SYSTEM FOR REPLICATION-DRIVEN REPOSITORY CACHE INVALIDATION ACROSS MULTIPLE DATA CENTERS

• US 20140310293A1
• Filed: 04/13/2013
• Published: 10/16/2014
• Est. Priority Date: 04/13/2013
• Status: Active Grant

• Current Assignee: Oracle International Corporation (Oracle Corporation)
• Original Assignee: Oracle International Corporation (Oracle Corporation)
• Inventors: Zhu, Zhenyu, Knoll, Phillip O.
• Granted Patent: US 9,507,842 B2
• Time in Patent Office: Days
• US Class Current: 707/756
• CPC Class Codes: G06F 16/24552 Database cache management
• 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

Abstract

A distributed cache invalidation system operating on multiple data centers utilizes metadata, read from a replication stream transmitted between data centers, to identify cached items to be invalidated.

Claims

1. A method, performed by one or more processors at a first data center, for invalidating items using a distributed cache mode at the first data center, the method comprising:

writing replication data, using the one or more processors, to a notifier table, with the replication data indicating updates made to tables of a database at a second data center that are replicated as updates to corresponding tables of a database at the first data center, with each row of the notifier table represented by a notification item holding metadata including the name of an updated first table of the database at the first data center, a timestamp indicating when an update occurred to the updated first table and a name/value pair, where the second data center is remote from the first data center;

periodically polling, using the one or more processors, the metadata to access notification items having a timestamp indicating that the age of the notification item is less than a maximum value;

mapping, using the one or more processors, a first table name stored in a first accessed notification item to one or more mapped object relational repository items that use the distributed cache mode;

constructing, using the one or more processors, a unique identity for a mapped object relational repository item using one or more name/value pairs stored in a first accessed notification item and representing the primary key column(s) of the first table name stored in the first accessed notification item;

invoking, using the one or more processors, a distributed cache invalidation system implemented only at the first data center; and

providing, using the one or more processors, the unique identity of the mapped object relational depository item to be invalidated to the distributed cache invalidation system to invalidate all cached copies of the mapped object relational depository item at the first data center.

2. The method of claim 1 where mapping a table name further comprises:

inspecting item descriptors of a plurality of items that use the distributed cache mode to identify a group of one or more items in the plurality that reference the first table; and

associating the item descriptors of the one or more items to the first table name.

3. The method of claim 1 where the distributed cache invalidation system implemented only at the first data center includes:

a mesh connecting event servers of all server applications using the distributed cache mode.

4. The method of claim 1 further comprising:

representing a row of the notifier table as an item in a replication update repository.

5. The method of claim 1 with periodically polling further comprising:

adjusting the duration of a scheduled polling period.

6. The method of claim 1 with mapping further comprising:

storing references to all item descriptors that use distributed cache mode.

7. The method of claim 1 with providing the identity further comprising:

providing primary keys stored in a notification item to a cache invalidation system subscriber table.

8. An apparatus configured to invalidate items using a distributed cache mode at a first data center, the apparatus comprising:

one or more digital processors coupled to a non-transitory processor-readable storage device, with the one or more digital processors configured to execute one or more instructions included in the non-transitory processor-readable storage device to perform the following acts;

writing replication data to a notifier table, with the replication data indicating updates made to tables of a database at a second data center that are replicated as updates to corresponding tables of a database at the first data center, with each row of the notifier table represented by a notification item holding metadata including the name of an updated first table of the database at the first data center, a timestamp indicating when an update occurred to the updated first table and a name/value pair, where the second data center is remote from the first data center;

periodically polling the metadata to access notification items having a timestamp indicating that the age of the notification item is less than a maximum value;

mapping, using the one or more processors, a first table name stored in a first accessed notification item to one or more mapped object relational repository items that use the distributed cache mode;

constructing, using the one or more processors, a unique identity for a mapped object relational repository item using one or more name/value pairs stored in a first accessed notification item and representing the primary key column(s) of the first table name stored in the first accessed notification item;

invoking, using the one or more processors, a distributed cache invalidation system implemented only at the first data center; and

providing, using the one or more processors, the unique identity of the mapped object relational depository item to be invalidated to the distributed cache invalidation system to invalidate all cached copies of the mapped object relational depository item at the first data center.

