database m 310 to the database n 320.

At this time, the transaction reflected in the database m 310 during the migration 330 may be simultaneously reflected in the database n 320 using the transaction log 311. For example, if during the migration 330 the first operation is reflected on the specific data of the database m 310, the transaction log for the first operation may be analyzed so that the first operation may be simultaneously reflected in the second database . Accordingly, the replication delay time can be reduced and the access blocking time for the data can be reduced.

Techniques for enabling simultaneous reflection of such transactions are described in more detail.

As described above, the data in units of the shard key can be independently processed. Therefore, when data is migrated in units of shard keys, transactions can be simultaneously reflected on the data of the shard key units already migrated. For example, consider the case where the data identified by the shard key 'a' in database m 310 has been migrated to database n 320. At this time, if a first operation associated with the shard key 'a' is requested, a first operation can be performed on the data corresponding to the shard key 'a' in the database m 310, The first operation may be performed on the migrated data corresponding to the shard key 'a'.

To this end, a computer device according to embodiments of the present invention may select data stored in database m 310 on a shard key basis and insert selected data into database n 320 .

Meanwhile, in the embodiments of the present invention, a group identifier may be utilized for the consistency check.

4 is a diagram illustrating an example of utilization of a group identifier in an embodiment of the present invention. Each of the database servers according to the present embodiments can perform consistency checking on sharding data when performing all DML (Data Manipulation Language) queries such as INSERT, UPDATE, and DELETE.

4, an example of JDBC (Java DataBase Connectivity) 420 extracting a shard key 'id1' and hashing a shard key 'id1' to obtain a hash value '3' in an input query statement 410 Respectively. At this time, the hash value '3' may be the group identifier of the group including the shard key 'id1'. For example, each of the shard keys may be used as a parameter of a predetermined hash function so that group identifiers for each shard key may be computed. In a more specific example, one million group identifiers may be computed through a hash function of one million shard keys, and grouped into 10,000 groups for each group identifier.

In this case, even if a new shard key is added, a group or group identifier is not added because it is classified as one of the 10,000 groups in the process of hashing through the hash function. Therefore, each database server does not manage the shard keys managed by itself among the 1 million shard keys but manages only the group identifier managed by itself among the 10,000 group identifiers, so that the specific shard key is managed by itself Group is included in the group.

At this time, the data movement between the database servers may be performed in units of data corresponding to the group identifier or the shard key. For example, in moving data corresponding to one group identifier, data may be selected and inserted in units of a shard key included in the group of the group identifier. For example, when the database server a stores data for the group identifier 1, the movement of data from the database server a to the database server b may be performed in units of data corresponding to the group identifier 1, Data may be selected and inserted in units of the shard keys of the corresponding group.

3, the database server 430 includes a group identifier bit for indicating a group identifier corresponding to data managed by the group identifier, and a group identifier corresponding to data not managed by the database server 430, The map 440 can be managed. For example, in FIG. 4, the database server 430 stores and manages data corresponding to the group identifiers 1, 3, and n in the database J 450 (the values of the group identifiers 1, 3, and n are set to 1 ), The data corresponding to the group identifier 2 is not managed (the value of the group identifier 2 is set to 0).

At this time, as described above, the JDBC 420 extracts the shard key 'id1' from the query statement 410 and extracts the group identifier '3' by hashing the extracted shard key 'id1' through the hash function have. At this time, the extracted group identifier '3' may be transmitted to the database server 430, and the database server 430 searches the group identifier bitmap 440 for the extracted group identifier '3' Is stored in the database J (450) and managed by the database server (430). In other words, the database server 430 can check the consistency of the data associated with the requested operation. If the extracted group identifier is '2', the database server 430 can recognize that a wrong data change request has been input.

Such a group identifier is utilized for checking the consistency of data, and a shard key-group identifier table in which a shard key and a corresponding group identifier are managed in association with each other can be utilized. For example, the computer device illustrated in FIG. 3 may identify the shard keys corresponding to the group identifier to be moved in the shard key-group identifier table, and perform a SELECT and an INSERT in each table according to the shard key. So that data movement in shad key units can be processed. The movement of the data in units of the shard key may be performed for data corresponding to at least one group identifier. In other words, the movement of data may be the movement of data corresponding to at least one group identifier. At this time, data corresponding to one group identifier is repeatedly selected (SELECT) and insert (INSERT) Lt; / RTI >

