JP2004102631A - Database retrieving program, data base retrieval method and database retrieval device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the deterioration of the processing speed of a retrieval request for a non-uniform multiple database by a simple method. <P>SOLUTION: A retrieval request for a non-uniform multiple DB 27 or the like is divided by a retrieval request reception decomposing part 52, and a plurality of divided retrieval requests for a plurality of division unit data are generated, and registered in a common queue 80 in the order of the receiving time of the retrieval request. When the processing of the divided retrieval request newly registered in the common queue or the already inputted divided retrieval request is ended by any DB server device, whether or not any DB server device or the DB server in which the processing is ended fulfills a condition that the oldest divided retrieval request registered in the common queue is processable and a condition that the divided retrieval request is processable in parallel with another divided retrieval request under processing is decided. When those conditions are fulfilled, the divided retrieval request is inputted to the DB server device. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a database search program, a database search method, and a database search device for accessing a database stored in a non-uniform and multiple manner in a plurality of database server devices.
[0002]
[Prior art]
2. Description of the Related Art In an information retrieval system constructed on a network such as the Internet or an intranet, a large number of computers (database server devices) that store a database and control access to the database have a distributed configuration, so that the storage capacity per computer is increased. It is possible to construct a large-scale information database system without being limited by a platform such as a CPU, a CPU performance, and an OS. However, in such a large-scale information database system, the time required for information retrieval processing is generally very long. In particular, in the case of a multimedia information database system, the amount of data transferred as a search result also becomes large, a heavy load is imposed on a computer or a network, and the response time for one information search request tends to increase. In such a large-scale information database system, it is desired that the search processing speed is not significantly deteriorated even when information search requests are issued from a large number of client devices at the same time.
[0003]
For this reason, conventionally, in an information search system constructed as a client-server system or a WWW system, a method of distributed parallel processing and load distribution has been performed. That is, in the distributed parallel processing, different data is stored in different database server devices so that those data can be accessed in parallel, and a plurality of data in which a relatively large number of search requests are generated is provided. It is so-called multiplexed, and the multiplexed data is stored in different database server devices. This allows a plurality of search requests for the same data from different clients to be processed in parallel. Since the frequency of occurrence of a search request for data differs for each data, the degree of multiplexing differs depending on the data, and a database that is non-uniformly multiplexed in that sense is often used (for example, see Patent Document 1).
[0004]
[Patent Document 1]
JP-A-6-119383 (paragraphs 17 to 19, FIG. 5)
[0005]
Another form of heterogeneous multiplex database is to store different combinations of different databases in a plurality of database server devices. In such a database system, the multiplicity can be changed not in data units but in database units (units of data groups constituting the same database). For example, in a database system of a company, the head office stores masters of all databases, each branch stores a copy of a plurality of databases for each branch, and a plurality of databases in the branch are stored in the branch via an intranet. It can be used in. In some cases, the database for each branch stores a different database for each department in the database server for the department in accordance with the needs and frequency of use of a plurality of departments constituting the branch.
[0006]
For example, as an example of a database for each section related to map information, a database server apparatus for the first section stores a house map database, a road map database, and a city map database, and a database server apparatus for the second section. Stores a house map database, a road map database, a topographic map database, and a facility map database. The database server device for the third part stores a house map database, a road map database, a city map database, and a wide area map database. I do. Here, the facility map database is a database representing a facility map, which is a map of facilities provided inside or on the road. Each of the databases is composed of a plurality of data divided into a plurality of layers, and these data are overlapped to constitute one map.
[0007]
The members of each section proceed from the client apparatus by accessing a database server apparatus provided corresponding to the section to which the section belongs. For data not stored in the database server for one's own department, the data stored in the database server for another department in the same branch is used. As can be seen from the above example, the house map database and the road map database are stored in the database server device for each department, so that in each department, search requests from many client devices are sent to these databases. Is expected to occur. On the other hand, since the city map database is stored in the database server devices for the second and third parts, a search request for this database is expected to occur in these parts. The facility map database, the topographic map database, and the wide area map database are stored only in the database server devices for the second part, the second part, and the third part, respectively. Search requests to these databases reflect that they are expected to only come from members of the corresponding department.
[0008]
Load distribution distributes search requests from client devices to a plurality of computers so that the load on each computer is as uniform as possible, thereby preventing computers with extremely long processing times from occurring. It is. As typical methods of load distribution, a static load distribution method and a dynamic load distribution method are known. In an example of the static load distribution method, a search request from a client device is distributed to a plurality of computers having the same processing performance in a fixed order, and the actual load of each computer is not detected. One example of the method is a round robin method, in which a search request from a client device is cyclically distributed to a plurality of computers in a certain order. The dynamic load distribution method monitors loads such as a CPU load and an I / O load on each computer, and distributes a load as nearly as possible when a new search request is input from a client device. , The computer to which the data is to be input is dynamically selected. Since the above prior art related to load distribution is well known to those skilled in the art, the description of the prior art related to load distribution is omitted.
[0009]
[Problems to be solved by the invention]
In order to quickly process many search requests for a plurality of databases stored in the non-uniform multiplex and shorten the turn-around time, the search requests are distributed and executed by as many database server devices as possible, and the processing is performed accordingly. It is desirable not to make the time extremely large. Further, at this time, it is desirable to maximize the performance as much as possible without deteriorating the performance of each database server device.
[0010]
In order to apply a static load distribution method such as a round robin method to a plurality of database server devices, it is assumed that the same data is stored in each database server device. Therefore, in the case of a non-uniform multiplex database in which a combination of stored data is different for each database server device as in the map database server device exemplified above, the search request is simply and cyclically different from each other. Cannot be distributed to Further, even if the round robin method is applied in any form, the effect is small.
[0011]
Further, the round robin method is based on the premise that the processing load of a search request to each database server device is substantially uniform. However, the processing load of a search request usually differs depending on the database to be searched. Therefore, in the case of a database in which a plurality of map databases are stored in the same database server device as in the above-described map database server device, the processing load of a search request for each database server device is It depends on whether it is a search request for. Therefore, even if the same number of search requests are input to each database server device, the processing load of the plurality of database server devices is different, so that the effect cannot be expected by the round robin method. Similarly, when the database processing apparatuses have different hardware processing capabilities (CPU, memory, disk speed, and the like), the effect cannot be expected by the round robin method.
