Transactional and parallel log replay for asynchronous table replication

• US 9,959,178 B2
• Filed: 03/13/2015
• Issued: 05/01/2018
• Est. Priority Date: 11/25/2014
• Status: Active Grant

• Current Assignee: SAP SE
• Original Assignee: SAP SE
• Inventors: Lee, Juchang, Park, Chang-Gyoo, Na, Hyoung-Jun, Kim, Kyu-Hwan
• Primary Examiner(s): Burke, Jeffrey A
• Assistant Examiner(s): VU, THONG H
• Application Number:
  US14/657,948
• Publication Number:
  US 20160147859A1
• Time in Patent Office: 1,145 Days
• Field of Search: 707615, 707602, 707687, 707741, 707703, 707759, 707622, 707726, 707812, 707649, 707611, 707626, 707634
• CPC Class Codes: G06F 11/1464 for networked environments
• CPC Class Codes: G06F 11/1469 Backup restoration techniques
• CPC Class Codes: G06F 11/1471 involving logging of persistent data for recovery
• CPC Class Codes: G06F 11/1474 in transactions G06F16/20 takes precedence
• CPC Class Codes: G06F 11/1662 the resynchronized component or unit being a persistent storage device re-synchronization of failed mirror storage G06F11/2082; rebuild or reconstruction of parity RAID storage G06F11/1008
• CPC Class Codes: G06F 11/2094 Redundant storage or storage space G06F11/2056 takes precedence
• CPC Class Codes: G06F 16/2358 Change logging, detection, and notification replication G06F16/27
• CPC Class Codes: G06F 16/2365 Ensuring data consistency and integrity
• CPC Class Codes: G06F 16/2379 Updates performed during online database operations; commit processing
• 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: G06F 16/273 Asynchronous replication or reconciliation
• CPC Class Codes: G06F 16/955 using information identifiers, e.g. uniform resource locators [URL]
• CPC Class Codes: G06F 2201/80 Database-specific techniques
• CPC Class Codes: G06F 2201/835 Timestamp

Abstract

Disclosed herein are system, method, and computer program product embodiments for replicating a database transaction to a replica table. An embodiment operates by receiving a replication log entry and an associated transaction commit log entry for a database transaction to be replayed to a row at a replica table. A row-ID value of the replication log entry is compared to a row-ID column value of the row at the replica table. The replication log entry is then replayed at a parallel log replayer based on the comparison. The database transaction is then committed to the replica table by replaying the associated transaction commit log entry at a transaction log replayer.

Claims

1. A computer implemented method for replicating a database transaction to a replica table, comprising:

receiving, by at least one processor, a replication log entry and an associated transaction commit log entry, the replication log entry and the associated transaction commit log entry together representing a database transaction to be replayed to a row at a replica table, the row at the replica table having a row-ID value and the replication log entry having a row-ID value that identifies a data state of the row at the replica table;

dispatching, by the at least one processor, the replication log entry to a parallel log replayer and the associated transaction commit log entry to a transaction commit log replayer;

comparing, by the at least one processor, the row-ID value of the replication log entry to the row-ID value of the row at the replica table;

replaying, by the at least one processor, the replication log entry at the parallel log replayer based on the comparison; and

committing, by the at least one processor, the database transaction to the replica table by replaying the associated transaction commit log entry at the transaction log replayer;

wherein at least one of the receiving, dispatching, comparing, replaying, and committing are performed by one or more computers.

2. The method of claim 1, wherein the database transaction to be replayed to the row at the replica table is an update row operation or delete row operation.

3. The method of claim 1, wherein the parallel log replayer simultaneously replays a plurality of replication log entries at the replica table.

4. The method of claim 1, wherein the transaction log replayer serially replays a plurality of transaction commit log entries at the replica table.

5. The method of claim 1, the comparing further comprising:

comparing whether the row-ID value of the row at the replica table has the immediate preceding value of the row-ID value of the replication log entry.

6. The method of claim 1, the replaying the replication log entry at the parallel log replayer further comprising:

updating the row-ID value of the row at the replica table with the row-ID value of the replication log entry.

7. The method of claim 1, the replaying the replication log entry at the parallel log replayer further comprising:

replaying the replication log entry asynchronously at the parallel log replayer based on the comparison.

8. The method of claim 1, wherein a source node generates the replication log entry for a changed row of a source table at the source node, and wherein the source node creates the transaction commit log entry in response to committing the database transaction to the source table.

9. The method of claim 1, wherein the row-ID value of the row at the replica table comprises a monotonically increasing integer.

10. The method of claim 1, wherein the row-ID value of the row at the replica table is associated with a single database transaction.

11. A system, comprising:

a memory; and

at least one processor coupled to the memory and configured to;

receive a replication log entry and an associated transaction commit log entry, the replication log entry and the associated transaction commit log entry together representing a database transaction to be replayed to a row at a replica table, the row at the replica table having a row-ID value and the replication log entry having a row-ID value that identifies a data state of the row at the replica table;

dispatch the replication log entry to a parallel log replayer and the associated transaction commit log entry to a transaction commit log replayer;

compare the row-ID value of the replication log entry to the row-ID value of the row at the replica table;

replay the replication log entry at the parallel log replayer based on the comparison; and

commit the database transaction to the replica table by replaying the associated transaction commit log entry at the transaction log replayer.

12. The system of claim 11, wherein the database transaction to be replayed to the row at the replica table is an update row operation or delete row operation.

13. The system of claim 11, wherein the parallel log replayer simultaneously replays a plurality of replication log entries at the replica table.

14. The system of claim 11, wherein the transaction log replayer serially replays a plurality of transaction commit log entries at the replica table.

15. The system of claim 11, the at least one processor further configured to:

compare whether the row-ID value of the row at the replica table has the immediate preceding value of the row-ID value of the replication log entry.

16. The system of claim 11, the at least one processor further configured to:

update the row-ID value of the row at the replica table with the row-ID value of the replication log entry.

17. A tangible computer-readable device having instructions stored thereon that, when executed by at least one computing device, causes the at least one computing device to perform operations comprising:

receiving a replication log entry and an associated transaction commit log entry, the replication log entry and the associated transaction commit log entry together representing a database transaction to be replayed to a row at a replica table, the row at the replica table having a row-ID value and the replication log entry having a row-ID value that identifies a data state of the row at the replica table;

dispatching the replication log entry to a parallel log replayer and the associated transaction commit log entry to a transaction commit log replayer;

comparing the row-ID value of the replication log entry to the row-ID value of the row at the replica table;

replaying the replication log entry at the parallel log replayer based on the comparison; and

committing the database transaction to the replica table by replaying the associated transaction commit log entry at the transaction log replayer.

18. The computer-readable device of claim 17, wherein the database transaction to be replayed to the row at the replica table is an update row operation or delete row operation.

19. The computer-readable device of claim 17, wherein the parallel log replayer simultaneously replays a plurality of replication log entries at the replica table.

20. The computer-readable device of claim 17, wherein the transaction log replayer serially replays a plurality of transaction commit log entries at the replica table.

21. The computer-readable device of claim 17, the comparing comprising:

comparing whether the row-ID value of the row at the replica table has the immediate preceding value of the row-ID value of the replication log entry.

22. The computer-readable device of claim 17, the replaying comprising:

updating the row-ID value of the row at the replica table with the row-ID value of the replication log entry.