JPH07282073A - Data retrieving device and its method - Google Patents

Abstract

PURPOSE:To provide a data retrieving device and its method capable of more speedily retrieving data in the reverse direction time sequentially. CONSTITUTION:This device is provided with a ring buffer control part 20 controlling a point for retrieval which is set for each block divided by each unit capable of most efficiently reading production instructing information within an external storage device 2 into a main storage device 16 at one time. The ring buffer control part 20 is provided with information at the top and the last storing positions of production instructing information stored in the external storage device 2, an output finish point showing production instructing information which is already outputted presently and the point for retrieval. On the other hand, the device is provided with a data retrieving part 18 which reads a block indicated by a point for retrieval just before the above-mentioned one if there is not production instructing information corresponding to a retrieving key in a block indicated by the point for retrieval which is read from the external storage device 2 to the main storage device 16 in accordance with information provided for the ring buffer control part 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data retrieving apparatus and a method therefor capable of more efficiently detecting target data when resuming a retrieving operation for an external storage device once suspended.

[0002]

2. Description of the Related Art Conventionally, for example, in a data retrieval device for retrieving data relating to production instruction information, a regular process or a process of retrieving and outputting production instruction information designated by an operator is usually performed. FIG. 5 is an example of a conventional data search device. In FIG. 5, the data search device is an external storage device 2 that stores production instruction information.
A terminal device 4 operated by an operator for inputting and outputting search instruction information such as a search key; a computer 6 for accessing the external storage device 2 to perform a search process; and an output device 8 for outputting a search result. There is. FIG. 6 is an example of data stored in the external storage device 2. For the external storage device 2 in which data is sequentially stored, it is common to search information in the forward direction. Therefore, since the search process is cyclically performed such that when the end of the external storage device 2 is reached, the search process is repeated at the beginning and the external storage device 2 is logically ring buffer-shaped as shown in FIG. Is composed of.

In the data retrieval apparatus as described above, when the data stored in the external storage device 2 are sequentially retrieved and output, an event occurs in the output device, so that the output is started from the predetermined data during the retrieval. You may want to restart. For example, when a paper shortage or a paper jam occurs during the output to the printer, the case where it is desired to start the output from the data traced back slightly before the data recognized as the output by the data search device, and the like. The processing in this case will be described.

As shown in FIG. 6, the computer 6 recognizes that the data up to "113" has been output, and its pointer (output position) is "113".
C) The operator searches the data in the external storage device 2 with "111" as a search key when the operator wants to re-output from "111a", which is slightly before the output completed position. This method of using the search key is especially effective when the number of characters in the data is large,
It is usually done.

[0005]

However, since the external storage device used in the conventional data search device is normally searched in the forward direction as described above, the output data is output again using the search key. In this case, even if it is originally desired to re-output from “111” in FIG. 6, the oldest data “109
It is necessary to start the search from "A". In this case, the search time requires a lot of time in proportion to the amount of data.

Further, as shown in FIG. 6, "109A"
When you start the search from "11
There was a problem that I wanted to re-output from "1a" but searched for "111C" first, and then re-outputted from there.

On the other hand, in order to avoid the above-mentioned problem, a method of retrieving and outputting from the latest data from the output position can be considered, but considering the input / output characteristics between the computer and the external storage device. After once searching all the data in the external storage device, the previous and latest "111" in the time series direction from the output position is found.

The present invention has been made to solve the above problems, and an object thereof is to provide a data search device and a data search device method capable of searching backward data in a time series faster. To do.

[0009]

In order to achieve the above object, a data search apparatus according to the present invention cyclically searches data in an external storage device in which data is sequentially stored. In the data retrieval device, ring buffer control means for managing retrieval points set for each block divided into units capable of reading the data in the external storage device into the main storage device at one time, and reading into the main storage device Data retrieval means for designating the retrieval point corresponding to the power block in the reverse direction.

