Troubleshooting Guide: Advanced/Multimaster Replication Propagation
(Doc ID 1035874.6)
Last updated on JUNE 13, 2023
Applies to:
Oracle Database Cloud Exadata Service - Version N/A and laterOracle Database Cloud Service - Version N/A and later
Oracle Database - Enterprise Edition - Version 7.2.2.0 to 11.2.0.2 [Release 7.2.2 to 11.2]
Oracle Database Cloud Schema Service - Version N/A and later
Gen 1 Exadata Cloud at Customer (Oracle Exadata Database Cloud Machine) - Version N/A and later
Information in this document applies to any platform.
Purpose
The purpose of this article is to provide basic steps for troubleshooting advanced replication propagation and the underlying mechanism it uses; the deferred queue. Additional notes are referenced through out this article that address specific issues or provide additional information on a particular component used by Advanced Replication.
Scope & Application
To be used by Oracle support analysts and replication DBA's to understand and employ basic troubleshooting techniques for advanced replication propagation.
Troubleshooting Steps
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In this Document
| Purpose |
| Scope & Application |
| Troubleshooting Steps |
| 1. Overview of how data moves between Replicated Site |
| 2. Checking the replication propagation environment is configured correctly |
| 2.1 Replication group status |
| 2.2 Replicated object triggers, packages and status |
| 2.3 Status of existing admin requests |
| 2.4 Check database links |
| 3. Checking the automatic propagation mechanism is working |
| 3.1 Checking for errors |
| 3.2 Check job_queue_processes is set |
| 3.3 Has a push / purge job been scheduled |
| 3.4 Check the status of the propagation jobs |
| 3.5 Check the propagator and their private database links |
| 3.6 Check if the push job is currently running |
| 3.7 Terminating a deferred queue push job that is currently running |
| 4. Diagnosing the progress and status of replicated transactions |
| 4.1 Verify transactions can be manually pushed |
| 4.2 Verifying transactions are being propagated |
| 4.3 Deferred transaction propagated but not applied to receiving site |
| 4.3.1 Checking for deferred errors in the queue |
| 4.3.2 Stop on Error |
| 4.4 Verify the purge transaction operation |
| 4.4.1 Verify transactions can be manually purged |
| 4.4.2 Verifying transactions are being purged |
| 4.5 Large deferred transactions and slow propagation |
| 5. Diagnosing hanging propagation |
| 5.1 Check for locks |
| 5.2 Check the wait events |
| 5.3 Check if a large error is being queued |
| 5.4 Advanced Analysis |
| 6. How to clear down large deferred queues |
| 7. Example of how deferred transactions are propagated |
| 7.1 Data is inserted into the table: |
| 7.2 Interrogating the deferred queue: |
| 7.3 Identify the next transaction to be pushed: |
| 7.4 Manually push transactions to REP901 and interrogate the deferred queue |
| 7.5 Identify unpurged transactions |
| References |