KR20190143428A - Method for moving data extent - Google Patents

Abstract

According to one embodiment of the present invention, disclosed is a computer program stored in a computer readable storage medium. When executed in one or more processors of a computing device, the computer program performs a following method to transfer an extent. The method comprises the steps of: allowing a processor to determine transfer of the extent stored in a first disk of a disk space containing at least two disks; allowing the processor to determine whether there is a recording on the extent based on extent mapping information for the extent; if the recording on the extent does not exist, allowing the processor to switch a state of the extent to a read-only in the extent mapping information; allowing the processor to transfer the extent in the first disk to a second disk; and allowing the processor to update the extent mapping information based on the complete of the extent transfer. Accordingly, the present invention provides a method for transferring an extent of a data file to other storing locations.

Description

How to move data extents {METHOD FOR MOVING DATA EXTENT}

The present disclosure relates to a method of managing a database, and more particularly, to a method of moving data.

Corporate business is expanding rapidly with the explosion of data and the emergence of diverse environments and platforms. As new business environments arrive, more efficient and flexible data services, information processing, and data management capabilities are required. In response to these changes, research continues to explore databases that address the high-performance, high-availability and scalability issues that underpin enterprise business implementation.

A database management system (DBMS) may allow data files to be stored on each disk. And, the database management system can manage the disk space including these disks. As a result, the database management system can enhance data integrity and improve access to data. Such database management systems include Tibero, Oracle, and IMS.

Korean Patent Registration No. 10-0561229 discloses a duplication apparatus in which a plurality of original databases and a plurality of replicate databases form a duplication relationship. However, this invention has a problem that the input and output speed is slow because of a lot of processing work, the capacity balance between the databases is not balanced.

Accordingly, there may be a need in the art for an extent movement method that minimizes the time for which operations on data are limited while maintaining consistency between data in the movement of data.

The present disclosure has been made in response to the foregoing background, and is intended to provide a method of moving an extent of a data file to another storage location.

Disclosed is a computer program stored in a computer readable storage medium according to one embodiment of the present disclosure for realizing the above-described problem. The computer program performs the following method for moving an extent when executed on one or more processors of a computing device, the method comprising: the processor comprising a disk space—the disk space comprising at least two disks. Determining a movement of the extent stored in the first disk, wherein the processor determines whether there is a write operation for the extent based on extent mapping information for the extent, and the processor Changing the state of the extent to read-only in the extent mapping information if the write operation for the extent does not exist, wherein the processor changes the extent located on the first disk to a second disk Moving the processor and the processor The extent mapping information may be updated based on the completion of the disk movement of the existing extents.

Alternatively, the extent mapping information may be configured for each extent, and may include at least one of address information of the extent, state information of the extent, and a transaction sequence number of the extent. .

Alternatively, the transaction sequence number of the extent may be updated with the transaction sequence number of the worker thread performing the work on the extent when the work on the extent occurs.

Alternatively, the processor determines whether there is a write operation for the extent based on extent mapping information for the extent, wherein the processor determines a transaction sequence number of the extent mapping information and a transaction sequence number of a worker thread. In comparison, if there is a transaction sequence number of the worker thread that is less than or equal to the transaction sequence number of the extent mapping information, determining that a write operation for the extent exists and a write operation for the extent exists. In this case, the worker thread performing a move operation on the extent may include a step of going to a sleep state.

Alternatively, when the writing operation for the extent is completed, the transaction sequence number of the extent mapping information may further include the step of modifying the transaction sequence number of the worker thread.

Alternatively, the updating of the extent mapping information based on the completion of the disk movement of the extent may include the processor determining whether a task for the extent exists when the disk movement of the extent is completed. And when the job for the extent exists, changes the extent state of the extent mapping information to being in use, waits for the completion of the job to update the extent mapping information, or if the job for the extent does not exist, mapping the extent It may include updating the information.

Alternatively, if an extent state of the extent mapping information is in use, a worker thread that accesses the extent mapping information may be switched to a wait state and written to the wait list.

Alternatively, a move to the extent stored on the first disk may occur if a new disk is added to the disk space, the one or more disks are removed, or an error occurs in one of the at least two disks. Can be determined for balancing.

Alternatively, the processor may further include resuming a recording operation on the extent based on the update of the extent mapping information.

In the alternative, the processor may further include deleting an extent located on the first disk.

Also disclosed is an extent movement method performed in one or more processors of a computing device, in accordance with one embodiment of the present disclosure. The method includes determining, by the processor, a movement to an extent stored on a first disk of the disk space, the disk space including at least two disks, wherein the processor determines an extent for the extent. Determining whether a write operation for the extent exists based on mapping information, and when the write operation for the extent does not exist, the processor read-only the state of the extent in the extent mapping information. ), The processor moving the extent located on the first disk to the second disk, and the processor updating the extent mapping information based on the completion of the disk movement of the extent. have.

In addition, a computing device is disclosed in accordance with one embodiment of the present disclosure. The computing device includes at least one processor and a memory storing instructions executable on the at least one processor, the at least one processor comprising a disk space, the disk space including at least two disks. Determine a movement to the extent stored in the disk, determine whether a write operation for the extent exists based on extent mapping information for the extent, and if the write operation for the extent does not exist, map the extent Change the state of the extent in the information to read-only, move the extent located on the first disk to the second disk, and update the extent mapping information based on completion of the disk movement of the extent can do.

The present disclosure can provide a method for moving extents of a data file to another storage location.

1 shows a schematic diagram of a database system according to one embodiment of the disclosure.
2 is a conceptual diagram of a disk space according to an embodiment of the present disclosure.
3 is a flow chart of an extent movement method according to an embodiment of the present disclosure.
4 is a partial flowchart illustrating a movement of an extent from completion of movement of the extent to completion of movement of the extent according to an embodiment of the present disclosure.
5 is a partial flow chart from completion of movement of an extent to resumption of recording operation on the extent according to one embodiment of the present disclosure.
6 is a flow chart illustrating means for moving extents in a database system in accordance with one embodiment of the present disclosure.
7 is a flowchart illustrating a module for moving extents in a database system related to an embodiment of the present disclosure.
8 is a flow diagram illustrating logic for moving extents in a database system in accordance with one embodiment of the present disclosure.
9 is a flow chart illustrating circuitry for moving extents in a database system in accordance with one embodiment of the present disclosure.
10 is a block diagram of a computing device according to an embodiment of the present disclosure.