At this time, the group identifier may be changed at the time when the migration is terminated. As described above with reference to FIG. 4, the group identifier is used for data consistency. On the other hand, in FIG. 3, the transaction is first applied to the database m (310) with respect to the data of the shard key unit already transferred as described above. In this case, if the specific group identifier is immediately changed in accordance with the migration of data in the database m 310, an error in terms of consistency with respect to the database m (310) occurs for the group identifier. For example, it is assumed that the database m 310 manages data of the group identifier 1 (for example, a value corresponding to the group identifier 1 in the group identifier bitmap is set to '1'). 3, it is assumed that a value corresponding to the group identifier 1 is set to '0' in the group identifier bitmap immediately after the database m 310 migrates the data of the group identifier 1 to the database n 320.

In this case, since the operation associated with group identifier 1 (actually an operation associated with the shard key contained in the group of group identifier 1) can not be applied to database m 310 (consistency error), database m 310 and database n The data in the memory 320 can not be synchronized. In this case, access to the data to be migrated must be blocked in order to synchronize the data, and thus, the section for preventing the entry of the user into the SQL becomes longer.

In the embodiment of FIG. 3, by changing the group identifiers managed in the database m 310 and the database n 320 at the time when the migration of data ends, the access blocking time to the migrated data can be minimized .

5 is a block diagram for explaining an internal configuration of a computer apparatus according to an embodiment of the present invention. The computer device 500 may include a memory 510, a processor 520, a communication interface 530, and an input / output interface 540. The memory 510 may be a computer-readable recording medium and may include a permanent mass storage device such as a random access memory (RAM), a read only memory (ROM), and a disk drive. The non-decaying mass storage device, such as a ROM and a disk drive, may be included in the computer device 500 as a separate persistent storage device separate from the memory 510. The memory 510 may also store an operating system and at least one program code. These software components may be loaded into the memory 510 from a computer readable recording medium separate from the memory 510. [ Such a computer-readable recording medium may include a computer-readable recording medium such as a floppy drive, a disk, a tape, a DVD / CD-ROM drive, and a memory card. In other embodiments, the software components may be loaded into the memory 510 via the communication interface 530 rather than a computer-readable recording medium. For example, the software components may be loaded into the memory 510 of the computer device 500 based on the computer program installed by the files received via the network 560.

The processor 520 may be configured to process instructions of a computer program by performing basic arithmetic, logic, and I / O operations. The instructions may be provided to the processor 520 by the memory 510 or the communication interface 530. For example, processor 520 may be configured to execute instructions received in accordance with program code stored in a recording device, such as memory 510. [

The communication interface 530 may provide functionality for the computer device 500 to communicate with another device (e. G., The storage devices described above) via the network 560. [ For example, a request or command, data, file, or the like, generated by the processor 520 of the computer device 500 according to the program code stored in the recording device such as the memory 510, 560 to other devices. Conversely, signals, commands, data, files, etc., from other devices may be received by the computer device 500 via the network 560 and the communication interface 530 of the computer device 500. Data or the like received via the communication interface 530 may be transferred to the processor 520 or the memory 510 and the file or the like may be transferred to a storage medium Permanent storage).

The input / output interface 540 may be a means for interfacing with the input / output device 550. For example, the input device may include a device such as a microphone, a keyboard or a mouse, and an output device may include a device such as a display, a speaker, and the like. As another example, the input / output interface 540 may be a means for interfacing with a device having integrated functions for input and output, such as a touch screen. The input / output device 550 may be composed of the computer device 500 and one device.

Also, in other embodiments, the computer device 500 may include fewer or more components than the components of FIG. However, there is no need to clearly illustrate most prior art components. For example, the computer device 500 may be implemented to include at least some of the input / output devices 550 described above, or may include other components such as a transceiver, Global Positioning System (GPS) module, camera, As shown in FIG.

Such a computer device 500 may correspond to the database servers 330, 410, and 420 described with reference to FIGS. 3 and 4, for example.

6 is a flowchart showing an example of a data migration method in an embodiment of the present invention. The data migration method according to the present embodiment can be performed by the computer apparatus 500 described above. For example, the processor 520 of the computer device 500 may be implemented to execute a control instruction according to code of an operating system loaded in the memory 510 or code of at least one program. Here, the processor 520 may control the computer apparatus 500 so that the computer apparatus 500 performs the steps 610 and 650 included in the data migration method of FIG. 6 according to this control instruction.

