JP5747770B2 - Data storage control device, data storage control program, and data storage control method - Google Patents

Description

The present invention relates to a data storage control device, a data storage control program, and a data storage control method.

  Conventionally, performance data is referred to by a plurality of users for a plurality of servers provided in a data center or the like. As a technique for managing the performance data of a plurality of servers, there is a system that collects performance data from each server, centrally manages it with a database, and provides performance data in response to a reference request from a user. In such a system, for example, software for measuring performance is installed on a management target server. The managed server periodically collects performance data for each resource, such as CPU (Central Processing Unit), memory, disk, middleware, and application, and sends the collected performance data to the management server. Is done. The management server accumulates and manages performance data transmitted from each management target server in a database.

  By the way, for example, when the types of performance to be managed increase and the amount of performance data increases, the amount of data notified from each server becomes enormous in the management server. When the data notified from each server is congested, storage in the database becomes a bottleneck, and the user may not be able to refer to the latest performance data.

  For example, when a plurality of users refer to server performance data, such as in a cloud environment, the server and performance data referred to are different for each user, and the frequency of reference is also different for each user. Therefore, for example, it is conceivable to perform priority control for preferentially storing performance data in a database by increasing the priority of performance data referred to by a frequently accessed user. Further, as a prior art, for example, in a system for monitoring a failure of an image forming apparatus, a failure score obtained by quantifying the importance of the failure for each type of failure is stored, and the failure score of the failure information notified from the image forming device is stored. There is a technique for notifying the monitoring source when the accumulated value of the threshold reaches a threshold value.

JP 2008-77315 A

  However, with priority control that increases the priority of performance data that is frequently referred to by users who access frequently, the priority of performance data that is frequently referenced becomes excessively high, and performance data that is sometimes referred to by users who access it. There may be a delay in storing

  Further, the prior art is a technique for notifying the monitoring source according to the importance of the failure, and cannot prevent the performance data from being delayed.

  According to one aspect of the disclosed technology, the present invention has been made in view of the above, and an object thereof is to suppress a delay in storing performance data referred to by a user.

  The data storage control device disclosed in the present application includes, in one aspect, a storage unit and a determination unit. The storage unit stores, for each of a plurality of types of performance data, a ratio that is referred to next to a certain type of performance data. The determination unit refers to the storage unit and obtains an elapsed time after the specification with respect to the reference time corresponding to the specified client device and performance data. In addition, when the client device refers to the certain type of performance data, the determination unit collects the plurality of types collected from the server device based on the ratio for each of the plurality of types of performance data stored in the storage unit. The storage order for storing the performance data in the storage device is determined.

  According to one aspect, it is possible to suppress a delay in storing performance data referred to by a user.

FIG. 1 is a diagram illustrating an example of a functional configuration of a data storage control device. FIG. 2 is a diagram illustrating an example of a functional configuration of the management system. FIG. 3 is a diagram illustrating an example of a data configuration of the first table. FIG. 4 is a diagram illustrating an example of a data configuration of the second table. FIG. 5 is a diagram illustrating an example of a data configuration of the third table 30c. FIG. 6 is a diagram illustrating an example of the data configuration of the fourth table. FIG. 7 is a diagram illustrating an example of a data configuration of the fifth table. FIG. 8 is a diagram illustrating an example of an operation log. FIG. 9 is a diagram illustrating an example of a data configuration of the performance data notification queue. FIG. 10 is a diagram for explaining an example of a flow for creating the second table. FIG. 11 is a flowchart showing the procedure of the operation specifying process. FIG. 12 is a flowchart showing the procedure of the operation log analysis process. FIG. 13 is a flowchart illustrating the procedure of the operation result update process. FIG. 14 is a flowchart illustrating the procedure of the urgency level determination process. FIG. 15 is a flowchart illustrating a procedure of the emergency level calculation process. FIG. 16 is a flowchart illustrating a procedure of priority determination processing. FIG. 17 is a flowchart showing a procedure of performance data storage processing. FIG. 18 is a flowchart showing the procedure of the notification queue storage process. FIG. 19 is a diagram illustrating an example of another data configuration of the performance data notification queue. FIG. 20 is a diagram illustrating a computer that executes a data storage control program.

  Embodiments of a data storage control device, a data storage control program, and a data storage control method disclosed in the present application will be described below in detail with reference to the drawings. Each embodiment does not limit the disclosed technology. Each embodiment can be appropriately combined within a range in which processing contents are not contradictory.

  A data storage control device 10 according to the first embodiment will be described. FIG. 1 is a diagram illustrating an example of a functional configuration of a data storage control device. As illustrated in FIG. 1, the data storage control device 10 includes a storage unit 11 and a determination unit 12. The data storage control device 10 is a device that performs data storage control for storing performance data transmitted from the server device 13 in the storage device 14, and is, for example, a computer such as a management server. The storage device 14 may be a storage device such as an HDD (Hard Disk Drive) provided in the data storage control device 10. The storage device 14 may be a storage device such as an external disk array device or an HDD provided in another server. The performance data stored in the storage device 14 is provided in response to a reference request from the client device 15. In the example of FIG. 1, one server device 13 is illustrated, but two or more server devices 13 may be provided. In the example of FIG. 1, two client devices 15 are illustrated, but the number of client devices 15 may be one or three or more.

  Various types of information are stored in the storage unit 11. For example, the storage unit 11 stores, for each of a plurality of types of performance data, a ratio that is referenced next to a certain type of performance data. This performance data indicates the performance of the resource installed in the apparatus, and there are various types according to the resource. For example, the performance data includes CPU, memory, disk usage, middleware, application CPU usage, memory usage, and the like. Examples of the device of the storage unit 11 include a semiconductor memory such as a flash memory and a non-volatile static random access memory (NVSRAM), and a storage device such as a hard disk and an optical disk.

  The determination unit 12 determines the storage order in which the performance data transmitted from the server device 13 is stored in the storage device 14. For example, when the client device 15 refers to a certain type of performance data, the determination unit 12 uses a plurality of types of performance data collected from the server device 13 based on a ratio for each of the plurality of types of performance data stored in the storage unit 11. A storage order for storing the performance data in the storage device 14 is determined. By determining the storage order in this way, the specified performance data is immediately stored in the storage device 14 when the user refers to the next, so that a delay occurs in the storage of the performance data referred to by the user. This can be suppressed. An example of a device of the determination unit 12 is an electronic circuit such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). Note that an integrated circuit such as an application specific integrated circuit (ASIC) or a field programmable gate array (FPGA) may be employed as the device.

