JP6293966B2 - Database management apparatus, database management method, and database management program - Google Patents

Description

  Embodiments described herein relate generally to a database management apparatus, a database management method, and a database management program.

  In a database management system (DBMS), adjustment for securing a storage area is performed before the storage area of a storage device (for example, a hard disk) that stores data is completely used. The following description is based on the assumption of a hard disk. As a trigger for the above adjustment or the like, information that a disk full error has occurred may be notified by the monitoring system or the like. A certain amount of free space is required to safely handle a disk full error. Also, in a disk full state where a disk full error occurs, the behavior of an OS (Operating System) that is activated on the system becomes unreliable, and there is a high possibility of a crash unexpectedly. However, in the conventional technique, since the disk full error is notified based on the state at that time, it is necessary to notify the safety at an early stage.

JP 2011-18363 A JP 2007-179551 A JP 2006-163729 A

  The problem to be solved by the present invention is to provide a database management device, a database management method, and a database management program that can alert a free space at a more appropriate timing.

  The database management apparatus according to the embodiment includes a capacity monitoring unit, a control unit, and a cycle setting unit. The capacity monitoring unit monitors the free capacity of the storage device that stores data. The control unit outputs warning information regarding the free space based on the free space of the storage device obtained by the capacity monitoring unit and the free space of the storage device in the future when written at a predetermined write rate. To do. The period setting unit sets a period for the capacity monitoring unit to check the free capacity based on the free capacity of the storage device. The cycle setting unit writes the free space of the storage device, the first threshold value, and the storage device at the predetermined write rate when the free space of the storage device is larger than a first threshold value. The period for checking the free capacity is set using the data capacity in the case of the data. Further, the cycle setting unit, when the free capacity is equal to or less than the first threshold value, when the free capacity is larger than a second threshold value that is smaller than the first threshold value, The free capacity is confirmed by discounting a value based on the capacity, the second threshold value, and the data capacity when data is written to the storage device at the predetermined write rate based on a predetermined safety factor. Set the cycle.

The figure which shows the function structural example of the database management apparatus in this embodiment. The figure which shows an example of a setting file. The figure which shows an example of an error check flag. The figure which shows the hardware structural example of a database management apparatus. The figure for demonstrating the database management process in this embodiment. The figure for demonstrating the 1st example of a setting of a check period. The figure for demonstrating the 2nd example of a setting of a check period. The flowchart which shows the 1st Example of the setting process of a check period. The flowchart which shows the 2nd Example of the setting process of a check period. The flowchart which shows an example of a capacity | capacitance monitoring process. The flowchart which shows an example of SQL execution processing.

  Hereinafter, a database management device, a database management method, and a database management program according to embodiments will be described with reference to the drawings.

  FIG. 1 is a diagram illustrating a functional configuration example of a database management apparatus according to the present embodiment. A database management apparatus 100 shown in FIG. 1 includes a setting information receiving unit (receiving unit) 110, a check cycle setting unit (cycle setting unit) 120, a capacity monitoring unit 130, a process execution unit 140, a control unit 150, And a storage unit 160. Some or all of these functional units may be realized by hardware such as LSI (Large Scale Integration), ASIC (Application Specific Integrated Circuit), and FPGA (Field-Programmable Gate Array). The storage unit 160 includes a setting file 162, an error check flag 164, and the like.

  In the example of FIG. 1, the database 200 to be managed by the database management apparatus 100 is expressed as an apparatus separate from the database management apparatus 100, but these may be an integrated apparatus. The database 200 may be a cloud type database. The database 200 is provided with one or a plurality of storage devices (disk devices D1, D2,... In the example of FIG. 1). The following description will be made on the assumption that a storage device includes a hard disk (disk device), but the storage device may be a flash memory or other storage device. Further, the database management apparatus 100 has a function such as a DBMS, for example.

  In the example of FIG. 1, the database management apparatus 100 receives input of setting information from the client 300 used by the user (operator) and input of instructions for executing processing, and based on the received content, Various processes relating to management 200 are executed.

  The client 300 causes the database 200 to execute predetermined processing (data writing, reading, deletion, etc.) by outputting data to the database management apparatus 100 or issuing a predetermined instruction using a command or the like. The client 300 is an information processing apparatus such as a PC (Personal Computer), a tablet terminal, or a mobile phone. The client 300 may be an information processing apparatus used by a user of the database management apparatus 100, and is an apparatus that transmits various commands to the database management apparatus 100 based on a command received from another apparatus. Also good. Further, the client 300 may be a device that generates various commands based on the result of information processing inside and transmits the commands to the database management device 100.

  For example, in order for the client 300 to cause the database management apparatus 100 to execute predetermined processing, a write command for instructing data writing, a read command for instructing data reading, a deletion command for instructing data deletion, etc. Send. In addition, the client 300 acquires a processing result for the content instructed from the database management apparatus 100.

  The database management apparatus 100 and the client 300 are connected in a state where data can be transmitted and received by a communication network represented by the Internet, a LAN (Local Area Network), or the like. The communication network may be wired or wireless, or a combination thereof. Various functions of the client 300 may be provided in the database management apparatus 100. In the example of FIG. 1, one client 300 is shown as an apparatus that uses the database management apparatus 100, but a plurality of clients 300 may use the database management apparatus 100.