Various embodiments are now described with reference to the drawings, wherein like reference numerals are used to refer to like elements throughout. In this specification, various descriptions are presented to provide an understanding of the present disclosure. It is evident, however, that such embodiments may be practiced without these specific details. In other instances, well-known structures and devices are provided in block diagram form in order to facilitate describing the embodiments.

As used herein, the terms “component”, “module”, “system” and the like refer to computer-related entities, hardware, firmware, software, a combination of software and hardware, or the execution of software. For example, a component may be, but is not limited to being, a process running on a processor, a processor, an object, an thread of execution, a program, and / or a computer. For example, both an application running on a computing device and the computing device can be a component. One or more components can reside within a processor and / or thread of execution, and a component can be localized within one computer or distributed between two or more computers. In addition, these components can execute from various computer readable media having various data structures stored thereon. The components may for example be signals having one or more data packets (e.g., data from one component interacting with another component in a local system, distributed system, and / or data over a network such as another system and the internet via signals and / or signals May communicate via local and / or remote processes.

The description of the presented embodiments is provided to enable any person skilled in the art to make or use the present disclosure. Various modifications to these embodiments will be apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the scope of the present disclosure. Thus, the present disclosure should not be limited to the embodiments presented herein but should be construed in the broadest scope consistent with the principles and novel features presented herein.

1 shows a schematic diagram of a database system according to an embodiment of the present disclosure.

As shown in FIG. 1, the database system 10 according to the present disclosure may include a client 200 and a database server 100.

As shown in FIG. 1, client 200 may refer to a node (s) in a database system having a mechanism for communicating over a network. For example, client 200 may include a PC, laptop computer, workstation, terminal, and / or any electronic device having network connectivity. In addition, the client 200 may include any server implemented by at least one of an agent, an application programming interface (API), and a plug-in. For example, the client 200 in FIG. 1 may be associated with a user (eg, DBA (DataBase Administration)) using the database server 100.

Database server 100 may include any type of computer system or computing device, such as, for example, a microprocessor, mainframe computer, digital single processor, portable device, and device controller. Each of these database servers 100 may include a database management system (DBMS) 110 and a persistent storage 130. In addition, the database server 100 may be used interchangeably with an apparatus for executing a query.

In addition, although only one database server 100 is shown in FIG. 1, more database servers may also be included in the scope of the present invention, and that the database server 100 may include additional components. It will be apparent to those of ordinary skill in the art. That is, the database server 100 may be composed of a plurality of computing devices. The set of plural nodes may constitute the database server 100. For example, although not shown in FIG. 1, the database server 100 may include one or more memories 120 including a buffer cache. In addition, although not shown in FIG. 1, the database server 100 may include one or more processors 111. Accordingly, the DBMS 110 may be operated by the processor 111 on the memory 120.

The memory 120 herein is directly accessed by a processor, such as, for example, random access memory (RAM), such as dynamic random access memory (DRAM), static random access memory (SRAM), or the like. The main storage device may mean, but is not limited to, a volatile storage device in which stored information is erased momentarily when the power is turned off. The memory 120 may be operated by the processor 111. The memory 120 may temporarily store a data table including data values. The data table may include a data value, and in one embodiment of the present invention, the data value of the data table may be recorded from the memory 120 to the permanent storage medium 130. In an additional aspect, memory 120 includes a buffer cache, where data may be stored in a data block of the buffer cache. Data stored in the buffer cache may be written to the persistent storage medium by a background process.

Persistent storage medium 130 is, for example, a storage device based on flash memory and / or battery-backup memory, as well as magnetic disks, optical disks and magneto-optical storage devices. It may mean a non-volatile storage medium capable of continuously making any data. The persistent storage medium 130 may communicate with a processor and a memory of the database server 100 through various communication means. In a further embodiment, such persistent storage medium 130 may be located external to the database server 100 and communicate with the database server 100.

The DBMS 110 is a program for allowing the database server 100 to perform operations such as parsing a query, searching for, inserting, modifying, and / or deleting necessary data. As described above, the database server 100 The memory 120 may be implemented by the processor 111.

The client 200 and the database server 100 or database servers may communicate with each other via a network (not shown). The network according to an embodiment of the present invention is a Public Switiched Telephone Network (PSTN), x Digital Subscriber Line (xDSL), Rate Adaptive DSL (RADSL), Multi Rate DSL (MDSL), and Very High Speed DSL (VDSL). ), Various wired communication systems such as Universal Asymmetric DSL (UDASL), High Bit Rate DSL (HDSL), and Local Area Network (LAN).

In addition, the networks presented herein include Code Division Multi Access (CDMA), Time Division Multi Access (TDMA), Frequency Division Multi Access (FDMA), Orthogonal Frequency Division Multi Access (OFDMA), and Single Carrier-FDMA (SC-FDMA). And various wireless communication systems such as < RTI ID = 0.0 >). ≪ / RTI > For example, the network may include a database link (dblink), such that a plurality of database servers may communicate with each other via such database link to obtain data from another database server 100. The techniques described herein may be used in the networks mentioned above as well as in other networks.

2 is a conceptual diagram of a disk space 300 according to an embodiment of the present disclosure.

The database server 100 may include a disk space 300 and a processor 111 capable of storing data. The disk space may store an encrypted signal, a database table, or a data stream that is a blur of data transmitted to the database server 100 through a network. The disk space 300 may include one or more disks 310 and 330 capable of storing data files. In addition, the processor 111 may determine to separate the received data stream into extents and store the data stream in one or more disks.

In the following text, an extent is a series of data units having a size of 0 bit or more and may mean a basic unit for data storage. For example, the extent may be configured to a size of 1Mb, but the present disclosure is not limited thereto. The extent may include an original extent located on the first disk 310 before moving and a copy extent stored on the second disk 330 after moving.

The processor 111 may divide the data stream into extent units and allocate the data stream to one or more disks 310 and 330. Here, the one or more disks 310 and 330 may be at least one of the disks included in the disk space 300. For example, when the processor 111 receives a data stream of "A, A ', B, B', C and C '" through a network, the processor 111 may designate the data stream as "A 311" or "A' ( 331 "," B 312 ". It can be divided into six extents, "B '332", "C 313", and "C' 333". Here, each extent may be configured to a size of 1Mb. Then, the processor allocates "A 311", "B 312", and "C 313" to the first disk 310, and assigns the second disk 330 as shown in FIG. "A '331", "B' 332", and "C '333" may be allocated respectively. Accordingly, the processor 111 may divide and store the data stream in one or more disks 310 and 330. Detailed descriptions of the above-described allocation and storage operations are merely examples, and the present disclosure is not limited thereto.

