Real-time distributed database system and method

A method for generating a data update message corresponding to a database stored at a node in a distributed database system, which includes a plurality of nodes each storing a database, to distribute updates to each database, each database overlapping at least partially with a database stored on one other node, each database containing a plurality of tables, each table having a table update flag associated therewith and containing at least one record, each record having a record update flag associated therewith, said table update flag and said record update flag indicating that a corresponding table and record, respectively, have been modified when set, the method comprising:

• (a) locating a modified table in said database based on said table update flags;
• (b) locating a modified record in said modified table based on said record update flags;
• (c) writing a header in said data update message, said header including a table identifier and record number, said table identifier identifying said modified table, said record number identifying said modified record in said modified table;
• (d) writing contents of said modified record in said data update message;
• and
• (e) sending said data update message to each node via a communication medium connecting said nodes.

A method for generating a data update message corresponding to a database stored at a node in a distributed database system, which includes a plurality of nodes each storing a database, to distribute updates to each database, each database overlapping at least partially with a database stored on one other node, each database containing a plurality of tables, each table having a table identifier associated therewith and containing at least one record, each record having a record number associated therewith, said database at each node having an updated table list associated therewith, said updated table list storing said table identifier for each modified table in said database, each table having an updated record list associated therewith, said updated record list storing said record number for each modified record in an associated table, the method comprising:

• (a) locating a modified table in said database based on said updated table list;
• (b) locating a modified record in said modified table based on said updated record list associated with said modified table;
• (c) writing a header in said data update message, said header including said table identifier for said modified table and said record number for said modified record;
• (d) writing contents of said modified record in said data update message;
• and
• (e) sending said data update message to each node via a communication medium connecting said nodes.

A method of updating a database stored at a node in a distributed database system, which includes a plurality of nodes each storing a database and connected via a communication medium, each database overlapping at least partially with a database stored on one other node, each database containing a plurality of tables, each table containing at least one record, the method comprising:

• (a) receiving, at a node, a data update message on said communication medium, said data update message including at least one header associated with a record and contents of said record, said header including a table identifier identifying a table containing said record and a record number associated with said record;
• (b) extracting said header from said data update message;
• (c) locating said record in said database stored at said node based on said table identifier and said record number in said extracted header;
• and
• (d) writing said contents of said record in said data update message into said record of said database located in step (c).

A distributed database system, comprising:

• a plurality of nodes connected via a communication medium;
• and wherein
• each node includes,
• at least one application;
• a database stored on said node, said database at least partially overlapping at least one other database, said database including a plurality of tables, and each table including at least one record, ownership of each table in said database being assigned to only one application, and only an owning application being able to modify a table owned by said owning application;
• scheduling means for scheduling running of said applications on said node such that only one application reads from and writes to said database at a time;
• distributing means for distributing updates made to said database to every other database;
• and
• updating means for updating said database in accordance with received distributed updates.

A method of communication between applications in a distributed database system which includes a plurality of nodes connected via a network medium, each node running at least one application and storing a database, each database at least partially overlapping at least one other database, each database including a plurality of tables, and each table including at least one record and being owned by only one application, the method comprising:

• (a) sending modification requests from non-owning applications to an owning application via said communication medium, said modification requests indicating a desired modification to a record in a table not owned by said non-owning application and owned by said owning application;
• (b) receiving, by said owning application, modification requests which request modification of a record in a table owned by said owning application;
• and
• (c) modifying tables owned by said owning application in accordance with modifications generated by said owning application and modifications in said received modification requests.