PARALLEL EVENT PROCESSING IN A DATABASE SYSTEM

• US 20090019456A1
• Filed: 07/13/2007
• Published: 01/15/2009
• Est. Priority Date: 07/13/2007
• Status: Active Grant

• Current Assignee: Oracle International Corporation (Oracle Corporation)
• Original Assignee: Oracle International Corporation (Oracle Corporation)
• Inventors: Saxena, Abhishek, Bhatt, Neerja
• Granted Patent: US 8,448,186 B2
• Time in Patent Office: Days
• US Class Current: 719/318
• CPC Class Codes: G06F 16/24532 of parallel queries

Abstract

Techniques for processing events in parallel are provided. Multiple publishers publish events in parallel to a plurality of channels. Each channel is a queue that maintains a list of events that are awaiting to be processed by one or more slave processes. In one approach, all events that need to be persistent are published to a persistent channel, whereas all events that do not need to be persistent are published to one or more in-memory channels. In another approach, for each event, a publisher determines which channel of the plurality of channel to publish the event. The determination is based, at least in part, on the number of events in each channel and, optionally, the type of each event in each channel. In either approach, each event from a single publisher is published to the same channel.

Claims

1. A method comprising:

receiving a first event that occurs in a database system;

for each queue of a plurality of queues, determining a number of events that are enqueued in said each queue;

determining a particular queue, of the plurality of queues, to which to enqueue the first event based, at least in part, on the number of events that are enqueued in each queue of the plurality of queues; and

enqueuing the first event to the particular queue.

2. The method of claim 1, further comprising executing a plurality of slaves, wherein each slave of the plurality of slaves is dedicated to processing events only from a single queue of the plurality of queues.

3. The method of claim 1, further comprising, for each event that is subsequent to the first event and that is generated from the same database session as the first event, enqueuing said each event to the particular queue.

4. The method of claim 1, wherein:

determining the number of events includes determining a type of each event in said each queue;

determining the particular queue is also based, as least in part, on the type of said each event in said each queue.

5. The method of claim 4, wherein:

determining the type of each event in said each queue includes determining a number of events of each type in said each queue;

determining the particular queue is also based, at least in part, on the number of events of each type in said each queue.

6. The method of claim 5, wherein:

determining the number of events of each type in said each queue includes determining the number of events of each type in said each queue relative to the number of events in said each queue;

determining the particular queue is also based, at least in part, on the number of events of each type in said each queue relative to the number of events in said each queue.

7. The method of claim 1, wherein determining the particular queue is also based, as least in part, on a type of the first event.

8. The method of claim 1, wherein determining the particular queue is also based, as least in part, on whether one or more publishers, of a plurality of publishers that have published to each queue of the plurality of queues, are currently active.

9. The method of claim 1, wherein determining the particular queue is also based, at least in part, on the average time between when each event in said each queue was published to said each queue and when said each event was removed from said each queue.

10. The method of claim 1, wherein determining the particular queue is also based, at least in part, on the average time between a when each event in said each queue was removed from said each queue and when said each event was fully processed.

14. A machine-readable medium carrying one or more sequences of instructions which, when executed by one or more processors, causes the one or more processors to perform the method recited in claim 1.

15. A machine-readable medium carrying one or more sequences of instructions which, when executed by one or more processors, causes the one or more processors to perform the method recited in claim 2.

16. A machine-readable medium carrying one or more sequences of instructions which, when executed by one or more processors, causes the one or more processors to perform the method recited in claim 3.

17. A machine-readable medium carrying one or more sequences of instructions which, when executed by one or more processors, causes the one or more processors to perform the method recited in claim 4.

18. A machine-readable medium carrying one or more sequences of instructions which, when executed by one or more processors, causes the one or more processors to perform the method recited in claim 5.

19. A machine-readable medium carrying one or more sequences of instructions which, when executed by one or more processors, causes the one or more processors to perform the method recited in claim 6.

20. A machine-readable medium carrying one or more sequences of instructions which, when executed by one or more processors, causes the one or more processors to perform the method recited in claim 7.

21. A machine-readable medium carrying one or more sequences of instructions which, when executed by one or more processors, causes the one or more processors to perform the method recited in claim 8.

22. A machine-readable medium carrying one or more sequences of instructions which, when executed by one or more processors, causes the one or more processors to perform the method recited in claim 9.

23. A machine-readable medium carrying one or more sequences of instructions which, when executed by one or more processors, causes the one or more processors to perform the method recited in claim 10.

11. A method comprising:

receiving a plurality of events that occur in a database system;

enqueuing a first event, of the plurality of events, to a first queue that resides in volatile memory;

enqueuing the second event, of the plurality of events, to a second queue that resides in non-volatile memory;

a first slave process dequeuing the first event from the first queue, wherein the first slave process is dedicated to processing events only from the first queue; and

a second slave process dequeuing the second event from the second queue, wherein the second slave process is dedicated to processing events only from the second queue.

12. The method of claim 11 further comprising:

enqueuing a third event, of the plurality of events, to a third queue that resides in the volatile memory; and

a third slave process dequeuing the third event from the third queue, wherein the third slave process is dedicated to processing events only from the third queue.

24. A machine-readable medium carrying one or more sequences of instructions which, when executed by one or more processors, causes the one or more processors to perform the method recited in claim 11.

25. A machine-readable medium carrying one or more sequences of instructions which, when executed by one or more processors, causes the one or more processors to perform the method recited in claim 12.

13. A method comprising:

determining that an event has occurred in a database system;

determining a type of the event;

if the type is a first type, then (a) determining which first channel, of a plurality of channels, is least loaded among the plurality of channels, and (b) placing the event in the first channel; and

if the type is a second type, then (a) determining which second channel, of the plurality of channels, is most loaded among the plurality of channels, and (b) placing the event in the second channel.

26. A machine-readable medium carrying one or more sequences of instructions which, when executed by one or more processors, causes the one or more processors to perform the method recited in claim 13.