  The setting information receiving unit 110 receives input of setting information for setting a cycle for checking (checking) the disk capacity from the client 300. The setting information receiving unit 110 receives setting information by a user input operation on the client 300, for example. The received setting information is stored in the storage unit 160 as a setting file 162. In addition, the setting information receiving unit 110 may receive an instruction from the client 300 for executing the predetermined processing described above.

  FIG. 2 is a diagram illustrating an example of a setting file. For example, the setting files 162-1 and 162-2 shown in FIG. 2 are setting information corresponding to the disk devices D1 and D2, respectively. The setting information receiving unit 110 generates a setting file 162 for each disk device in the database 200. In the setting files 162-1 and 162-2 shown in FIG. 2, one or more threshold values (for example, threshold values A1 to C1, A2 to C2) and a predetermined writing rate for the disk device are set. The predetermined write rate is a maximum write rate assumed for each disk device. Note that the maximum write rate may be set slightly smaller (or larger) than the assumed maximum write rate. “Slightly” means, for example, about ± 10%. In FIG. 2, maximum write throughputs T1 and T2 are set as an example of a predetermined write rate with respect to the disk devices D1 and D2. The setting file 162 is stored in the storage unit 160 together with the disk device identification information.

  The thresholds A to C shown in FIG. 2 are parameters for checking whether or not to output a check cycle parameter and a disk full error (warning information regarding free space). The thresholds A to C are all threshold values related to the free capacity of the disk device, but may be threshold values related to the used capacity of the disk. For example, of the three threshold values A to C, two threshold values (for example, threshold values A and B) are used to set the next check period of the disk capacity, and the remaining threshold values (for example, threshold value C) are: Used to check whether the disk is full (whether there is no free space). The three thresholds A to C may have a preset magnitude relationship (for example, “threshold A> threshold B> threshold C”).

  For example, the thresholds A to C may be set using a preset ratio to the total capacity of the disk device, or may be arbitrarily set by the user. For example, the threshold A, which is the first threshold, is set to a value with a sufficient free capacity in consideration of processing for the disk device. Further, the threshold B, which is the second threshold, is a value used as a reference for determining whether or not to check the free space at the time of data writing, and is therefore a value smaller than the threshold A and larger than the threshold C. Set.

  The threshold value C, which is the third threshold value, is a value used as a reference for determining whether or not the disk device has a disk full error. Therefore, at least the maximum capacity required for one error process and the error process It is necessary to secure a capacity obtained by adding the capacity consumed during one time. For example, when 1 MB is required for error processing and further 9 MB is required for the error processing time (90 ms), the threshold C is set to a value of 10 MB or more by adding them.

  Further, the maximum write throughput T in the setting file 162 can be acquired from, for example, a catalog specification provided by a disk vendor (database provider or the like) 400 that provides the disk devices D1, D2 and the like of the database 200. The disk vendor 400 is an information processing apparatus such as a PC or a server, and may be connected to the client 300 or the database management apparatus 100 in a state where data can be transmitted / received via a communication network.

  For example, the client 300 accesses the disk vendor 400 via the communication network, acquires catalog specification data of the disk devices D1, D2, etc., and inputs the data to the setting information receiving unit 110, thereby increasing the maximum write throughput T. Can be acquired. Further, the user may input the maximum writing throughput T using the client 300 from a catalog specification such as a print medium. Further, the database management apparatus 100 may inquire of the disk vendor 400 directly about the maximum write throughput T via the communication network and acquire corresponding data. As a result, even a user who does not have knowledge or experience regarding the disk device can easily set the maximum write throughput value.

  Note that the maximum write throughput T may be arbitrarily set by a user using the client 300. Further, at least one of the above-described thresholds A to C may be set based on information provided from the disk vendor 400. At least one of the thresholds A to C and the maximum write throughput T described above may be a fixed value set in advance. The maximum write throughput T may be set to a value measured in advance using, for example, a disk performance measurement program.

  The check cycle setting unit 120 reads the setting file 162 set by the setting information receiving unit 110 from the storage unit 160, and calculates a cycle (check cycle) for checking the respective disk capacities of the disk devices D1, D2, and the like. A method for calculating the check cycle will be described later.

  The capacity monitoring unit 130 monitors the free capacity of the disk devices D1, D2, etc. in the database 200 based on the check cycle obtained by the check cycle setting unit 120. For example, the capacity monitoring unit 130 makes an inquiry about the free capacity of the disk devices D1, D2, etc. to the control unit 150 when the check cycle is reached, and sets the free capacity acquired from the control unit 150 and the setting file 162. By comparing with the threshold value, it is determined whether or not the disk is full for each disk device.

  In addition, the capacity monitoring unit 130 uses the current free capacity obtained by the inquiry and the future disk when written at the maximum write throughputs T1 and T2 of the disk devices D1 and D2 set in the setting file 162, respectively. The free capacity of the next disk device D1, D2, etc. is confirmed in the first cycle determined based on the free capacity of the disk device.

  Further, the capacity monitoring unit 130 compares the acquired current free capacity with the threshold set in the setting file 162 of each disk device, and stores the check contents based on the comparison result in the storage unit 160 as error flag information. The error check flag 164 is set.

  FIG. 3 is a diagram illustrating an example of an error check flag. The items of the error check flag 164 include “disk type” for identifying one or a plurality of disk devices managed as the database 200, and free space when executing processing such as data writing to or reading from the disk devices. There is a “check flag” or the like for determining whether to perform the check. The error check flag 164 determines whether or not to check the disk capacity in the process execution unit 140 for each disk device, asynchronously with the disk capacity check period in the capacity monitoring unit 130.