[0012]
On the other hand, in the dynamic load distribution method, all database server devices do not necessarily have to have the same performance, but the problem is how to predict the load. There is a problem with accuracy. Further, the processing load for monitoring the load of each database server device and estimating the load of a search request to be submitted becomes large, and as a result, the performance of each database server device is reduced. There is also a problem that an adverse effect occurs and the processing time of the search request does not decrease so much, and there is a problem that dynamic load distribution is not always effective.
[0013]
As a result, in the related art, it is not possible to appropriately determine which database server device should be used to input a new search request for a heterogeneous multiplex database.
[0014]
In general, each database server device can process different search requests in parallel by a multi-thread function using a plurality of threads. However, when a search request is input beyond the limit value of the number of threads, the received search request is registered in an internal queue provided in the database server apparatus, and is kept in a waiting state. For this reason, a search request input to any one of the database server devices is not always executed immediately, and the database server device may be kept in a processing waiting state for a long time.
[0015]
In a state where such a waiting state occurs, even if an additional search request is input to the same database server device, it is similarly registered only in the internal queue, and the processing is not started. Therefore, maintaining the search request in the waiting state in the database server device only apparently inputs the search request to the database server device, and does not reduce the processing time. On the contrary, before the database server apparatus can process the search request, there is a possibility that another database server apparatus can process the same search request. The processing speed time is reduced when the data is input to another database server device. Therefore, the start of the processing of the search request is delayed by inputting the search request to the preceding database server apparatus, and as a result, the processing time is increased.
[0016]
In the present invention, in consideration of the above-described problems of the related art, a plurality of search requests for a plurality of databases stored in a non-uniform manner in a plurality of database servers can be distributed and input, and the processing speed can be increased. It is an object of the present invention to provide a database search program, a database search method, and a database search device that can suppress the deterioration of a database by a simple method.
[0017]
[Means for Solving the Problems]
In order to achieve the above object, a database search program according to the present invention is programmed to cause a computer to execute the following steps. That is, a search request received from any client device for a non-uniform multiplex database composed of a plurality of databases each having a different combination of a plurality of divided unit data and stored in a plurality of database server devices, respectively. It divides and generates a plurality of divided search requests each requesting a search for one of the plurality of divided unit data. The generated plurality of divided search requests are stored in a common queue provided commonly to the plurality of database server devices so that the order of the reception times of the search requests from which the respective divided search requests are generated can be identified. register.
Further, each time a plurality of divided search requests are newly registered in the common queue, the plurality of divided search requests are sequentially selected, and a processable condition that the selected divided search request can be processed, One or more database server devices that can be additionally input that satisfy the parallel processing enabling condition that the selected divided search request can be processed in parallel with the other divided search requests in it are determined, and the additional input can be performed by the determination. Then, the selected divided search request is additionally input to one database server device or one of the plurality of database server devices determined to be.
Further, in synchronization with the termination of the processing of any of the divided search requests by any of the database server devices, the oldest divided search requests satisfying the processable condition and the parallel processable condition are output from the common queue. And then submit it to the database server device.
[0018]
Thus, a plurality of divided search requests obtained by dividing a newly generated search request can be processed in parallel by a plurality of database server devices. Can be processed under the condition that it can be processed, so that it is possible to prevent a search request from being input to one of the database server devices and being kept in a waiting state in the database server device. Can be suppressed, and the processing time of the search request can be shortened.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, some embodiments of a database search program, a database search method, and a database search device according to the present invention will be described. It should be noted that only differences from the first embodiment will be described after the second embodiment.
[0020]
<First Embodiment of the Invention>
FIG. 1 is a schematic configuration diagram of an information search system using a database search program according to the present invention. The information search system 1 includes a search server device 10, a plurality of database server devices 21, 22, 23,..., A network 30 such as an intranet or the Internet connecting them, and a plurality of clients connected to the network 30. Device 40. Although only one client device 40 is shown in the figure for simplicity, a plurality of client devices can be used in practice.
[0021]
The database server 21 stores a database management program (DBMS) 24 and a database 27. The database management program 24 is a program that executes a search command for the database transmitted from the search server device 10 to the database 27, and returns an obtained search result to the search server device 10. Similarly, the database server 22 stores a database management program 25 and a database 28, and the database server 23 stores a database management program 26 and a database 29.
[0022]
As will be described later, one embodiment of the database search program according to the present invention is used in the search server device 10, and the program and the search server device 10 use one embodiment of the database search method according to the present invention. The embodiment is used, and the search server device 10 realizes one embodiment of the database search device according to the present invention. Although one search server device 10 is provided in common for the plurality of database server devices 21, 22, and 23, a plurality of search server devices may be provided.
[0023]
In the following, it is assumed that the database 27 and the like stored in each of the database server devices 21 and the like are map databases. However, the invention is not limited to such a database. For example, as described in Japanese Patent Application Laid-Open No. 2000-81839, a map database generally includes data of a plurality of layers, and an area on a map is divided into meshes of a plurality of unit sizes. A plurality of layers of data belonging to each layer can be read.
[0024]
When the user uses the map database, from the client device 40, when specifying the type of the map information to be used and the information for specifying the area for which the map information is to be used, for example, the lot number or the area name, the database 27, 28 or 29 Data of a plurality of layers belonging to one mesh including the lot number is read out, or information of a plurality of layers belonging to each mesh is obtained for each of a plurality of meshes constituting an area of the designated area name. Is output, and information of a plurality of layers is combined with the information and displayed on the display screen of the client device.
[0025]
Hereinafter, for simplification, a case will be described in which a search request specified by a user requests a search for map information belonging to one mesh. When the search request specified by the user requests a search for map information belonging to a plurality of meshes, the process described below for map information belonging to one mesh may be repeated by the number of meshes. In the above-mentioned publication, the user can specify a layer to be output among information of all layers included in the map database, but the present embodiment can also make it. .
