Dequeuing using queue batch numbers

• US 5,870,760 A
• Filed: 12/19/1996
• Issued: 02/09/1999
• Est. Priority Date: 12/19/1996
• Status: Expired due to Term

• Current Assignee: Oracle International Corporation (Oracle Corporation)
• Original Assignee: Oracle Corporation
• Inventors: Jain, Sandeep, Demers, Alan
• Primary Examiner(s): Black, Thomas G.
• Assistant Examiner(s): ALAM, SHAHID AL
• Application Number:
  US08/769,740
• Time in Patent Office: 782 Days
• Field of Search: 707/201, 707/203, 707/202, 395/280
• US Class Current: 1/1
• CPC Class Codes: G06F 16/2308 Concurrency control transaction processing G06F9/466
• CPC Class Codes: G06F 16/2343 Locking methods, e.g. distributed locking or locking implementation details
• CPC Class Codes: G06F 16/27 Replication, distribution or synchronisation of data between databases or within a distributed database system; Distributed database system architectures therefor
• CPC Class Codes: Y10S 707/99952 Coherency, e.g. same view to multiple users
• CPC Class Codes: Y10S 707/99953 Recoverability

Abstract

A method and system are provided for processing records from a set of records, where records are repeatedly being added to the set of records, and where each record in the set of records has to be processed once for each of a plurality of entities. According to the method, each record that is added to the set of records is marked with a default batch value. For each entity of the plurality of entities, a batch of the records is processed by performing the steps of: reading a last batch value associated with the entity, processing the records in the set of records that are marked with batch values that are more recent than the last batch value associated with the entity, and updating the last batch value associated with the entity to a most recent batch value of the records processed for the entity. Between processing consecutive batches for an entity of the plurality of entities, the set of records are marked by performing the steps of: updating a batch counter value to reflect a more recent batch number; and marking all records in the set of records that have the default batch value with the batch counter value.

Claims

1. A method for processing records that belong to a set of records, where records are repeatedly being added to said set of records, where each record in said set of records has to be processed once for each of a plurality of entities, the method comprising the steps of:

marking each record that is added to said set of records with a default batch value;

for each entity of said plurality of entities, processing a batch of said records by performing the steps of;

reading a last batch value associated with said entity;

processing the records in said set of records that are marked with batch values that are more recent than said last batch value associated with said entity; and

updating the last batch value associated with said entity to a most recent batch value of the records processed for said entity;

between processing consecutive batches for an entity of said plurality of entities, marking said set of records by performing the steps of;

updating a batch counter value to reflect a more recent batch number; and

marking all records in said set of records that have said default batch value with said batch counter value.

2. The method of claim 1 wherein:

the plurality of entities is a plurality of destination sites;

the set of records is a deferred transaction queue where each record corresponds to a set of changes to be propagated to one or more of said plurality of destination sites;

the step of marking each record that is added to said set of records with a default batch value includes marking each record that is added to said deferred transaction queue with a default batch value;

the step of reading a last batch value associated with said entity includes the step of reading a last batch value associated with a destination site of said plurality of destination sites;

the step of processing the records in said set that are marked with batch values that are more recent than said last batch value associated with said entity includes the step of dequeuing for said destination site the records in said set that are marked with batch values that are more recent than said last batch value associated with said destination site; and

the step of updating the last batch value associated with said entity to a most recent batch value of the records processed for said entity includes the step of updating the last batch value associated with said destination site to a highest batch value of the records dequeued for said destination site.

3. The method of claim 2 wherein:

said deferred transaction queue comprises a table; and

the step of dequeuing is performed by executing a query on said table.

4. The method of claim 2 wherein:

each record includes a prepared time; and

the step of processing a batch of said record further includes the step of sorting said records in said batch based on said prepared time.

5. The method of claim 1 wherein the step of marking said set of records is performed every time the step of processing a batch of said records is performed.