9. The apparatus of claim 8 with the distributed cache mode further comprising:

a mesh connecting event servers of all server applications using the distributed cache mode.

10. The apparatus of claim 8 with the one or more digital processors further configured to perform the act of:

inspecting item descriptors of a plurality of items that use the distributed cache mode to identify a group of one or more items in the plurality that reference the first table; and

associating the item descriptors of the one or more items to the first table.

11. The apparatus of claim 8 with the one or more digital processors further configured to perform the act of:

representing a row of the notifier table as an item in a replication update repository.

12. The apparatus of claim 8 with the one or more digital processors further configured to perform the act of:

adjusting the duration of a scheduled polling period.

13. The apparatus of claim 8 with the one or more digital processors further configured to perform the act of:

storing references to all item descriptors that use distributed cache mode.

14. The apparatus of claim 8 with the one or more digital processors further configured to perform the act of:

providing primary keys stored in a notification item to a cache invalidation system subscriber table.

15. A non-transitory computer-readable storage medium comprising encoded program code for execution by one or more computer processors on a computer to invalidate items using a distributed cache mode at a first data center, the program code when executed is executable to perform the acts of:

writing replication data to a notifier table, with the replication data indicating updates made to tables of a database at a second data center that are replicated as updates to corresponding tables of a database at the first data center, with each row of the notifier table represented by a notification item holding metadata including the name of an updated first table of the database at the first data center, a timestamp indicating when an update occurred to the updated first table and a name/value pair, where the second data center is remote from the first data center;

periodically polling the metadata to access notification items having a timestamp indicating that the age of the notification item is less than a maximum value;

mapping, using the one or more processors, a first table name stored in a first accessed notification item to one or more mapped object relational repository items that use the distributed cache mode;

constructing, using the one or more processors, a unique identity for a mapped object relational repository item using one or more name/value pairs stored in a first accessed notification item and representing the primary key column(s) of the first table name stored in the first accessed notification item;

invoking, using the one or more processors, a distributed cache invalidation system implemented only at the first data center; and

providing, using the one or more processors, the unique identity of the mapped object relational depository item to be invalidated to the distributed cache invalidation system to invalidate all cached copies of the mapped object relational depository item at the first data center.

16. The non-transitory computer-readable storage medium of claim 15 further comprising program code that when executed is executable to perform the acts of:

inspecting item descriptors of a plurality of items that use the distributed cache mode to identify a group of one or more items in the plurality that reference the first table; and

associating the item descriptors of the one or more items to the first table.

17. The non-transitory computer-readable storage medium of claim 15 further comprising program code that when executed is executable to perform the act of:

representing a row of the notifier table as an item in a replication update repository.

18. The non-transitory computer-readable storage medium of claim 15 further comprising program code that when executed is executable to perform the act of:

adjusting the duration of a scheduled polling period.

19. The non-transitory computer-readable storage medium of claim 15 further comprising program code that when executed is executable to perform the act of:

storing references to all item descriptors that use distributed cache mode.

20. The non-transitory computer-readable storage medium of claim 15 further comprising program code that when executed is executable to perform the act of:

providing primary keys stored in a notification item to a cache invalidation system subscriber table.

21. An apparatus configured to invalidate repository items using a distributed cache mode at a first data center, the apparatus comprising:

one or more digital processors coupled to a non-transitory processor-readable storage device, with the one or more digital processors configured to execute one or more instructions included in the non-transitory processor-readable storage device to perform the following acts;

writing replication data to a notifier table, with the replication data indicating updates made to tables of a database at a second data center that are replicated as updates to corresponding tables of a database at the first data center, with each row of the notifier table represented by a notification item holding metadata including the name of an updated first table of the database at the first data center, a timestamp indicating when an update occurred to the updated first table and a identification of a row updated in the first table, where the second data center is remote from the first data center;

periodically polling the metadata to access notification items having a timestamp indicating that the age of the notification item is less than a maximum value;

invoking, using the one or more processors, a distributed cache invalidation system implemented only at the first data center; and

providing, using the one or more processors, a unique identity of an invalid repository item, mapped to an updated row of the first table, to the distributed cache invalidation system to invalidate all cached copies of the invalid depository item at the first data center.