Distributed database management system for retrieving data files from databases selected based upon retrieval time

• US 5,379,424 A
• Filed: 05/12/1993
• Issued: 01/03/1995
• Est. Priority Date: 05/10/1990
• Status: Expired due to Term

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Kato, Nobuhiro, Sekiguchi, Koichi, Morimoto, Yojiro, Muranaga, Miho
• Primary Examiner(s): Shaw, Gareth D.
• Assistant Examiner(s): Toplu, Lucien
• Application Number:
  US08/060,506
• Time in Patent Office: 601 Days
• Field of Search: 364/DIG. 1, 364/DIG. 2, 395/600
• US Class Current: 707/758
• CPC Class Codes: G06F 16/24542 Plan optimisation
• CPC Class Codes: G06F 16/27 Replication, distribution or synchronisation of data between databases or within a distributed database system; Distributed database system architectures therefor
• CPC Class Codes: G06F 16/275 Synchronous replication
• CPC Class Codes: Y10S 707/922 Communications
• CPC Class Codes: Y10S 707/966 Distributed
• CPC Class Codes: Y10S 707/99932 Access augmentation or optimizing
• CPC Class Codes: Y10S 707/99939 Privileged access

Abstract

A distributed database management system includes a plurality of computers, each including a database for storing data files to be processed. The plurality of computers are interconnected by communication lines. Each computer has stored data file names, and corresponding address area and location information for all databases, and measures data file retrieval time from the databases. A retrieval time memory section stores data file retrieval times corresponding to the address areas of data stored in the databases. A retrieval time prediction section retrieves the data file retrieval times for data files corresponding to a data file name requested by a user when the requested data file is stored in at least two databases, utilizing stored data file retrieval times and corresponding address areas and location information on where the data file is stored. A data retrieval optimization section selects the database location information and the address area associated with the requested data file name according to the retrieval result by the retrieval time prediction section, and retrieves the requested data file from the appropriate database according to the location information and address area. The system can also register input data files according to a desired retrieval time.

Claims

1. A distributed database management system, comprising:

a plurality of computers, each including a database for storing at least one data file to be processed, each data file being identifiable by a corresponding data file name, and each database being identifiable by a corresponding database name, the plurality of computers being interconnected by communication lines, each computer including;

input means for inputting a data file name of a requested one of the data files to be processed, wherein at least one of a plurality of predetermined data file names corresponds to the requested data file name, the requested data file being stored in at least one of the databases;

memory management means for storing the plurality of predetermined data file names and an address code corresponding to each of the plurality of predetermined data file names, wherein the address code for each predetermined data file name includes a database name of a database in which a data file identifiable by the predetermined data file name, is stored, and an address area identifying the address within each database where the data file is stored;

data file name identification means for identifying which of the plurality of predetermined data file names correspond to the requested data file name;

retrieval time measurement means for measuring a data retrieval time for each data file identifiable by one of the predetermined data file names, wherein a data retrieval time is an amount of time necessary to retrieve a data file from a database in which the data file is stored;

retrieval time memory means for storing each data retrieval time measured by the retrieval time measurement means, and for storing, in association with each data retrieval time, the address area within the database where the data file, whose retrieval time was measured, is stored;

selection means for selecting one of the at least one predetermined data file names which corresponds to the requested data file based upon a comparison of data retrieval times stored in the retrieval time memory means which correspond to the at least one predetermined data file name;

address code identification means for identifying the address code in which the requested data file, as identified by the selected predetermined data file name, is stored; and

retrieving means for retrieving the requested data file from the address area of a database identified by the address code identification means when the requested data file is stored in at least two of the databases, and, when the requested data file is stored in only one database, for retrieving the requested data file from the address area of the one database in which the requested data file is stored,

wherein the selection means includes retrieval selecting means for selecting the one predetermined data file name which has the shortest data retrieval time compared with data retrieval times for retrieving the requested data file from each of the databases in which the requested data file is stored.