  As described above, the data storage control device 10 stores, for each of a plurality of types of performance data, the ratio referred to next to a certain type of performance data. When the client device 15 refers to a certain type of performance data, the data storage control device 10 uses a plurality of types of performance data collected from the server device 13 based on the ratio for each of the plurality of types of performance data stored in the storage unit 11. A storage order for storing the performance data in the storage device 14 is determined. Thereby, in the data storage control device 10, the storage order is determined so that the performance data to be referred to next by the client device 15 is preferentially stored. Therefore, according to the data storage control device 10, it is possible to suppress a delay in storing performance data referred to by the user.

  Next, Example 2 will be described. In the second embodiment, a system 20 that collects performance data from a plurality of server devices 21 provided in a data center and performs centralized management using a database and provides performance data in response to a request for reference from a user will be described. FIG. 2 is a diagram illustrating an example of a functional configuration of the system. The system 20 includes a first server device 22 and a second server device 23 that function as a data storage control device.

  The first server device 22 receives the performance data transmitted from each server device 21, and performs control to sequentially store the received performance data in the second server device 23 in the determined storage order.

  Each server device 21 is installed with software 21a for measuring performance. The software 21a periodically measures the performance of each resource mounted on the server device 21. For example, the software 21a periodically measures the performance of each resource such as a CPU, memory, disk, middleware, and application. The software 21 a transmits performance data indicating the measured performance of each resource to the first server device 22. In the example of FIG. 2, four server devices 21 are illustrated, but the number of server devices 21 may be any.

  The second server device 23 stores the performance data sequentially stored from the first server device 22 in the database 40a of the storage device 40 and performs centralized management. The second server device 23 can refer to the performance data stored in the database 40 a from the client device 24. The user transmits a reference request for the performance data of the resource of the server device 21 to be confirmed to the second server device 23 using the client device 24. The second server device 23 provides performance data in response to the reference request, and transmits the performance data in response to the reference request to the requesting client device 24. The second server device 23 generates an operation log 42 indicating the content requested by the user. In this embodiment, the user to be used for the client device 24 is fixed, and the client device 15 is specified by specifying the user. The first server device 22, the second server device 23, the server device 21, and the client device 24 are communicably connected via a network (not shown). As an aspect of such a network, there is an arbitrary communication network such as the Internet (Internet), a LAN (Local Area Network), and a VPN (Virtual Private Network) regardless of wired or wireless.

  As illustrated in FIG. 2, the first server device 22 includes a storage unit 30, a specification unit 31, a determination unit 32, a storage unit 33, an operation result generation unit 34, and a reference pattern update unit 35.

  Various information is stored in the storage unit 30. For example, the storage unit 30 stores a first table 30a, a second table 30b, a third table 30c, a fourth table 30d, and a fifth table 30e. Examples of the device of the storage unit 30 include a semiconductor memory such as a flash memory and an NVSRAM, and a storage device such as a hard disk and an optical disk.

  The first table 30a is a table that stores reference patterns in past operations for each user that refers to performance data. The first table 30a is provided in a similar data configuration for each user who refers to performance data. FIG. 3 is a diagram illustrating an example of a data configuration of the first table. As shown in FIG. 3, the first table 30a has items such as a state, an average time, and a reference probability. The item of reference probability is divided into a plurality of items for each performance data of each server device 21. In the example of FIG. 3, the items of reference probability are “Server 1: Performance A-1”, “Server 1: Performance A-2”, “Server 1: Performance A-3”,. It is divided into items of “Server 3: Performance A”.

  The status item is an area for storing information indicating the status of the reference operation or the referenced performance data. For example, in the status item, a name indicating the status of the reference operation and a name of performance data are stored. The item of average time is an area for storing the average time in which the state of the state item is maintained or the performance data is referenced in seconds. Each item of the reference probability is an area for storing a rate at which each piece of performance data is referenced next to the state or performance data of the state item. Hereinafter, the rate at which performance data is referred to is also referred to as “reference probability”. In each item of the reference probability, a value indicating the reference probability is registered when there is a record referred to next to the state of the state item or the performance data. In addition, in each item of the reference probability, when there is no record referred to next to the state or performance data of the state item, “NULL” indicating that there is no record is set in the reference probability item.

  In the example of FIG. 3, the state immediately after login indicates that the average time is 1 second, and then the reference probability of the performance A-1 of the server 1 is 100%. The reference state of the performance A-1 of the server 1 is that the average time is 32 seconds, and then the reference probability of the performance item A-2 of the server 1 is 50%. The reference probability is 30%, and the reference probability of the performance item A of the server 3 is 30%. The reference state of the performance A-2 of the server 1 is that the average time is 16 seconds, the reference probability of the performance item A-1 of the server 1 is 10%, and the performance item A-3 of the server 1 The reference probability is 80%, and the reference probability of the performance item A of the server 3 is 10%. Further, the reference state of the performance A of the server 3 has an average time of 72 seconds, and then the reference probability of the performance item A-1 of the server 1 is 80%, and the reference probability of the performance item A-3 of the server 1 Is 30%.

  Information of each item is registered in the first table 30a by a reference pattern update unit 35 described later. The first table 30 a is used for processing executed by the determination unit 32.

  The second table 30b is a table that stores a reference pattern of a user who referred to performance data immediately before. FIG. 4 is a diagram illustrating an example of a data configuration of the second table. As shown in FIG. 4, the second table 30b has the same data structure as the first table 30a, and has items such as a state, an average time, and a reference probability.

  The status item is an area for storing information indicating the status of the reference operation in the previous performance data reference operation or the referenced performance data. The item of average time is an area for storing the average time in the reference operation of the last performance data in seconds. Each item of reference probability is an area for storing a reference probability in the reference operation of the immediately preceding performance data. In each item of the reference probability, a value indicating the reference probability is registered when there is a record referred to next to the state of the state item or the performance data. Further, each item of reference probability is set to “NULL” indicating that there is no track record when there is no track record referenced next to the status of the status item or the performance data.

