JPH10124358A - Cursor system sql statement processing method of rda server - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the response time of a cursor system SQL statement while maintaining a RDA(remote data base access) protocol. SOLUTION: The RDA server 20 consists of a data base access preparation part 40 and a data base access execution part 41, which operate on different processors of a multiprocessor type server computer system 2 in parallel. The execution part 41 inputs access modules in a queue 26 one after another to access the data base 3, and saves a FETCH statement as an access result in a data storage part 25 and reports others to the preparation part 40. The preparation part 40 generates respective access modules of a declaration statement, an OPEN statement, a FETCH statement, and a CLOSE statement at a time and registers them in the queue 26 when the SQL statement received from a RDA client 11 is a cursor declaration statement, and then acquires response results corresponding to the individual SQL statements received from the RDA client 11 from a data storage part 25 or execution part 41 and returns them to the RDA client 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an RDA (Remote Datab) which is a kind of distributed database system.
More specifically, the present invention relates to a technique for improving the processing speed of a cursor SQL statement.

[0002]

2. Description of the Related Art RDA is a function for remotely operating and processing databases existing on computer systems distributed in various places. The RDA is located in the application layer of the seventh layer of OSI, and is used for association management and resource handling. Provides general-purpose service functions such as transaction management and data manipulation. The present invention mainly relates to the data operation portion among these, and further targets SQL which is recognized by ISO as a data operation method.

FIG. 12 is a block diagram of a conventional RDA system. As shown in FIG.
The client computer system 1 comprises a client computer system 1 and a server computer system 2 'connected to the client computer system 1 via a network (not shown).
And an RDA client 11, and an RDA server 20 'and a database 3 exist in the server computer system 2'. Further, the RDA server 20 ′ includes a protocol analysis / generation unit 21 and an access module generation unit 2.
2 'and a database access means 23'.

In such a conventional RDA system, data manipulation using a cursor SQL statement has been performed as follows.

[0005] In FIG. 12, when the user program 10 issues a cursor declaration statement in the form of an SQL statement to the RDA client 11, the RDA client 11
Change protocol of cursor declaration statement to R according to A protocol
Transmit to DA server 20 '. In this specification, RD
A series of data exchanged between the A client and the RDA server according to the RDA protocol is called "protocol" or "RDA protocol". This protocol is analyzed by the protocol analyzing / generating means 21 of the RDA server 20 ', and the analysis result including the cursor declaration sentence in the SQL sentence is transmitted to the access module generating means 22'. The access module generation means 22 'analyzes the syntax and semantic analysis of the cursor declaration statement based on the SQL statement in the analysis result, analyzes the syntax and meaning of the requested cursor declaration statement, and meets the request. An optimization process for deciding a processing procedure is performed, an object is generated, and the like, a cursor declaration statement access module composed of an executable SQL statement and host variable information is generated. It is transmitted to the database access means 23 '. Since the cursor declaration statement is actually executed on the database 3 when the OPEN statement for enabling the cursor is executed, it is determined by the protocol that the cursor declaration statement processing in the RDA server 20 'is successful. The information is transmitted to the analysis / generation means 21. The protocol analysis / generation unit 21 generates a protocol of the execution result of the cursor declaration statement according to the RDA protocol, and transmits the protocol to the RDA client 11 that has issued the request. Upon receiving this, the RDA client 11 notifies the user program 10 of the execution result of the cursor declaration statement.

Next, when the user program 10 issues an OPEN statement in the form of an SQL statement to the RDA client 11, the RDA client 11 transmits the protocol of the OPEN statement to the RDA server 20 'in accordance with the RDA protocol and receives the RDA server 20'. The protocol analysis / generation means 21 and the access module generation means 22 'of the server 20' generate an OPEN statement access module in the same procedure as in the protocol of the cursor declaration statement and transmit it to the database access means 23 '. At this point, the database access means 23 'executes the cursor declaration statement access module and the OPEN statement access module, and outputs the execution results to the access module generation means 2
The protocol analysis / generation means 21 'is transmitted to the RDA client 11 via 2', and the protocol analysis / generation means 21 transmits the protocol including the execution result to the RDA client 11. R
The DA client 11 notifies the user program 10 of the execution result.

