JPS5897742A - Retrieving device - Google Patents

Abstract

PURPOSE:To simplify the transmission of data between a host computer and the auxiliary storage devices and to improve the processing capacity, by adding a binary tree (B-tree) retrieving function to the auxiliary storage devices which are connected to the host computer. CONSTITUTION:A host computer 11 contains a main storage device 12 and a central processor 13 and connected to plural auxiliary storage devices 15 via a common data bus 14. Each device 15 is provided with a control part 21 and a storing part 22. With a retrieving instruction given from the computer 11, the part 21 compares its retrieving key with the node data of the B-tree stored in the part 22 and performs the retrieving. Thus the computer 11 can obtain the result of retrieving just by transferring the retrieving key and an retrieving instruction to the device 15. Thus the computer 11 is not occupied, and as a result the efficiency of operation is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an information retrieval device, and particularly to a retrieval device that implements a data management method using B-trees.

2. Description of the Related Art In information processing devices, demands for data management are increasing due to the need for high-speed processing such as an increase in the capacity of target data and free search based on data contents. Among these, B-tree (Binary tree) is a useful method for data management and is widely adopted as an index organization for data.In database management systems, B-tree (Binary tree) is also used on the premise of high-speed searches such as transposed files. 1r
...and its modified method are often used.@Here, B-tree means that each WI (is@d@) has k
It has a tree structure in which keys are stored such that if the upper limit of k is m, the minimum value of k is m/a. However, II (l@
The branch pointer at the node in the root node (t
The minimum number of branches of o.t) is ko. Like this -1r
... is called m-th order B-tr.

The lit diagram shows an example of Teiji's B-tr..., where,
The numbers in the clause / indicate key values, and branch pointers are stored on both sides of the key. The structure of each node l is the same, and the keys are arranged in ascending order of key values. The node l pointed to by the branch pointer octopus stores a key greater than the key on the left side of the branch pointer octopus and smaller than the key on the right side of the branch pointer octopus, but at leaf λ, the branch pointer is empty. Furthermore, B-tr... is maintained at the same level from the root node to the leaves. With this configuration, the worst number of accesses to reach a certain key is defined as the number of levels,
Storage area usage efficiency is guaranteed to be 1 or higher. B-tr・
The basic operations of . are to search, add, and delete keys, and for this purpose, the above-mentioned structure is always maintained.

In addition to the main memory, an information processing device that manages data through information retrieval has an auxiliary memory that stores each section of B-tr... to realize the basic operations of B-tr@e. In general, the auxiliary storage device has data reading and writing functions, and the central processing unit has B-trve
Each section is read from the auxiliary storage to the main storage, manipulated, and written to the auxiliary storage as necessary. however,
In this conventional method, the requirements for data management depend on the data retrieval performance, the calculation speed of the central processing unit of the information processing device, the size of the main storage device, and the data transfer speed between the main storage device and the auxiliary storage device. As functionality increases, sufficient performance is often not achieved due to the resource constraints described above. Furthermore, the exclusive use rate of the central processing unit and main storage device due to data management increases, and the throughput, response time, etc. of the information processing device as a whole often become insufficient.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate such conventional drawbacks and provide a search device in which an auxiliary storage device can perform a B-try search and transfer the search results to a host computer.

The present invention will be described in detail below with reference to the drawings. FIG. 1 shows an example of the configuration of the search device of the present invention, where:
// is a host computer, which has a main storage device 12 and a central processing unit 13, and an auxiliary storage device /j is connected to this host computer // via a data bus /#. FIG. 3 shows the internal configuration of this auxiliary storage device /j, where I is a control section and n is a storage section.

Furthermore, the control unit I is configured as shown in FIG. 1, where J/ is a register in which the key to be searched sent from the host computer @// is stored, and The search command supplies the search key to the comparator 32. This comparison @32 is stored in the storage unit B-
It also supplies node data of tr.

Comparator J2 compares key values of λ pieces of data according to clock φλ. 33. The input is 7 lips and 7 tabs for latching the comparison result, and operates at timing T/ shown in FIG. If the comparison results are equal, the flip 70 knob 33 turns on, and the flip 70 knob 3da turns on.
・It turns on when the key value in the section data is large. B is a register for holding the branch pointer before the key of the node data compared according to the clock φl, and 36 is a register for holding the branch pointer after the key of the node data compared according to the clock φl. This is a register.

