JPS63113645A - Repeating processing system for decentralized data base system - Google Patents

Abstract

PURPOSE:To improve flexibility by allowing a decentralized data base control part to transmits protocol forth and back by using a preliminary communication line based on previously stored data when recognizing the use of a communication line which is used preferentially. CONSTITUTION:Data on the communication line which connects respective nodes 1-1-1-3 directly and is used with top priority when the protocol is transmitted forth to and back from the nodes and data on the preliminary communication line that connects nodes which are not relative directly to the transmission of the protocol as repeating nodes and is used when said communication line is not used are stored previously. Then, when a decentralized data base control part 5 recognizes that the communication line which is used most preferentially can not be used, the preliminary communication line is used on the basis of the data to transmit the protocol. Consequently, the flexibility of the processing system can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a relay processing method for a distributed database system in which a database is distributed to a plurality of nodes.

[Prior Art] Fig. 4 is a diagram showing the configuration of a general distributed database system, and in the figure, (1-1) to (1-3)
are nodes, (2-1) to (2-3) are application programs executed on each node, (3-1) to (3-3) are databases distributed on each node, and (4-1) are application programs executed on each node. )～(
4-3) is a communication line connecting each node, that is, a communication path. In the distributed data system configured as described above, for example, the application program (2) of the node (1-1)
-1) uses the database (3-2) of node (1-2), first the notebook (1-1) uses the database (3-2) of node (1-2).
2) is established, and then the communication path (4-1) is established between the node (1-1) and the node (1-2).
) performs protocol transmission and reception for accessing the database of node (1-2).

A series of processing operations in the above-mentioned distributed database system will be further explained in detail with reference to FIG.

When the node (1-2) where a database exists is specified by issuing a database operation command from the application program (2-1) executed at the processing requesting node (1-1), the requesting node (1-1) After establishing a communication path (4) with the specified node, that is, the node (1-2) where the database is located, the distributed database control unit (5) of 1-1) executes a protocol corresponding to the database operation command. is transmitted to the node (1-2). Next, in the node (1-2), the distributed database control unit (5) of this node (1-2) transmits the protocol for the database operation command received from the node (1-1) to the database processing unit (6). Transfer the payment to the database (
3) is accessed.

[Problems to be Solved by the Invention] The relay processing method in the conventional distributed database system was configured as described above.

The communication path (4) connecting the node (1-1) and the node (1-2) is the application program (2) in the node (1-1).
-1) or if it is being used by another program in the node (1-1), the application program (2-i) of the node (1-1) that is subsequently started;
In some cases, the database (3) located in the node (1-2) cannot be accessed. Therefore, in order to access the database (3) of the node (1-2) using the application program (2-i) of this node (1-1).

It is necessary to check whether the communication path (4) is being used by the application program (2-1), and to check whether the communication path (4) is used by the database (3) except when the communication path (4) is not used. There was a problem that access could not be executed.

This invention was made in order to solve the above-mentioned problems, and is based on a communication path that directly connects a database processing request source node and a node that receives a processing request from this node and provides the database. Even if it is already in use by another program or cannot be used,
The object of the present invention is to obtain a distributed database system that can perform database processing between the two nodes by setting up a relay node that relays between the two nodes.

[Means for Solving the Problems] The relay processing method of the distributed database system according to the present invention provides each node with the above-mentioned methods that are used most preferentially when exchanging protocols between the above-mentioned respective nodes. A node that is not directly related to the exchange of data regarding the communication line that directly connects the nodes and the protocol used when this communication line is unavailable is used as a relay node to connect the above nodes. Data regarding the preliminary communication line is stored in advance, and when the distributed database control unit recognizes that the communication line that is to be used preferentially cannot be used, the data regarding the preliminary communication line is stored in advance based on the above data. This system is characterized in that protocols are exchanged using a communication line.

[Operation] The relay processing method of the distributed database system in this invention is such that when the distributed database control unit recognizes that the communication line that is used most preferentially cannot be used,
Since protocols are exchanged using a preliminary communication line based on pre-stored data, the flexibility of the processing method is improved.