In step 610, the computer device 500 generates a group of sharded data, in association with the group identifiers of each of the predetermined number of groups generated by classifying the shardkeys of the sharded data, And can manage the identifier and the group identifier of the second database.

In step 620, the computing device 500 may identify the shard keys for data to be replicated from the first database to the second database. For example, in the computer device 500, a shard key-group identifier table in which a shard key included in a group is stored in association with a group identifier of a group, a shard key for data to be duplicated through a group identifier managed by the first database, Keys can be identified. As described with reference to FIG. 4, the group identifiers for each database can be managed, and the shard keys of the data to be migrated through the group identifiers and the shard key-group identifier table can be identified.

In step 630, the computer device 500 may migrate data corresponding to the identified shard keys from the first database to the second database. As described above, the computer device 500 selects the data to be duplicated in the first database using the identified shard key, inserts the selected data into the second database, You can migrate data in units.

At step 640, during the migration, the computer device 500 may concurrently reflect the transaction reflected in the first database to the second database using the transaction log. At this time, the computer device 500 can confirm the transaction of the data of the shard key migrated from the first database to the second database through the analysis of the transaction log and reflect the transaction to the second database. As described above, since the shad key unit data can be independently operated, the transaction can be applied to both the first database and the second database with respect to the data of the shard key that has been migrated. Accordingly, the data can be synchronized by performing operations on both data of the first database and the second database during the migration without blocking access to the data of the shard key that has been migrated.

At step 650, the computer device 500 may change the group identifiers managed in the first database and the second database, respectively, in accordance with the migration of data. As described above, the computer device 500 may change the group identifiers of the first database and the second database at the time when the migration of data ends, in order to minimize the access blocking time to the migrated data.

For example, the computer device 500 may store one bit of a group identifier bitmap (e.g., the group identifier bitmap 440 described in FIG. 4) in a first database that is a source database and a second database that is a target database. ) Can be repeated by the number of groups to be migrated. In this case, the migration may be repeated as many times as the number of groups to be migrated, that is, the process of sequentially moving the data corresponding to the plurality of shard keys belonging to the group and the process of reflecting the transaction log belonging to the group.

As described above, in the process of moving data corresponding to the shard key, data is selected for each table for a plurality of tables having data corresponding to the shard key in the first database, To the corresponding table in the second database. In this case, the computer device 500 performs an exclusive select (for example, a select for update syntax for updating in SQL) when data is selected on the basis of a specific shard key in the first database, To the second database and then complete the above-mentioned exclusive selection. Changing the data from the first database to the corresponding shard key while the exclusive select is maintained may be blocked through a lock. When the exclusive select is terminated, the locked data change (reflection of the transaction) may proceed while the lock is released, and the change of data in the first database is reflected in the second database through the transaction log Reflected in the data). In other words, since the operation of changing the shifting interval corresponding to the shard key and the data corresponding to the shard key are not overlapped with each other, integrity according to the movement of the data can be assured.

In the case where data of all the shard keys belonging to one group are moved and all the transactions occurring during the movement of the data are reflected by using the transaction log, the first database (more specifically, the database server managing the first database) If there is no transaction related to the group among the currently active transactions, the bit corresponding to the corresponding group in the group identifier bitmap of the first database Can be turned off. For example, the first database may change the value of the bit set in association with the group identifier of the group from '1' to '0'. On the other hand, the computer device 500 accesses the corresponding group in the group identifier bitmap of the second database according to the log which turns off the bit corresponding to the corresponding group in the group identifier bitmap of the first database through the transaction log Bit can be turned on. For example, the computer device 500 may cause the second database (more specifically, the database server managing the second database) to change the value of the bit set in association with the group identifier of the group from '0' to '1' Can be controlled.

FIG. 7 and FIG. 8 are views illustrating an example of a process of applying the data migration method according to an embodiment of the present invention.

First, FIG. 7 illustrates an example in which migration occurs as new nodes are added. All nodes in the database sharding environment can maintain the same schema and share global tables. The node 1 710, which is an existing node shown in FIG. 7, can also share a schema and a global table. 7 shows an example in which the node 1 710 includes a master database 1 711 and a slave database 1 712.

At this time, it is possible to consider a situation in which node 2 720, which is a new node, is added. As already explained, since all the nodes in the database sharding environment share the same schema and global table, this schema and the global table can be shared with the node 2 720 as well. At this time, the schema to be shared and the global table can be copied from the master database 1 711 of the node 1 710 to the master database 2 721 of the node 2 720 according to the data migration method described with reference to FIG. Here, the migrator 730 may be a module that the above-described computer device 500 includes for data migration.