Hereinafter, the same processing is performed when the user program 10 issues a FETCH statement based on an SQL statement, and the same processing is performed when the user program 10 finally issues a CLOSE statement based on an SQL statement. Will be That is, in the RDA server 20 ', the protocol analysis / generation unit 21 analyzes the RDA protocol, and the access module generation unit 22' executes the SDA based on the analysis result.
Requests are processed in the order of performing syntax analysis, semantic analysis, optimization, access module generation, and the like of the QL statement, and the database access means 23 ′ accesses the database 3 based on the generated access module. The data is returned to the RDA client 11 in the RDA protocol format from the database access means 23 'via the access module generation means 22' and the protocol module analysis / generation means 21, and transmitted to the user program 10.

[0008]

As described above, conventionally, the RDA server 20 'receives a SQL sentence from the RDA client 11 in the same manner as a non-cursored SQL sentence even if the sentence is a cursor-based SQL sentence. The first access to the database 3 was adopted.

However, in a cursor SQL statement, the target data is specified by a cursor declaration statement,
This is for a series of operations of opening with the PEN statement, fetching each line one by one with the FETCH statement, and closing the cursor with the CLOSE statement at the end. The subsequent SQL statement after the cursor declaration is expected in advance You. Therefore, like the conventional RDA server 20 ', the RD
In a configuration in which the database 3 cannot be accessed until the next SQL statement is received from the A client 11, the user program 10 transmits the RDA protocol to the RDA server 20 'via the RDA client 11, and the RDA server 20' Since the process of accessing the database 3 and returning the execution result to the user program 10 via the RDA client 11 is performed every time an SQL statement is performed, performance degradation when remote database access is used, that is, response time degradation Was one of the causes.

Accordingly, a first object of the present invention is to reduce the response time of a cursor SQL statement.

Japanese Patent Application Laid-Open No. Hei 5-61747 discloses that
When a cursor declaration statement is received from the client computer system, one server process of the server computer system analyzes the cursor declaration statement and executes an OPEN statement, F
The ETCH statement and the CLOSE statement are collectively created, and the result of accessing the database with them is collectively returned to the client computer system. The client computer system saves the access result and transmits the OPEN instruction from the user program to the OPEN instruction. A distributed database access method has been proposed in which the number of requests and responses transferred between a client computer system and a server computer system is reduced by returning the stored execution result when receiving the instruction. .

However, in the method described in this publication, the OPEN statement, the FETCH statement, and the CLOSE statement are not communicated between the client computer and the server computer, and thus do not conform to the RDA protocol.
The reason is that in the RDA protocol, the OPEN statement, FE
This is because, for each of the TCH statement and the CLOSE statement, it is necessary to follow the procedure of issuing a request from the RDA client to the RDA server and returning a response from the RDA server to the RDA client in response to the request. .

In view of the above, the method described in the above publication is improved, and the access results based on the OPEN statement, FETCH statement and CLOSE statement are not returned to the client computer all at once, but are stored in the server process of the server computer. OPEN statement, FETC from client computer
When the H sentence and the CLOSE sentence are transmitted, it is possible to return the stored result. By doing so, the RDA client issues a request to the RDA server for each of the OPEN, FETCH, and CLOSE statements, and the RDA server responds to the request with the RDA server.
The procedure of returning a response to the DA client can be followed. However, in the prior art, one server process itself is composed of an OPEN statement, a FETCH statement and a CLOSE statement.
Since the access to the database for the statement and the reception of the next request from the client computer are performed, whether the next request from the client computer is received until the processing of the OPEN statement, the FETCH statement, and the CLOSE statement is completed. , OPEN statement, FETCH statement and CL
It is an option to interrupt the processing of the OSE statement and accept the next request from the client computer. In the former case, the response is delayed, and in the latter case, the OPEN statement and FETCH
Statement and the CLOSE statement are delayed, resulting in a delayed response time.