The data search method according to the present invention is a data search method in which data stored in a ring buffer is cyclically searched for, and blocks are divided into units that can be read at one time. Of the above, a step of reading a block including data pointed to by the current point into the main memory and a step of reading a block immediately before the block when there is no data to be searched in the read block. Characterize.

[0011]

Therefore, according to the present invention, the ring buffer control means reads the block containing the data pointed to by the current point from the external storage device. If there is no data to be searched in the data included in the read block, the data search means obtains the block immediately before the block. The ring buffer control means is part 1 again
Read the previous block.

In this way, the search speed can be increased by searching the external storage device in block units in the reverse direction.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. The same elements as those in the conventional example are designated by the same reference numerals.

FIG. 1 is a diagram showing a configuration of a data retrieval apparatus according to the present invention, and in the present embodiment, it is a diagram showing an apparatus for retrieving and outputting production instruction information for particularly giving a production instruction. .

In the figure, the data retrieval device comprises an external storage device 2 for sequentially storing production instruction information as data, a terminal device 4 operated by an operator for inputting / outputting retrieval instruction information such as a search key, and an external storage device 2. It has a computer 60 for accessing and performing search processing, and an output device 8 such as a printer for outputting search results. The output device 8 may be used also as the terminal device 4, or may be another computer. The computer 60 outputs the production instruction information to the output device 8 by the production instruction output unit 10
And a production instruction unit 12 that stores production instruction information in the external storage device 2 via a ring buffer control unit 20 described later and issues an output instruction to the production instruction output unit 10, and a re-output instruction to the production instruction output unit 10. Production instruction re-output unit 1
4 and. The production instruction output unit 10, the production instruction unit 12, and the production instruction re-output unit 14 can be realized by software loaded in the main storage device 16 and processed by the CPU.

A feature of the present embodiment is that the ring for managing the search points set for each block divided into units in which the production instruction information in the external storage device 2 can be read into the main storage device 16 at one time. The data search means has the buffer control unit 20, and specifies the search points corresponding to the blocks to be read from the external storage device 2 to the main storage device 16 in the reverse direction according to the information held by the ring buffer control unit 20. Is to have. The data search means can be realized by software processed by the CPU.

FIG. 2 is a diagram showing information held by the ring buffer control unit 20. The ring buffer control unit 20
In order to logically handle the external storage device 2 that is physically organized as a ring buffer as shown in FIG. 6, the head storage position of the production instruction information stored in the external storage device 2 (hereinafter referred to as the top point). ) And the last storage location (hereinafter referred to as the bottom point). According to FIG. 2, it is understood that the production instruction information for 100 records can be stored from the value of the bottom point. In addition, it has information on a current point (hereinafter referred to as an output completed point) indicating to which position in the external storage device 2 the output has been completed. Further, a search point is provided to quickly search the production instruction information stored in the external storage device 2 when the production instruction information is output again. The (record) position pointed to by this search point is from the external storage device 2 to the main storage device 1.
It is decided according to the capacity that can be read in 6 at a time. This is obtained as follows.

If the capacity of one block that can be read most efficiently from the external storage device 2 at a time is x, the size of one production instruction information is y, the top point is a, and the bottom point is b, the number of search points is set. n is calculated by n = (b−a + 1) / (x / y), and the i-th Pi of the search point can be calculated by Pi = a + (i−1) x / y. In addition, when x / y is not an integer in the above equation, the fractional part is truncated.

In this way, the production instruction information in the external storage device 2 is divided into blocks that can be read into the main storage device 16 most efficiently, and each divided block is used for retrieval unique to each block. Assign points. According to FIG. 2, the search point in this embodiment is divided into 10 blocks in order to read the production instruction information for 100 records 10 records at a time, and the search point is represented by the head record number of each block. ing. The search point is dynamically set by the values of x, y, a, and b even after the production instruction information is stored in the external storage device 2. Note that FIG. 3 shows a correspondence relationship between the information held by the ring buffer control unit 20 shown in FIG. 2 and the external storage device 2.