The memory 120 according to an embodiment of the present disclosure may store extent mapping information related to a location where each extent is stored. In another embodiment of the present disclosure, one of the nodes constituting the database server may store extent mapping information including information about a node where each extent is stored. More specifically, the processor 111 may store extent mapping information on a location (eg, a disk number and a storage location) where each extent is stored on the instance cache of the DB or the memory 120. In addition, the worker thread of the processor 111 may access the corresponding extent based on the extent mapping information to perform a task related to the extent.

Additionally, the database server 100 may include at least two nodes (computing devices) (not shown). The node may include a DBMS node and a storage manager node. The storage manager may be a separate node capable of generating or delivering a command related to the operation of the DBMS 110. That is, the storage manager may be a node separate from the DBMS, or another instance running on the same computing device as the DBMS. More specifically, the database server 100 may include one or more processors 111. In addition, each of the DBMS 110 and the storage manager may be a separate instance operated by different processors. In addition, the storage manager is a DBMS 110 to control the DBMS 110 to perform any operation in managing the persistent storage medium 130 (for example, a move command to the extent, etc.) to the DBMS (110). Can transmit The storage mission manager may manage the extent mapping information by storing the extent mapping information in a separate buffer cache. In addition, according to an embodiment, the storage manager may be included in the database system 10 and configured to communicate with the database server 100 via a network as a computing device different from the database server 100.

In addition, the extent mapping information according to an embodiment of the present disclosure may include at least one of address information of the extent, state information of the extent, and a transaction sequence number of the extent. The address information of the extent may include information for accessing the extent, such as a disk number and a storage location of the extent. The extent status information indicates whether work is being performed on the extent (eg, loading, used), or whether access to the extent is available (eg, read only) read-only), read / write available, etc.). And, the transaction sequence number of the extent may be a time stamp in a preset format that is determined based on the time of occurrence of the transaction for each extent. For example, the transaction sequence number is composed of eight hexadecimal digits, and may be stored on the extent mapping information for each extent. The description regarding the configuration of the above-described transaction sequence number is only an example and the present disclosure is not limited thereto. Detailed description of the extent mapping information described above is merely an example, and the present disclosure is not limited thereto.

The transaction sequence number of the extent on the extent mapping information according to an embodiment of the present disclosure may be updated with the transaction sequence number of the worker thread performing the work on the extent when the work on the extent occurs.

More specifically, the processor 111 may manage extent mapping information for each extent and a worker thread that performs work on the extents. In addition, when the worker thread accesses an arbitrary extent to perform a task, the processor 111 is determined based on an access time on an item included in the worker thread (eg, a variable item in one of the headers of the worker thread). You can store the transaction sequence number. In addition, when the work on the extent occurs, the processor 111 may update the transaction sequence number of the extent to the transaction sequence number of the worker thread performing the work on the extent. Therefore, the processor 111 may store, in the extent mapping information for the extent, a transaction sequence number determined based on the time when the worker thread accesses the extent.

Accordingly, the processor 111 according to an embodiment of the present disclosure may determine whether a write operation for an extent exists based on extent mapping information. Detailed description thereof will be described later with reference to FIGS. 3 and 4.

3 is a flow chart of an extent movement method according to an embodiment of the present disclosure.

Extent movement according to one embodiment of the present disclosure may be performed by a computing device. The computing device may include one or more processors 111 and a memory that stores instructions executable on the one or more processors. Hereinafter, the order in which the computing device moves the extents will be described in detail.

The computing device according to one embodiment of the present disclosure may determine 401 a movement of an extent stored in the first disk 310 of the disk space. Here, the move command for the extent may be received from an external client 200 or may be generated when the DBMS process determines that the extent needs to be moved. Further, according to another embodiment of the present disclosure, a move request for an extent may be received from a storage manager node different from the computing device.

More specifically, the computing device may use the first disk 310 for rebalancing when a new disk is added to the disk space 300, one or more disks are removed, or one of the at least two disks fails. It may be determined to move the extent stored in the second disk 330. The disk space may include at least two disks 310 and 330. Further, in another embodiment of the present disclosure, when the database server is configured with a plurality of nodes, the database server may include a storage manager node. Further, in another embodiment of the present disclosure, the disk space may include disks of different nodes or may include a plurality of disks in one node.

More specifically, as the third disk (not shown) is added to the disk space 300, the computing device may include extents 211, 212, 213, and 231 stored in the first disk 310 and the second disk 330. , 232, 233 may be moved to a third disk (not shown). Accordingly, the computing device may perform rebalancing between disks by reallocating extents between the disks. Extent reassignment here may be performed based on, for example, the capacity of each disk.

For example, a third disk (not shown) having a capacity of 10 Mb may be added to a disk space including the first disk 310 and the second disk 330 each having a capacity of 10 Mb. In this case, the computing device may select a third disk (not shown) of the extents “A 311”, “B 312”, and “C 313” stored in the first disk 310. FIG. And move the extent "C '333" stored in the second disk 330 to the third disk (not shown). Detailed description of the extent movement operation described above is merely an example, and the present disclosure is not limited thereto.

In addition, the computing device according to an embodiment of the present disclosure may determine whether there is a write operation for the extent based on the extent mapping information on the extent (402). The entry included in the extent mapping information may store a transaction sequence number determined based on a time at which a work performed on each extent is started.

More specifically, the computing device may divide the data stream into extents and allocate the data streams to one or more disks included in the disk space. The computing device may store extent mapping information for each extent in a cache memory or main memory. The extent mapping information may include at least one of address information of the extent, state information of the extent, and a transaction sequence number of the extent. The transaction sequence number is a type of time stamp that increases in time series and may change with time.

In addition, the computing device may include a worker thread that performs work on the extents. In addition, when the worker thread accesses any extent to perform the task, the computing device determines a transaction that is determined based on the access time on an item included in the worker thread (eg, a variable item of one of the worker thread's headers). You can store the sequence number. In addition, when a work on an extent occurs, the computing device may update the transaction sequence number of the extent to the transaction sequence number of the worker thread performing the work on the extent. Thus, the computing device may store, in the extent mapping information entry of the extent, the transaction sequence number determined based on the time the worker thread accessed the extent.

Accordingly, the computing device may compare the transaction sequence number stored in the entry of the extent mapping information with the transaction sequence number stored in the running worker threads, respectively. The computing device determines whether a task (eg, a write operation for the extent) exists for the extent according to whether a worker thread having a transaction sequence number lower than or equal to the transaction sequence number of the extent mapping information exists. Can be determined.

In addition, when the computing device according to an embodiment of the present disclosure determines that a task for an extent exists, the computing device may determine to switch a worker thread that performs a movement task for the extent to a sleep state.