[0026]
In the present embodiment, it is assumed that a plurality of types of map databases are used as the map database. For example, a house map database, a road map database, a facility map database, and the like described in the related art. It is further assumed that each map database comprises a plurality of stratified data for a plurality of layers. Each database server device stores a plurality of stratified data of each of a plurality of map databases. The same map database may be stored in a plurality of database server devices, but some map databases may not be stored in some database server devices.
[0027]
Even when the same map database is stored in different database server devices, different sets of a plurality of stratified data constituting the map database may be stored in the plurality of database server devices. Accordingly, the databases 27, 28, and 29 stored in the plurality of database server devices 21, 22, and 23 may partially differ in the type of the map database included therein, but in the sense that some are the same. It is a heterogeneous multiplex database. Further, even when the same map database is stored in a plurality of database server devices 21 or the like, the database is a non-uniform multiplex database in the sense that the stored stratified data may be different depending on the database server device.
[0028]
In the present embodiment, the following description will be made on the assumption that a plurality of map databases are stored in a plurality of database server devices 21 or the like in a non-uniform multiplex manner, but the technology used in the present embodiment will be described. Can also be used in a case where stratified data of different layers of a single map database are stored in a non-uniform multiplex manner in each database server device 21 or the like.
[0029]
Which map database is to be stored in multiplex or which of the plurality of stratified data constituting the map database to be stored in multiplex is stored in multiplex depending on the frequency of use of each map database and Can be determined by the frequency of use of the stratified data.
[0030]
In the present embodiment, as described in detail below, a search request from a user is divided into a plurality of divided search requests each requesting one of a plurality of stratified data of any of the map databases requested by the user. And each divided search request is processed in parallel. In this sense, the stratified data is data that is a unit of division of a search request, and such a data unit is referred to as division unit data in this specification.
[0031]
The database server device 21 and the like can process a plurality of search requests in parallel under a certain condition by a multi-thread function. The division unit data is a constituent unit of the map database, and at least a plurality of division search requests relating to different division unit data can be processed in parallel using a plurality of threads as division unit data.
[0032]
In the search server device 10, a database search program 50 is stored and executed. The database search program 50 receives a search request output from the client device 40 and divides the received search request into a plurality of divided search requests. Unit 52, a search request input control unit 53 for inputting each divided search request to one of the databases, an input possibility determination unit 54 for determining the input possibility of the divided search request to the database, and a divided search for each database A database-based input status monitoring unit 55 for monitoring a request input status, a database communication unit 56 for communicating with a database server device, and a plurality of divided search requests generated from one search request from a user; A plurality of search result data output from the database server device 21 etc. Is transmitted to the user of the client device 40 includes a program part such as a search result combining unit 57.
[0033]
When a search request is input from the search server device 10 to the database server device 21 or the like, the database management program 24 in the database server device 21 or the like transmits the split search request to a database stored in the database server device 21 or the like. In this specification, inputting a divided search request from the search server device 10 to the database server device 21 or the like is simply referred to as inputting a divided search request to a database stored in the database server device 21 or the like, or simply This is sometimes referred to as submitting a divided search request to a database.
[0034]
Further, the database search program 50 obtains the division unit data arrangement information 60 indicating the division unit data included in the database 27 and the like provided in each of the database server devices 21 and the like, and monitoring by the database-based input status monitoring unit 55. A database-based input status table 70 indicating the input status of the divided search requests for each database, a common queue 80 for registering the divided search requests generated by division from the search requests output from the same user, The information includes information such as a search result management table 90 for managing the reception status of a plurality of search result data 91 for a divided search request generated by division from a search request output from the same user.
[0035]
FIG. 2 is a diagram showing an example of the division unit data arrangement information 60. The division unit data arrangement information 60 is information indicating division unit data included in the database 27 or the like provided in each database server device 21 or the like. In the figure, a database # field 601 stores numbers DB # 1, DB # 2, and DB # 3 of databases 27, 28, and 29 that can be searched by the search server device 10. In the figure, reference numerals 27 etc. of the respective databases 27 etc. are also described in parentheses. The division unit data arrangement status storage field 602 indicates whether or not the division unit data of each division unit data # is arranged in each of the databases 27, 28, and 29. A circle mark is stored or remains blank corresponding to each division unit data #. A circle indicates that the corresponding division unit data is arranged in each of the databases 27, 28, and 29.
[0036]
In the figure, division unit data # 1 is included in any of databases 27, 28, and 29, division unit data # 2 is included in databases 28 and 29, and division unit data # 3 is included in databases 27 and 29. And the division unit data # 4 and # 5 are included in the databases 27 and 28. Division unit data # 6 and # 8 are included only in database 28, division unit data # 7 is included only in database 27, and division unit data # 9 is included only in database 29.
[0037]
In FIG. 2, a priority 603 is further stored for each division unit data. Here, the priority is determined in inverse proportion to the multiplicity of the divided unit data corresponding to each divided unit data. For example, in the example shown in the figure, since the division unit data # 1 can be processed by three databases, the priority is set to 1/3. Since the division unit data # 2 can be processed by two databases, the priority is set to 1/2. Since the division unit data # 7 can be processed by only one database, the priority is set to 1/1. Such a priority is such that when a plurality of divided search requests registered in the common queue 80 (FIG. 1) at the same time can be input to any database, one divided search request to be input to that database is determined. It can be used for selection criteria.
[0038]
FIG. 3 is a diagram showing an example of the database-based input status table 70 usable in the present embodiment. The database-based input status table 70 indicates the input status of the divided search request for each database obtained by monitoring by the database-based input status monitor 55. As is usually the case, also in the present embodiment, each database server device 21 and the like processes a plurality of received search requests (in the present embodiment, divided search requests) using different threads. A threshold value of the number of usable threads is determined for each database server device. In the present embodiment, when the total number of threads for the divided search request input to the database server device does not exceed the threshold value, Are assumed to be processed in parallel. When the threshold value of the total number of threads that can be used is different from the threshold value of the total number of threads that can be processed in parallel, the latter threshold value is used. Therefore, in the present embodiment, the threshold value of the total number of threads is the threshold value of the total number of threads that can be processed in parallel.
