Automatic adoption of parallelized database garbage collection

A system comprising:

• at least one data processor;
• and
• memory storing instructions, which when executed by the at least one data processor, result in operations comprising:
• initiating recovery of a database system by taking the database system offline;
• replaying recovery operations specified by a redo log of the database system;
• generating a cleanup log identifying cleanup operations occurring during the replay of the recovery operations requiring garbage collection;
• initiating, concurrent with at least one of the startup of the database or the replay of the recovery operations, garbage collection of the cleanup operations as specified in a last database savepoint or by the cleanup log, the garbage collection being implemented by a plurality of garbage collection threads;
• monitoring, during garbage collection, processor usage of the database system in connection with the garbage collection;
• adding, during garbage collection, more garbage collector threads if the monitored processor usage is below a first pre-defined threshold;
• decreasing, during garbage collection, a current number of garbage collector threads if the monitored processor usage is above a second threshold;
• and
• bringing the database system online after all of the recovery operations are replayed;
• wherein:
• the replay operations are executed by recovery threads and the cleanup operations are executed by garbage collection threads;
• and
• the database system comprises a plurality of programmable processor cores and the threads are striped such that each core executes a maximum of one recovery thread and one garbage collection thread.

A non-transitory computer program product storing instructions, which when executed by at least one data processor, result in operations comprising:

• initiating recovery of a database system by taking the database system offline;
• replaying recovery operations specified by a redo log of the database system;
• generating a cleanup log identifying cleanup operations occurring during the replay of the recovery operations requiring garbage collection;
• initiating, concurrent with at least one of the startup of the database or the replay of the recovery operations, garbage collection of the cleanup operations as specified in a last database savepoint or by the cleanup log, the garbage collection being implemented by a plurality of garbage collection threads;
• monitoring, during garbage collection, processor usage of the database system in connection with the garbage collection;
• adding, during garbage collection, more garbage collector threads if the monitored processor usage is below a first pre-defined threshold;
• decreasing, during garbage collection, a current number of garbage collector threads if the monitored processor usage is above a second threshold;
• and
• bringing the database system online after all of the recovery operations are replayed,
• wherein:
• the replay operations are executed by recovery threads and the cleanup operations are executed by garbage collection threads;
• and
• the database system comprises a plurality of programmable processor cores and the threads are striped such that each core executes a maximum of one recovery thread and one garbage collection thread.