More specifically, the computing device may determine that there is a job for the extent when the worker thread having a transaction sequence number lower than or equal to the transaction sequence number of the extent mapping information exists. The computing device may then decide to put the worker thread that has approached to move the extent to sleep. Here, the sleep state is waiting for a moving operation on the extent, and the computing device may determine that the worker thread accesses the extent again after a preset time. Accordingly, the computing device may wait for the worker thread performing the moving operation of the extent until the worker thread performing the writing operation on the extent is completed. The computing device may maintain consistency in the transaction by determining whether there is a worker thread's work on the extent before the move operation of the extent, and performing a move operation when there is no work on the extent.

The computing device according to an embodiment of the present disclosure may change the state of the extent to read-only in the extent mapping information when there is no write operation for the extent (403).

More specifically, the computing device may compare the transaction sequence number of the extent mapping information with the transaction sequence number of the worker thread to determine whether a write operation for the extent exists. The computing device may determine that a write operation for the extent does not exist if a worker thread having a transaction sequence number smaller than or equal to the transaction sequence number of the extent mapping information does not exist. In addition, the computing device may change the state information of the extents included in the extent mapping information to read-only. In this case, the read-only state locks writing to a corresponding extent, and may allow access of a worker thread to perform reading.

In addition, the computing device according to an embodiment of the present disclosure may move 404 the extent located in the first disk 310 to the second disk 330. More specifically, the computing device may read and copy the original extent located on the first disk 310. In addition, the computing device may store the duplicate extent copied from the original extent on the second disk 330. In addition, after the movement of the extent is completed and the modification of the extent mapping information is completed, the computing device may delete the original extent located on the first disk 310. By deleting the extent before movement after the modification of the extent mapping information as well as the extent movement is completed, the extent movement method of an embodiment of the present disclosure can efficiently manage storage space of the computing device while maintaining consistency.

When the recording operation for the extent is completed, the computing device may modify the transaction sequence number of the extent mapping information to the transaction sequence number of the worker thread. More specifically, the computing device may initialize the transaction sequence number of the worker thread when the writing operation of the worker thread for the extent is completed. Herein, the initialization of the transaction sequence number may be a change to the transaction sequence number at the completion of the work. In addition, the initialization of the transaction sequence number may mean a change to a preset value (eg, FFFFFFFF, etc. of 8 hexadecimal digits). The above-described preset values are merely examples and the present disclosure is not limited thereto.

The computing device according to an embodiment of the present disclosure may update the extent mapping information 405 based on the completion of the disk movement of the extent. According to an embodiment, when the disk movement of the extent is completed, the computing device may determine whether a task for the extent exists. The computing device may also change the extent state of the extent mapping information to active if there is a job for the extent, wait for the job to complete, update the extent mapping information, or if the job for the extent does not exist, the extent mapping information. May update 405.

More specifically, the computing device may store an entry of extent mapping information for each extent on the cache. The extent mapping information may include at least one of address information (eg, a disk number) of the extent, state information of the extent, and a transaction sequence number of the extent. In addition, the transaction sequence number is a type of time stamp that increases in time series and may change with time. The computing device may store a transaction sequence number that is determined based on the access time in an item included in a worker thread that accesses a move operation on an extent. In addition, when a move operation on the extent occurs, the computing device may update the transaction sequence number of the extent to the transaction sequence number of the worker thread performing the move operation on the extent. Thus, the computing device may store, in the extent mapping information entry of the extent, the transaction sequence number determined based on the time the worker thread accessed the extent.

The computing device may compare the transaction sequence number stored in the entry of the extent mapping information with the transaction sequence number stored in the running worker threads, respectively. In addition, the computing device determines whether a work thread (for example, a read or write operation for the extent) for the extent depends on whether a worker thread having a transaction sequence number lower than or equal to the transaction sequence number of the extent mapping information exists. It can be determined whether it exists or not. More specifically, the computing device may determine that there is a job for the extent when the worker thread having a transaction sequence number lower than or equal to the transaction sequence number of the extent mapping information exists. On the other hand, the computing device may determine that there is no work for the extent when the worker thread with the transaction sequence number lower than or equal to the transaction sequence number of the extent mapping information does not exist.

In addition, when a task for an extent exists, the computing device may change the extent state included in the extent mapping information to loading. In addition, the computing device may change the extent state to loaded after there is no work on the extent or after completion. The computing device may then wait for an update to the extent mapping information until the extent state changes to complete use. In one embodiment of the present disclosure, if there is a task for an extent (eg, a read operation, etc.), the extent includes information for accessing the extent, in the situation where the extent is stored in the existing storage location and the moved storage location. By waiting for updates to extent mapping information, work on extents can be performed on extents stored in existing storage locations, thereby minimizing downtime due to movement of extents.

According to an embodiment of the present disclosure, when the extent state of the extent mapping information is in use, the computing device may switch a worker thread that accesses the extent mapping information to the standby state and write it to the standby list. More specifically, the computing device may determine to allow access of the worker thread based on the extent state included in the extent mapping information. Where the extent status can be loading or loaded to indicate that work is being performed on the extent, and read-only to indicate whether the extent is accessible. , Or read / write available.

The computing device may determine to suspend the operation of the worker thread when the worker thread approaches the extent in which the extent state is in use. In addition, the computing device may generate a wait list on the cache to sequentially stack one or more worker threads whose operation is suspended. The wait list may be generated for one extent, for each disk, or for one wait list for the entire disk space. In addition, the computing device may reconfirm the extent state after a preset time and determine to resume operation of the worker thread if the extent state is complete.

Accordingly, the extent movement method according to an embodiment of the present disclosure can minimize the time that the read request is blocked in the movement of the extent. In addition, by comparing only the transaction sequence numbers of the entry and the worker thread, it is possible to determine whether to work on the extent, thereby reducing the memory usage.

In addition, since the extent movement operation is performed by determining whether the recording operation is performed for each extent, the consistency of data can be maintained. In addition, when I / O work on an extent is being performed, update of extent mapping information can be waited to prevent duplication and error of data.

Extent movement method according to an embodiment of the present disclosure, by performing the operation of duplicating the extent to another storage location while allowing the read operation for the extent, thereby minimizing the time that the read operation on the extent is blocked (block). Can be. In addition, the extent movement method according to an embodiment of the present disclosure may maintain consistency by checking the existence of a read operation for an extent and then updating extent mapping information indicating a storage location of the extent only when the operation does not exist. have. That is, the extent movement method according to an embodiment of the present disclosure can maintain the consistency while minimizing the time that the read and write operations on the extents are blocked, thereby improving the performance of the database computer device.

