Electrical computers and digital processing systems: multicomput – Computer network managing – Computer network monitoring
Reexamination Certificate
1998-06-25
2001-12-18
Maung, Zarni (Department: 2152)
Electrical computers and digital processing systems: multicomput
Computer network managing
Computer network monitoring
C709S225000, C345S215000
Reexamination Certificate
active
06332160
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of matching transactions performed by a plurality of clients connected to a distributed network system through a network server.
This application is based on patent application No. Hei 09-187401 filed in Japan, the content of which is incorporated herein by reference.
2. Description of the Related Art
In a distributed network system connected to a plurality of clients sharing a common network server, when transactions involving different commands are requested by each client, different approaches have been used to respond to such a situation.
First conventional method which is a generally accepted approach in a distributed network system, can execute a plurality of transactions in parallel, by locking those preceding updating transactions of a common data base, and other transactions requesting inquiry or updating of the common data base are made to wait, so that the transactions calling for the common data base can be serialized chronologically.
In a second conventional method disclosed in a Japanese Patent Application, First Publication, Sho. 63-310042, when a plurality of clients issue commands of different semantics to a common data base, a consultation process is invoked so that the different clients can cooperate to arrive at a correct operational step.
In such methods of matching conflicting transactions, one of the problems is that the method can only offer a uniform mediation solution. The reason is that, in the first method, all the conflicting transactions are always serialized regardless of the contents of semantics conflicts. In the second method, mediation of conflicting transactions is carried out by consultations regardless of the contents of semantics conflicts.
Further problem in the second method is that for each conflicting transaction, a consulting step must always be carried out among the clients so that, if the cooperative step is being carried out on-line, the processes are frequently interrupted and become quite cumbersome.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a method for matching transactions in a distributed network system, in which application programs such as word and graphics processing are shared to provide a cooperative conflict resolution, to enable a plurality of conflicting transactions with semantics conflicts to be resolved in the network server, in each application program and for each content of semantic conflicts.
The object has been achieved in a method for matching transactions in a distributed network system serving a plurality of clients connected through a network server having network applications, wherein; a transaction of a data-change operation requested by a user application is received in a transactions manager of the network server; a received transaction is inspected for semantics conflicts with other transactions received from other clients by a semantics conflict detection section; the received transaction in the transactions manager is executed according to the data-change operation, when there is no semantics conflict; but when there is a semantics conflict, an address of a processing routine for resolving the semantics conflict is forwarded from the semantics conflict detection section to the transactions manager; the processing routine is executed by the transactions manager to resolve the semantics conflict.
More specifically the method is comprised by the following steps:
(1) forwarding a transaction generated by a change-data operation requested by a user application to the transactions manager;
(2) inspecting the transaction for accessing conflicts with respect to a group of data common to other transactions by using the transaction conflict detection section;
(3) requesting network applications to inspect for semantics conflicts in access-conflicting transactions by using respective semantics conflict detection section;
(4) inspecting the access-conflicting transactions for semantics conflicts by using own semantics conflict detection sections in each application;
(5) continuing execution of the transaction in transactions manager when there is no semantics conflict; but, when there is a semantics conflict,
(6) receiving in the transactions manager, from a semantics conflict detection section, an address of a processing routine having a method consistent with contents of the semantics conflict for resolving the semantics conflict; and
(7) executing the processing routine in the transactions manager, thereby resolving the semantics conflict.
Accordingly, when there is a semantics conflict in a number of conflicting transactions, a resolution method can be selected for each application and for each content of the semantics conflicts.
Also, when a semantics conflict in access-conflicting transactions relates to a value change of a common attribute in a common group of data, it is inspected to determine whether the difference in the extent change is within a range of pre-determined values, and if the change is within the pre-determined range, an address of a processing routine to execute only those transactions whose change values exceed a pre-determined difference range is forwarded to the transactions manager, or an address of a processing routine to execute transactions in a sequence of arrival of access-conflicting transactions is forwarded to the transactions manager.
Also, the method may include a step of pre-selecting processing routines for each network application and for each type of semantics conflicts from a plurality of processing routines for resolving semantics conflicts. This approach facilitates execution of any resolution method.
Also, the transactions manager may base a decision of whether a transaction being received from an on-line client conflicts with transactions received from other clients by detecting a wait-status for a locked common group of data.
A modified method for matching distributed transactions in a distributed network system serving a plurality of clients connected through a network server, is comprised by processes wherein: a transaction generated by a change-data operation requested by a user application is received in a transactions manager of the network server; a received transaction is inspected for a semantics conflict with other transactions received and recorded in a reception log from other clients by using a semantics conflict detection section; the received transaction is executed by the transactions manger when there is no semantics conflict; but when there is a semantics conflict, an address of a processing routine for resolving a semantics conflict is forwarded from the semantics conflict detection section to the transactions manager; and the processing routine is executed by the transactions manager, thereby resolving the semantics conflict.
In this case, when a transaction is received in the network server from a reconnected client, an inspection range for semantics conflicts of the transaction is restricted to a portion of transactions received from other clients and recorded in a reception log.
The methods present superior resolution of conflicts in a distributed network system, because the method enables to resolve conflicts for each application and for each content of semantics conflicts, thereby providing a resolution method consistent with the nature of the content of semantics conflicts.
Also, because, when semantics conflicts for a plurality of conflicting transactions are related to changing the value of common attributes and common data base, the method first examines whether the value to be changed is within a pre-determined range of values, and if it is within the range, a routine to execute only those transactions with large values of change, or a routine to execute those transactions in the order of arrival is applied. By adopting this approach, those conflicts with negligible degree of change can be executed without intervention by the user, thereby facilitating the process of executing cooperative work.
REFERENC
Cardone Jason D.
Maung Zarni
McGinn & Gibb PLLC
NEC Corporation
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