![]() Thus, you want to start with a reasonable amount of memory, and then adjust iteratively as required. If you allocate significantly more memory to your CDC instance than CDC requires, it could actually cause performance to degrade as large garbage collection could occur. More memory does not necessarily mean better performance. The– default amount of memory, 1GB, has been carefully chosen to work for most cases. Be aware that significant performance degradation will result from insufficient physical memory due to relying on virtual memory, disk I/O and higher CPU due to time spent cleaning up memory. ![]() For instance on some systems you can use TOP and verify that there is sufficient resident memory available. Note that it does need to be physical memory and available to CDC. It is very important to allocate and configure a suitable amount of physical memory to an InfoSphere CDC instance. IBM Data Replication Community Wiki - DataStageīest Practice - Memory Requirements on LUW Link to Wiki containing best practices for integration with DataStage ![]() A separate process would have to be put in place to de-dup duplicate records produced during the "in-doubt" period of a refresh (the captured changes that occurred while the source date was being refreshed). The CDC External Refresh does not work when targeting DataStage.The maximum number of tables per CDC subscription is lower if targeting DataStage.Incorrect DataStage job design can negatively affect transactional integrity and cause data corruption.There is significant development effort developing DataStage jobs for each additional table added to replication.When integrating with DataStage, there are two independent GUIs for configuration, and two places required to monitor the replication stream.Having a resilient CDC installation is more complex if DataStage is also involved.Adding DataStage into the replication stream introduces additional points of failure.The exception to this rule is when targeting Teradata, if you use DataStage flat file integration, the throughput will be higher than CDC direct to Teradata.Performance going through DataStage (no matter which integration option is chosen) will be significantly slower than applying via a CDC target directly to the database.Complex transformations are required that could not be handled natively with CDC, such as complex table look-upsĬons of replicating from CDC to DataStage to an eventual target database:.You need to target a database that CDC doesn't directly support and is not appropriate for CDC FlexRep.do not add DataStage to the mix).ĬDC integration with DataStage is the right solution for replication when: If possible, the best solution is always to use CDC direct replication (i.e. The deployment option selected will significantly affect the complexity, performance, and reliability of the implementation. There are many deployment models available for InfoSphere Data Replication's CDC technology of which DataStage integration is a popular one. Best Practice - CDC / CDD to DataStage Integration
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