Therefore, a second object of the present invention is to provide an OPEN
Statement, FETCH statement and CLOSE statement, the RDA client issues a request to the RDA server, and the RDA server returns a response to the RDA client in response to this request. The goal is to be as short as possible.

Further, in the above publication, when a cursor declaration statement is received, a cursor declaration statement, an O
PEN, FETCH and CLOSE statements are created and executed. Such a configuration has no problem if there is no input host variable in the cursor declaration statement. However, if there is an input host variable in the cursor declaration statement, the value of the input host variable in the cursor declaration statement is
Since it is specified to be specified in the RDA protocol of the PEN statement, the cursor declaration statement created at the time of receiving the cursor declaration statement is insufficient and cannot be dealt with.

Therefore, a third object of the present invention is to enable a process to be executed without any problem even when an input host variable exists in a cursor declaration statement.

[0017]

According to the present invention, there is provided an RD operating on a client computer system connected via a network in order to achieve the first and second objects.
In a cursor-based SQL statement processing method in an RDA server that accesses a database of a server computer system in response to a request from a client A, the RDA server is composed of a database access preparation unit and a database access execution unit, and these are configured in a multiprocessor configuration A process of allocating to the different processors in the server computer and operating them in parallel, sequentially inputting the access modules registered in the queue queue to the database access execution unit to access the database, and In the case of an FETCH statement, the data is stored in a data storage unit exclusively used between the database access preparation unit and the database access execution unit, and otherwise, a process of notifying the database access preparation unit is performed. When the SQL statement received from the RDA client is a cursor declaration statement, the database access preparation unit creates a cursor declaration statement access module, an OPEN statement access module, a FETCH statement access module, and a CLOSE statement access module collectively. The processing of registering in the queue queue and the response result for each SQL statement received from the RDA client are performed from the data storage unit for the FETCH statement, and from the database access execution unit for the OPEN and CLOSE statements. The process of acquiring and returning to the RDA client is performed.

In the cursor-based SQL statement processing method in the RDA server having such a configuration, when a cursor declaration sentence in an SQL statement is sent from the RDA client of the client computer system to the server computer system according to the RDA protocol, the database Access preparation unit is cursor declaration statement access module, OPEN
The statement access module, the FETCH statement access module, and the CLOSE statement access module are collectively generated and registered in the queue. Thereafter, the database access execution unit sequentially inputs the access modules registered in the queue and accesses the database, and stores the access result in the data storage unit in the case of the FETCH statement. In the case of, a process of notifying the database access preparation unit is performed, and in parallel with this, the database access preparation unit acquires a response result for each SQL statement received from the RDA client from the data storage unit or the database access execution unit. To return to the RDA client.

In order to achieve the first to third objects, the present invention accesses a database of a server computer system according to a request from an RDA client operating on a client computer system connected via a network. In the cursor-based SQL statement processing method in the RDA server, the RDA server is composed of a database access preparation unit and a database access execution unit, and these are assigned to different processors in a multiprocessor type server computer to operate in parallel. Processing for sequentially inputting the access modules registered in the queue queue to the database access execution unit and accessing the database; and, in the case of the FETCH statement, the database access preparation unit. Stored in the data storage unit to be used exclusively with the over database access execution unit, to perform the processing for notifying the database access preparing unit in other cases, the database access preparation unit, RDA
If the SQL statement received from the client is a cursor declaration statement that does not include an input host variable, the cursor declaration statement access module, OPEN statement access module, and FE
A process of collectively creating a TCH statement access module and a CLOSE statement access module and registering them in the queue, and an SQ received from the RDA client.
When the L statement is a cursor declaration statement including an input host variable, the cursor declaration statement access module, the OPEN statement access module, and the FETCH statement access module wait for the input host variable value to be specified in the RDA protocol of the OPEN statement. And a process of completing a total of four access modules including a CLOSE statement access module and registering the access module in the queue, and a response result for each SQL statement received from the RDA client to the FET.
The CH statement is acquired from the data storage unit, and the OPEN statement and the CLOSE statement are acquired from the database access execution unit, and are returned to the RDA client.

