JPH0740277B2 - Search continuation control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is composed of a central processing unit, a data content retrieval device, and a secondary storage device, and the data content retrieval device is stored in the secondary storage device. In the information retrieval system that selects only the record group having the content that matches the condition specified by the central processing unit from the various record groups and transfers it to the central processing unit, especially when the search is performed in plural times. The present invention relates to a search continuation control method that does not cause excess or deficiency in search results.

[Conventional technology]

Conventionally, in the field of information retrieval, in order to reduce the load on the central processing unit, a data content retrieval unit is installed between the secondary storage unit and the central processing unit, and an enormous number of records stored in the secondary storage unit are installed. A so-called content search process of selecting only a record group having a content satisfying a predetermined condition from the group is performed by the data content search device, and the search is executed in synchronization with the data read from the secondary storage device. The method of making is realized. The conventional technique in such a case will be described below.

FIG. 1 is a diagram showing an example of the configuration of this type of information retrieval system. 1 is a secondary storage device for storing a data group, 2 is a data content retrieval device, 3 is a central processing unit, and 4 is an I / O interface. is there. Among them, 1, 3 and 4 have the same configurations as the secondary storage device, the central processing unit and the I / O interface in the general-purpose computer system which is widely used at present.
The data content retrieval device 2 operates under the control of a channel program prepared in the main storage device 31 in the central processing unit 3, and selects a record group that matches the condition from the record group in the secondary storage device 1. , To the central processing unit 3. A reception buffer is secured in the main memory 31 of the central processing unit 3 in order to store the record group transferred by the data content retrieval device 2.

FIG. 2 shows a conventional configuration example of a channel program for operating the data content retrieval device 2. The format of the channel program and its constituent commands is the same as that of the general-purpose computer system currently in wide use. In the command format, the "command section" is an operation command to the data content searching device 2, and the "data address" is a central processing unit in which data to be transferred between the data content searching device 2 and the central processing unit 3 is stored. 3 is an address on the main storage device 31 in "3", and "data size" is the capacity of the data. In the case of the configuration example of this channel program, command 1 is a command for transferring the search condition to the data content search device 2 and starting the content search.
The symbols n to n are commands for collecting search results in transfer units and transferring them to the central processing unit 3. A reception buffer is secured in the main memory 31 for each transfer command.

FIG. 3 shows an operation example of content search executed by the data content search device 2 based on the channel program of FIG. In this example, 100 storage units (pages) stored in the secondary storage device 1 as shown in FIG. 2A are search targets, and each page has 12 records. Here, the Jth record in the Ith page is described as "IJ". The content itself of each record is omitted.

The data content search device 2 transfers the record group that matches the search condition from the record group in the secondary storage device 1 to the main storage device 31 of the central processing unit 3. FIG. 3B shows the record number (IJ) that matches the search condition. this is,
It is shown that the records that meet the conditions are grouped by 8 to form a transfer unit, and the number of transfer units is 10. That is, in this example, the transfer command is executed 10 times, and the transfer of the record group that matches the search condition is completed. Corresponding to this, the reception buffer 1 in the main memory 31
~ 10 is used.

[Problems to be Solved by the Invention]

In content search, the ratio of records that match the search conditions (called the hit ratio) is unknown before the search starts, so
Unless you prepare the transfer command as much as the total of the receive buffer of the transfer command is equal to the data capacity of the search target,
The transfer command may end before all the search results can be transferred, and the search may be interrupted. Therefore, the above conventional method has the following problems.

If interrupted, it is difficult to determine the starting position to resume the search.

In order to prepare transfer commands only without interruption,
It is necessary to secure a receive buffer of the same capacity as the search target in the main storage device.

With few transfer commands (small receive buffer capacity),
In order to perform a search without interruption, the search range must be chopped.

As a result of the search, when there are few records that match the search condition, the prepared transfer command (reception buffer) is wasted.

In view of the problems of the conventional method, an object of the present invention is to continue a search by repeatedly executing a channel program consisting of a small number of transfer commands (reception buffers) without finely specifying the search range. To provide.

[Means for Solving the Problems]

According to the present invention, when the data content search device transfers a record group having a predetermined capacity that matches the search condition to the central processing unit, the status information indicating the progress status of the search is transferred to the central processing unit to interrupt the search, The processing device changes the search start position based on the status information transferred from the data content search device, reissues the same channel program as before except otherwise, and based on this reissued channel program. The data content retrieval device is characterized by restarting the retrieval.