[0039]
In the database-specific input status table 70, a field 701 for storing a threshold value of the total number of threads that can be processed in parallel in the database corresponding to each of the databases 27, 28, 29, and a field for storing the number of input divided search requests 702 and a field 703 storing an entry prohibition flag indicating whether or not the corresponding database is in a state of prohibiting new entry of a divided search request. When the value of this flag is 1, it indicates a closing prohibition state.
[0040]
The database-based input status monitoring unit 55 sets the threshold value of the total number of threads that can be processed in parallel determined by the database server device 21 or the like in which each database 27 or the like is stored in the field 701 of the database-based input status table 70 as an initial value. To be stored. Further, when a new divided search request is input to any database by the search request input control unit 53, the number of input divided search requests in the field 702 corresponding to the database is increased by one.
[0041]
Further, when the processing of any of the input divided search requests is completed in any of the database server devices 21 and the like, the database server device 21 and the like transmits the search result data to the search server device 10. In the search server device 10, when the database communication unit 56 receives the search result data, the database communication unit 56 notifies the search result data to the search result combining unit 57, and further receives the search result data and transmits the search result data to the database server. The identification information of the device is notified to the search request input control unit 53 and the input status monitoring unit 55 for each database. Upon receiving this notification, the database-based input status monitoring unit 55 decreases the number of input divided search requests in the field 702 corresponding to the database included in the database server device by one.
[0042]
When the number of input divided search requests in the field 702 for any database is changed, the input status monitoring unit 55 for each database changes the number of input divided search requests in the field 701 for the same database as the number of input divided search requests in the field 702. When the number of input divided search requests in the field 702 becomes equal to the threshold of the total number of threads in the field 701, the entry prohibition flag in the field 703 for the same database is set to 1.
[0043]
On the other hand, when the number of input divided search requests in the field 702 becomes equal to or less than the threshold value of the total number of threads in the field 701, the input prohibition flag in the field 703 for the same database is set to 0. In this way, a new divided search request can be input to the database whose input prohibition flag is 0. Further, when the new divided search request is input, a plurality of divided search requests already input to the same database can be input. It will be processed in parallel with the search request.
[0044]
When an ordinary database server device receives a number of search requests exceeding the threshold value, it registers the received search requests in an internal queue (not shown) in the database server device. However, in the present embodiment, the total number of threads used by the database server device 21 or the like is set to the threshold value in order to avoid maintaining the divided search request in a waiting state inside the database server device 21 or the like. When the search request is reached, the search request input control unit 53 does not input a new divided search request to the database server device 21 or the like.
[0045]
In the present embodiment, it is assumed that each database server device 21 and the like can process a plurality of divided search requests in parallel using a plurality of threads within a range not exceeding a threshold value of the total number of threads determined by the database server device 21 or the like. I have. Therefore, in the present embodiment, when a plurality of divided search requests input to each database server device 21 and the like are input, they are processed in parallel with the already input divided search requests. That is, when the search request input control unit 53 inputs a new divided search request to the database server device 21 or the like, the search condition can be processed by the database server device 21 or the like. The division unit data requested by the divided search request is included in the database 27 or the like stored in the database server device 21 or the like), and the new divided search request is processed in parallel with the inputted divided search request. It is confirmed that the condition for parallel processing is satisfied.
[0046]
FIG. 4 is a schematic block diagram of the client device 40. The client device 40 includes a processing device 41, an input device 42 including a data input unit such as a pointing device such as a mouse and a keyboard, and a display device 43 such as a CRT. The processing device 41 includes a map display program 44 and a web browser program. 45 is executed. The map display program 44 includes a search control processing unit 441, a map information display processing unit 442, and the like. In the client device 40, the user inputs the name of the map database to be searched and information specifying the area to be displayed in the map database by the search control processing unit 441. It is transmitted to the search server device 10 by the control processing unit 441. The map information display processing unit 442 receives a series of search result data transmitted from the search server device 10, generates map information indicated by each data, superimposes the map information, and superimposes the map information on the display device 43. Display.
[0047]
The search request specified by the user is processed as follows. In the search server device 10, when the client device communication unit 51 receives the search request from the client device 40, the client device communication unit 51 assigns a user identification number (user ID) to the user, and the search request And the time at which the search request was received (request reception time). The search request receiving and disassembling unit 52 receives the received search request, assigns a request registration number, and registers the received search request in the search result management table 90. The contents of the search result management table 90 will be described later. Further, the search request reception decomposing unit 52 decomposes the search request into a plurality of divided search requests, and stores the request registration number, the plurality of divided search requests, the user ID, and the request reception time in the common queue 80. Register with. Each divided search request includes information for specifying the divided unit data to be searched and other information used for the search.
[0048]
FIG. 5 is a diagram illustrating an example of the common queue 80. In the figure, 801, 802, 803,... Are areas for storing a plurality of search requests obtained by dividing one search request, respectively, and the areas 801, 802, 803,. The information about the search request is stored. In each area 801 and the like, a field 811 for storing a request registration number and a field for storing user identification information (simply indicated by ID1, ID2, and the like in the figure) assigned to the user who issued the search request. 812, a field 813 for storing a plurality of divided search requests for each of the plurality of divided unit data corresponding to the plurality of divided unit data, and a search request serving as a source of the plurality of divided search requests are received by the client communication unit 51. And a field 814 for storing a request reception time indicating the time when the request was made. Note that the request reception time may use another time, for example, a time when the search request is decomposed into a plurality of search requests by the search request reception decomposing unit and the divided search requests are registered in the common queue 80. Good.
[0049]
In the figure, it can be seen that the user ID of the first search request is ID1 and the user ID of the second search request is ID2. In the field 813, a circle mark is stored for a division unit data for which a division search request is made among a plurality of division unit data. Four divided search requests for the division unit data # 1, 3, 5, and 6 are generated and registered from the first search request. Similarly, five division search requests for division unit data # 2, 3, 4, 6, and 8 are generated and registered from the second search request.