In the cursor-based SQL statement processing method in the RDA server having such a configuration, when a cursor declaration statement based on an SQL statement is sent from the RDA client of the client computer system to the server computer system in accordance with the RDA protocol, a database is prepared. The access preparation unit, if the input host variable does not exist in the cursor declaration statement, the cursor declaration statement access module,
The OPEN statement access module, the FETCH statement access module and the CLOSE statement access module are collectively generated and registered in the queue, and if an input host variable exists, the input host variable value is included in the RDA protocol of the OPEN statement. Is specified, the cursor declaration statement access module, the OPEN statement access module, the FETCH statement access module, and the CLO
A total of four access modules of the SE statement access module are completed and registered in the queue. After this,
The database access execution unit accesses the database by sequentially inputting the access modules registered in the queue and accessing the database.
In the case of a sentence, it is stored in the data storage unit, otherwise, a process of notifying the database access preparation unit is performed,
In parallel with this, the database access preparation unit
A process of acquiring a response result for each SQL statement received from the client from the data storage unit or the database access execution unit and returning it to the RDA client is performed.

The database access preparation unit and the database access execution unit only need to be in a form that can be simultaneously assigned to different processors, for example, each is configured as a thread, or each is configured as a process.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described in detail with reference to the drawings.

Referring to FIG. 1, one embodiment of the present invention comprises a client computer system 1 and a server computer system 2 connected to the client computer system 1 via a network (not shown). Have been.

The client computer system 1 includes a user program 10 and an RDA client 11.

The server computer system 2 includes an RDA server 20 and a database 3.

The RDA server 20 has a database access preparation unit 40 and a database access execution unit 41. Here, the server computer system 2 has a multiprocessor-type hardware configuration, and the database access preparation unit 40 and the database access execution unit 41 are configured so that processors can be assigned independently. For example, the database access preparation unit 40 and the database access execution unit 41 are threads, respectively, and operate in parallel by being simultaneously assigned to different processors constituting the server computer system 2 having a multiprocessor configuration. In another embodiment, the database access preparation unit 40 and the database access execution unit 41 are each a process,
It operates in parallel by being simultaneously assigned to different processors constituting the server computer system 2 having a multiprocessor configuration. In short, any form can be used as long as it can be assigned to different processors simultaneously.

The database access preparation unit 40 has an RD
When the RDA protocol is received from the A client 11, the database access execution unit 41 performs necessary preparations so that the SQL statement in the RDA protocol can be executed on the database 3, and the database access execution unit 41 executes the SQL statement. This function returns the result to the RDA client 11 in a format according to the RDA protocol.
It comprises a protocol analysis / generation means 21 and an access module generation means 22.

The database access execution section 41 has a function of accessing the database 3 in response to an input from the database access preparation section 40 and returning the execution result to the database access preparation section 40 again. The data storage unit 25 includes an exclusive control unit 24 that performs exclusive control so that the database access unit 23 and the access module generation unit 22 do not refer to the data storage unit 25 at the same time. The database access unit 23 has a queue 26.

The protocol analyzing / generating means 21 includes an RDA
It functions as a window that controls transmission and reception of the RDA protocol with the client 11. It analyzes the RDA protocol received from the RDA client 11 and transmits the result to the access module generation means 22. In addition, the database access execution result is expressed in RDA protocol format as RDA
In order to return to the client 11, a protocol generation process is performed.

The access module generation means 22 generates a database accessible format based on the analysis result passed from the protocol analysis / generation means 21. The generated one is an access module. The access module generation unit 22 generates an access module by performing syntax analysis, semantic analysis, optimization, object generation, and the like of the SQL sent from the RDA client 11 using the RDA protocol. The host variable attribute information and the host variable value information when the input / output host variable exists in the SQL statement are also converted and analyzed here. The access module created here is passed to the queue 26 of the database access means 23. The access module generation unit 22 also has a role of transferring a database access execution result to the protocol analysis and generation unit 21.

The database access means 23 is an interface with the database 3 and has a queue 26. When an input is made in the queue 26, an SQL statement is executed on the database 3 according to the input. If the SQL statement is a FETCH statement, the execution result is stored in the data storage unit 25, and the other result is returned to the access module generation unit 22.

