Performance Improvements

New Query Plan Operator ResegmentMerge

New optimizer operator ResegmentMerge can optimize performance of queries with distinct aggregates. The Vertica optimizer uses this operator to execute parallel group by operations after the merge. The ResegmentMerge operator reads input data concurrently from multiple ROS containers, and executes parallel merge and resegmentation operations. This approach can achieve noticeable performance improvements in queries that group large amounts of data.

Faster Mergeout on Wide Tables

Vertica has increased the default amount of memory assigned to the Tuple Mover (TM) resource pool from 200MB to 5% of available memory to improve performance merging out wide tables.