Please take this survey to help us learn more about how you use third party tools. Your input is greatly appreciated!
MaxMrgOutROSSizeMB changes suggested by VAdvisor
Tim_1
✭
Hi,
Just had a scrutinize analyzed by VAdvisor and one of the recommendations was setting MaxMrgOutROSSizeMB to 20480 to reduce the time taken for mergeout.
Once this parameter is set the documentation implies that a "rebalance" has to be run for this to be implemented, is that correct?
Any other ways of triggering ROS containers over 20GB to be split?
Regards
Tim
0
Leave a Comment
Can't find what you're looking for? Search the Vertica Documentation, Knowledge Base, or Blog for more information.
Answers
What is the current setting for MaxMrgOutROSSizeMB? Vertica won't split containers automatically, instead this setting should only prevent new containers from exceeding the size. Rebalance_cluster will fix container sizes to fall below MaxMrgOutROSSizeMB but this can be time- and resource-intensive since it will try to run in parallel across all containers. Instead, you can identify projections that have containers exceeding 20GB in storage_containers, then run REBALANCE_TABLE only on the tables that have containers needing split.
Current settings is default.
Thanks for the update, we have a number of tables with Hierarchical Partitioning, some of the old ROS containers are 100+GB in size. Occasionally they do insert data into these partitions that does cause lengthy MergeOuts running for hours. This has a knock on impact to the performance of the cluster, so need to mange when the ROS containers get rebuilt.