Note that the clock φ/ is the branch pointer jl- of the node data V.
It operates in synchronization with / , j/-λ, . Furthermore, timing T/ is synchronized with the end of comparison data.

Next, the flow of processing when performing a search in the search device of the present invention will be explained with reference to FIG. First, the host computer
When the search key and search command are sequentially transferred from the storage unit /j to the tank dynamic storage device /j, the search key is stored in the register 31 of the control unit J, and then the first root node data is read from the storage unit n. The data is supplied to the control unit J, and the data search is started (procedure T/, Tco.

TJ'), now if Oboroji's root node data O as shown in Figure 7 is supplied, the clock φl operates in synchronization with the branch main tough 1-7, and the branch pointer 7 is set in register 3≦. /-l is latched (see procedure T) The incoming key '12-/ following the 0 branch pointer 7/-/ is supplied to comparator n. In comparator n, this key 74-/
The search key supplied from the register 3/ by the clock φ operating in synchronization with the input of the key 72 and the input key 72
-/ is performed (procedure Tj').

If the comparison results are equal, 79 and 79 keys are turned on (step T7), and since the corresponding key Il has been detected, the search ends. However, if the key 7J -/ of the incoming clause data is large, the 7 lip 7p key is turned on (step Tr).

Here, in synchronization with the end of the comparison in the comparator 32, the next branch pointer 7/-1 comes in and is stored in the register 36. As a result, the branch pointer 7/-/ stored in the register is shifted and stored in register B (step 9). The branch pointer 7/-l stored in this register n is retrieved (step 11T10) and it is determined whether it is empty (step T//).

If it is empty, it is detected that the search has reached the node data of the leaf, and the search is terminated by proceeding along the flow of YKsJ.However, if it is not empty, this branch pointer 7
The node data in the storage unit n specified by /-/ is read out and supplied to the control unit I.
Return to step g and repeat the search operation described above.

On the other hand, if the key 7 call l is small in the procedure T≦, both the flips 70 knobs n and 71' are in the off state (
In step 'f/3), the branch pointer 71-2 held in register 3B is taken out and the search for the next node data is started as described above. Such operations are repeated until the corresponding key is detected or a leaf is reached, and the search for B-tr@e is performed.

As explained above, according to the present invention, B
Since we added the function to search for -trs・, B-tr@
When implementing data management using e, the host computer can obtain search results simply by transferring the search key and search command to the divine assistant storage device. That is, the resources such as the main storage device and central processing unit of the auxiliary host computer are never occupied. Therefore, in an information processing device to which the search device of the present invention is applied, throughput, response time, etc. are significantly improved. Furthermore, the amount of data transferred on the path connecting the host computer and the auxiliary storage device can be significantly reduced, and the present invention is particularly effective when there are many additional devices sharing the bus.

[Brief explanation of drawings]

Fig. 1g is m1iti showing an example of an m-order B-tree, Fig. 2 is a block diagram showing an example of the search device of the present invention, Fig. 3 is a block diagram of its auxiliary storage device, and Fig. 3 is a block diagram of its control unit. A block diagram showing an example of the configuration, Fig. 1 is a timing chart for explaining the operation of the control section, Fig. 1 is a 7p-chart showing the search process of the present invention, Fig. 7 is an m-order node FIG. 3 is a configuration diagram of data. ／...clause, ko...branch pointer,
//...Host computer, /2...Main storage device, 13
...Central processing unit, /F...Data bus, /1...
- Auxiliary storage device, 1...control unit, n...storage unit, 3/...register, 3/...comparator, 33...
・7 lip flop, 3 da...7 lip flop, 3
3...Register, 3bu...Register, 〃
... section data! /-/...-branch pointer, j/-
−? ...branch linter, jλ-7...key,
j2-2...key, φl...ri stomach pain,
φco...clock, Tl...timing, 70
... section data, 7/ -/ ... branch pointer, 71
-2...branch pointer, 7J-/...key, -72
-One...key. Patent applicant: Canon Co., Ltd. Figure 1/ Figure 2 Figure 3

Claims (1)

[Claims] A host computer having an input means for inputting information to be searched and a search command means, a storage means storing various information in the form of B-tr@, and the input means and the search command means search for the various information. What is claimed is: 1. A search device comprising: an auxiliary storage device having a search means for searching.