[0050]
FIG. 6 is a schematic flowchart of a part of the processing of the search request input control unit 53. FIG. 7 is a schematic flowchart of another part of the process of the search request input control unit 53. First, the search request input control unit 53 checks whether or not the processing of the divided search request input to any of the database server devices 21 or the like has been completed (step S531). When the processing of the divided search request that has been input by any of the database server devices 21 or the like ends, the search result is notified to the search server device 10 as described above, and the search request input control unit 53 also sends the relevant database server. Since the reception of the search result from the device 21 or the like is notified, the search request input control unit 53 can know that the processing of the input divided search request has been completed when the reception notification is received.
[0051]
If it is determined in step S531 that the processing of the divided search request that has been input to any of the databases has not been completed, the process proceeds to step S537. When it is determined in step S531 that the processing of the divided search request that has been input to any of the databases has been completed, in synchronization with the completion, the processing of the plurality of divided search requests in the common queue 80 is performed as follows. Therefore, the divided search request that can be input to the database is detected with priority given to the oldest search request.
[0052]
Specifically, in order to specify the oldest divided search request in the common queue 80, for example, the oldest request registration number 811 (FIG. 5) is specified as an argument, and the database is also specified as an argument and input. The possibility determination unit 54 is called (step S532), and the input possibility determination unit 54 determines whether the divided search request having the request registration number can be input to the database.
[0053]
When the database and the request registration number are specified as arguments, the input possibility determination unit 54 reads one or a plurality of divided search requests having the request registration number from the common queue 80, and reads the plurality of divided search requests. When the search is performed, a divided search request that can be input to the database specified by the argument is detected from the plurality of divided search requests. Here, the split search request that can be input means that the division unit data requested by the split search request is included in the database specified by the argument, and thus the split search request can be processed by the database. It satisfies the condition. Furthermore, the entry prohibition flag 703 (FIG. 3) of the database is off, and therefore, even if the divided search request is entered into the database, the divided search request is executed in parallel with other divided search requests already entered in the database. Satisfies the condition that the parallel processing is possible.
[0054]
When it is determined that a plurality of split search requests can be input, the input possibility determination unit 54 selects one of the plurality of input search requests that can be input based on a predetermined criterion. For this selection criterion, for example, the priority 603 shown in FIG. 2 can be used. That is, a division search request that requests the division unit data with the highest priority may be selected from among the plurality of division unit data included in the input destination database.
[0055]
Since the division unit data having a higher priority is not included in another database server device, the possibility that a division search request requesting the division unit data is processed by another database is caused by the division unit data having a lower priority. Lower. Therefore, it is presumed that it is desirable to input a divided search request requesting division unit data having a high priority first among a plurality of divided search requests determined to be inputtable. When there are a plurality of division search requests requesting the division unit data having the highest priority, one of them may be selected by an appropriate method.
[0056]
The input possibility determination unit 54 determines the request registration number previously notified from the search request input control unit 53 and information for identifying the selected one divided search request (for example, the division unit data requested by the divided search request). No.) and the identification information of the database of the input destination previously notified from the search request input control unit 53 are notified to the search request input control unit 53 together.
[0057]
In step S533, the search request input control unit 53 determines whether the input possibility determination unit 54 has detected a split search request that can be input. If no split search request that can be input is detected, it is determined whether a split search request with the next oldest request registration number is registered in the common queue 80 (step S534). One or more divided search requests having the next oldest request registration number registered in the common queue 80 are changed to the processing target (step S535), and the above-described step S532 and subsequent steps are repeated for those divided search requests. . If it is determined in step S534 that the divided search request of the next oldest request registration number has not been registered in the common queue 80 (No in step S534), the process proceeds to step S537.
[0058]
In step S533, when it is determined by the input possibility determining unit 54 that an inputtable divided search request has been detected, the inputtable split search request notified by the input possibility determining unit 54 is extracted from the common queue 80, It is input to the database server device 21 or the like that stores the database after the above processing is completed (step S536). Thereafter, the process proceeds to step S537.
[0059]
In step S537, it is determined whether a new divided search request has been registered in the common queue 80. Here, the newly registered divided search request refers to a plurality of divided search requests received by the client communication unit 51 at times after the checked request reception time stored by the search request input control unit 53 and obtained by division. The search request is a divided search request registered in the common queue 80. As will be described later, the search request input control unit 53 checks whether the divided search requests registered in the common queue 80 can be input to any one of the databases in order from the oldest registered divided search request. The checked request reception time is the time at which the client communication unit 51 receives the latest divided search request registered in the common queue 80 among the divided search requests for which the search request input control unit 53 has checked the input possibility. It is. When the search request input control unit 53 subsequently checks the possibility of inputting the divided search request newly registered in the common queue 80, the search request input control unit 53 checks the divided search request having the request reception time 814 (FIG. 5) after the above time. Good.
[0060]
If it is determined in step S537 that the new divided search request has not been registered in the common queue 80, the process proceeds to step S531. If it is determined in step S537 that a new divided search request is registered, the oldest divided search request determined to be newly registered is received by the client communication unit 51 as a checked request reception time. The stored time is stored (step S538 in FIG. 7). Thereafter, the input possibility determining unit 54 is called by designating the request registration number of the divided search request received at the oldest time determined to be newly registered in the common queue 80 as an argument (step S539), The input possibility determination unit 54 determines whether the divided search request having the request registration number can be input to any database. When there are a plurality of divided search requests registered in the common queue 80 at the same time, the input possibility determination unit 54 simultaneously determines whether or not each of the divided search requests can be input to any one of the databases.
[0061]
Although the request registration number is specified by the argument, unlike the case where the request registration number is called in step S532, if the input destination database is not specified by the argument, the input possibility determination unit 54 determines from all the databases. Detect databases that are ready to be submitted and select split search requests that can be submitted to those databases that are ready to be submitted.