  For example, the capacity monitoring unit 130 compares the current disk capacity of the disk devices D1, D2, and the like with the threshold value B of the setting file 162, and as a result, the error check flag 164 is determined. The check flag for the target disk device is set to “TRUE”. If the current disk capacity is larger than the threshold B (including the case where it is larger than the threshold A), the error check flag is set to “FALSE”. The type of the check flag is not limited to “TRUE / FALSE”, but may be identification information such as “1/0”, “ON / OFF”, and the like.

  The capacity monitoring unit 130 described above may activate the processing in the capacity monitoring unit 130 as a disk capacity monitoring thread (first processing thread). A thread is a minimum execution unit of a program on an OS that supports parallel processing in, for example, software or a program. The database management apparatus 100 executes each process in the capacity monitoring unit 130 described above by, for example, starting a disk capacity monitoring thread when the database management apparatus 100 is started.

  The process execution unit 140 executes a process according to an instruction from the client 300. For example, the process execution unit 140 executes one or a plurality of SQL (Structured Query Language) process threads (second process threads) corresponding to commands obtained from the client 300. SQL is a language used for issuing commands to the database management apparatus 100 from a user (client 300), external software, or the like. SQL can define, for example, command words, syntax, grammar, and the like for adding, changing, and deleting tables (data) in each disk device of the database 200, relationships between tables, definitions of each table, and the like.

  For example, the process execution unit 140 performs a process for an SQL request issued by the user using an SQL processing thread, and requests the control unit 150 to perform a process including data writing or reading as necessary. For example, the process execution unit 140 refers to the error check flag 164 when writing data to the disk device, and makes a write request to the disk device when the check flag of the disk device to which data is written is “TRUE”. At the timing, the controller 150 is requested to inquire about the free space. When the check flag is “FALSE”, the process execution unit 140 requests only the data write process from the control unit 150 without making an inquiry about the free space.

  Further, the process execution unit 140 compares the acquired free space with a threshold (for example, threshold C), and outputs a disk full error to the client 300 or the like when the free space is equal to or less than the threshold. The process execution unit 140 may request the control unit 150 to output the above-described disk full error and cause the control unit 150 to execute the request.

  The above-described SQL processing thread is activated after the above-described disk capacity monitoring thread (first processing thread) is activated, and is executed asynchronously with the disk capacity monitoring thread. That is, in the present embodiment, the capacity monitoring unit 130 and the process execution unit 140 can operate by starting threads that operate asynchronously.

  The control unit 150 controls processing of the entire components shown in FIG. Various controls by the control unit 150 are functions executed by the OS, for example. The control unit 150 performs various controls such as data writing / reading to / from the disk devices D1, D2, etc., data deletion, and table updating. For example, the control unit 150 receives a data write request from the process execution unit 140 and performs writing to the disk devices D1, D2, and the like. In addition, the control unit 150 updates the free space after writing. Information regarding the updated free space may be managed in the internal memory of the control unit 150 or the like.

  In response to an inquiry about the free space from the capacity monitoring unit 130 or the process execution unit 140, the control unit 150 obtains the free space of the disk device from the database 200 or the internal memory, The data is output to the capacity monitoring unit 130 or the processing execution unit 140. Further, the control unit 150 may output a disk full error to the client 300 based on the free capacity of the disk devices D1 and D2.

  The storage unit 160 stores a program (for example, a database management program) executed by the computer of the database management apparatus 100, other various setting information (setting file 162), error flag information (error check flag 164), log information, and the like. To do. The storage unit 160 may be a non-volatile storage medium such as a ROM (Read Only Memory), a flash memory, an HDD (Hard Disk Drive), an SSD (Solid State Drive), an SD card, etc., and may be a RAM (Random Access Memory), a register, etc. A volatile storage medium such as

  FIG. 4 is a diagram illustrating a hardware configuration example of the database management apparatus. The database management device 100 includes, for example, a CPU (Central Processing Unit) 100A, a RAM (Random Access Memory) 100B, a nonvolatile storage device 100C, a portable storage medium drive device 100D, an input / output device 100E, and a communication interface. 100F. The database management apparatus 100 may include an arbitrary form of processor instead of the CPU 100A, or some of the components shown in FIG. 4 may be omitted.

  The CPU 100A develops the program stored in the nonvolatile storage device 100C or stored in the portable storage medium attached to the portable storage medium drive device 100D in the RAM 100B, and executes various programs in the present embodiment. I do. Note that the database management apparatus 100 may include another type of processor instead of the CPU 100A. The RAM 100B is an example of a volatile memory, and is used as a working area by the CPU 100A. The non-volatile storage device 100C is, for example, an HDD, a flash memory, a ROM, or the like. The portable storage medium drive device 100D is loaded with a portable storage medium such as a DVD (Digital Versatile Disc), a CD (Compact Disc), or an SD card. The input / output device 100E includes, for example, a keyboard, a mouse, a touch panel, a display device, and the like. The communication interface 100F functions as an interface when the database management apparatus 100 communicates with other apparatuses via a communication network. Various processes in the present embodiment can be realized by causing the computer of the database management apparatus 100 to cooperate with hardware such as that shown in FIG. 4 and software such as a program.