  In the example of FIG. 4, the state immediately after login indicates that the average time is 1 second, and then the reference probability of the performance A-1 of the server 1 is 100%. Further, the reference state of the performance A-1 of the server 1 indicates that the average time is 23 seconds, and then the reference probability of the performance item A-2 of the server 1 is 100%. Further, the reference state of the performance A-2 of the server 1 indicates that the average time is 18 seconds, and then the reference probability of the performance item A of the server 3 is 100%. Further, the reference state of the performance A of the server 3 indicates that the average time is 60 seconds, and there is no particular reference to the performance item next.

  Information of each item is registered in the second table 30b by an operation result generation unit 34 described later. The second table 30 b is used for processing executed by the reference pattern update unit 35.

  The 3rd table 30c is a table which memorize | stores the urgency of each performance data of each server apparatus 21 for every user. The third table 30c is provided in the same data configuration for each user who refers to the performance data. FIG. 5 is a diagram illustrating an example of a data configuration of the third table. As illustrated in FIG. 5, the third table 30 c includes items of a server, a record, and an urgency level.

  The server item is an area for storing information representing any one of the server devices 21. For example, the machine name of the server device 21 is stored in the server item. The item of record is an area for storing information representing performance data. For example, the name of performance data is stored in the item of server. The item of urgency is an area for storing a value representing the urgency of the performance data.

  In the example of FIG. 5, for the user A, the performance data A-1 of the server 1 indicates that the urgency is 2.5. Further, the performance data A-2 of the server 1 indicates that the urgency is 1.9. Further, the performance data B-1 of the server 2 indicates that the urgency is 1.9. The performance data A of the server 3 indicates that the urgency is 1.03. In the example of FIG. 5, for the user C, the performance data A-1 of the server 1 indicates that the urgency is 1.2. Further, the performance data B-1 of the server 2 indicates that the urgency is 1.2. The performance data A of the server 3 indicates that the urgency is 1.03.

  Information of each item is registered in the third table 30c by the determination unit 32 described later. The second table 30b is used for processing executed by the determination unit 32.

  The fourth table 30 d is a table that stores the priority of each performance data of each server device 21. FIG. 6 is a diagram illustrating an example of the data configuration of the fourth table. As illustrated in FIG. 6, the fourth table 30d includes items of a server, a record, and a priority.

  The server item is an area for storing information representing any one of the server devices 21. For example, the machine name of the server device 21 is stored in the server item. The item of record is an area for storing information representing performance data. For example, the name of performance data is stored in the item of record. The priority item is an area for storing a value representing the degree to which performance data should be stored with priority.

  In the example of FIG. 6, the performance data B-1 of the server 2 indicates that the priority is 2. Further, the performance data A-1 of the server 1 indicates that the priority is 1. Further, the performance data A-2 of the server 1 indicates that the priority is 1. Further, the performance data A of the server 3 indicates that the priority is 1.

  Information on each item is registered in advance in the fourth table 30d. The fourth table 30d is used for processing executed by the determination unit 32.

  The fifth table 30e is a table for storing the storage order of each performance data of each server device 21. FIG. 7 is a diagram illustrating an example of a data configuration of the fifth table. As shown in FIG. 7, the fifth table 30e has items of storage order, server, record, and storage order frequency.

  The item of storage order is an area for storing a value indicating the storage order of each performance data of each server device 21. The server item is an area for storing information representing the server device 21 that transmits performance data in the storage order. For example, the machine name of the server device 21 is stored in the server item. The item of the record is an area for storing information representing the performance data in the storage order. For example, the name of performance data is stored in the item of server. The item of storage rank frequency is an area for storing the value of the storage rank frequency calculated by the determination unit described later.

  In the example of FIG. 7, the performance data B-1 of the server 2 has a storage rank frequency of 2.5, indicating that the storage rank is first. Further, the performance data A-1 of the server 1 indicates that the storage rank frequency is 1.9 and the storage rank is second. Further, the performance data A-2 of the server 1 indicates that the storage rank frequency is 1.9 and the storage rank is second. Further, the performance data A of the server 3 indicates that the storage rank frequency is 1 and the storage rank N.

  Information of each item is registered in the fifth table 30e by the determination unit 32 described later. The fifth table 30e is used for processing executed by the storage unit 33.

  Returning to the description of FIG. 2, the specifying unit 31 specifies the user of the client device 24 referring to the performance data stored in the second server device 23 and the performance data. For example, the specifying unit 31 refers to the operation log 42 generated by the second server device 23 and specifies the user of the client device 24 that is referring to the performance data and the performance data.

  FIG. 8 is a diagram illustrating an example of an operation log. As shown in FIG. 8, the operation log 42 records a plurality of records representing operation details. Each record is separated by commas and includes items of time, log type, user, and operation. The time item is an area in which the operated time is recorded. The item of log type is an area in which the type of content of the log is recorded. In the example of FIG. 8, “change_status” indicates that the operation is related to the change of the access state of the client device 24 with respect to the second server device 23. “Refer_record” indicates that the performance data is a reference operation. The user item is an area in which the user name of the client device 24 that performed the operation is recorded. The operation item is an area in which operation details are recorded. In the operation item, “login” is recorded when the operation related to the change of the access state is login, and “logout” is recorded when the operation related to the change of the access state is logout. Further, in the operation item, when the performance data is a reference operation, information indicating the reference operation is recorded. In the example of FIG. 8, SQL (Structured Query Language) executed on the database 40a is recorded as information representing the reference operation.

  In the example of FIG. 8, the record 42a indicates that the user A has logged in at 2011/2/28 9:35:00. The record 42b indicates that the user A requested to refer to the performance data A-1 of the server 1 at 20111/2/28 9:35:01.

  The identifying unit 31 constantly monitors the operation log 42 generated by the second server device 23 and reads the added operation log 42 when a new operation log 42 is added. Then, the specifying unit 31 analyzes the read operation log 42 and specifies the user of the client device 24 that refers to the performance data and the performance data. Further, when any user logout is detected as a result of the analysis of the read operation log 42, the specifying unit 31 notifies the operation log generation unit 34 described later of the logged out user.

  The determination unit 32 determines the storage order in which the performance data transmitted from the server device 21 is stored in the second server device 23. For example, the determination unit 32 reads a record corresponding to the user and performance data specified by the specification unit 31 from the first table 30 a stored in the storage unit 30. For example, when the identified user is the user A and the referenced performance data is the performance data A-1, the determination unit 32 reads a record of the performance data A-1 from the first table 30a illustrated in FIG. . Then, the determination unit 32 obtains the average time and the reference probability of each performance data referred to next from the read record.