FIG. 4 is a flow chart showing the flow of processing in this embodiment, and the operation of this apparatus will be described with reference to this figure.

Normally, the production instruction section 12 stores the production instruction information in the external storage device 2 via the ring buffer control section 20 and outputs it to the output device 8. Here, when it is desired to retrieve and re-output the output production instruction information due to some event, the production instruction re-output unit 14
The operator is made to specify the search key from the terminal device 4. The ring buffer control unit 20 obtains the search points assigned to the block including the output-completed points (step 101). Next, the block indicated by the obtained search point is read into the main storage device 16 (step 102). The data search unit 18 searches the read production instruction information for the production instruction information corresponding to the search key in the forward direction from the search point to the output point (step 10).
3). At this time, when there are a plurality of relevant production instruction information, the one closer to the output point is adopted (step 104).

Here, if the corresponding production instruction information does not exist, the data retrieval section 18 designates a retrieval point in the reverse direction in time series. That is, the search point immediately before the search point read this time is obtained (step 105). If the block read this time corresponds to the first search point in the external storage device 2, since the external storage device 2 is handled as a ring buffer, the search point immediately before in this case is the external storage device 2. Is the last search point in. When the previous search point is obtained, the block pointed to by the search point is read into the main storage device 16 (step 106). The last production instruction information of the read block is the production instruction information immediately before the previously read production instruction information. After that, the process returns to step 103, and the production instruction information corresponding to the search key is within the predetermined range,
That is, this search process is repeated until the current search point is found within the range immediately before the previous search point.

When the production instruction information corresponding to the search key is found by repeating the above processing, the production instruction re-outputting section 14
The output device 8 is made to re-output the production instruction information via the production instruction output unit 10 in order from the production instruction information.

As described above, according to this embodiment, the external storage device 2 is divided into fixed block units in consideration of the characteristics of the computer 60 serving as the data search device and the external storage device 2, and each block unit is divided. Since the search is performed in the reverse direction and in the forward direction in each block, the data search can be performed at a higher speed.

In this embodiment, the device for retrieving the production instruction information has been described. However, the present invention is not limited to this, and another system for retrieving ordered information such as output of information after a specified time of an error log, Needless to say, it can be applied to other fields.

[0026]

According to the present invention, the ring buffer control means efficiently manages data by dividing the external storage device into blocks that can be read into the main storage device at one time.
It is possible to reduce the number of input / output times between the data search device and the external storage device.

Further, since the data search means searches the data backward in time series for each block unit, and forward in each block, the data search can be performed faster. Is possible.

Further, with the configuration according to the present invention, the process of re-outputting using this device is a simple process, and it is possible to reduce the man-hours for developing an application using this process.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a data search device according to the present invention.

FIG. 2 is a diagram showing information held by a ring buffer control unit in the present embodiment.

FIG. 3 is a diagram showing a correspondence relationship between information held by a ring buffer control unit and an external storage device in this embodiment.

FIG. 4 is a flowchart showing the flow of processing in this embodiment.

FIG. 5 is a diagram showing a conventional data search device.

FIG. 6 is a diagram showing an example of data stored in an external storage device.

[Explanation of symbols]

 2 external storage device 4 terminal device 6, 60 computer 8 output device 10 production instruction output unit 12 production instruction unit 14 production instruction re-output unit 16 main storage device 18 data retrieval unit 20 ring buffer control unit

Claims (2)

[Claims] 1. A data search device for cyclically searching data in an external storage device in which data is sequentially stored, wherein the data in the external storage device is divided into units that can be read into the main storage device at one time. A ring buffer control means for managing the search points set for each of the selected blocks, and a data search means for designating the search points corresponding to the blocks to be read into the main storage device in the reverse direction. Characteristic data retrieval device. 2. A data search method for cyclically searching for data stored in a ring buffer, wherein the data pointed to by the current point among blocks divided into units that can be read at one time is The step of reading the containing block into main memory, and if there is no data to be searched in the read block,
And a step of reading a block immediately before the block, the data retrieval method comprising: