Method of using cache to determine the visibility to a remote database client of a plurality of database transactions

A database data propagation computing system for partially propagating a central database to a partially replicated database, comprising:

• a visibility determination subsystem that determines whether a visibility of a user of the partially replicated database to data being propagated is stored in a cache memory, and if so, accessing said visibility from said cache memory, and if not, determining said visibility and selectively storing said visibility in said cache memory;
• and
• a propagation subsystem that propagates said data to the partially replicated database according to said visibility determined by said visibility determination subsystem.

A system for propagating data in a database, wherein the database includes a central database and a partially replicated database, the system comprising:

• means for determining whether a visibility of a user of the partially replicated database to data being propagated is stored in a cache memory, and if so, accessing said visibility from said cache memory, and if not, determining said visibility and selectively storing said visibility in said cache memory;
• and
• means for propagating said data to the partially replicated database according to said visibility.

One or more computer memories that together store a visibility cache data structure, comprising, for each of a plurality of data items residing in a first database, an indication of the outcome of earlier determining visibility of the data item by a second database,

• such that the indications can be used to discern visibility of a selected data item among the plurality by the second database, and thereby determine whether to propagate the selected data item from the first database to the second database, without re-determining visibility of the selected data item by the second database.

One or more generated data signals that together convey a data item propagation data structure, the data item propagation data structure containing a data item propagated from a first database to a second database as the result of querying a visibility cache indicating that the propagated data item is visible to the second database,

• wherein the generated data signals together further convey a second data item propagation data structure, the second data item propagation data structure containing a second data item propagated from the first database to the second database as the result of applying a visibility rule to determine that the propagated data item is visible to the second database at a time when the visibility cache does not indicate whether the propagated data item is visible to the second database.