  The determination unit 32 calculates the urgency of each performance data using the obtained reference probability of each performance data. For example, the determination unit 32 changes the next standby time to a shorter time each time the elapsed time after specifying the user and the performance data by the specifying unit 31 passes the standby time. As an example of such a change in the next standby time, the determination unit 32 sets the initial standby time to half the average time, and each time the standby time elapses, the determination unit 32 sets the next standby time to 1 of the immediately preceding standby time. Change to / 2. Then, each time the standby time elapses, the determination unit 32 adds the value of the reference probability of the performance data to the predetermined initial value for each performance data, and calculates the urgency of each performance data. As an example of calculating the urgency level, the determination unit 32 sets the initial value of the urgency level of each performance data to 1. Then, the determination unit 32 adds the value of the reference probability to the urgency every time the standby time elapses. Thus, the urgency level of each performance data is calculated as a larger value as the reference probability is higher and the elapsed time is longer. Note that the determination unit 32 calculates the urgency level for performance data having a reference probability equal to or higher than a threshold value. For example, the threshold is 10%. Thereby, in the 1st server apparatus 21, the performance data whose reference probability is less than 10% can be excluded from the urgent level calculation target. Moreover, in the 1st server apparatus 21, the load of the process which calculates an urgency level can be reduced by excluding the performance data with a reference probability of less than 10% from the urgent level calculation target. In addition, when the performance data stays in the performance data notification queue 33a of the storage unit 33 (to be described later) when the standby time has elapsed, the determination unit 32 sets the reference probability to the urgency of the staying performance data. You may make it add a value. The performance data not staying is quickly stored even if it is stored in the performance data notification queue 33a. Thereby, in the 1st server apparatus 21, it can prevent that the urgency of the performance data which is not staying becomes high carelessly. Each time the determination unit 32 calculates a new urgency level of each performance data, the determination unit 32 stores the calculated urgency level for each performance data of the user in the third table 30c.

  The determination unit 32 determines the storage order of the performance data using the urgency level for each performance data of each user stored in the third table 30c and the priority for each performance data stored in the fourth table 30d. . For example, the determination unit 32 reads the urgency for each performance data of each user stored in the third table 30c, and specifies the urgency for each performance data. Then, the determination unit 32 determines whether there is a plurality of urgency levels for the same performance data. When there are a plurality of urgency levels for the same performance data, the determination unit 32 identifies the urgency level having a large value as the urgency level for the performance data. For each piece of performance data, the determination unit 32 calculates the storage rank frequency by multiplying the urgency level of the specified performance data by the priority stored in the fourth table 30d. The determining unit 32 determines the storage order of the performance data in descending order of the calculated storage order frequency, and stores the determined storage order, the server that transmits the performance data, the performance data, and the storage order frequency in the fifth table 30e.

  The storage unit 33 stores the performance data transmitted from each server device 21 and received by the first server device 21 in the performance data notification queue 33a. FIG. 9 is a diagram illustrating an example of a data configuration of the performance data notification queue. As shown in FIG. 9, the performance data notification queue 33a has an area 33b for storing the received performance data. In the example of FIG. 9, the performance data A-1 of the server 1 is stored in the top area 33b of the performance data notification queue 33a, and the performance data A-2 of the server 1 is stored in the next area 33b. . In the example of FIG. 9, the performance data B-1 of the server 2 is stored in the area 33b next to the performance data A-2, and the performance data A-3 of the server 1 is stored in the next area 33b. Indicates.

  When the storage order of the performance data stored in the fifth table 30e is updated, the storage unit 33 rearranges the performance data in the updated storage order. In addition, when the performance data is received, the storage unit 33 stores the received performance data in the area 33b if there is an area 33b corresponding to the storage order of the performance data. In addition, when there is no area 33b corresponding to the storage order of the received performance data, the storage unit 33 rearranges the performance data in the storage order. When the first server device 21 is ready to store performance data, the storage unit 33 sequentially stores the performance data stored in the performance data notification queue 33a from the performance data stored in the head area to the storage device 40. Control to store sequentially.

  When the user who has logged out is notified from the specifying unit 31, the operation result generating unit 34 accesses the operation log 42 generated by the second server device 23 and reads the operation log 42 of the logged out user. Then, the operation result generation unit 34 specifies which performance data is referred to next for each performance data from the reference order of each performance data indicated by the read operation log 42. Then, for each piece of performance data, the operation result generation unit 34 refers to each piece of performance data with respect to the total number of times of reference that next refers to the performance data, from the reference number of times referred to next. Is calculated. In addition, the operation result generation unit 34 calculates an average time for which each performance data is referred to, with the time from the time when each performance data is referred to the time when the next performance data is referenced as a reference time. The operation result generation unit 34 creates the second table 30b in which the average time calculated for each performance data and the reference probability for referring to each performance data next are stored.

  FIG. 10 is a diagram for explaining an example of a flow for creating the second table. In the example of FIG. 10, for example, a case where the operation log 42 of the user A is read as a user who has logged out from the operation log 42 illustrated in FIG. 8 is illustrated. In the example of FIG. 10, the reference probability and average time for referring to each performance data are calculated from the read operation log 42 of the user A, and the second table 30b is created. The created second table 30b shown in FIG. 10 has the same contents as those in FIG.

The reference pattern update unit 35 reflects the average time for each performance data stored in the second table 30b and then the reference probability of each performance data in the first table 30a. For example, when the first table 30a corresponding to the logged out user does not exist, the reference pattern update unit 35 generates the first table 30a and stores each record of the second table 30b in the first table 30a. Further, when there is the first table 30a corresponding to the logged out user, the reference pattern update unit 35 sets the values of the corresponding fields in the first table 30a and the second table 30b at a predetermined ratio for each performance data. The reflected first table 30a is created. For example, the reference pattern update unit 35 performs the following calculation on the values of the corresponding fields in the first table 30a and the second table 30b to obtain values in the new first table 30a.
First table value = (first table value × α + second table value × β) ÷ (α + β)

  α and β are coefficients that determine which of the past operation results and the most recent operation results are important. α and β are both set to 1, for example. In the example of FIG. 2, since the functional configuration is shown, the specifying unit 31, the determining unit 32, the storage unit 33, the operation result generating unit 34, and the reference pattern updating unit 35 are separately provided. For example, you may comprise with one device. An example of the device is an electronic circuit such as a CPU or MPU. Note that an integrated circuit such as an ASIC or FPGA can also be adopted as the device.