  FIG. 5 is a diagram for explaining database management processing in the present embodiment. In the example of FIG. 5, the database management apparatus 100, the database 200, and the client 300 are included. FIG. 5 shows an example of checking the disk capacity of the database 200 by the multi-thread method. For example, the disk capacity monitoring thread 500 illustrated in FIG. 5 corresponds to the capacity monitoring unit 130 described above, the OS 502 corresponds to the control unit 150 described above, and the SQL processing thread 504 corresponds to the process execution unit 140 described above. ing. The OS 502 is provided in the database management apparatus 100, but may be provided on the database 200 side.

  Here, the disk capacity check in the present embodiment refers to, for example, an inquiry about the free capacity for each disk device performed by the database management apparatus 100, and a comparison result between the free capacity acquired by the inquiry and a predetermined threshold. This is a process for outputting an error or setting the next check cycle. In this embodiment, a cycle according to the free capacity (or used capacity) of the disk device is set, and the disk capacity is checked at the set cycle.

  In the example of FIG. 5, the disk capacity monitoring thread 500 of the database management apparatus 100 acquires a setting file 162 having three thresholds A to C and the maximum write throughput T of the disk device ((1) shown in FIG. 5). . Further, the disk capacity monitoring thread 500 inquires of the OS 502 about the free disk capacity at the period set by the check period setting unit 120 ((2) shown in FIG. 5). In response to the free space inquiry from the disk capacity monitoring thread 500, the OS 502 makes an inquiry to the database 200 ((3) shown in FIG. 5) and acquires the free capacity of the corresponding disk device (shown in FIG. 5). 4)). Further, the OS 502 outputs the acquired free capacity to the disk capacity monitoring thread 500 ((5) shown in FIG. 5). Note that the OS 502 may output the information to the disk capacity monitoring thread 500 when information about the free capacity of the disk device is stored in advance in the internal memory or the like.

  The disk capacity monitoring thread 500 compares the threshold A or threshold B set in the setting file 162 with the current free capacity, and updates the check flag of the error check flag 164 based on the comparison result (shown in FIG. 5 ( 6)). Further, the disk capacity monitoring thread 500 checks the next free capacity at the check cycle set by the check period setting unit 120 based on the check result of the free capacity and the threshold value.

  Further, the process execution unit 140 processes an SQL request issued by a user, for example. The process execution unit 140 generates a SQL processing thread 504 corresponding to the number of one or a plurality of SQL requests, and executes the generated SQL processing thread. Here, the process execution unit 140 reads the error check flag 164 when executing an SQL processing thread that performs a write process, for example, among a write process, a read process, a delete process, and the like of the database 200 in the disk device (see FIG. (7) shown in FIG.

  Further, when the check flag of the disk device to which data is to be written is “TRUE”, the process execution unit 140 inquires of the free space with respect to the OS 502 together with the data write process ((8) shown in FIG. 5). . When there is a write process to the disk device by the SQL processing thread 504, the OS 502 writes to the target disk device of the database 200 and updates the free capacity ((9) shown in FIG. 5). Note that the OS 502 also updates the free capacity of the disk device even when the free capacity is changed by data deletion processing or the like.

  Also, the OS 502 acquires the execution result of the writing process to the disk device and the disk free space updated by the writing process ((10) shown in FIG. 5), and the acquired execution result and the free capacity are displayed in the SQL processing thread 504. ((11) shown in FIG. 5). Note that the OS 502 may output the information to the SQL processing thread 504 when information about the free capacity of the disk device is stored in the internal memory or the like in advance.

  The SQL processing thread 504 outputs a disk full error when the free capacity of the disk device is smaller than the threshold value C. The SQL processing thread 504 does not output a disk full error when the current disk capacity is equal to or greater than the threshold value C. The disk full error is an error that occurs when data cannot be written to the target disk device. In this case, the process execution unit 140 may output an error message on the screen of the client 300. Further, the process execution unit 140 may execute processes such as deletion, compression, movement, and expansion of the disk capacity of stored data so that the free capacity of the disk device increases. Even when the free capacity is checked by the SQL processing thread 504, the free capacity may be checked by the disk capacity monitoring thread 500. In this case, the next check cycle of the disk capacity monitoring thread 500 does not need to be checked immediately in consideration of the time until the free capacity increases, so a long fixed value (for example, after 10 seconds) is set. Is done.

  As described above, in this embodiment, the disk capacity monitoring thread 500 confirms the free capacity asynchronously with the SQL processing thread 504. In this embodiment, the disk capacity monitoring thread 500 changes the period for checking the free capacity based on the result of comparing the free capacity and the threshold value related to the capacity. As a result, it is possible to check the free space at a more appropriate timing, and to alert the free space as necessary.

  Next, the setting contents of the check period of the free capacity based on the relationship between the current free capacity of the disk device, the threshold value, and the maximum write throughput T will be specifically described. For example, if the free capacity of the disk device is large, it is useless to check the free capacity at short intervals. In addition, when the free space is small, checking at short intervals can grasp the shortage of the free space of the disk device at an early stage, and can prevent a system error or the like. Therefore, in this embodiment, the disk check cycle is set based on the current free capacity, one or more threshold values, and the maximum disk write and throughput T.