Next, the operation of this embodiment will be described.

In FIG. 1, the user program 10
When requesting the DA client 11 to access the database 3, the RDA client 11 performs remote database access to the RDA server 20 according to the RDA protocol.

Referring to FIG. 2, the protocol analyzing / generating means 21 transmits the R
The DA protocol is analyzed (steps A1 to A3), and if the analysis result is correct, the obtained analysis result is passed to the access module generation means 22 (A4, A7). When the result is returned from the access module generation unit 22, a protocol for returning the result to the RDA client 11 is generated (step A5), transmitted to the RDA client 11 (step A6), and waits for reception again. (Steps A1 and A2). On the other hand, if the RDA protocol transmitted from the RDA client 11 is an invalid protocol, an error protocol is generated (step A).
4, A5), transmit to the RDA client 11 (step A6), and wait for reception again (steps A1, A)
2).

Referring to FIG. 3, the access module generating means 22 which has received the analysis result from the protocol analyzing / generating means 21 analyzes the syntax of the SQL statement in the analysis result, and obtains the host variable information included in the SQL statement. A semantic analysis such as analysis is performed (steps B1 and B2), and further optimization is performed (step B3). Then, the following processing is performed according to the type of the SQL statement.

(1) Cursor Declaration Statement If the SQL statement is a cursor declaration statement (Yes in step B4), a series of access modules from the cursor declaration statement to the CLOSE statement, that is, a cursor declaration statement access module, an OPEN statement access module, FETCH
A statement access module and a CLOSE statement access module are generated (steps B5 to B8).

Further, it is checked whether or not an input host variable is included in the cursor declaration statement (step B).
9).

If the input host variable does not exist in the cursor declaration statement, the four access modules generated in steps B5 to B8 are put into the queue 26 in that order (step B20), and then the result of the cursor declaration statement (step B20). (Success) (step B10).

On the other hand, if the input host variable exists in the cursor declaration statement (Yes in step B9), the process of step B20 is not performed, and the process proceeds to step B10 to create a result (success) of the cursor declaration statement.

The access module generating means 22 analyzes the result of the cursor declaration statement created in this way by protocol analysis /
The information is passed to the generation means 21 (step B21).

(2) OPEN Statement If the SQL statement is not a cursor declaration statement but an OPEN statement (NO in step B4, YES in B11), it is checked whether an input host variable value is specified (step B12). This is because the RDA implementation regulations stipulate that the value of the input host variable in the cursor declaration statement is specified by the RDA protocol of the OPEN statement.

If the input host variable value has been designated (Yes in B12), the access module generation means 22
Generates a cursor declaration statement access module in consideration of the specified input host variable value by overwriting the cursor declaration statement access module generated in step B5 when the cursor declaration statement is received (step B13), and receives the cursor declaration statement. At times, a total of four access modules are put into the queue 26 together with the OPEN statement access module, FETCH statement access module and CLOSE statement access module generated in steps B6, B7 and B8 (step B14).

Thereafter, the execution result of the OPEN statement is obtained from the database access means 23 (step B15).
Transfer to the protocol analysis / generation means 21 (step B2
1).

(3) FETCH statement When the SQL statement is a FETCH statement (step B4,
(No in B11, Yes in B16), the access module generation unit 22 directly acquires the execution result from the data storage unit 25 (Step B17), and passes it to the protocol analysis / generation unit 21 (Step B21).

(4) CLOSE Statement When the SQL statement is a CLOSE statement (step B4)
(No in B11 and B16, Yes in B18), the access module generating means 22
3 to obtain the execution result of the CLOSE statement (step B1).
5), and pass it to the protocol analysis / generation means 21 (step B21).

(5) Non-cursor SQL statement If the SQL statement is a non-cursor SQL statement (NO in steps B4, B11, B16 and B18), the access module generation means 22 generates an access module corresponding to the SQL statement. (Step B19), queue queue 2
No. 6 (step B14). Then, the result is obtained from the database access unit 23 (step B1).
5), and pass it to the protocol analysis / generation means 21 (step B21).