[0062]
That is, one or a plurality of divided search requests having the request registration number are read from the common queue 80, and when a plurality of the divided search requests are read, it can be input to any one of the plurality of the divided search requests. A complex split search request. Here, the database that can be input is a database that includes the division unit data requested by the divided search request (processable condition), and the input prohibition flag 703 (FIG. 3) of the database is off. That is, the database satisfies the parallel processing condition.
[0063]
As described in the case where it is called in step S532, when it is determined that a plurality of split search requests can be input, the input possibility determination unit 54 determines one of the plurality of input search requests in advance. Select based on the criteria For this selection criterion, for example, the priority 603 shown in FIG. 2 can be used. That is, since the division unit data having a higher priority is not included in another database server device, the division search request requesting the division unit data is not likely to be processed by another database. Lower than the data. Therefore, it is presumed that it is desirable to input a divided search request requesting division unit data having a high priority first among a plurality of divided search requests determined to be inputtable. When there are a plurality of division search requests requesting the division unit data having the highest priority, one of them may be selected by an appropriate method.
[0064]
The input possibility determination unit 54 determines the request registration number previously notified from the search request input control unit 53 and information for identifying the selected one divided search request (for example, the division unit data requested by the divided search request). ) And the identification information of the database of the input destination determined to be inputtable, together with the search request input control unit 53.
[0065]
In the search request input control unit 53, it is determined whether the input possibility determination unit 54 has detected the inputtable divided search request (step S540). When no split search request that can be input is detected, it is determined whether there is a split search request having the next oldest request registration number newly registered in the common queue 80 (step S541) and registered. If so, the plurality of divided search requests having the next oldest request registration number registered in the common queue 80 are changed to processing targets (step S542), and thereafter, the process proceeds to step S538.
[0066]
In step S538, the request reception time 814 (FIG. 5) of the divided search request having the registration number changed to the processing target is stored as the checked request reception time, and each divided search request changed to the processing target is further stored. Are repeated from step S539. If it is determined in step S541 that the next oldest divided search request is not registered in the common queue 80 (No in step S541), the process proceeds to step S531 (FIG. 6).
[0067]
If it is determined in step S540 that the input possibility determination unit 54 has detected the inputtable divided search request, the input possible search request notified by the input possibility determination unit 54 is extracted from the common queue 80, and The database is entered into the database server device that stores the database that can be entered, which is notified from the entry possibility determination unit 54 (step S543). Thereafter, the process proceeds to step S531.
[0068]
In this way, each time the processing of a divided search request that has already been input to one of the databases is completed, a split search request that can be input is selected from the input divided search requests and input. Therefore, in the processed database, the newly input divided search request is also processed in parallel with the already input divided search request, so that the processing speed of the database server device storing the database is reduced. I will not. Moreover, since a new divided search request is input to the database after the processing of one divided search request is completed, it can be seen that the processing load does not increase significantly.
[0069]
Further, each time a search request is newly received from a client device and a plurality of divided search requests are newly registered in the common queue 80, a split search request that can be input among them is detected, and such a divided search request is detected. If there is a search request, the divided search request is input to an appropriate database. At this time, as the input condition, the input prohibition flag for the input destination database is off. Therefore, even if a new split search request is added and input, the split search request is not the same as the already input split search request. Since processing is performed in parallel, it is expected that the processing speed will not decrease.
[0070]
FIG. 8 is a diagram showing an example of the search result management table 90 for one of the search requests. The search result management table 90 is generated by the search request accepting / disassembling unit 52 in response to any search request received by the search request accepting / disassembling unit 52. The search result management table 90 is similarly generated for other search requests, but only one search result management table 90 is illustrated in the figure.
[0071]
The search result management table 90 includes a field 901 for storing a user ID, a field 902 for storing a request registration number, a field 903 for storing a request flag indicating the presence or absence of a divided search request for each divided unit data, A field 904 for storing the total number, a field 905 for storing a completion flag indicating whether or not the search by each divided search request has been completed, a field 906 for storing the total number of uncompleted divided search requests (the number of incomplete), A field 907 for storing an address (search result data pointer) of a memory of the search server device 10 in which search result data obtained by the completed divided search request is stored is provided. Update of the search result management table 90 is managed by the search result combining unit 57.
[0072]
When the search result management table 90 is generated by the search request reception / disassembly unit 52, the user ID is stored in the field 901 and the request registration number assigned to the search request is stored in the field 902. In the field 903, flags corresponding to a plurality of divided search requests generated from the search request are set to 1. The field 904 stores the total number of generated divided search requests, the field 905 stores a value of 0 as an initial value of a completion flag for each divided search request, and the field 906 stores an initial value of an uncompleted number. Is stored as the total number of divided search requests in the field 904. Nothing is stored in the field 907 at this time.
[0073]
As shown in FIG. 3B, the search result data 91 for each divided search request includes the identification information (user ID) 911 of the user who issued the divided search request and the divided unit data requested by the divided search request. 912, the data length 913 of the data 914 obtained by the search, and the data 914.
[0074]
The user ID (911) is the user ID stored in the common queue 80 for the divided search request when the search request input control unit 53 submits the divided search request to any one of the database server devices. Is input together with the divided search request, and the database server 21 or the like at the input destination attaches the user ID to the search result data when returning the search result data obtained by the search to the search server 10. Has become. The division unit data number 912 in the search result data 91 is included in the divided search request input to any one of the database server devices, and the input destination database server device is obtained by the search. When the search result data is returned to the search server device 10, the search result data is given the number 912 of the division unit data.
[0075]
FIG. 9 is a schematic flowchart of the processing of the search result combining unit 57. First, it is checked whether or not search result data for a search requested by any of the divided search requests has been received from any of the databases (step S571). If not, the same step S571 is repeated. When the search result data is received, the search result data pointer 907 (FIG. 9) corresponding to the division unit data # added to the search result data in the search completion management table for the user ID added to the search result data. 8), the address of the received search result data (the address of a memory (not shown) in the search server device 10 where the search result data is stored) is stored (step S572). Similarly, the search completion flag 905 corresponding to the division unit data # is turned on (step S573), and the unfinished number 906 in the table is reduced by 1 (step S574).