  On the other hand, the second server device 23 includes a storage device 40 and a user operation recording unit 41. The storage device 40 stores a database 40a that stores performance data. The user operation recording unit 41 generates an operation log 42 indicating the content requested by the user.

  Next, a processing flow of the system 20 according to the present embodiment will be described. FIG. 11 is a flowchart showing the procedure of the operation specifying process. This operation specifying process is always executed, for example, after the first server device 21 is activated.

  As illustrated in FIG. 11, the specifying unit 31 constantly monitors the operation log 42 generated by the second server device 23 and determines whether or not a new operation log 42 has been added (step S <b> 10). If a new operation log 42 has not been added (No at Step S10), the specifying unit 31 proceeds to Step S10 again and waits for the addition of a new operation log 42. On the other hand, when a new operation log 42 is added (Yes at Step S10), the specifying unit 31 acquires the added new operation log 42 (Step S11). And the specific | specification part 31 specifies the user who performed operation from the acquired operation log 42 (step S12). The specifying unit 31 determines whether or not an operation log analysis process described later has been started (step S13). When the operation log analysis process is not activated (No at Step S13), the specifying unit 31 activates the operation log analysis process (Step S14). Then, the identifying unit 31 notifies the operation log analysis process of the new operation log 42 (step S15). On the other hand, when the operation log analysis process has been started (Yes at Step S13), the specifying unit 31 proceeds to the process at Step S15 described above. The specifying unit 31 determines whether or not the first server device 21 has been instructed to end (step S16). When the termination is not instructed (No at Step S16), the specifying unit 31 proceeds to the process at Step S10. On the other hand, when the end is instructed (Yes at Step S16), the specifying unit 31 ends the process.

  FIG. 12 is a flowchart showing the procedure of the operation log analysis process. This operation log analysis process is executed at the timing when activation is instructed from the operation specifying process.

  As illustrated in FIG. 12, the specifying unit 31 determines whether or not the operation log 42 is notified from the operation specifying process (step S20). When the operation log 42 is not notified from the operation specifying process (No at Step S20), the specifying unit 31 proceeds to Step S20 again and waits for the operation log 42 to be notified. On the other hand, when the operation log 42 is notified from the operation specifying process (Yes at Step S20), the specifying unit 31 determines whether or not the operation recorded in the operation log 42 is a logout operation (Step S21). When the operation is not a logout operation (No at Step S21), the specifying unit 31 determines whether or not the first table 30a corresponding to the specified user is stored in the storage unit 30 (Step S22). When the first table 30a corresponding to the identified user is not stored (No at Step S22), the identifying unit 31 proceeds to the process at Step S20. On the other hand, when the 1st table 30a corresponding to the specified user is memorized (Step S22 affirmation), specific part 31 starts emergency degree determination processing mentioned below (Step S23), and shifts to Step S20. On the other hand, when the operation is a logout operation (Yes at Step S21), the specifying unit 31 notifies the end to an emergency level determination process described later (Step S24). And the specific | specification part 31 notifies the user who logged out, starts the operation performance update process mentioned later (step S25), and complete | finishes a process.

  FIG. 13 is a flowchart illustrating the procedure of the operation result update process. This operation result update process is executed at the timing when activation is instructed from the operation log analysis process.

  As illustrated in FIG. 13, the operation record generation unit 34 reads the operation log 42 of the user who has logged out (step S30). Then, the operation result generating unit 34 calculates an average time referred to for each performance data and a reference probability for referring to each performance data next, and refers to the average time for each performance data and then each performance data. The second table 30b in which the reference probability to be stored is stored (step S31). The reference pattern update unit 35 determines whether or not the first table 30a corresponding to the logged out user exists (step S32). When the first table 30a does not exist (No at Step S32), the reference pattern update unit 35 generates the first table 30a and stores each record of the second table 30b in the first table 30a (Step S33). On the other hand, when the first table 30a exists (Yes at Step S32), the reference pattern update unit 35 reflects the values of the corresponding fields of the first table 30a and the second table 30b at a predetermined ratio for each performance data. The first table 30a thus created is created (step S34). The operation result generation unit 34 deletes the operation log 42 of the user who has logged out from the operation log 42 generated by the second server device 23 (step S35). Then, the operation result generating unit 34 deletes the second table 30b (step S36) and ends the process.

  FIG. 14 is a flowchart illustrating the procedure of the urgency level determination process. This urgency determination process is executed at the timing when activation is instructed from the operation log analysis process.

  As illustrated in FIG. 14, the determining unit 32 sets the machine name of each server device 21 and the name of the performance data of each performance data in the server and record items, and the third table of users specified by the specifying unit 31. 30c is created (step S40). And the determination part 32 determines whether operation which refers performance data was specified by the specific | specification part 31 (step S41). When the operation referring to the performance data is not specified (No at Step S41), the determination unit 32 determines whether or not the end of the process is notified (Step S42). When the end of the process is not notified (No at Step S42), the determination unit 32 proceeds to Step S41. On the other hand, when the end of the process is notified (Yes at Step S42), the determination unit 32 deletes the third table 30c of each user (Step S43). And the determination part 32 starts the priority determination process mentioned later (step S44), and complete | finishes a process. On the other hand, when the operation referring to the performance data is specified (Yes at Step S41), the determination unit 32 deletes all the records in the third table 30c of the user specified by the specifying unit 31 (Step S45). And the determination part 32 starts the emergency degree calculation process mentioned later (step S46), and transfers to step S41.

  FIG. 15 is a flowchart illustrating a procedure of the emergency level calculation process. This urgent level calculation process is executed at the timing when activation is instructed from the urgent level determination process.