Referring to FIG. 4, the database access means 23 always checks whether or not an access module is input to the queue 26 (steps C1 and C2). When an input is found, the access module is taken out of the queue 26 and the database 3 is accessed accordingly to obtain an execution result (step C3).

The handling of the execution result differs depending on the executed SQL statement. If the executed SQL statement is a FETCH statement (Yes in step C4), the data storage unit 2
5 is stored (step C5). On the other hand, FE
In the case other than the TCH statement (No in step C4), the execution result is returned to the access module generation unit 22 (C
6).

FIG. 5 shows that the access module generation means 22 and the database access means 23 are exclusive control means 24.
9 is a flowchart illustrating a processing example when accessing the data storage unit 25 using the.

When the database access preparation unit 40 and the database access execution unit 41 refer to and update the data storage unit 25, they request the exclusive control unit 24 to lock the data storage unit 25 (step D).
1). When the data storage unit 25 is not locked, the exclusive control unit 24 locks the data storage unit 25 and notifies the request source that the lock has succeeded, and notifies the request source of the lock failure when the data storage unit 25 is already locked. The database access preparation unit 40 or the database access execution unit 4 that issued the lock request
1 indicates that the lock was successful (yes in step D2)
The data storage unit 25 is accessed to write or refer to data (step D3). After the access is completed, the exclusive control unit 24 is requested to release the lock, and the data storage unit 25 is unlocked (step D4). When the lock failure is notified (No in D2), the database access preparation unit 40 or the database access execution unit 41 retries until the lock succeeds.

As described above, in the present embodiment, the database access preparation unit 40 and the database access execution unit 4
1 can operate simultaneously, and the cursor SQL
The statement can be executed continuously from the cursor declaration to CLOSE irrespective of the timing of receiving the SQL statement from the RDA client 11. Therefore, the cursor system S
Regarding the QL statement, the database access interval from one SQL statement to the next SQL statement can be shortened.
Further, when the FETCH result is stored and the FETCH statement is received from the RDA client 11, the time until the result can be returned can be reduced by referring to the stored result, and the processing speed can be increased. it can.

[0052]

Next, the operation of an embodiment of the present invention will be described with reference to FIGS.

In FIG. 6, the user program 10
SQL to database 3 for DA client 11
When the cursor declaration statement is issued, the RDA client 11 transmits an RDA protocol including the cursor declaration statement to the RDA server 20. Here, it is assumed that an input host variable: H is included in the cursor declaration statement as shown in FIG.

The protocol analyzing / generating means 21 having received the RDA protocol including the cursor declaration statement analyzes the RDA protocol (step A3), and passes the analysis result to the access module generating means 22 (step A7). The access module generation means 22 performs syntax analysis, semantic analysis, and optimization based on the analysis result (steps B1 to B3), and generates a cursor declaration statement access module because it is a cursor declaration statement (step B).
5) Then, open statement access module, FET
A CH statement access module and a CLOSE statement access module are also generated (steps B6 to B8). At this time, since the input host variable: H is included in the cursor declaration statement, the
Input host variable in RDA protocol of PEN statement: H
, And nothing is passed to the queue 26 at this stage. Thereafter, the access module generation means 22 creates the result of the cursor declaration statement and passes it to the protocol analysis / generation means 21 (steps B10, B
21), the protocol analyzing / generating means 21 sends the protocol related to the result of the cursor declaration statement to the RDA client 11
(Steps A5 and A6).

Referring to FIG. 7, the user program 10
Is connected to the RDA server 20 through the RDA client 11.
After receiving the result of the cursor declaration statement from, the OPEN statement is issued to the RDA client 11, and the RDA client 11 sets the RDA protocol related to the OPEN statement to RDA.
It is transmitted to the server 20. Where the input host variable: H
Is passed from the RDA client 11, the access module generation means 22 completes the assembly of the access module of the cursor declaration statement (step B13). Then, a total of four access modules are registered in the queue 26 of the database access unit 23 (step B14).