[0076]
Further, it is determined whether or not the unfinished number 906 is 0 (step S575). If the unfinished number 906 is not 0, the process returns to step S571, and waits for reception of new search result data. If it is determined in step S575 that the unfinished number 906 is 0, the plurality of search result data 91,... Is stored in the memory (not shown) in the search server device 10 using the plurality of search result data pointers stored in the field 908. Are added to the search result data 91,... And the user ID stored in the field 901 is output to the client device communication unit 51 (step S576), and the search result management table 90 is deleted (step S576). (Step S577) Then, the process returns to step S571.
[0077]
The client device communication unit 51 determines the client device 40 of the transmission destination based on the user ID added to the plurality of output search result data, and transmits a series of search result data 91 thereto. In the client device 40, as shown in FIG. 4, the map information display processing unit 442 receives the above series of search result data, generates map information indicated by each data, and superimposes the map information. Is displayed on the display device 43.
[0078]
As described above, a search request requesting a search for a plurality of divided unit data stored in a non-uniformly multiplexed manner in a plurality of database server devices 21 and the like is divided into a plurality of divided search requests. Under the condition that the performance of the device 21 or the like is not deteriorated, it is possible to process as many divided search requests as possible in parallel, and the processing speed of the search request itself does not decrease.
[0079]
<Second Embodiment of the Invention>
In the first embodiment, it is assumed that a plurality of divided search requests are processed in parallel as long as a thread that is equal to or less than a threshold of the total number of threads that can be input to each database server device is used. However, in an actual database server device, even if the total number of threads does not exceed the threshold, the former is parallel to the latter depending on the relationship between the divided search request to be submitted and the submitted divided search request. May not be processed.
[0080]
For example, when the divided unit data requested by a subsequent divided search request to be input matches the divided unit data used by any of the input preceding divided search requests, the divided unit data according to the preceding divided search request is used. Until the use of the divided unit data is completed, the subsequent divided search request may not be processed in parallel with the divided search request. Therefore, when the subsequent division search request is input, the division unit data is provided in the database server device in which the division unit data is stored and registered in the waiting queue.
[0081]
Therefore, in the present embodiment, when determining the input possibility, a database search program, a database search method, and a database search device that more closely reflect the parallel processing possibility executed by the input destination database server device. Show. More specifically, in the present embodiment, the relationship between a plurality of input divided search requests that have been input and the subsequent divided search requests to be input is checked, and the subsequent divided search request It is possible to determine whether it can be processed in parallel with the search request.
[0082]
FIG. 10 is a diagram showing an example of the database-based input status table 70A usable in the present embodiment. The database-based input status table 70A is provided with fields 701 to 703 in the same manner as the database-based input status table 70 shown in FIG. 3, and further uses division unit data in the database corresponding to each database. A field 704 is provided for storing a division unit data in use flag indicating whether or not the data is medium. However, the total number of threads stored in the field 702 is a threshold value of the total number of threads that can be used simultaneously by each database, and it may be determined whether or not threads below the threshold value are processed in parallel.
[0083]
In the field 704, a value 1 is stored for the division unit data used by any of the input division search requests. When the search request input control unit 53 inputs any of the divided search requests to any of the databases, the database-specific input status monitoring unit 55 (FIG. 1) transmits the data to the database in the database-specific input status table 70A. The flag 1 is stored for the division unit data requested by the division search request in the corresponding field 703. Further, when the processing of any of the divided search requests is completed in any of the databases, the value of the flag for the division unit data requested by the divided search request in the field 703 corresponding to the database in the database-specific input status table 70A To 0.
[0084]
In the present embodiment, when the split search request satisfies the following two conditions, the input possibility determination unit 54 determines that the split search request can be input. First, as in the first embodiment, the first condition is that the division unit data requested by the divided search request to be input is included in the input destination database (processable condition). Further, the parallel processing possible condition of the input destination database is checked. This parallel processing possible condition is composed of two conditions. First, the first condition is that the number of input divided search requests in the field 702 does not exceed the threshold value of the total number of threads in the field 701, and therefore, the input prohibition flag in the field 703 is 0. That is, the input destination database is in a state where a new divided search request can be input. Further, the second condition is that the division unit data requested by the division search request to be input is the same as the division unit data in use stored in the field 704 for the input destination database in the database-specific input status table 70A. They do not match. When this condition is satisfied, the divided search request to be submitted does not collide with the divided unit data being used by the entered divided search request. It can be seen that the request is processed in parallel with the divided search request.
[0085]
By judging the input possibility in this way, not only the number of used threads but also the collision of the divided unit data requested by the preceding divided search request and the subsequent divided search request to be input occurs. It is possible to determine whether or not it is. That is, by making the input possibility determination unit 54 check whether or not the parallel processing enabled condition, which is performed by the database server device of the input destination, is satisfied, the search server device 10 can more accurately satisfy the parallel processing enabled condition. It is possible to determine whether or not each of the database server devices 21 and the like can process a large number of divided search requests without lowering the performance.
[0086]
When each database server device decides whether or not to start processing a new divided search request as a new thread, it tries to start processing with the divided unit data used by the divided search request being processed. In some cases, conditions different from the presence / absence of collision with the division unit data used by the subsequent divided search request may be considered. For example, even if a division unit data is used in response to a division search request, the division unit data may actually be further divided into a plurality of partial areas, and only one of the partial areas may be used. .
[0087]
Even though the preceding divided search request and the subsequent divided search request require the same divided unit data, if they request different partial areas in the divided unit data, those divided search requests can be processed in parallel. It may be done. In such a case, a flag indicating whether or not each divided unit data is in use is stored in the divided unit data in use flag 704 in the database-based input status table 70A in correspondence with the plurality of partial areas of each divided unit data. Whether the preceding divided search request can be processed in parallel with the preceding divided search request depending on whether the preceding divided search request and the subsequent divided search request require the same partial area of the same divided unit data. May be determined.