  As illustrated in FIG. 15, the determination unit 32 reads a record corresponding to the user and performance data specified by the specifying unit 31 from the first table 30 a stored in the storage unit 30 (Step S <b> 50). And the determination part 32 calculates | requires the reference time of the average time and each performance data referred next from the read record (step S51). The determination unit 32 sets 1 as an initial value in the item of urgency of each performance data of each server in the third table 30c (step S52). The determination unit 32 sets the waiting time T to a half of the average time (step S53). The determination unit 32 determines whether or not the standby time T has elapsed (step S54). When the standby time T has not elapsed (No at Step S54), the determination unit 32 determines whether or not the specifying unit 31 specifies a reference operation for another performance data of the same user (Step S55). When the reference operation for the other performance data is not specified (No at Step S55), the determination unit 32 proceeds to Step S54. On the other hand, when the reference operation with respect to another performance data is specified (step S55 affirmation), the determination part 32 complete | finishes a process. On the other hand, when the standby time T has elapsed (Yes at Step S54), the determination unit 32 adds the value of the reference probability of the performance data to the urgency for each performance data of the third table 30c, and The urgency level is updated (step S56). The determination unit 32 activates the priority determination process (step S57). Then, the determination unit 32 updates the waiting time T to a half time of the waiting time T (step S58). The determination unit 32 determines whether or not the standby time T is shorter than a predetermined allowable time (step S59). This allowable time is the shortest time for updating the urgency level. This allowable time is set to 0.5 seconds, for example. When the standby time T is equal to or longer than the allowable time (No at Step S59), the determination unit 32 proceeds to Step S54. On the other hand, when the standby time T is shorter than the predetermined allowable time (Yes at Step S59), the determination unit 32 ends the process. Thereby, when the initial value of the waiting time T is, for example, 30 seconds, the waiting time T is 30 seconds, 15 seconds, 7.5 seconds,.・ ・ Updated. Each time the update time T elapses, the value of the reference probability is added to the urgency of each performance data.

  FIG. 16 is a flowchart illustrating a procedure of priority determination processing. This priority determination process is executed at the timing when activation is instructed from the urgent level determination process and the urgent level calculation process.

  As illustrated in FIG. 16, the determination unit 32 reads the third table 30 c of all users stored in the storage unit 30 and specifies the urgency level for each performance data (Step S <b> 60). The determination unit 32 determines whether there is a plurality of urgency levels for the same performance data (step S61). When there are a plurality of urgency levels for the same performance data (Yes at Step S61), the determination unit 32 identifies the urgency level having a large value as the urgency level for the performance data (Step S62). Then, the determination unit 32 calculates the storage rank frequency for each performance data by multiplying the urgency level of the identified performance data by the priority stored in the fourth table 30d, and calculates the storage rank frequency in descending order. The storage order of performance data is determined (step S63). On the other hand, when a plurality of urgency levels do not exist for the same performance data (No at Step S61), the determination unit 32 proceeds to Step S63 described above. The determination unit 32 notifies the performance data storage process, which will be described later, of the change in storage order (step S64), and ends the process.

  FIG. 17 is a flowchart showing a procedure of performance data storage processing. This performance data storage process is always executed after the first server device 21 is started, for example.

  As illustrated in FIG. 17, the storage unit 33 determines whether or not performance data can be stored in the first server device 21 (step S <b> 70). When the first server device 21 is in a state where performance data can be stored (Yes at step S70), the storage unit 33 sequentially stores performance data from the performance data stored in the top area 33b of the performance data notification queue 33a. Control to sequentially store in the storage device 40 is performed (step S71), and the process proceeds to step S70. On the other hand, when the first server device 21 is not in a state where performance data can be stored (No at Step S70), the storage unit 33 determines whether or not a change in storage order has been notified (Step S72). When the storage order change is not notified (No at Step S72), the storage unit 33 determines whether or not the first server device 21 is instructed to end (Step S73). When the end is not instructed (No at Step S73), the storage unit 33 proceeds to the process at Step S70. On the other hand, when the end is instructed (Yes at Step S73), the storage unit 33 ends the process. On the other hand, when the storage order change is notified (Yes at Step S72), the storage unit 33 reads the storage order of each performance data from the fifth table 30e (Step S74). The storage unit 33 initializes variable I and variable J to 1 (step S75). The storage unit 33 saves each piece of performance data in the performance data notification queue 33a in another storage area (step S76). The storage unit 33 determines whether or not rearrangement of all the saved performance data has been completed (step S77). When the rearrangement is completed (Yes at Step S77), the storage unit 33 proceeds to Step S70. On the other hand, if the rearrangement has not been completed (No at Step S77), the storage unit 33 determines whether or not the saved performance data includes performance data whose storage order is J (Step S78). When there is no performance data whose storage order is the value of the variable J (No at Step S78), the storage unit 33 increments the value of the variable J (Step S79), and proceeds to Step S77. On the other hand, when there is performance data whose storage order is the value of variable J (Yes in step S78), the storage unit 33 stores the performance data whose storage order is the value of variable J in the variable I-th area of the performance data notification queue 33a. Store (step S80). The storage unit 33 increments the value of the variable I (step S81), and proceeds to step S77.

  FIG. 18 is a flowchart showing the procedure of the notification queue storage process. This notification queue storage process is executed, for example, at the timing when performance data is received from the server device 21.

  As illustrated in FIG. 18, the storage unit 33 determines whether there is a storage area corresponding to the storage order of the received performance data (step S90). If there is a storage area (Yes at Step S90), the storage unit 33 stores the received performance data in the storage area corresponding to the storage order (Step S91), and ends the process. On the other hand, if there is no storage area (No at Step S90), the storage unit 33 determines whether or not the fifth table 30e has a storage order corresponding to the received performance data (Step S92). When there is no storage order (No at Step S92), the storage unit 33 sets the storage order of the received performance data as the lowest order (Step S93). On the other hand, when there is a storage order (Yes at Step S92), the storage unit 33 reads the storage order of each performance data from the fifth table 30e (Step S94). The storage unit 33 initializes variable I and variable J to 1 (step S95). The storage unit 33 saves each performance data in the performance data notification queue 33a in another storage area (step S96). The storage unit 33 determines whether rearrangement of all the saved performance data has been completed (step S97). When the rearrangement is completed (Yes at Step S97), the storage unit 33 ends the process. On the other hand, when the rearrangement has not been completed (No at Step S97), the storage unit 33 determines whether or not the saved performance data includes performance data whose storage order is J (Step S98). When there is no performance data whose storage order is the value of the variable J (No at Step S98), the storage unit 33 increments the value of the variable J (Step S99), and proceeds to Step S97. On the other hand, when there is performance data whose storage order is the value of variable J (Yes at step S98), the storage unit 33 stores the performance data whose storage order is the value of variable J in the variable I-th area of the performance data notification queue 33a. Store (step S100). The storage unit 33 increments the value of the variable I (step S101), and proceeds to step S97.