6. The method of claim 1 wherein the step of processing a batch of said records is performed by a different process for each of said plurality of entities.

7. The method of claim 1 further comprising the step of initializing said batch counter value to a value that is greater than said default batch value.

8. A method for processing records that have been added to a set of records, where records are repeatedly being added to said set of records, where each record in said set of records has to be processed once for each of a plurality of entities, the method comprising the steps of:

assigning each record that is added to said set of records to a temporary batch that is marked older than any prior batch;

for each entity of said plurality of entities, processing said records by repeatedly performing the steps of;

determining a last batch processed for said entity; and

processing the records in all batches that are newer than said last batch processed for said entity; and

between processing said records twice for an entity of said plurality of entities, marking said temporary batch as newer than any prior batch.

9. The method of claim 8 wherein:

the step of assigning each record that is added to said set of records to a temporary batch that is marked older than any prior batch includes the step of adding a default batch number to each record;

the step of determining a last batch processed for said entity includes the step of reading a last batch number for said entity;

the step of processing the records in all batches that are newer than said last batch processed for said entity includes the step of processing all records that have been marked with batch numbers that are more recent than the last batch number for said entity.

10. The method of claim 9 further comprising the steps of:

maintaining a batch number counter;

wherein the step of marking said temporary batch as newer than any prior batch includes the steps of;

incrementing the batch number counter; and

assigning the batch number counter to all records that currently contain the default batch number.

11. The method of claim 8 wherein:

the plurality of entities are destination sites to which changes must be replicated; and

the step of processing said records for each of said entities includes, for each destination site, repeatedly performing the steps of;

determining a last batch processed for said destination site; and

processing the records in all batches that are newer than said last batch processed for said destination site.

12. The method of claim 11 wherein:

the step of processing the records in all batches that are newer than said last batch processed for said destination site includes placing in a data container entries for transactions associated with said records; and

the method further comprises the step of propagating to the destination site changes made by the transactions represented by said entries in the data container.

13. A computer-readable medium having stored thereon sequences of instructions for processing records that have been added to a set of records, where records are repeatedly being added to said set of records, where each record in said set of records has to be processed once for each of a plurality of entities, the sequences of instructions including sequences of instructions for performing the steps of:

assigning each record that is added to said set of records to a temporary batch that is marked older than any prior batch;

for each of said entities, processing said records by repeatedly performing the steps of;

determining a last batch processed for said entity; and

processing the records in all batches that are newer than said last batch processed for said entity; and

between processing said records twice for an entity of said plurality of entities, marking said temporary batch as newer than any prior batch.

14. The computer-readable medium of claim 13 wherein:

the step of assigning each record that is added to said set of records to a temporary batch that is marked older than any prior batch includes the step of adding a default batch number to each record;

the step of determining a last batch processed for said entity includes the step of reading a last batch number for said entity;

the step of processing the records in all batches that are newer than said last batch processed for said entity includes the step of processing all records that have been marked with batch numbers that are more recent than the last batch number for said entity.

15. The computer-readable medium of claim 14 further comprising sequences of instructions for performing the steps of:

maintaining a batch number counter;

wherein the step of marking said temporary batch as newer than any prior batch includes the steps of;

incrementing the batch number counter; and

assigning the batch number counter to all records that currently contain the default batch number.

16. The computer-readable medium of claim 13 wherein:

the plurality of entities are destination sites to which changes must be replicated; and

the step of processing said records for each of said entities includes, for each destination site, repeatedly performing the steps of;

determining a last batch processed for said destination site; and

processing the records in all batches that are newer than said last batch processed for said destination site.

17. The computer-readable medium of claim 16 wherein:

the step of processing the records in all batches that are newer than said last batch processed for said destination site includes placing in a data structure entries for transactions associated with said records; and

the computer-readable medium further comprises sequences of instructions for performing the step of propagating to the destination site changes made by the transactions represented by said entries in the data structure.