[0088]
<Third Embodiment of the Invention>
In the above embodiment, the search result combining unit 57 confirms that the search result combining unit 57 has obtained all of the plurality of search result data for the plurality of divided search requests generated from the search request from the same user. After that, the search result data is transferred to the requesting client device 40 as a whole.
[0089]
In the present embodiment, a database search program and a database search that transmit the obtained search result data to the requesting client device each time the search result data is obtained without combining the plurality of search result data 1 shows a method and a database search device.
[0090]
That is, the search result combining unit 57 and the search result management table 90 used in the first embodiment are not used on the search server device 10, and any of the search result data can be obtained by any of the database server devices. Each time, the obtained search result data is directly transmitted from the database server device to the requesting client device without passing through the search server device 10. For this reason, when submitting any of the divided search requests to any of the database server devices, the search server device 10 sends the user ID and the IP address of the client device together with the divided search request to the database server device. Send.
[0091]
When the search result data is obtained in response to any of the divided search requests in any of the database server devices 21 or the like, the database server device uses the IP address of the client device received in response to the divided search request. The search result data is transmitted to the requesting client device via the network 30, and the search server device 10 is notified that the processing of the divided search request has been completed.
[0092]
Upon receiving the notification, the search server device 10 can issue a new divided search request to the database server device, as in the first embodiment. The client device 40 is provided with the search result combining unit 57 and the search result management table 90 so that the search result combining unit 57 monitors a plurality of obtained search result data and maps the search result data to map information. What is necessary is just to display by the display processing part 442 (FIG. 4).
[0093]
【The invention's effect】
As described above, according to the present invention, a plurality of divided search requests obtained by dividing a newly generated search request can be processed in parallel by a plurality of database server devices. , A new split search request is submitted under the condition that it can be processed in parallel, so that after a search request is submitted to one of the database server devices, it is avoided that the search request is maintained in a waiting state in the database server device. As a result, it is possible to suppress an increase in the processing time for all the divided search requests, and to shorten the processing time for the search requests.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an information search system using one embodiment of a database search program according to the present invention.
FIG. 2 is a diagram illustrating an example of division unit data arrangement information.
FIG. 3 is a diagram showing an example of a database-based input status table.
FIG. 4 is a schematic block diagram of a client device.
FIG. 5 is a diagram illustrating an example of a common queue.
FIG. 6 is a schematic flowchart of a part of a process of a search request input control unit.
FIG. 7 is a schematic flowchart of another part of the processing of the search request input control unit.
FIG. 8 is a diagram illustrating an example of a search result management table.
FIG. 9 is a schematic flowchart of processing of a search result combining unit.
FIG. 10 is a diagram illustrating an example of a database-based input status table usable in the second embodiment.

Claims (3)

A search request received from any client device for a non-uniform multiplex database which is stored in a plurality of database server devices and is configured by a plurality of databases each including a different combination of a plurality of division unit data is divided. Generating a plurality of divided search requests each requesting a search for one of the plurality of divided unit data,
The generated plurality of divided search requests are stored in a common queue provided commonly to the plurality of database server devices so that the order of the reception times of the search requests from which the respective divided search requests are generated can be identified. Register,
Each time a plurality of divided search requests are newly registered in the common queue, the plurality of divided search requests are sequentially selected, and a processable condition that the selected divided search request can be processed, Determine one or more database server devices that can be additionally input that satisfy the parallel processing enabling condition that the selected divided search request can be processed in parallel with another divided search request,
The selected divided search request is additionally input to one database server device or one of a plurality of database server devices determined to be additionally inputtable by the determination,
In synchronization with the completion of the processing of any of the divided search requests by any of the database server devices, the oldest divided search request that satisfies the processable condition and the parallel processable condition is selected from the common queue. To the database server device
A database search program, which is programmed to cause a computer to execute steps. Any one of the client devices requested by any user for the heterogeneous multiplex database stored in the plurality of database server devices and configured by the plurality of databases composed of different combinations of the plurality of divided unit data, Divides the search request received from, to generate a plurality of divided search requests to request a search for each of the plurality of divided unit data,
The generated plurality of divided search requests are stored in a common queue provided commonly to the plurality of database server devices so that the order of the reception times of the search requests from which the respective divided search requests are generated can be identified. Register,
Each time a plurality of divided search requests are newly registered in the common queue, the plurality of divided search requests are sequentially selected, a processable condition that the selected divided search request can be processed, and Determine one or more database server devices that can be additionally input that satisfy the parallel processing enabling condition that the selected divided search request can be processed in parallel with another divided search request,
The selected divided search request is additionally input to one database server device or one of a plurality of database server devices determined to be additionally inputtable by the determination,
In synchronization with the completion of the processing of any of the divided search requests by any of the database server devices, the oldest divided search request that satisfies the processable condition and the parallel processable condition is selected from the common queue. To the database server device
A database search method comprising the steps of: Any one of the clients requested by any user for the heterogeneous multiplex database stored in the plurality of database server devices and configured by the plurality of databases composed of different combinations of the plurality of divided unit data, Means for dividing a search request received from the device, and generating a plurality of divided search requests each requesting a search for one of the plurality of divided unit data,
The generated plurality of divided search requests are stored in a common queue provided commonly to the plurality of database server devices so that the order of the reception times of the search requests from which the respective divided search requests are generated can be identified. Means to register;
Each time a plurality of divided search requests are newly registered in the common queue, the plurality of divided search requests are sequentially selected, and a processable condition that the selected divided search request can be processed, and Means for determining one or more database servers that can be additionally input that satisfy the parallel processing enabling condition that the selected divided search request can be processed in parallel with the other divided search requests in;
Means for additionally inputting the selected divided search request to one database server device or one of a plurality of database server devices determined to be additionally inputtable by the determination,
In synchronization with the completion of the processing of any of the input divided search requests by any of the database server devices, the oldest divided search request that satisfies the processable condition and the parallel processable condition from the common queue. Means for selecting and inputting to the database server device;
A database search device comprising:

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