[Embodiment] Hereinafter, one embodiment of the present invention will be explained with reference to two drawings. In Figure 1, (1-1) to (1-3) are nodes, (
2-1) to (2-i) are application programs executed on node (1-1), (3) is a database located in node (1-2), and (4-1) to (4- 3) is a communication line or communication path that moves between each node, (5) is a distributed database control unit that exists in each node, and (6) is a white node that processes database and access requests for nodes (1-2). Database processing section, (7-1)
-(7-3) are self-node information tables existing in each node, and (8-1) and (8-3) are distributed control tables existing in each node. Own node information table (7-1)
~ (7-3) and distributed control table (8-1) (8-3)
is a table referenced by the distributed database control unit (5). Own node information table (7-1) to (7-
3) defines the own node name. In addition, one distributed control table (8-1) (8-3) is composed of multiple elements, and each element is the other node name, the regular communication path name connecting the other node and the own node, and the own It consists of a communication path name that connects a node and a relay node. In the configuration of the embodiment shown in FIG. 1, a node (1-1) is a database processing requesting node, a node (1-2) is a node providing a database, and a node (1-3) is a node This is a relay node set between node (1-1) and node (1-2).

Next, the operation of the distributed database system according to an embodiment of the present invention will be explained with reference to the flowchart of FIG. 2 showing the operation of the distributed database control section (5). First, the application program (2-1) of the node (1-1) issues a database operation command to the distributed database control unit (5) in order to access the database (3) of the node (1-2) (step 101). In the case of a request from this application program (2-1), the node (1-
1) and the node (1-2).
) can be established to transmit and receive protocols for database access between nodes (1-1) and (1-2). Next, when the application program (2-i) of the node (1-1) issues a database operation command to the distributed database control unit (5) in order to access the database (3) of the node (1-2), ( Step 102), the distributed database control unit (5) obtains the regular communication path name (4-1) corresponding to the specified other node name (1-2) from the distributed control table (8-1) (Step 104).

However, since the communication path (4-1) is already in use by the application program (2-1) (step 1o5), the distributed database control unit (5) uses the distributed control table (g-
From i), the relay node communication path name corresponding to the other node name is obtained (step 106). A relay node communication path (4-2) connecting this node (1-1) and node (1-3) is established (step 107), and a database is established between node (1-1) and node (1-3). Transmission and reception of the access protocol is started (step 108). In the relay node (1-3), the distributed database control unit (5) also operates, and the designated node (1) is activated from the distributed control table (8-3). -2) Communication path name (4-
3) and transmits the database access protocol received from node (1-1) to node (1-2). The distributed database control unit (5) also operates in the node (1-2) (step 101);
Since the specified node name in the protocol received from -3) matches the own node name (step 102), a request is made to the database processing unit (6) to access the database (3) (step 103). In this way, under the control of the distributed data control unit of each node, the database access protocol from the processing requesting node (1-1) is transferred to the node providing the database via the relay node (1-3). (1-2).

Further, in this embodiment, an example of application to a network configuration system using communication lines has been shown, but the same effect can be achieved in a local area network configuration system or a composite network system thereof. Furthermore, according to the control method of the distributed database control unit of the present invention, the third
As shown in the figure, the database processing request source node (1
-1) and the node (1-2) providing the database, there are multiple relay nodes (10-1) (10-2) (1
It is also possible to configure and transmit a protocol for database access in multiple stages.

[Effects of the Invention] As described above, according to the present invention, when the distributed database control unit recognizes that the most preferentially used communication line cannot be used, it Since the protocol is exchanged using a backup communication line, it is possible to construct a highly flexible distributed database system that makes effective use of the network.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing a distributed database system according to an embodiment of the present invention, FIG. 2 is a flowchart showing the operation of a distributed database M control section according to an embodiment of the present invention,
FIG. 3 is a schematic block diagram showing a distributed database system according to another embodiment of the present invention, FIG. 4 is a schematic block diagram showing a general distributed database system, and FIG. 5 is a conventional distributed processing method in a distributed database system. FIG. In the figure, (1-1) to (1-3) are nodes, (2-
1) to (2-i) are application programs, (3-1) to (3
-3) is a database, (4-1) to (4-3) are communication paths, (5) is a distributed database processing unit, (7-1) to
(7-3) is the own node information table, (8-1) (8
-3) is a distributed control table. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] Connecting a plurality of nodes including an application program, a distributed database control unit that sends out a database access protocol corresponding to a database operation command in the application program, and a database to be accessed, and the plurality of nodes. In a distributed database system having a communication line, a communication circuit that directly connects each of the above nodes and is used most preferentially when exchanging protocols between each of the above nodes. and data regarding a preliminary communication line that connects each of the above nodes by using a node that is not directly related to the exchange of protocols used when this communication line is unavailable as a relay node. and when the distributed database control unit recognizes that the most preferentially used communication line cannot be used, the protocol is sent and received using the preliminary communication line based on the data. A relay processing method for a distributed database system that is characterized by the following.