[Action]

The status information that the data content retrieval device transfers to the central processing unit indicates that if the retrieval has not reached the end position at that time,
It includes the start position where the search can be restarted when the search is interrupted. When the central processing unit receives the status information and recognizes the search interruption, the central processing unit restarts the data content searching device with the same channel program as before, but only the search start position in the search condition is from the data content searching device. Change to the transferred one. As a result, the same channel program can be repeatedly executed and the search results can be transferred without excess or deficiency simply by changing the search start position. Therefore, a small number of transfer commands and a small receiving buffer are sufficient.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

FIG. 4 shows an example of the structure of a channel program for operating the data content searching device in the present invention. The relationship between the data content retrieval device and the central processing unit in the secondary storage device is the same as in FIG.

In FIG. 4, the format of the channel program and the command which is the element thereof is the same as that of the general-purpose computer system which is widely used at present, as in the case of FIG. The difference from the conventional example of FIG. 2 is that a command (state transfer command) for newly transferring the progress status of the search is used. Since the command for ending the search is not known in advance, the state transfer command can be executed next to each command.

FIG. 5 shows an operation example of content search executed by the data content search device 2 based on the channel program of FIG. This example is similar to the example of FIG.
As shown in FIG. 1A, 100 storage units (pages) stored in the secondary storage device 1 are search-enabled, and each page has 12 records.

The data content search device 2 selects records that match the search conditions from the record group in the secondary storage device 1 and transfers them to the central processing unit 3. FIG. 5B shows this situation. Here, it is assumed that the search condition is the same as that of the example of FIG. 3, and that 8 condition-matching records are grouped into a transfer unit and that the transfer unit is 10.
It is the same as the example in the figure. However, the transfer method is completely different. That is, in the channel program of FIG. 4, after the search condition command is issued (command 1), the transfer command is issued twice (command 3, command 5),
After that, the state transfer command is issued (command 6), and one search is to be completed. In the example of FIG. 5B, this is repeated 5 times, and the transfer of all the records that meet the conditions is completed. And
Receive buffers 1 and 2 on the main storage device 31 during the first to fifth transfers (reception buffers corresponding to commands 3 and 5)
Is used repeatedly.

The operation of the data content searching device 2 will be described below in detail with reference to the flowchart of FIG. 6 for the example of FIG.

The data content search device 2 receives the command 1 from the central processing unit 3 (step 101), and the command part thereof "search start".
If so (step 102), based on the data address and data size of the command 1, the search condition which is the data of the command 1 is fetched from the search condition transmission buffer in the main memory 31 (step 103). The search conditions include the selection condition for records, and the page number to start the search, the record number, the page number to end the search, the record number, and the transfer unit capacity and the number of transfer units to be transferred. ing. The capacity of the transfer unit in the example of FIG. 5 is eight records, and the number of transfer units is two. The search is started based on these conditions (step 104).
The search is continued until the page / record number ending the search is detected or the condition-matching record reaches the transfer unit (steps 105, 106, 107).

When the condition-matching record reaches the transfer unit (eight in this example), a jump command chain is requested to the central processing unit 3 (step 108). As a result, the command 3 is received from the central processing unit 3 (step 109). The data content retrieval device 2 determines that the command part of the command 3 is "result transfer" (step 110), and based on the data address and data size of the command 3, transfer unit 1 (8 records). Is transferred to the reception buffer 1 of the main storage device 31 (step 111). If it is not the final transfer (step 112), the search is continued (step 10).
7). When the condition-matching record reaches the transfer unit again (step 106), the central processing unit 3 is requested to make a jump command chain (step 108). As a result, the command 5 is received from the central processing unit 3 (step 109). The data content retrieval device 2 transfers the transfer unit 2 to the reception buffer 2 of the main storage device 31 based on the command 5 (steps 110 and 111).

In the example of FIG. 5, since the number of transfer units in one search process is 2, the transfer of the above transfer unit 2 is the final transfer, and the data content search device 2 is normally transferred to the central processing unit 3. Request a command chain (step 113). As a result, the command 6 is received from the central processing unit 3 (step 114). The data content retrieval device 2 determines that the command part of the command 6 is "state transfer" (step 11).
5) Based on the command 6, the status is "suspended", the search restart position information page, and the record number is "4-"
6 "(page 4, record 6) is transferred to the central processing unit 3 (step 116). This completes the search.