  Here, when the check cycle is set, it is necessary to leave a free space that can be processed by the database management apparatus 100 when the free space check is executed. However, since there are several tens to several hundred processes related to error processing, and the database management apparatus 100 may write data other than error processing, it is difficult to check the maximum write throughput of the entire disk device.

  Therefore, in this embodiment, the disk capacity check is set by the maximum write throughput T (MB / s) acquired from the catalog specifications of the disk device. This check cycle is a cycle that is executed asynchronously (with different timing) from the execution of the SQL process.

  FIG. 6 is a diagram for explaining a first setting example of the check cycle. In the example of FIG. 6, the horizontal axis represents time, and the vertical axis represents the free capacity of the disk device. In the example of FIG. 6, the actual free capacity of the disk device and the state of free capacity reduction based on the maximum write throughput are shown. Further, in the example of FIG. 6, the case where the actual free space is larger than the threshold A is shown in any of the first to third check cycles.

  The check cycle setting unit 120 sets the time when the future free space that decreases when data is written based on the maximum write throughput T to the write destination disk device is reduced to the threshold A capacity (see FIG. 6). The indicated time t1a) is set as the check cycle (first time).

  Here, as a result of the capacity check in the cycle (first time), when the actual free space is larger than the threshold A, the check cycle setting unit 120 uses the current free space acquired at the check in the check cycle (first time). Based on the maximum write throughput T with respect to the write destination disk device as a reference, the time when the future free space that decreases when data is written decreases to the threshold A capacity (time t2a shown in FIG. 6). ) Is set as the next check cycle (second time). Similarly, the check cycle setting unit 120 decreases when data is written based on the maximum write throughput T when the actual free space acquired at the check in the check cycle (second time) is larger than the threshold A. The time (time t3a shown in FIG. 6) when the future free capacity decreases until reaching the capacity of the threshold A is set as the next check cycle (third time). Hereinafter, when the actual free space is larger than the threshold A, the same processing is performed.

  FIG. 7 is a diagram for explaining a second setting example of the check cycle. In the example of FIG. 7, as in the example of FIG. 6, the horizontal axis indicates time, and the vertical axis indicates the free capacity of the disk device. The example of FIG. 7 shows the actual free capacity of the disk device, the reduction of the free capacity based on the maximum write throughput, and the state in which the check cycle is discounted based on a predetermined safety factor. Further, in the example of FIG. 7, the actual free space is equal to or smaller than the threshold A and larger than the threshold B in any of the first to third check cycles.

  As shown in the example of FIG. 7, for example, when the actual free space is equal to or smaller than the threshold A and larger than the threshold B, the check cycle setting unit 120 is based on the maximum write throughput T with respect to the write destination disk device. The time (time t1b shown in FIG. 7) is acquired when the free capacity that decreases when data is written decreases to the threshold B capacity. Furthermore, the check cycle setting unit 120 sets a time (t1b ′ shown in FIG. 7) obtained by discounting from the time t1b by a predetermined safety factor as the check cycle (first time). Here, the safety factor is a parameter for guaranteeing that the free capacity check is surely performed before the disk capacity becomes the threshold value B or less.

  Here, as a result of the capacity check in the cycle (first time), when the actual free space is equal to or smaller than the threshold A and larger than the threshold B, the check cycle setting unit 120 is acquired at the time of the check in the check cycle (first time). The time when the free space that decreases when data is written based on the maximum write throughput T with respect to the write destination disk device is reduced to the threshold B capacity based on the current free space (see FIG. 7). The indicated time t2b) is acquired. Further, the check cycle setting unit 120 sets a time (t2b ′ shown in FIG. 7) obtained by discounting from the time t2b by a predetermined safety factor as the next check cycle (second time).

  Similarly, the check cycle setting unit 120 sets the data based on the maximum write throughput T when the actual free space acquired at the check in the check cycle (second time) is equal to or less than the threshold A and greater than the threshold B. The time (time t3b shown in FIG. 7) is acquired when the future free space that decreases when the value is written is reduced to the threshold A capacity. Further, the check cycle setting unit 120 sets a time (t3b ′ shown in FIG. 7) obtained by discounting from the time t3b by a predetermined safety factor as the check cycle (third time). Hereinafter, when the actual free space is equal to or smaller than the threshold A and larger than the threshold B, the same processing is performed. The processes in FIGS. 6 and 7 can be switched based on the relationship between the free space and the threshold value based on the check cycle. Note that the check cycle setting method shown in FIGS. 6 and 7 is not limited to this.

  As shown in FIG. 6 and FIG. 7 described above, the database management apparatus 100 can change the check period of the free capacity of the disk device according to the actual free capacity of the disk device. More specifically, the check cycle can be lengthened when the free space of the disk device has a margin, and the check cycle can be shortened when the free space is likely to be insufficient. Thereby, it is possible to call attention regarding the free space at a more appropriate timing. Moreover, since the free space can be confirmed at an appropriate frequency, the monitoring cost of the database management apparatus 100 can be reduced, and the processing performance can be improved.

  Next, various processes in the database management apparatus 100 according to the present embodiment described above will be described with reference to flowcharts. FIG. 8 is a flowchart showing a first embodiment of the check cycle setting process. In the following description, it is assumed that the free capacity of the disk device to be checked has already been acquired.