However, since the schema or the global table is not arbitrary data or sharded data according to the user's request, it is not necessary to consider the reflection of the transaction or the change of the group identifier during the migration.

Meanwhile, FIG. 8 shows an example of rebalancing data by migrating the sharded data of the existing node 710 to the new node 2 720. For example, a process of migrating data corresponding to the group identifier '3' managed by the node 1 710 to the node 2 720 and rebalancing the data may be considered.

Migrator 730 may identify the shard keys for data corresponding to group identifier '3'. As described above, the computer device 500 can identify the shard keys corresponding to the group identifier '3' through the shard key-group identifier table. The migrator 730 may also migrate data corresponding to the identified shard keys in the slave database 1 712 of the node 1 710 to the master database 2 721 of the node 2 720. In this case, the source database of the data to be migrated may be the slave database 1 712 of the node 1 710, and the target database to which the data is transferred may be the master database 2 721 of the node 2 720 have. According to an embodiment, master database 1 711 of node 1 710 may be the source database.

For example, it is assumed that the shard keys corresponding to the group identifier '3' are 'a', 'b', 'c', and 'd'.

During the migration, a transaction for data corresponding to the shard key 'a' has occurred, and the data corresponding to the shard key 'a' is assumed to have been migrated from the slave database 1 712 to the master database 2 721. In this case, the data corresponding to the shard key 'a' stored in the master database 1 711 and the data corresponding to the shard key 'a' stored in the slave database 1 712 and the master database 2 721 may be different from each other .

Therefore, the transactions reflected in the master database 1 711 must be reflected in the slave database 1 712 and the master database 2 721, respectively. At this time, the migrator 730 may analyze the transaction log and simultaneously reflect the transaction in the slave database 1 712 and the master database 2 721, respectively. As described above, since the shard key units of data can be processed independently of each other, if the migration is completed for data corresponding to a specific shard key, can do. Therefore, the replication delay time can be reduced.

On the other hand, the information on the node managing the group identifier " 3 " can be changed after the migration for all the shard keys is completed. For example, when the migration is in progress, since the node 1 710 manages the data of the group identifier '3', the transaction occurring for the data of the group identifier '3' (711) and can be simultaneously reflected in the slave database 1 (712) and the master database 2 (721) using the transaction log. On the other hand, after the migration is completed, the node managing the group identifier '3' may be changed from the node 1 710 to the node 2 720. At this time, access to the data corresponding to the group identifier '3' may be blocked only for a very short time to change the node managing the group identifier '3'. Therefore, it is possible to drastically reduce the access blocking time to the migrated data. Once the node managing group identifier '3' is changed, transactions associated with the shard keys included in group identifier '3' may be applied to node 2 720.

As described above, the data migration method according to the embodiments of the present invention can be utilized not only for data replication between a master database and a slave database, but also for data replication between nodes.

As described above, according to the embodiments of the present invention, the transaction reflected in the first database during the data migration between the first database and the second database is simultaneously reflected in the second database using the transaction log, thereby reducing the replication delay time And can reduce the access blocking time to the migrated data. In addition, by changing the group identifiers managed in the first database and the second database at the time when the migration of the data is terminated while simultaneously reflecting the transactions, the access blocking time to the migrated data can be minimized.

The system or apparatus described above may be implemented as a hardware component, a software component or a combination of hardware components and software components. For example, the apparatus and components described in the embodiments may be implemented within a computer system, such as, for example, a processor, a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable gate array (FPGA) , A programmable logic unit (PLU), a microprocessor, or any other device capable of executing and responding to instructions. The processing device may execute an operating system (OS) and one or more software applications running on the operating system. The processing device may also access, store, manipulate, process, and generate data in response to execution of the software. For ease of understanding, the processing apparatus may be described as being used singly, but those skilled in the art will recognize that the processing apparatus may have a plurality of processing elements and / As shown in FIG. For example, the processing unit may comprise a plurality of processors or one processor and one controller. Other processing configurations are also possible, such as a parallel processor.