4 is a partial flowchart illustrating a movement of an extent from completion of movement of the extent to completion of movement of the extent according to an embodiment of the present disclosure.

The computing device according to one embodiment of the present disclosure may determine 501 a movement for an extent stored on the first disk. Here, the movement to extent may be determined for rebalancing when a new disk is added to the disk space 300, one or more disks are removed, or an error occurs in one of the at least two disks. The description of the situation in which the movement of the above-described extent is determined is merely an example, and the present disclosure is not limited thereto.

More specifically, the computing device may use the first disk 310 for rebalancing when a new disk is added to the disk space 300, one or more disks are removed, or one of the at least two disks fails. It may be determined to move the extent stored in the second disk 330. The disk space may include at least two disks 310 and 330. In addition, the computing device may include a DBMS processor and a storage manager node in accordance with embodiments. The storage manager node may transmit a command about moving an extent to the DBMS processor.

Extent mapping information according to an embodiment of the present disclosure may include at least one of address information of the extent, state information of the extent, and a transaction sequence number of the extent. The extent mapping information may be configured for each extent and stored in at least one of a cache, a memory, and an external storage manager.

The address information of the extent may include information for accessing the extent, such as a disk number and a storage location of the extent. The extent status information indicates whether work is being performed on the extent (eg, loading, used), or whether access to the extent is available (eg, read only) read-only), read / write available, etc.). And, the transaction sequence number of the extent may be a time stamp in a preset format that is determined based on the time of occurrence of the transaction for each extent.

In addition, according to an embodiment of the present disclosure, the transaction sequence number of an extent may be configured for each extent and stored in an entry on extent mapping information. In addition, the computing device may store the transaction sequence number in the worker thread when the worker thread approaches for work with the extent. When a work on an extent occurs, it may be updated with a transaction sequence number of a worker thread that performs work on the extent. Accordingly, each entry on the extent mapping information may store a transaction sequence number of a worker thread that has accessed to perform a task on the corresponding extent. By updating the transaction sequence number, the processor may compare the transaction sequence number of the extent mapping information with the transaction sequence number of the worker thread to determine whether there is a task for the corresponding extent.

In addition, the computing device may check the transaction sequence number stored in each of the worker threads. Here, the computing device may determine whether there is a transaction sequence number of a worker thread less than or equal to the transaction sequence number of the extent mapping information (502).

First, when there is a transaction sequence number of a worker thread that is less than or equal to the transaction sequence number of the extent mapping information, the computing device may determine that there is a task for the extent (503).

In this case, the computing device may switch 504 to a sleep thread (that is, a worker thread performing an extent movement operation) that has approached to move the extent. Here, the sleep state is waiting for a moving operation on the extent, and the computing device may determine that the worker thread accesses the extent again after a preset time. Accordingly, the computing device may wait for the worker thread performing the moving operation of the extent until the worker thread performing the writing operation on the extent is completed.

In addition, when the writing operation for the extent is completed, the computing device may modify the transaction sequence number of the extent mapping information to the transaction sequence number of the worker thread (that is, the worker thread that performed the writing operation for the extent) (505). .

More specifically, the computing device may initialize the transaction sequence number of the worker thread when the writing operation of the worker thread for the extent is completed. Herein, the initialization of the transaction sequence number may be a change to the transaction sequence number at the completion of the work. In addition, the initialization of the transaction sequence number may mean a change to a preset value (eg, FFFFFFFF, etc. of 8 hexadecimal digits).

In addition, when there is no transaction sequence number of the worker thread that is less than or equal to the transaction sequence number of the extent mapping information, the computing device may determine that the writing operation for the extent is completed (506).

In this case, the computing device may change the state information of the extent included in the extent mapping information to read-only (507). In this case, the read-only state locks writing to a corresponding extent, and may allow access of a worker thread to perform reading.

In addition, the computing device may transition 508 the worker thread that performs the move operation on the extent that was in the sleep state to an awake state. Here, the awake state refers to a state in which moving or moving of the corresponding extent may be performed, and the computing device may resume moving of the worker thread.

In addition, the computing device may move 509 an extent located on the first disk 310 to the second disk 330 by a worker thread performing an extent moving operation. More specifically, the computing device may cause the worker thread corresponding to the extent movement task to copy the original extent located on the first disk 310. In addition, the computing device may allow the worker thread to store the duplicate extent copied from the original extent on the second disk 330. Additionally, the computing device may cause the worker thread to delete the original extent located on the first disk 310 after the duplicate extent is stored on the second disk 330.

For example, as shown in FIG. 2, extents “A 311”, “B 312” and “C 313” may be stored in the first disk 310. In addition, the computing device may receive a command for moving the extents "A 311", "B 312", and "C 313" to the second disk 330. Accordingly, the computing device checks the transaction sequence number consisting of eight hexadecimal digits of the extent mapping information corresponding to "A 311", "B 312", and "C 313", respectively, and is a working worker. You can compare the thread's transaction sequence number with this. Where the transaction sequence number for "A (311)" is "2018AA99", the transaction sequence number for "B (312)" is "2018AB00", and the transaction sequence number for "C (313)" is "2018DD80" Can be. In addition, the lowest transaction sequence number among working worker threads may include a transaction sequence number of "2018AB12". Accordingly, the computing device may determine that a recording job corresponding to extent "C 313" exists, and may determine that there are no recording jobs corresponding to "A 311" and "B 312". . In addition, the computing device may cause a worker thread for performing the extent movement operation to perform the movement operation for the extents "A 311" and "B 312". In addition, the computing device may put a worker thread to sleep state to perform a move operation on extent “C 313”. The computing device may then confirm the end of the move operation by causing the worker thread to attempt to access extent “C 313” at intervals of 1/100 second. In addition, when the writing operation for “C 313” is completed, the computing device may switch the worker thread in the sleep state to the awake state. Accordingly, the computing device moves extents "A 311", "B 312", and "C 313" located in the first disk 310 to the second disk 330, thereby moving the "A '331. ) "," B '332 "and" C' 333 ". The detailed descriptions of the write operation existence determination operation for the above-described extent and the moving operation of the worker thread are only examples, and the present disclosure is not limited thereto.

Accordingly, in the extent movement method according to an embodiment of the present disclosure, since the extent movement operation is performed by determining whether the recording operation is performed for each extent, the consistency of data may be maintained. .

In addition, by changing the state of the extent included in the extent mapping information to read-only, it is possible to minimize the time that the read request is blocked. In addition, by comparing only the transaction sequence numbers of the entry and the worker thread, it is possible to determine whether to work on the extent, thereby reducing the memory usage.

