Journaled tables in database systems

A method comprising:

• defining a journal table of a database, the journal table comprising a snapshot and a log table, the snapshot comprising an up-to-date representation of data in the journal table at a point in time;
• assigning a timestamp to the snapshot, the timestamp indicating the point in time;
• receiving a query directed to the database;
• identifying that the journal table needs to be processed to respond to the query;
• generating a query task in response to identifying that the journal table needs to be processed to respond to the query, the query task comprising instructions to read the snapshot and the log table to respond to the query;
• assigning the query task to at least one execution node of an execution platform;
• reading the snapshot;
• reading the timestamp assigned to the snapshot;
• reading the log table, the log table comprising a listing of changes requested to be made to the snapshot since the point in time indicated by the timestamp;
• identifying data in the snapshot that is responsive to the query;
• and
• identifying whether the identified data in the snapshot has been modified by any requested changes listed in the log table.

A non-transitory computer readable storage media containing instructions executable by at least one processor for causing the at least one processor to perform operations comprising:

• defining a journal table of a database, the journal table comprising a snapshot and a log table, the snapshot comprising an up-to-date representation of data in the journal table at a point in time;
• assigning a timestamp to the snapshot, the timestamp indicating the point in time;
• receiving a query directed to the database;
• identifying that the journal table needs to be processed to respond to the query;
• generating a query task in response to identifying that the journal table needs to be processed to respond to the query, the query task comprising instructions to read the snapshot and the log table to respond to the query;
• assigning the query task to at least one execution node of an execution platform;
• reading the snapshot;
• reading the timestamp assigned to the snapshot;
• reading the log table, the log table comprising a listing of changes requested to be made to the snapshot since the point in time indicated by the timestamp;
• identifying data in the snapshot that is responsive to the query;
• and
• identifying whether the identified data in the snapshot has been modified by any requested changes listed in the log table.

A system comprising:

• at least one processor;
• and
• one or more non-transitory computer readable storage media containing instructions executable by the at least one processor for causing the at least one processor to perform operations comprising:
• defining a journal table of a database, the journal table comprising a snapshot and a log table, the snapshot comprising an up-to-date representation of data in the journal table at a point in time;
• assigning a timestamp to the snapshot, the timestamp indicating the point in time;
• receiving a query directed to the database;
• identifying that the journal table needs to be processed to respond to the query;
• generating a query task in response to identifying that the journal table needs to be processed to respond to the query, the query task comprising instructions to read the snapshot and the log table to respond to the query;
• assigning the query task to at least one execution node of an execution platform;
• reading the snapshot;
• reading the timestamp assigned to the snapshot;
• reading the log table, the log table comprising a listing of changes requested to be made to the snapshot since the point in time indicated by the timestamp;
• identifying data in the snapshot that is responsive to a query;
• and
• identifying whether the identified data in the snapshot has been modified by any requested changes listed in the log table.