  As described above, for each user of the client device 24, the first server device 22 according to the present embodiment associates the performance data reference time with the first table 30a in association with the performance data referred to by the user. Remember. In addition, for each user of the client device 24, the client device 24 stores, in the first table 30a, the reference probability of each performance data referred to next to the performance data in association with the performance data referred to by the user. Further, the first server device 22 identifies the user of the client device 24 that is referring to the performance data stored in the storage device 40 and the performance data. And the 1st server apparatus 22 calculates | requires the elapsed time after specifying with respect to the reference time corresponding to the specified client apparatus and performance data with reference to the 1st table 30a. Further, the first server device 22 refers to the first table 30a, and obtains the reference probability of each performance data referred to next corresponding to the identified client device and performance data. And the 1st server apparatus 22 stores the performance data transmitted from the server apparatus 21 in the memory | storage device 40 based on the elapsed time after specifying and the reference probability of each performance data referred next. Determine the ranking. As a result, the first server device 22 determines the storage order so that the next performance data that the client device 24 refers to is preferentially stored. Therefore, according to the 1st server apparatus 22, it can suppress that a delay generate | occur | produces in storage of the performance data which a user refers.

  Also, the first server device 22 according to the present embodiment further stores the priority for each performance data in the fourth table 30d. The first server device 22 calculates the urgency of each performance data as a larger value as the reference probability is higher and the ratio of the elapsed time to the reference time is larger. Then, the first server device 22 determines the storage order for each performance data in descending order of the value obtained by multiplying the calculated urgency level and the priority stored in the storage unit. As a result, the first server device 22 also has higher reference probability for performance data with low importance, and the greater the ratio of elapsed time to reference time, the greater the urgency is calculated and the higher the storage order. Therefore, according to the first server device 22, it is possible to store performance data with low importance while suppressing delay until the performance data is referred to by the user.

  In addition, the first server device 22 according to the present embodiment changes the next standby time to a shorter time each time the elapsed time after specifying the user and the performance data by the specifying unit 31 passes the standby time. . Then, each time the standby time elapses, the first server device 22 adds the value of the reference probability of the performance data to a predetermined initial value for each performance data, and calculates the urgency of each performance data. . Thereby, the first server device 22 has a long elapsed time, and the urgency becomes higher as the referenced timing approaches. Therefore, according to the first server device 22, the performance data with the closer timing to be referenced can be preferentially stored.

  In addition, the first server device 22 gives priority to the performance data referred to by each user by determining the priority using the two indexes of importance and urgency calculated from the reference characteristics for each user. Store. Therefore, according to the 1st server apparatus 22, since many users can refer performance data efficiently, the whole service level can be improved.

  Although the embodiments related to the disclosed apparatus have been described so far, the disclosed technology may be implemented in various different forms other than the above-described embodiments. Therefore, another embodiment included in the present invention will be described below.

  For example, in the above-described second embodiment, a case has been described in which the performance data stored in the performance data notification queue 33a is rearranged in the order of storage order, but the disclosed apparatus is not limited to this. For example, the performance data may be rearranged in the order of storage order by providing an address area indicating the storage location of the next performance data in the area 33b for storing performance data and updating the information in the address area. FIG. 19 is a diagram illustrating an example of another data configuration of the performance data notification queue. Each area 33b of the performance data notification queue 33a is provided with an address area 33c. For example, performance data notification queue 33a stores performance data A-1 of three servers 1, performance data A-2 of server 1, and performance data B-1 of server 2. In this state, when storing the performance data A-3 of the server 1 having the second highest storage order, the storage unit 33 stores, for example, the performance data A-3 of the server 1 in the fourth area 33b. Then, the storage unit 33 stores the address of the area 33b in which the performance data A-3 of the server 1 is stored as the next performance data in the address area 33c of the head area 33b. Further, the storage unit 33 stores the address of the area 33b in which the performance data A-2 of the server 1 is stored in the address area 33c of the area 33b in which the performance data A-3 is stored. Further, the storage unit 33 stores the address of the area 33b in which the performance data B-1 of the server 2 is stored in the address area 33c of the area 33b in which the performance data A-2 of the server 1 is stored. Thereby, the performance data can be rearranged in the order of the storage order without changing the physical storage order.

  Further, each component of each illustrated apparatus is functionally conceptual, and does not necessarily need to be physically configured as illustrated. In other words, the specific state of distribution / integration of each device is not limited to the one shown in the figure, and all or a part thereof may be functionally or physically distributed or arbitrarily distributed in arbitrary units according to various loads or usage conditions. Can be integrated and configured. For example, the identification unit 31, the determination unit 32, the storage unit 33, the operation result generation unit 34, the reference pattern update unit 35, and the like shown in FIG. 2 may be integrated.

[Data storage control program]
The various processes of the data storage control apparatus described in the above embodiments can be realized by executing a program prepared in advance on a computer system such as a personal computer or a workstation. Therefore, in the following, an example of a computer that executes a data storage control program having the same function as the data storage control device described in the above embodiment will be described with reference to FIG. FIG. 20 is a diagram illustrating a computer that executes a data storage control program.

  As shown in FIG. 20, the computer 300 includes a central processing unit (CPU) 310, a read only memory (ROM) 320, a hard disk drive (HDD) 330, and a random access memory (RAM) 340. These units 300 to 340 are connected via a bus 400.

  The ROM 320 has the same function as the determination unit 12 shown in the first embodiment, or the specifying unit 31, the determination unit 32, the storage unit 33, the operation result generation unit 34, and the reference pattern update unit shown in the second embodiment. A data storage control program 320a that exhibits the same function as that 35 is stored in advance. Note that the data storage control program 320a may be separated as appropriate.

  Then, the CPU 310 reads the data storage control program 320a from the ROM 320 and executes it.

  The HDD 330 is provided with a first table, a second table, a third table, a fourth table, and a fifth table. The first table, the second table, the third table, the fourth table, and the fifth table are respectively the first table 30a, the second table 30b, the third table 30c, the fourth table 30d, and the first table shown in FIG. This corresponds to 5 tables 30e.

  Then, the CPU 310 reads out the first table, the second table, the third table, the fourth table, and the fifth table and stores them in the RAM 340. The CPU 310 executes the data storage control program 320a using the first table, the second table, the third table, the fourth table, and the fifth table stored in the RAM 340. Each data stored in the RAM 340 does not always need to be stored in the RAM 340, and only the data necessary for the process may be stored in the RAM 340.

  The data storage control program 320a is not necessarily stored in the HDD 330 from the beginning.