2. A distributed database management system, comprising:

a plurality of computers, each including a database for storing at least one data file to be processed, each data file being identifiable by a corresponding data file name, and each database being identifiable by a corresponding database name, the plurality of computers being interconnected by communication lines, each computer including;

input means for inputting a data file name of a requested one of the data files to be processed, wherein at least one of a plurality of predetermined data file names corresponds to the requested data file name, the requested data file being stored in at least one of the databases;

memory management means for storing the plurality of predetermined data file names and an address code corresponding to each of the plurality of predetermined data file names, wherein the address code for each predetermined data file name includes a database name of a database in which a data file identifiable by the predetermined data file name, is stored, and an address area identifying the address within each database where the data file is stored;

data file name identification means for identifying which of the plurality of predetermined data file names correspond to the requested data file name;

retrieval time measurement means for measuring a data retrieval time for each data file identifiable by one of the predetermined data file names, wherein a data retrieval time is an amount of time necessary to retrieve a data file from a database in which the data file is stored;

retrieval time memory means for storing each data retrieval time measured by the retrieval time measurement means, and for storing, in association with each data retrieval time, the address area within the database where the data file, whose retrieval time was measured, is stored;

selection means for selecting one of the at least one predetermined data file names which corresponds to the requested data file based upon a comparison of data retrieval times stored in the retrieval time memory means which correspond to the at least one predetermined data file name;

address code identification means for identifying the address code in which the requested data file, as identified by the selected predetermined data file name, is stored; and

retrieving means for retrieving the requested data file from the address area of a database identified by the address code identification means when the requested data file is stored in at least two of the databases, and, when the requested data file is stored in only one database, for retrieving the requested data file from the address area of the one database in which the requested data file is stored,

wherein the retrieval time measurement means includes means for updating the data retrieval time stored in said retrieval time memory means which corresponds to the selected predetermined data file name.

3. A distributed database management system, comprising:

a plurality of computers, each including a database for storing at least one data file to be processed, each data file being identifiable by a corresponding data file name, and each database being identifiable by a corresponding database name, the plurality of computers being interconnected by communication lines, each computer including;

input means for inputting a data file to be registered and a retrieval time desired by a user;

memory management means for storing data file names corresponding to a database name of a database in which a data file, identifiable by the data file name, is stored, and an address area identifying the address within each database where the data file is stored;

retrieval time measurement means for measuring a data retrieval time for each data file identifiable by one of the data file names, wherein a data retrieval time is an amount time necessary to retrieve a data file from a database in which the data file is stored;

retrieval time memory means for storing each data retrieval time measured by the retrieval time measurement means, and for storing, in association with each data retrieval time, the address area within the database where the data file whose retrieval time was measured, is stored;

address area locating means for locating an address area corresponding to the desired retrieval time in the retrieval time memory means which does not contain a previously stored data file;

data retrieval selecting means for selecting the database name stored in the memory management means which corresponds to the address area located by the address area locating means;

storing means for storing the input data file at the located address area in the database identified by the selected database name;

wherein the address area locating means includes means for extracting the data retrieval time associated with an address area stored in the retrieval time memory means which does not contain a previously stored data file when the desired retrieval time does not coincide with any of the data retrieval times previously stored in the retrieval time memory means.

4. The distributed database management system of claim 3, further including display means for displaying the data retrieval time extracted by the address area locating means, to allow the user to select the outputted data retrieval time as a desired retrieval time.

5. A distributed database management system, comprising:

a plurality of computers, each including a database for storing at least one data file to be processed, each data file being identifiable by a corresponding data file name, and each database being identifiable by a corresponding database name, the plurality of computers being interconnected by communication lines, each computer including;

input means for inputting a data file to be registered and a retrieval time desired by a user;

memory management means for storing data file names corresponding to a database name of a database in which a data file, identifiable by the data file name, is stored, and an address area identifying the address within each database where the data file is stored;

retrieval time measurement means for measuring a data retrieval time for each data file identifiable by one of the data file names, wherein a data retrieval time is an amount time necessary to retrieve a data file from a database in which the data file is stored;

retrieval time memory means for storing each data retrieval time measured by the retrieval time measurement means, and for storing, in association with each data retrieval time, the address area within the database where the data file whose retrieval time was measured, is stored;

address area locating means for locating an address area corresponding to the desired retrieval time in the retrieval time memory means which does not contain a previously stored data file;

data retrieval selecting means for selecting the database name stored in the memory management means which corresponds to the address area located by the address area locating means;

storing means for storing the input data file at the located address area in the database identified by the selected database name;

wherein the data retrieval selecting means includes means for storing a data file name corresponding to the input data in the memory management means in association with the located address area where the input data was stored after the input data has been stored in the database.