The default JVM driver has a default maximum heap size of 500MB. As a best practice, you can increase this value to 10GB when using the Oracle connector due to the increased workload on the driver node. You change the value by setting the Teradata Fabric system property driverMaxHeapSizeMB to 10000 (10GB) and restarting the tdqg-node service. Heap usage increases with the number of concurrent queries.