When the central processing unit 3 receives "interruption" as the status,
The command 1 is issued again to activate the data content search device 2. However, of the search conditions, only the search start position information is changed to "4-6" (page 4, record 6) that was previously received from the data content search device. Data content retrieval device 2
Thereafter, the operations of steps 101 to 116 are executed again.

The above operation is repeated, and in this example, after the channel program of FIG. 4 has been executed four times in total, the process proceeds to the final fifth search. In the fifth operation of the data content retrieval device 2, the transfer up to the transfer unit 1 by the command 3 is the same as the fourth operation. In the subsequent search, the data content search device 2 detects the end of the search range (last page number, last record number) (step 105). In this case, the data content retrieval device 2 checks whether or not there is a record to be transferred (step 117), and issues a shamp command chain request to the central processing unit 3 if there is one, and issues a normal command chain request to the central processing device 3 if none (steps 118 and 122). .

As shown in FIG. 5, when the search range is completed, since there are four condition-matching records as the transfer unit 2, the central processing unit 3 is requested to make a jump command chain (step 118). As a result, the command 5 is issued from the central processing unit 3 (step 119). Based on the command 5, the data content retrieval device 2 transfers the transfer unit 2 to the main storage device 31.
To the receiving buffer 2 (steps 120 and 121). Then, since this is the final transfer, a normal command chain is requested to the central processing unit 3 at this point (step 12).
2). As a result, the command 6 is received from the central processing unit 3 (step 123). Based on the command 6, the data content retrieval device 2 transfers "end" as the status (steps 124, 125). This completes all searches.

As described above, the central processing unit 3 prepares two reception buffers in the main storage device 31 and repeatedly uses them, so that the entire search range can be searched. It should be noted that the capacities, the numbers of times, etc. used in the above description are for simplifying the description, and are not limited to these.

〔The invention's effect〕

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

The interruption of the search is not an overhead to the central processing unit because the data content search unit reports the restart position of the search to the central processing unit.

By repeatedly using the same channel program, the number of transfer commands, which is one of the constituent elements of this type of channel program, can be reduced, and the area for storing the channel program in the main storage device can be reduced.

By reducing the number of transfer commands, it is possible to reduce the receive buffer capacity required for one execution of the channel program. Eventually, the capacity of the receive buffer prepared in the main storage device is made smaller than the search target capacity, and interruption is performed. Since it is repeated, it is possible to continue the search.

Since the search is interrupted, it is possible to assign the data content retrieval device to a higher priority job at each break of the channel program without a job occupying the data content retrieval device for a long time. This improves the performance of the entire system.

[Brief description of drawings]

FIG. 1 is a schematic block diagram of an information retrieval system targeted by the present invention, FIG. 2 is a diagram showing a channel program configuration example for operating a data content retrieval apparatus in a conventional method, and FIG. 3 is a channel program of FIG. FIG. 4 is a diagram showing an example of the operation of the data content retrieval apparatus executed in FIG. 4, FIG. 4 is a diagram showing an example of the configuration of a channel program for operating the data content retrieval apparatus in one embodiment of the present invention, and FIG. FIG. 6 is a diagram showing an operation example of the data content search device executed by the channel program, and FIG. 6 is a flow chart for explaining the operation of the data content search device in one embodiment of the present invention. 1 ... Secondary storage device, 2 ... Data content retrieval device, 3 ...
... Central processing unit, 31 ... Main memory, 4 ... I / O interface.

Claims (1)

[Claims] 1. A central processing unit, a data content retrieval device, and a secondary storage device are provided, said central processing unit holding a channel program for operating said data content retrieval device,
Based on the channel program, the data content retrieval device reads out a record group in a designated search range from the secondary storage device, selects a record group that matches a designated search condition, and transfers it to the central processing unit. In the information continuation control method in the information retrieval system, the data content retrieval apparatus transfers status information indicating a progress status of retrieval to the central unit when transferring a record group of a predetermined capacity that matches a retrieval condition to the central processing unit. Transfer to the processing device to interrupt the search, the central processing unit changes the search start position based on the state information transferred from the data content searching device,
Otherwise, the same channel program as before the change is reissued, and the data content retrieval device restarts the retrieval based on the channel program reissued by the central processing unit. Method.