5 is a partial flow chart from completion of movement of an extent to resumption of recording operation on the extent according to one embodiment of the present disclosure.

The computing device according to an embodiment of the present disclosure may update the extent mapping information based on the disk movement completion 510 of an extent. More specifically, when the disk movement of the extent is completed, the computing device may determine whether there is a task for the extent. When there is a job for the corresponding extent, the computing device may change the extent state of the extent mapping information to being in use, wait for the task to be completed, and update the extent mapping information. On the other hand, if there is no task for an extent, the computing device may update the extent mapping information 514.

Here, the operation of determining whether the computing device exists for the corresponding extent may be performed by comparing the transaction sequence number stored in the extent mapping information and the transaction sequence number stored in the worker thread as described above with reference to FIG. 4. . More specifically, the computing device may store an entry of extent mapping information for each extent on the cache. The extent mapping information may include at least one of address information (eg, a disk number) of the extent, state information of the extent, and a transaction sequence number of the extent. In addition, the transaction sequence number is a type of time stamp that increases in time series and may change with time. The computing device may store a transaction sequence number that is determined based on the access time in an item included in a worker thread that accesses a move operation on an extent. In addition, when a move operation on the extent occurs, the computing device may update the transaction sequence number of the extent to the transaction sequence number of the worker thread performing the move operation on the extent. Thus, the computing device may store, in the extent mapping information entry of the extent, the transaction sequence number determined based on the time the worker thread accessed the extent.

The computing device may compare the transaction sequence number stored in the entry of the extent mapping information with the transaction sequence number stored in the running worker threads, respectively. In addition, the computing device determines whether a work thread (for example, a read or write operation for the extent) for the extent depends on whether a worker thread having a transaction sequence number lower than or equal to the transaction sequence number of the extent mapping information exists. It may be determined whether or not there is (511). More specifically, the computing device may determine that there is a job for the extent when the worker thread having a transaction sequence number lower than or equal to the transaction sequence number of the extent mapping information exists. On the other hand, the computing device may determine that there is no work for the extent when the worker thread with the transaction sequence number lower than or equal to the transaction sequence number of the extent mapping information does not exist.

The computing device may change the extent state of the extent mapping information included in the extent mapping information to loading when there is a task for the extent. In addition, the computing device may change the extent state to loaded after there is no work on the extent or after completion. The computing device may then wait for an update to the extent mapping information until the extent state changes to complete use.

In addition, when the extent state of the extent mapping information is in use, the computing device according to an embodiment of the present disclosure may switch the worker thread that accesses the extent mapping information to the standby state and write 513 to the standby list. More specifically, the computing device may determine to allow access of the worker thread based on the extent state included in the extent mapping information. Where the extent status can be loading or loaded to indicate that work is being performed on the extent, and read-only to indicate whether the extent is accessible. , Or read / write available.

The computing device may determine to suspend the operation of the worker thread when the worker thread approaches the extent in which the extent state is in use. In addition, the computing device may generate a wait list on the cache to sequentially stack one or more worker threads whose operation is suspended. The standby list may be generated for one extent, for each disk, or for one standby list for the entire disk space 300. In addition, the computing device may reconfirm the extent state after a preset time and determine to resume operation of the worker thread if the extent state is complete.

In addition, the computing device may store a transaction sequence number that is determined based on the access time to the work thread that the extent status accesses for the extent in use. The computing device may determine the order of the wait list by comparing the size of the transaction sequence numbers stored in each work thread. For example, when the first work thread and the second work thread access an extent whose extent status is in use, the first work thread receives a transaction sequence number "201812FF" in the header based on the respective access time. The second work thread may receive a transaction sequence number "201870AB" in the header. The first work thread and the second work thread have been suspended by the computing device and stored in a wait list on the cache. In this case, the computing device compares the transaction sequence number "201812FF" of the first work thread with the transaction sequence number "201870AB" of the second work thread, and compares the first work thread storing the lower transaction sequence number with the second work thread. You can decide to process at a higher priority than a thread. The detailed description of the above-described transaction sequence number and the wait list is merely an example, and the present disclosure is not limited thereto.

Accordingly, the extent movement method according to an embodiment of the present disclosure can minimize the time that the read request is blocked in the movement of the extent. In addition, by comparing only the transaction sequence numbers of the entry and the worker thread, it is possible to determine whether to work on the extent, thereby reducing the memory usage.

In addition, since the extent movement operation is performed by determining whether the recording operation is performed for each extent, the consistency of data can be maintained. In addition, while I / O work on an extent is being performed, update of extent mapping information can be waited to prevent duplication and error of data.

FIG. 6 is a flow chart illustrating means for moving extents in a database system 10 in accordance with one embodiment of the present disclosure.

Means (601) for determining movement to the extent stored in a first disk of at least one processor of the computing device, the disk space including at least two disks; Means 602 for determining whether a write operation for the extent exists based on extent mapping information for the extent, and if the processor does not have a write operation for the extent, the extent mapping information in the extent mapping information. Means (603) for changing the state of an extent to read-only, means for the processor to move the extent located on the first disk to a second disk (604), and the processor Means for updating the extent mapping information based on completion of disk movement ( 605).

Alternatively, the extent mapping information may be configured for each extent, and may include at least one of address information of the extent, state information of the extent, and a transaction sequence number of the extent. .

Alternatively, the transaction sequence number of the extent may be updated with the transaction sequence number of the worker thread performing the work on the extent when the work on the extent occurs.

Alternatively, the means for the processor to determine whether there is a write operation for the extent based on extent mapping information for the extent may include the processor having a transaction sequence number of the extent mapping information and a transaction sequence number of a worker thread. Means for determining that there is a write operation for the extent and the write operation for the extent when there is a transaction sequence number of the worker thread that is less than or equal to the transaction sequence number of the extent mapping information. If present, the worker thread performing the move operation on the extent may include means for causing it to go to sleep.

Alternatively, when the writing operation for the extent is completed, the transaction sequence number of the extent mapping information may further include means for modifying the transaction sequence number of the worker thread.

Alternatively, the means for the processor to update the extent mapping information based on the completion of the disk movement of the extent may be determined by the processor to determine whether a task for the extent exists when the disk movement of the extent is completed. Means for changing the extent state of the extent mapping information to busy, and waiting for the completion of the task to update the extent mapping information, or if the task for the extent does not exist, It may include means for updating the extent mapping information.

Alternatively, if an extent state of the extent mapping information is in use, a worker thread that accesses the extent mapping information may be switched to a wait state and written to the wait list.