The software may include a computer program, code, instructions, or a combination of one or more of the foregoing, and may be configured to configure the processing device to operate as desired or to process it collectively or collectively Device can be commanded. The software and / or data may be in the form of any type of machine, component, physical device, virtual equipment, computer storage media, or device As shown in FIG. The software may be distributed over a networked computer system and stored or executed in a distributed manner. The software and data may be stored on one or more computer readable recording media.

The method according to an embodiment may be implemented in the form of a program command that can be executed through various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like, alone or in combination. The medium may be one that continues to store computer executable programs, or temporarily store them for execution or download. In addition, the medium may be a variety of recording means or storage means in the form of a combination of a single hardware or a plurality of hardware, and is not limited to a medium directly connected to a computer system, but may be dispersed on a network. Examples of the medium include a magnetic medium such as a hard disk, a floppy disk and a magnetic tape, an optical recording medium such as CD-ROM and DVD, a magneto-optical medium such as a floptical disk, And program instructions including ROM, RAM, flash memory, and the like. As another example of the medium, a recording medium or a storage medium managed by a site or a server that supplies or distributes an application store or various other software to distribute the application may be mentioned. Examples of program instructions include machine language code such as those produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like.

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. For example, it is to be understood that the techniques described may be performed in a different order than the described methods, and / or that components of the described systems, structures, devices, circuits, Lt; / RTI > or equivalents, even if it is replaced or replaced.

Therefore, other implementations, other embodiments, and equivalents to the claims are also within the scope of the following claims.

Claims (12)

A method for data migration of a computer device comprising at least one processor,
A group identifier of a first database and a group identifier of a first database in association with group identifiers of a plurality of groups of a predetermined number generated by sorting shardkeys of sharded data by the at least one processor, Managing a group identifier of the second database;
Identifying, by the at least one processor, shard keys for data to be replicated from the first database to the second database;
Migrating, by the at least one processor, data corresponding to the identified shard keys from the first database to the second database;
Concurrently reflecting, by the at least one processor, the transaction reflected in the first database in the second database using the transaction log during the migration; And
Changing, by the at least one processor, group identifiers managed in each of the first database and the second database in accordance with the migration of the data
The data migration method comprising the steps of: The method according to claim 1,
Wherein changing the group identifiers comprises:
Wherein the group identifiers are changed at a point of time when migration of the data is terminated in order to minimize access blocking time to the migrated data. The method according to claim 1,
Wherein the reflecting comprises:
Wherein a transaction for data of a shard key migrated from the first database to the second database is confirmed through analysis of the transaction log and reflected to the second database. The method according to claim 1,
Wherein identifying shard keys for data to be duplicated comprises:
Identifies shard keys for data to be duplicated through a group identifier managed by the first database in a shard key-group identifier table in which shard keys included in the group are stored in association with the group identifier of the group How to migrate data. The method according to claim 1,
Wherein the migrating comprises:
Selecting data to be duplicated in the first database by using the identified shard key, and inserting the selected data into the second database. A computer program stored in a computer-readable medium for causing a computer to execute the method of any one of claims 1 to 5 in combination with a computer. A computer readable recording medium storing a program for causing a computer to execute the method according to any one of claims 1 to 5. A computer device comprising:
At least one processor configured to execute computer readable instructions,
Lt; / RTI >
Wherein the at least one processor comprises:
Managing a group identifier of a first database and a group identifier of a second database in association with group identifiers of a plurality of groups of a predetermined number generated by sorting shardkeys of sharded data, ,
Identifying shard keys for data to be copied from the first database to the second database,
Migrating data corresponding to the identified shard keys from the first database to the second database,
During the migration, the transaction reflected in the first database is simultaneously reflected in the second database using the transaction log,
And changing group identifiers managed in the first database and the second database in accordance with the migration of the data
The computer device comprising: 9. The method of claim 8,
Wherein the at least one processor comprises:
And changes the group identifiers at a point of time when migration of the data ends, in order to minimize access blocking time to the migrated data. 9. The method of claim 8,
Wherein the at least one processor comprises:
And confirms the transaction for the data of the shard key that has been migrated from the first database to the second database through analysis of the transaction log and reflects the transaction to the second database. 9. The method of claim 8,
Wherein the at least one processor comprises:
Identifies shard keys for data to be duplicated through a group identifier managed by the first database in a shard key-group identifier table in which shard keys included in the group are stored in association with the group identifier of the group Computer device. 9. The method of claim 8,
Wherein the at least one processor comprises:
Selects data to be duplicated in the first database using the identified shard key, and inserts the selected data into the second database.

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