Methods, systems, and computer program product for remapping database sessions

A system, comprising:

• a processor or processor core;
• and
• a memory for holding programmable code which, when executed, causes the processor or processor core to perform a set of acts, the set of acts comprising:
• identifying a change in a cardinality of a database;
• assigning a new database session to a database instance of the database based at least in part upon the change in the cardinality of the database;
• determining one or more co-located database sessions for at least one database instance of multiple database instances, using a checker process for the database, wherein
• the checker process comprises a plurality of local checker processes each of which receives local data from each database instance of the plurality of database instances to provide each database instance with a global view of the plurality of database instances,
• at least one of the plurality of local checker processes detects, using the local data collected from the plurality of database instances, whether more than one database instance in the plurality of database instances has at least one co-located database session of the plurality of co-located database sessions,
• a co-located database session includes a database session that has been tagged to co-execute on a same computing node while the database session can execute on the same computing node or on a different computing node, and the co-located database session is tagged either before the change in the cardinality of the database occurs or after the change occurs;
• identifying, based at least in part upon a co-location data structure, multiple database instances of a plurality of database instances in the database that have the same co-location tag as the new database session and that respectively have one or more co-located database sessions of a plurality of co-located database sessions, wherein
• the co-location data structure stores therein an n-tuple that further comprises a first information pertaining to a database instance of the plurality of database instances and a second information pertaining to hashing of a co-location tag, and
• the co-location tag comprises a parameter that is used with a connect tag parameter to route co-located database sessions having the co-location tag to a single database instance of the plurality of database instances;
• and
• terminating at least one co-located database session of at least one database instance of the multiple database instances.

A non-transitory physical computer readable medium having stored thereon a sequence of instructions which, when executed by a processor or processor core, causes the processor or processor core to perform a set of acts, the set of acts comprising:

• identifying a change in a cardinality of a database;
• assigning a new database session to a database instance of the database based at least in part upon the change in the cardinality of the database;
• determining one or more co-located database sessions for at least one database instance of multiple database instances, using a checker process for the database, wherein
• the checker process comprises a plurality of local checker processes each of which receives local data from each database instance of the plurality of database instances to provide each database instance with a global view of the plurality of database instances,
• at least one of the plurality of local checker processes detects, using the local data collected from the plurality of database instances, whether more than one database instance in the plurality of database instances has at least one co-located database session of the plurality of co-located database sessions,
• a co-located database session includes a database session that has been tagged to co-execute on a same computing node while the database session can execute on the same computing node or on a different computing node, and the co-located database session is tagged either before the change in the cardinality of the database occurs or after the change occurs;
• identifying, based at least in part upon a co-location data structure, multiple database instances of a plurality of database instances in the database that have the same co-location tag as the new database session and that respectively have one or more co-located database sessions of a plurality of co-located database sessions, wherein
• the co-location data structure stores therein an n-tuple that further comprises a first information pertaining to a database instance of the plurality of database instances and a second information pertaining to hashing of a co-location tag, and
• the co-location tag comprises a parameter that is used with a connect tag parameter to route co-located database sessions having the co-location tag to a single database instance of the plurality of database instances;
• and
• terminating at least one co-located database session of at least one database instance of the multiple database instances.