Alternatively, a move command for the extent stored in the first disk may be generated when a new disk is added to the disk space, the one or more disks are removed, or an error occurs in one of the at least two disks. Can be created for rebalancing.

In the alternative, the processor may further comprise means for resuming a write operation to the extent based on the update of the extent mapping information.

In the alternative, the processor may further comprise means for deleting an extent located on the first disk.

7 is a flow chart illustrating a module for moving extents in a database system 10 in accordance with one embodiment of the present disclosure.

According to an embodiment of the present disclosure, a method for moving an extent in the database system 10 may be implemented by the following module.

According to one embodiment of the present disclosure, database system 10 is configured to determine movement to the extent stored on a first disk of disk space, the disk space including at least two disks. Module 701 for determining, by the processor, whether there is a write operation for the extent based on extent mapping information for the extent, and wherein the processor does not have a write operation for the extent. A module 703 for changing the state of the extent to read-only in the extent mapping information, and a module 704 for the processor to move the extent located on the first disk to a second disk. And the processor updates the extent mapping information based on the disk movement completion of the extent. Module 705 for retrieval.

8 is a flowchart illustrating logic for moving extents in a database system 10 in accordance with one embodiment of the present disclosure.

According to one embodiment of the present disclosure, a method for moving an extent in the database system 10 may be implemented by the following logic.

According to one embodiment of the present disclosure, database system 10 is configured to determine movement to the extent stored on a first disk of disk space, the disk space including at least two disks. Logic 801 for determining, by the processor, whether or not there is a write operation for the extent based on extent mapping information for the extent, and the processor does not have a write operation for the extent. In this case, logic 803 for changing the state of the extent to read-only in the extent mapping information, logic 804 for the processor to move the extent located on the first disk to a second disk. And the processor updates the extent mapping information based on the disk movement completion of the extent. Logic 805 may be included.

9 is a flowchart illustrating circuitry for moving extents in a database system 10 in accordance with one embodiment of the present disclosure.

According to an embodiment of the present disclosure, a method for moving an extent in the database system 10 may be implemented by the following circuit.

According to one embodiment of the present disclosure, database system 10 is configured to determine movement to the extent stored on a first disk of disk space, the disk space including at least two disks. For circuit 901, the processor for determining whether a write operation for the extent is present based on extent mapping information for the extent, the processor for the write operation for the extent does not exist A circuit 903 for changing the state of the extent to read-only in the extent mapping information, and a circuit 904 for the processor to move the extent located on the first disk to a second disk. And the processor updates the extent mapping information based on the disk movement completion of the extent. Circuit 905 may be included.

Those skilled in the art will further appreciate that the various illustrative logical blocks, configurations, modules, circuits, means, logics, and algorithm steps described in connection with the embodiments disclosed herein may be electronic hardware, computer software, or a combination of both. It should be appreciated that it can be implemented with To clearly illustrate the interchangeability of hardware and software, various illustrative components, blocks, configurations, means, logics, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented in hardware or as software depends on the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure.

10 is a block diagram of a computing device according to an embodiment of the present disclosure.

10 shows a brief general schematic diagram of an example computing environment in which embodiments of the present disclosure may be implemented.

Although the present disclosure has been described above generally with respect to computer executable instructions that may be executed on one or more computers, those skilled in the art will appreciate that the present disclosure may be implemented in combination with other program modules and / or as a combination of hardware and software. will be.

Generally, program modules include routines, programs, components, data structures, etc. that perform particular tasks or implement particular abstract data types. In addition, those skilled in the art will appreciate that the methods of the present disclosure may include uniprocessor or multiprocessor computer systems, minicomputers, mainframe computers as well as personal computers, handheld computing devices, microprocessor-based or programmable consumer electronics, And other computer system configurations, including one or more associated devices, which may operate in conjunction with one or more associated devices.

The described embodiments of the present disclosure can also be practiced in distributed computing environments where certain tasks are performed by remote processing devices that are linked through a communications network. In a distributed computing environment, program modules may be located in both local and remote memory storage devices.

Computers typically include a variety of computer readable media. Any medium that can be accessed by a computer can be a computer readable medium, which can be volatile and nonvolatile media, transitory and non-transitory media, removable and non-transitory media. Removable media. By way of example, and not limitation, computer readable media may comprise computer readable storage media and computer readable transmission media. Computer-readable storage media are volatile and nonvolatile media, temporary and non-transitory media, removable and non-removable implemented in any method or technology for storing information such as computer readable instructions, data structures, program modules or other data. Media. Computer storage media may include RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROMs, digital video disks or other optical disk storage devices, magnetic cassettes, magnetic tapes, magnetic disk storage devices or other magnetic storage devices, Or any other medium that can be accessed by a computer and used to store desired information.

Computer-readable transmission media typically embody computer readable instructions, data structures, program modules or other data in a modulated data signal, such as a carrier wave or other transport mechanism, and the like. Includes all information delivery media. The term modulated data signal means a signal that has one or more of its characteristics set or changed to encode information in the signal. By way of example, and not limitation, computer readable transmission media includes wired media such as a wired network or direct-wired connection, and wireless media such as acoustic, RF, infrared, or other wireless media. Combinations of any of the above should also be included within the scope of computer readable transmission media.

An example environment 1100 is illustrated that implements various aspects of the present disclosure, including a computer 1102, which includes a processing unit 1104, a system memory 1106, and a system bus 1108. do. System bus 1108 connects system components, including but not limited to system memory 1106, to processing unit 1104. Processing unit 1104 may be any of a variety of commercial processors. Dual processor and other multiprocessor architectures may also be used as the processing unit 1104.

The system bus 1108 may be any of several types of bus structures that may be further interconnected to a memory bus, a peripheral bus, and a local bus using any of a variety of commercial bus architectures. System memory 1106 includes read only memory (ROM) 1110 and random access memory (RAM) 1112. The basic input / output system (BIOS) is stored in nonvolatile memory 1110, such as ROM, EPROM, EEPROM, etc., and the BIOS provides a basic aid for transferring information between components in the computer 1102, such as during startup. Contains routines. RAM 1112 may also include fast RAM, such as static RAM, for caching data.