  In the example of FIG. 8, the check cycle setting unit 120 determines whether or not the free capacity of the disk device is larger than the threshold A (step S100). When the free space is larger than the threshold value A, the check cycle setting unit 120 subtracts the current free space by the threshold value A, and divides the value obtained by the subtraction by the maximum write throughput T (“(current Free capacity−threshold A) / maximum write throughput T ″) is set as the next check cycle (first cycle) (step S102). When the free space is larger than the threshold A, there is a free space. Therefore, the check cycle setting unit 120 may set a fixed value (for example, after 1 minute) as the next cycle in step S102.

  If the free space is equal to or less than the threshold A, the check cycle setting unit 120 determines whether or not the free space is larger than the threshold B (step S104). When the free space is larger than the threshold value B, the check cycle setting unit 120 subtracts the current free space by the threshold value B, calculates a value obtained by dividing the subtracted value by the maximum write throughput T, and further calculates the calculated value. Multiplied by the safety factor p (p <1) ("subtracted") ("(current free capacity-threshold B) / maximum write throughput T x safety factor p") for the next check cycle (second cycle) ) (Step S106).

  If the free space is equal to or less than the threshold B, the check cycle setting unit 120 determines whether the free space is greater than the threshold C (step S108). When the free space is larger than the threshold value C, the check cycle setting unit 120 sets the timing for executing the data writing process as the timing for performing the next check (step S110). That is, in the process of step S110, the timing for executing the SQL processing thread for writing data to the target disk device is set as the next check cycle of the free space. This check cycle is aperiodic, but will be described as the third cycle for convenience. The third cycle is a check cycle executed by the above-described SQL processing thread, but the capacity monitoring unit 130 may continuously check the free space. In that case, the check cycle setting unit 120 sets, for example, a fixed value (for example, after 10 seconds) as the next check cycle in the capacity monitoring unit 130.

  When the free space is equal to or less than the threshold value C, a disk full error is output, so the check cycle setting unit 120 ends the check cycle setting process without setting the check cycle.

  Further, when the difference between the current free space and each threshold value is less than a predetermined value (for example, when the free space is close to the threshold value), the database management device 100 compares the periods calculated under different conditions, The next check cycle may be set based on the comparison result. The above description will be described below as a second embodiment of the check cycle setting process.

  FIG. 9 is a flowchart showing a second embodiment of the check cycle setting process. In the example of FIG. 9, the calculation contents of the first period and the second period described above are the same as the above-described contents, and a specific description thereof is omitted here.

  In the example of FIG. 9, the check cycle setting unit 120 determines whether or not the free capacity of the disk device is larger than the threshold value A (step S200). When the free space is larger than the threshold A, the check cycle setting unit 120 determines whether or not the value (difference value) obtained by subtracting the free space by the threshold A is equal to or greater than a predetermined value (step S202). When the value obtained by subtracting the free space by the threshold A is equal to or larger than the predetermined value, the check cycle setting unit 120 sets the first cycle described above as the next check cycle (step S204).

  If the value obtained by subtracting the free space by the threshold A is less than the predetermined value, the check cycle setting unit 120 determines whether or not the second cycle is larger than the first cycle described above (step S206). ). When the first cycle is larger than the second cycle, the check cycle setting unit 120 sets the first cycle as the next check cycle, similarly to step S204 described above. If the first cycle is equal to or shorter than the second cycle, the check cycle setting unit 120 sets the second cycle described above as the next check cycle (step S208). That is, in the second embodiment, when the free space is in the vicinity of the threshold value A, the first cycle calculated by different calculation methods is compared with the second cycle, and the cycle with the larger cycle (interval) is used. Set. Thereby, the free capacity of the disk device can be checked at an appropriate cycle.

  In the above-described processing of step S200, when the free space is equal to or less than the threshold A, the check cycle setting unit 120 determines whether the free space is larger than the threshold B (step S210). When the free space is larger than the threshold value B, the check cycle setting unit 120 determines whether or not the value (difference value) obtained by subtracting the free space by the threshold value B is greater than or equal to a predetermined value (step S212). If the value obtained by subtracting the free space by the threshold value B is equal to or larger than the predetermined value, the second cycle is set as the next check cycle in the same manner as in step S208 described above.

  When the value obtained by subtracting the free space by the threshold value B is less than the predetermined value, the check cycle setting unit 120 calculates a value obtained by subtracting the threshold value C from the threshold value B and dividing the subtracted value by the maximum write throughput. Further, a value obtained by multiplying the calculated value by the safety factor p (“(threshold B−threshold C) / maximum write throughput T × safety factor p”) is calculated as the fourth period (step S214).

  Next, the check cycle setting unit 120 determines whether or not the second cycle is greater than the fourth cycle (step S216). When the second cycle is larger than the fourth cycle, the check cycle setting unit 120 sets the second cycle as the next check cycle, as in the process of step S208 described above. If the second period is equal to or less than the fourth period, the check period setting unit 120 sets the fourth period as the next check period (step S218). That is, in the second embodiment, when the free space is in the vicinity of the threshold B, the second cycle calculated by different calculation methods is compared with the fourth cycle, and the cycle with the larger cycle (interval) is used. Set. As a result, the disk capacity can be checked at an appropriate cycle.

  In the above-described processing of step S210, when the free space is equal to or smaller than the threshold value B, the check cycle setting unit 120 determines whether the free space is larger than the threshold value C (step S220). When the free space is larger than the threshold value C, the check cycle setting unit 120 sets the above-described third cycle as the next check cycle (step S222).