Referring to FIG. 8, since the database access means 23 has been input to the queue 26, it is sequentially processing it (steps C1 to C6). In this case, first, a cursor declaration statement and an OPEN statement are executed for the database 3, and the results are returned to the access module generation unit 22. The access module generation unit 22 passes the result to the protocol analysis / generation unit 21, and the protocol analysis / generation unit 21 passes it to the RDA client 11 and waits for the next request.

Referring to FIG. 9, the user program 10
Issues a FETCH statement to the RDA client 11, and the RDA client 11
The DA protocol is transmitted to the database access preparation unit 40. At this time, the database access execution unit 4
1 operates independently of the database access preparation unit 40, and therefore, regardless of the timing at which the protocol analysis / generation unit 21 receives the next SQL statement (FETCH statement), The next FETCH statement in 26 is executed. That is, the FETCH statement is executed on the database 3, and the result data is stored in the data storage unit 25 via the exclusive control unit 24.

Referring to FIG. 10, the FETCH statement received from the RDA client 11 is processed by the access module generating means 22 in steps B1 to B3 in FIG. Get the results directly.

Thus, the access module generating means 2
2 acquires the FETCH result, and the protocol analysis / generation unit 21 transmits the result data to the RDA client 11.

FIG. 11 is a diagram showing an example of the contents stored in the data storage unit 25. The database access means 23 is OP
When the table corresponding to the cursor declaration is generated by the execution of the EN statement access module, the write counter and the read counter of the initial value 1 are set in the entries 111 and 112, respectively. A data entry 113 stores the value of each row.

The database access means 23 stores the first F
When one line of data is acquired by the ETCH statement, the lock of the data storage unit 25 is acquired, the data is written in the first data entry 113, and the value of the write counter is set to +
1 to 2 to release the lock. When the next one row of data is obtained, it is written into the next data entry 113, and the value of the write counter is incremented by one to three. Thereafter, the value of the write counter is incremented by one each time one row of data is written. The last value to be written is E
OD.

On the other hand, access module generating means 22
Acquires the lock of the data storage unit 25 when acquiring the result from the data storage unit 25 in step B17 of FIG. 3, and first checks whether the value of the read counter is smaller than the value of the write counter, If the value is smaller, the data written in the data entry 113 corresponding to the value of the read counter is read, the value of the write counter is incremented by 1, and the lock is released. If the value of the read counter is not smaller than the value of the write counter, the lock is released, and a retry is performed, for example, after waiting for a certain time.

[0063]

As described above, according to the present invention, the following effects can be obtained.

The response time of a cursor SQL statement can be reduced. The reason is that the database access preparation unit and the database access execution unit are assigned to different processors in the multiprocessor type server computer and operate in parallel, and when the cursor declaration statement is received, the database access preparation unit opens.
, An access module is generated and placed in a queue so that the SQL statement of the statement, the FETCH statement, and the CLOSE statement can be executed.
Irrespective of the timing of receiving the FETCH statement or the like from the DA client, the access modules in the queue are sequentially executed in parallel with the processing of the database access preparation unit, and the database access preparation unit transmits the access result to the RDA. This is because it is returned to the client.

OPEN statement, FETCH statement and CLOS
The procedure of issuing a request from the RDA client to the RDA server for each of the E statements and returning a response from the RDA server to the RDA client for the request can be followed. The reason is that the database access preparation unit obtains a response result for each SQL statement received from the RDA client from the data storage unit or the database access execution unit and returns it to the RDA client.

Both the case where the input host variable exists in the cursor declaration statement and the case where it does not exist can be handled. The reason is that the database access preparation
This is because the processing is divided depending on whether or not there is an input host variable in the cursor declaration sentence received from the client A.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an example of an embodiment of the present invention.

FIG. 2 is a flowchart illustrating a processing example of a protocol analysis / generation unit.

FIG. 3 is a flowchart illustrating a processing example of an access module generation unit;

FIG. 4 is a flowchart illustrating a processing example of a database access unit.

