The Vertica Forum recently got a makeover! Let us know what you think by filling out this short, anonymous survey.
Please take this survey to help us learn more about how you use third party tools. Your input is greatly appreciated!

Merge Query Adding Duplicate Rows

I am facing a peculiar issue with Merge command. I assume it to be related to WOS\ROS. 


I am constantly polling a postgres database, and trying to keep Vertica data in sync. Vertica tables are denormalized form of multiple postgres tables. Merge queries are quite simple. I copy differential data from OLTP into a temp table, and then merge the temp table into target table using the merge key.Merge key is same as the Primary key for the table


Initially, I am loading close to 100K rows into a target table. Immediately after the initial load, I am running a unit test which updates the datasource and then tries to run a merge command from source to target table. If the update size is bigger like 30-40K, the merge ends up adding duplicate rows into table. The problem does not happen if the update size is smaller like 3-4K.


I also tried running the tuple mover explicitly after the initial load. Still it resulted in same issue. 


 Can somebody explain the reason here? Would having a larger WOS would help? Or what other configuration parameters need to be tweaked in order to avert this issue.

Leave a Comment

BoldItalicStrikethroughOrdered listUnordered list
Align leftAlign centerAlign rightToggle HTML viewToggle full pageToggle lights
Drop image/file