  If the free space is equal to or less than the threshold value C, a disk full error is output, so the check cycle setting unit 120 ends the process without setting the check cycle. As described above, according to the second embodiment, for example, when the free space is near the threshold value A or the threshold value B, the next check cycle is set based on the comparison result of the cycles calculated by different methods. Therefore, the capacity check can be performed at a more appropriate cycle.

  Here, a setting example of the check cycle in the present embodiment will be specifically described. For example, the threshold A = 500 [MB], the threshold B = 100 [MB], the threshold C = 10 [MB], and the maximum write throughput T = 100 [MB / s] of the disk device. Further, the safety factor p = 0.5.

  For example, when the free capacity of the disk device is 2 [GB], the next check cycle is “(2 [GB] −500 [MB]) / 100 [MB / s]” = After 15 seconds. When the free capacity of the disk device is 510 [MB], the threshold A-based cycle is “(510 [MB] −500 [MB]) by using the second embodiment of the check cycle setting process described above. / 100 [MB / s] ”= 0.1 [seconds], and the threshold B reference cycle is“ (510 [MB] −100 [MB]) / 100 [MB / s] × 0.5 ”= 2. 05 [seconds]. Therefore, the next check cycle is 2.05 seconds after the large value.

  When the free capacity of the disk device is 200 MB, the threshold B reference cycle is “(200 [MB] −100 [MB]) / 100 [MB / s] × 0.5” = 0.5 seconds later. Become. Further, when the free capacity of the disk device is 110 [MB] and the second embodiment of the check cycle setting process described above is used, the cycle based on the threshold B is “(110 [MB] −100 [MB]”. ) / 100 [MB / s] × 0.5 ”= 50 [ms], and the threshold C reference period is“ (100 [MB] −10 [MB]) / 100 [MB / s] × 0.5. "= 450 [ms]. Therefore, the next check cycle is 450 ms after the large value. Note that the check cycle calculation method described above is not limited to this, and the check cycle may be set by another calculation method.

  Next, capacity monitoring processing in the capacity monitoring unit 130 will be described using a flowchart. FIG. 10 is a flowchart illustrating an example of the capacity monitoring process. In the example of FIG. 10, the capacity monitoring unit 130 receives a disk device free capacity monitoring request from the client 300 or the like (step S300), and inquires about the free capacity of the disk device at a predetermined cycle based on the received request (step S300). Step S302). Next, the capacity monitoring unit 130 determines whether or not the free capacity of the disk device is larger than the threshold value B (step S304). When larger than the threshold value B, the capacity monitoring unit 130 sets the check flag of the target disk device in the error check flag 164 stored in the storage unit 160 to “FALSE” (step S306). If the free space is equal to or smaller than the threshold value B, the check flag of the target disk device in the error check flag 164 is set to “TRUE” (step S308).

  Next, the check cycle setting unit 120 sets the next check cycle using the first embodiment or the second embodiment of the check cycle setting process described above (step S310). Next, the capacity monitoring unit 130 determines whether or not the set check cycle has been reached (step S312). When the check cycle is reached, the capacity monitoring unit 130 returns to the process of step S302 and checks the free capacity of the disk. If the check cycle has not been reached, the capacity monitoring unit 130 determines whether a monitoring end request for the free capacity of the disk device has been received from the client 300 or the like (step S314). When the monitoring end request has not been received, the capacity monitoring unit 130 returns to the process of step S312. If a monitoring end request is received, the capacity monitoring unit 130 ends the capacity monitoring process. The process shown in FIG. 10 may be performed for each disk device in the database 200 or may be performed for all the disk devices at once. Further, the process shown in FIG. 10 can be executed as the disk capacity monitoring thread described above.

  Next, the SQL execution process in the process execution part 140 is demonstrated using a flowchart. FIG. 11 is a flowchart illustrating an example of the SQL execution process. In the following description, a process of writing data to the database 200 will be described as an example of the SQL execution process. However, a similar process may be performed for a data read process or the like. In the example of FIG. 11, the process execution unit 140 receives a data write request (step S400), refers to the check flag of the target disk device from the error check flag 164 stored in the storage unit 160, and checks the check flag. Is “TRUE” (step S402). When the error check flag is “TRUE”, the process execution unit 140 inquires of the free capacity of the disk device to the OS (control unit 150) or the like (step S404).

  Next, the process execution unit 140 determines whether or not the free space is larger than the threshold value C (step S406). When the free space is equal to or less than the threshold value C, the process execution unit 140 outputs a disk full error to the client 300 or the like (step S408). When the check flag of the target disk device is “FALSE” or when the free space is larger than the threshold C, the OS (control unit 150) or the like is requested to write data to the target disk device, and the data Is written (step S410). Note that the processing shown in FIG. 11 can be executed as the above-described SQL processing thread.

  In the above-described embodiment, the database management apparatus 100 performs monitoring based on the free capacity of each disk device included in the database 200. However, the present invention is not limited to this. For example, the used capacity of the disk device (disk Monitoring based on capacity) or usage rate may be performed.

  According to at least one of the embodiments described above, the capacity monitoring unit 130 that monitors the free capacity of the disk device that stores data, the free capacity of the disk device obtained by the capacity monitoring unit 130, and the predetermined write rate are written. By having the control unit 150 that outputs a disk full error based on the future free space capacity of the disk device in this case, it is possible to alert the free space at a more appropriate timing.