Computer 1102 also includes an internal hard disk drive (HDD) 1114 (eg, EIDE, SATA) —this internal hard disk drive 1114 may also be configured for external use within a suitable chassis (not shown). Yes—magnetic floppy disk drive (FDD) 1116 (eg, for reading from or writing to removable diskette 1118), and optical disk drive 1120 (eg, CD-ROM Disk 1122 for reading from or writing to or reading from other high capacity optical media such as DVD). The hard disk drive 1114, the magnetic disk drive 1116, and the optical disk drive 1120 are connected to the system bus 1108 by the hard disk drive interface 1124, the magnetic disk drive interface 1126, and the optical drive interface 1128, respectively. ) Can be connected. Interface 1124 for external drive implementation includes at least one or both of Universal Serial Bus (USB) and IEEE 1394 interface technologies.

These drives and their associated computer readable media provide nonvolatile storage of data, data structures, computer executable instructions, and the like. In the case of computer 1102, drives and media correspond to storing any data in a suitable digital format. Although the above description of computer readable media refers to HDDs, removable magnetic disks, and removable optical media such as CDs or DVDs, those skilled in the art will appreciate zip drives, magnetic cassettes, flash memory cards, cartridges, and the like. Other types of media readable by the computer, etc. may also be used in the exemplary operating environment and it will be appreciated that any such media may include computer executable instructions for performing the methods of the present disclosure.

Multiple program modules may be stored in the drive and RAM 1112, including operating system 1130, one or more application programs 1132, other program modules 1134, and program data 1136. All or a portion of the operating system, applications, modules and / or data may also be cached in RAM 1112. It will be appreciated that the present disclosure may be implemented in various commercially available operating systems or combinations of operating systems.

A user may enter commands and information into the computer 1102 via one or more wired / wireless input devices, such as a keyboard 1138 and a mouse 1140. Other input devices (not shown) may include a microphone, IR remote control, joystick, game pad, stylus pen, touch screen, and the like. These and other input devices are often connected to the processing unit 1104 via an input device interface 1142, which is connected to the system bus 1108, but the parallel port, IEEE 1394 serial port, game port, USB port, IR interface, Etc. can be connected by other interfaces.

A monitor 1144 or other type of display device is also connected to the system bus 1108 via an interface such as a video adapter 1146. In addition to the monitor 1144, the computer generally includes other peripheral output devices (not shown) such as speakers, printers, and the like.

Computer 1102 may operate in a networked environment using logical connections to one or more remote computers, such as remote computer (s) 1148, via wired and / or wireless communications. Remote computer (s) 1148 may be a workstation, computing device computer, router, personal computer, portable computer, microprocessor-based entertainment device, peer device, or other conventional network node, and typically is associated with computer 1102. Although many or all of the components described above are included, for simplicity, only memory storage 1150 is shown. The logical connections shown include wired / wireless connections to a local area network (LAN) 1152 and / or a larger network, such as a telecommunications network (WAN) 1154. Such LAN and WAN networking environments are commonplace in offices and businesses, facilitating enterprise-wide computer networks such as intranets, all of which may be connected to worldwide computer networks, such as the Internet.

When used in a LAN networking environment, the computer 1102 is connected to the local network 1152 via a wired and / or wireless communication network interface or adapter 1156. Adapter 1156 may facilitate wired or wireless communication to LAN 1152, which also includes a wireless access point installed therein for communicating with wireless adapter 1156. When used in a WAN networking environment, the computer 1102 may include a modem 1158, connect to a communication computing device on the WAN 1154, or establish communications over the WAN 1154, such as over the Internet. Other means. The modem 1158, which may be an internal or external and wired or wireless device, is connected to the system bus 1108 via the serial port interface 1142. In a networked environment, program modules or portions thereof described with respect to computer 1102 may be stored in remote memory / storage device 1150. It will be appreciated that the network connections shown are exemplary and other means of establishing a communications link between the computers can be used.

Computer 1102 is associated with any wireless device or entity disposed and operating in wireless communication, such as a printer, scanner, desktop and / or portable computer, portable data assistant, communications satellite, wireless detectable tag. Communicate with any equipment or location and telephone. This includes at least Wi-Fi and Bluetooth wireless technology. Thus, the communication can be a predefined structure as in a conventional network or simply an ad hoc communication between at least two devices.

Wireless Fidelity (Wi-Fi) allows you to connect to the Internet without wires. Wi-Fi is a wireless technology such as a cell phone that allows such a device, for example, a computer, to transmit and receive data indoors and outdoors, i. Wi-Fi networks use a wireless technology called IEEE 802.11 (a, b, g, etc.) to provide secure, reliable, high-speed wireless connections. Wi-Fi may be used to connect computers to each other, to the Internet, and to a wired network (using IEEE 802.3 or Ethernet). Wi-Fi networks can operate in unlicensed 2.4 and 5 GHz wireless bands, for example, at 11 Mbps (802.11a) or 54 Mbps (802.11b) data rates, or in products that include both bands (dual band). have.

Those skilled in the art will appreciate that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, instructions, information, signals, bits, symbols, and chips that may be referenced in the above description may include voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields. Or particles, or any combination thereof.

One of ordinary skill in the art of the disclosure will appreciate that the various illustrative logical blocks, modules, processors, means, circuits and algorithm steps described in connection with the embodiments disclosed herein may be implemented in electronic hardware, It will be appreciated that for purposes of the present invention, various forms of program or design code, or combinations thereof, may be implemented. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. One skilled in the art of the present disclosure may implement the described functionality in various ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure.

The various embodiments presented herein may be embodied in a method, apparatus, or article of manufacture using standard programming and / or engineering techniques. The term "article of manufacture" includes a computer program, carrier, or media accessible from any computer-readable device. Here, the medium may include a storage medium and a transmission medium. For example, computer-readable storage media may include magnetic storage devices (eg, hard disks, floppy disks, magnetic strips, etc.), optical discs (eg, CDs, DVDs, etc.), smart cards, and flashes. Memory devices (eg, EEPROM, cards, sticks, key drives, etc.), but are not limited to these. In addition, various storage media presented herein include one or more devices and / or other machine-readable media for storing information. In addition, the transmission medium includes, but is not limited to, a wireless channel and various other media capable of carrying command (s) and / or data.

It is to be understood that the specific order or hierarchy of steps in the processes presented is an example of exemplary approaches. Based upon design priorities, it is understood that the specific order or hierarchy of steps in the processes may be rearranged within the scope of the present disclosure. The accompanying method claims present elements of the various steps in a sample order, but are not meant to be limited to the specific order or hierarchy presented.

The description of the presented embodiments is provided to enable any person skilled in the art to make or use the present disclosure. Various modifications to these embodiments will be apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the scope of the present disclosure. Thus, the present disclosure should not be limited to the embodiments presented herein but should be construed in the broadest scope consistent with the principles and novel features presented herein.

Claims (1)

Computer program stored on a computer readable storage medium.

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