18. A method for processing records that have been added to a set of records, where records are repeatedly being added to said set of records, where each record in said set of records has to be processed once for each of a plurality of entities, the method comprising the steps of:

assigning each record that is added to said set of records to a temporary batch that is marked older than any prior batch;

processing for an entity of said plurality of entities the records in all batches that are newer than a last batch processed for said entity; and

before processing said records again for said entity, marking said temporary batch as newer than any prior batch.

19. The method of claim 18 wherein:

the plurality of entities are destination sites to which changes must be replicated; and

the step of processing for said entity the records in all batches that are newer than a last batch processed for said entity includes repeatedly performing the steps of;

determining a last batch processed for a destination site; and

processing the records in all batches that are newer than said last batch processed for said destination site.

20. A computer-readable medium having stored thereon sequences of instructions for processing records that belong to a set of records, where records are repeatedly being added to said set of records, where each record in said set of records has to be processed once for each of a plurality of entities, the sequences of instructions including sequences of instructions for performing the steps of:

marking each record that is added to said set of records with a default batch value;

for each entity of said plurality of entities, processing a batch of said records by performing the steps of;

reading a last batch value associated with said entity;

processing the records in said set of records that are marked with batch values that are more recent than said last batch value associated with said entity; and

updating the last batch value associated with said entity to a most recent batch value of the records processed for said entity;

between processing consecutive batches for an entity of said plurality of entities, marking said set of records by performing the steps of;

updating a batch counter value to reflect a more recent batch number; and

marking all records in said set of records that have said default batch value with said batch counter value.

21. The computer-readable medium of claim 20 wherein:

the plurality of entities is a plurality of destination sites;

the set of records is a deferred transaction queue where each record corresponds to a set of changes to be propagated to one or more of said plurality of destination sites;

the step of marking each record that is added to said set of records with a default batch value includes marking each record that is added to said deferred transaction queue with a default batch value;

the step of reading a last batch value associated with said entity includes the step of reading a last batch value associated with a destination site of said plurality of destination sites;

the step of processing the records in said set that are marked with batch values that are more recent than said last batch value associated with said entity includes the step of dequeuing for said destination site the records in said set that are marked with batch values that are more recent than said last batch value associated with said destination site; and

the step of updating the last batch value associated with said entity to a most recent batch value of the records processed for said entity includes the step of updating the last batch value associated with said destination site to a highest batch value of the records dequeued for said destination site.

22. The computer-readable medium of claim 21 wherein:

said deferred transaction queue comprises a table; and

the step of dequeuing is performed by executing a query on said table.

23. The computer-readable medium of claim 21 wherein:

each record includes a prepared time; and

the step of processing a batch of said record further includes the step of sorting said records in said batch based on said prepared time.

24. The computer-readable medium of claim 20 wherein the step of marking said set of records is performed every time the step of processing a batch of said records is performed.

25. The computer-readable medium of claim 20 wherein the step of processing a batch of said records is performed by a different process for each of said plurality of entities.

26. The computer-readable medium of claim 20 further comprising instructions for performing the step of initializing said batch counter value to a value that is greater than said default batch value.

27. A system for processing records, the system comprising:

a plurality of entities;

a scheduler heap containing a set of records, wherein records are repeatedly being added to said set of records;

a propagation mechanism, wherein the propagation mechanism is configured to process each record in said set of records, wherein each record in said set of records is processed once for each of the plurality of entities by performing the steps of;

marking each record that is added to said set of records with a default batch value;

for each entity of said plurality of entities, processing a batch of said records by performing the steps of;

reading a last batch value associated with said entity;

processing the records in said set of records that are marked with batch values that are more recent than said last batch value associated with said entity; and

updating the last batch value associated with said entity to a most recent batch value of the records processed for said entity;

between processing consecutive batches for an entity of said plurality of entities, marking said set of records by performing the steps of;

updating a batch counter value to reflect a more recent batch number; and

marking all records in said set of records that have said default batch value with said batch counter value.