  For example, the program is stored in a “portable physical medium” such as a flexible disk (FD), a CD-ROM, a DVD disk, a magneto-optical disk, or an IC card inserted into the computer 300. Then, the computer 300 may read and execute the program from these.

  Furthermore, the program is stored in “another computer (or server)” connected to the computer 300 via a public line, the Internet, a LAN, a WAN, or the like. Then, the computer 300 may read and execute the program from these.

  The following supplementary notes are further disclosed regarding the embodiment described above and its modifications.

(Supplementary Note 1) For each of a plurality of types of performance data, a storage unit that stores a ratio referred to next to a certain type of performance data;
When the client device refers to the certain type of performance data, the storage device stores the plurality of types of performance data collected from the server device based on the ratio for each of the plurality of types of performance data stored in the storage unit. A data storage control device comprising: a determination unit that determines a storage order of storage.

(Supplementary Note 2) The storage unit further stores a reference time and a priority for each of the performance data,
The determination unit calculates the urgency of each performance data as a larger value as the referenced ratio is higher and the ratio of the elapsed time with respect to the reference time is larger, and for each performance data, the calculated urgency and the storage The data storage control device according to appendix 1, wherein the storage order is determined in descending order of the value obtained by multiplying the priority stored in the unit.

(Supplementary Note 3) Each time the elapsed time after the client device refers to the certain type of performance data exceeds the standby time, the determination unit changes the next standby time to a shorter time, and the standby time has elapsed. The data storage control according to appendix 2, wherein each time the performance data is added, the value of the ratio of the performance data referenced is added to a predetermined initial value for each performance data to calculate the urgency of each performance data. apparatus.

(Appendix 4)
For each of a plurality of types of performance data stored in the storage unit, when the client device refers to the certain type of performance data based on the ratio referred to next to the certain type of performance data, from the server device A data storage control program for executing a process for determining a storage order for storing the collected types of performance data in a storage device.

(Additional remark 5) The process which determines the said storage order calculates the urgency of each performance data as a larger value, so that the said reference ratio is high and the ratio of the elapsed time with respect to the reference time memorize | stored in the said memory | storage part is large. The data storage control program according to appendix 4, wherein the storage order is determined in descending order of a value obtained by multiplying the calculated urgency level and the priority stored in the storage unit for each performance data.

(Additional remark 6) The process which determines the said storage order changes the next waiting time to a shorter time whenever the elapsed time after a client apparatus refers to the said certain kind of performance data passes standby time, Appendix 5 wherein the urgency of each performance data is calculated by adding a value of a ratio of the performance data referred to a predetermined initial value for each performance data every time the standby time elapses Data storage control program.

(Appendix 7) The computer
For each of a plurality of types of performance data stored in the storage unit, when the client device refers to the certain type of performance data based on the ratio referred to next to the certain type of performance data, from the server device A data storage control method, comprising: determining a storage order for storing the collected types of performance data in a storage device.

(Supplementary note 8) In the process of determining the storage order, the urgent degree of each performance data is calculated as a larger value as the referenced ratio is higher and the ratio of the elapsed time to the reference time stored in the storage unit is larger. The data storage control method according to appendix 7, wherein for each of the performance data, the storage order is determined in descending order of a value obtained by multiplying the calculated urgency level and the priority stored in the storage unit.

(Supplementary note 9) The process of determining the storage order is to change the next standby time to a shorter time each time the elapsed time since the client device referred to the certain type of performance data passes the standby time, Item 8. The urgent level of each performance data is calculated by adding the value of the ratio of the performance data referred to the predetermined initial value for each performance data every time the standby time elapses. Data storage control method.

DESCRIPTION OF SYMBOLS 10 Data storage control apparatus 11 Storage part 12 Determination part 13 Server apparatus 14 Storage apparatus 15 Client apparatus 21 Server apparatus 22 1st server apparatus 23 2nd server apparatus 24 Client apparatus 30a 1st table 30b 2nd table 30c 3rd table 30d Fourth table 30e Fifth table 30 Storage unit 31 Identification unit 32 Determination unit 33a Performance data notification queue 40 Storage device

Claims (5)

For each of a plurality of types of performance data, a storage unit that stores a ratio that is referenced next to the first type of performance data;
When the client device refers to the first type of performance data, the plurality of types of performance data collected from the server device based on the ratio for each of the plurality of types of performance data stored in the storage unit A determination unit for determining a storage order to be stored in the storage device ;
From the performance data stored in the temporary storage unit that temporarily stores the data collected from the server device until it is stored in the storage device, the storage device determines the data in the descending order of storage order determined by the determination unit. A data storage control device having a storage unit for storing . For each of a plurality of types of performance data, a storage unit that stores a ratio , a reference time, and a priority that are referred to next to the first type of performance data;
When the client device refers to the first type of performance data, the referenced rate is high based on the rate for each of the plurality of types of performance data stored in the storage unit, and the passage of the reference time The urgency level of each performance data is calculated as a larger value as the time ratio is larger, and for each performance data, the plurality of values are calculated in descending order of the value obtained by multiplying the calculated urgency level and the priority stored in the storage unit. A data storage control device comprising: a determination unit that determines a storage order for storing performance data of a type in a storage device. The determination unit changes the next standby time to a shorter time each time the elapsed time from the time when the client device refers to the first type of performance data elapses, and each time the standby time elapses. 3. The data storage control device according to claim 2, wherein the urgency level of each performance data is calculated by adding a value of a reference rate of the performance data to a predetermined initial value for each performance data. . On the computer,
Serial憶部stored in, for a plurality kinds of performance data each, based on the percentage referenced to the next first type of performance data, when the client device with reference to the first type of performance data Determining a storage order for storing the plurality of types of performance data collected from the server device in a storage device ;
Processing for storing data collected from the server device in the storage device in descending order of storage order determined from the performance data stored in the temporary storage unit that temporarily stores the data until the data is stored in the storage device A data storage control program that is executed. Computer
Serial憶部stored in, for a plurality kinds of performance data each, based on the percentage referenced to the next first type of performance data, when the client device with reference to the first type of performance data Determining a storage order for storing the plurality of types of performance data collected from the server device in a storage device ;
Processing for storing data collected from the server device in the storage device in descending order of storage order determined from the performance data stored in the temporary storage unit that temporarily stores the data until the data is stored in the storage device A data storage control method which is executed.

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