  Further, according to at least one embodiment, based on a request from the client 300, a process execution unit 140 that executes a process including writing or reading of data with respect to a disk device that stores data, and data by the process execution unit 140 By having a capacity monitoring unit 130 that confirms the free capacity of the disk device asynchronously with processing including writing or reading data, a system call is called each time an SQL process for writing or reading data is executed. Since there is no need to check the capacity, the SQL process can be speeded up, and the response time for the SQL process can be improved. Therefore, for example, when there are requests for registering a large amount of sensor data from a large number of clients 300 equipped with sensors or the like for the database management apparatus 100, the monitoring cost can be reduced and the processing performance can be improved. it can. Further, processing can be performed with priority given to the response time of the database management apparatus 100. In addition, it is possible to call attention regarding the free space at a more appropriate timing.

  In addition, according to at least one embodiment, based on the result of comparing the free capacity of the disk device that stores data and a threshold value related to the capacity, the period for checking the free capacity is changed, and at the changed period, By having a capacity monitoring unit 130 that acquires the free capacity of the disk device and a control unit 150 that outputs a disk full error based on the free capacity of the disk device obtained by the capacity monitoring unit 130, for example, there is a margin in the free capacity. If there is an error, the check cycle can be lengthened, and conversely, if the free space is likely to be insufficient, the check cycle can be shortened. Therefore, the monitoring cost can be reduced and the processing performance can be improved. In addition, it is possible to call attention regarding the free space at a more appropriate timing.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 100 ... Database management apparatus, 110 ... Setting information reception part (reception part), 120 ... Check period setting part (cycle setting part), 130 ... Capacity monitoring part, 140 ... Process execution part, 150 ... Control part, 160 ... Memory | storage part 162 ... Setting file, 164 ... Error check flag, 200 ... Database, 300 ... Client, 400 ... Disk vendor, 500 ... Disk capacity monitoring thread, 502 ... OS, 504 ... SQL processing thread

Claims (8)

A capacity monitoring unit for monitoring the free capacity of the storage device for storing data;
A control unit that outputs alert information relating to the free space based on the free space of the storage device obtained by the capacity monitoring unit and the free space of the storage device in the future when written at a predetermined write rate; ,
A cycle setting unit that sets a cycle in which the capacity monitoring unit checks the free capacity based on the free capacity of the storage device;
With
The period setting unit includes:
When the free space of the storage device is larger than a first threshold, the free space of the storage device, the first threshold, and the data capacity when written to the storage device at the predetermined write rate To set the period for checking the free space,
When the free space is equal to or less than the first threshold, and when the free space is larger than a second threshold smaller than the first threshold, the free space of the storage device and the second threshold Setting a period for checking the free capacity by discounting a value based on a threshold and a data capacity when written to the storage device at the predetermined write rate based on a predetermined safety rate;
Database management device. The predetermined write rate is a maximum write rate assumed for the storage device.
The database management device according to claim 1. A processing execution unit that executes processing including writing or reading of data to or from the storage device based on a request from a client;
The capacity monitoring unit confirms the free capacity asynchronously with processing including writing or reading of the data by the processing execution unit;
The database management apparatus according to claim 1 or 2. The capacity monitoring unit and the process execution unit operate by starting a thread that operates asynchronously,
The database management device according to claim 3. The period setting unit includes:
When the free space is equal to or less than the second threshold, set to check the free space at the timing of executing the process of writing data to the storage device,
The database management apparatus according to any one of claims 1 to 4. It further includes a reception unit for accepting an operator's input operation,
The cycle setting unit sets a cycle in which the capacity monitoring unit checks the free capacity based on one or more threshold values received by the receiving unit.
The database management device according to any one of claims 1 to 5. The computer of the database management device
Monitor the free space of the storage device that stores data,
Based on the free capacity of the storage device, set a cycle for checking the free capacity,
Based on the free space of the storage device and the free space of the storage device in the future when written at a predetermined write rate, output alert information about the free space,
Further, in the case of setting a cycle for checking the free space, when the free space of the storage device is larger than a first threshold, the free space of the storage device, the first threshold, and the storage device Using the data capacity when written at the predetermined write rate, and setting a cycle for checking the free capacity,
When the free space is equal to or less than the first threshold, and when the free space is larger than a second threshold smaller than the first threshold, the free space of the storage device and the second threshold Setting a period for checking the free capacity by discounting a value based on a threshold and a data capacity when written to the storage device at the predetermined write rate based on a predetermined safety rate;
Database management method. In the computer of the database management device,
Monitor the free space of the storage device that stores data,
Based on the free capacity of the storage device, to set a cycle for checking the free capacity,
Based on the free capacity of the storage device and the free capacity of the storage device in the future when written at a predetermined write rate, the alert information on the free capacity is output,
Further, in the case of setting a cycle for checking the free space, when the free space of the storage device is larger than a first threshold, the free space of the storage device, the first threshold, and the storage device Using the data capacity when written at the predetermined write rate, and setting a cycle for checking the free capacity,
When the free space is equal to or less than the first threshold, and when the free space is larger than a second threshold smaller than the first threshold, the free space of the storage device and the second threshold By setting a cycle for checking the free space by discounting a value based on a threshold and a data capacity when written to the storage device at the predetermined write rate based on a predetermined safety rate,
Database management program.

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