FIG. 5 is a flowchart illustrating an example of processing when an access module generation unit and a database access unit access a data storage unit using an exclusive control unit;

FIG. 6 is an operation explanatory diagram of one embodiment of the present invention, wherein RD when a cursor declaration statement including an input host variable is received;
It is a figure showing operation of A server.

FIG. 7 is an operation explanatory diagram of one embodiment of the present invention, wherein OP
FIG. 14 is a diagram illustrating an operation of the RDA server when receiving an EN sentence.

FIG. 8 is an operation explanatory diagram of one embodiment of the present invention, wherein RD
FIG. 14 is a diagram illustrating a state in which an A server is transmitting a processing result of an OPEN statement to an RDA client.

FIG. 9 is an operation explanatory diagram of one embodiment of the present invention, wherein RD
R independent of receiving FETCH statement from client A
FIG. 7 is a diagram illustrating a state in which the DA server is accessing a database using a FETCH statement.

FIG. 10 is an explanatory diagram of the operation of one embodiment of the present invention;
FIG. 14 is a diagram illustrating a state in which the DA server returns an execution result of the FETCH statement to the RDA client.

FIG. 11 is a diagram illustrating an example of storage contents of a data storage unit.

FIG. 12 is a block diagram of a conventional RDA system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Client computer system 2 ... Server computer system 3 ... Database 10 ... User program 11 ... RDA client 20 ... RDA server 21 ... Protocol analysis / generation unit 22 ... Access module generation unit 23 ... Database access unit 24 ... Exclusive control unit 25 ... Data storage unit 26 ... Queue queue 40 ... Database access preparation unit 41 ... Database access execution unit

Claims (4)

[Claims] 1. A cursor system S in an RDA server that accesses a database of a server computer system according to a request from an RDA client operating on a client computer system connected via a network.
In the QL statement processing method, an RDA server is composed of a database access preparation unit and a database access execution unit, and these are assigned to different processors in a multi-processor type server computer to operate in parallel, A process of sequentially inputting the access modules registered in the queue queue to access the database, and transmitting the access result between the database access preparation unit and the database access execution unit in the case of the FETCH statement. In the data storage unit used exclusively, a process of notifying the database access preparation unit is performed otherwise. The SQL statement received from the RDA client is transmitted to the database access preparation unit by a cursor declaration statement. If the cursor Genbun access module, OPEN statement access module, FETCH statement access module and C
The process of collectively creating a LOSE statement access module and registering it in the queue queue, and the response result to each SQL statement received from the RDA client
A cursor for acquiring the TCH statement from the data storage unit, and acquiring the OPEN statement and the CLOSE statement from the database access execution unit, and returning the acquired statement to the RDA client. System SQL statement processing method. 2. A cursor system S in an RDA server that accesses a database of a server computer system according to a request from an RDA client operating on a client computer system connected via a network.
In the QL statement processing method, an RDA server is composed of a database access preparation unit and a database access execution unit, and these are assigned to different processors in a multi-processor type server computer to operate in parallel, A process of sequentially inputting the access modules registered in the queue queue to access the database, and transmitting the access result between the database access preparation unit and the database access execution unit in the case of the FETCH statement. The data is stored in a data storage unit used exclusively, and otherwise, a process of notifying the database access preparation unit is performed. The SQL statement received from the RDA client is input to the database access preparation unit. Cursor not containing In the case of a language, a process of collectively creating a cursor declaration statement access module, an OPEN statement access module, a FETCH statement access module, and a CLOSE statement access module and registering it in the queue, and an SQL statement received from the RDA client Is a cursor declaration statement including an input host variable, the cursor declaration statement access module waits until the input host variable value is specified in the RDA protocol of the OPEN statement, and
EN statement access module, FETCH statement access module and CLOSE statement access module, total 4
One access module is completed and registered in the queue, and a response result for each SQL statement received from the RDA client is stored in the data storage unit for the FETCH statement.
A cursor-related SQL statement processing method in the RDA server, wherein the SE statement is obtained from the database access execution unit, and is returned to the RDA client. 3. The method according to claim 1, wherein the database access preparation unit and the database access execution unit are each a thread. 4. The method according to claim 1, wherein the database access preparation unit and the database access execution unit are processes.