BigQuery troubleshooting

Known issue DEV-49033: If while reading from BigQuery tables Database Reader experiences back pressure for approximately six hours or more it might experience a session timeout exception or partial read of the table data, in which case the app can go into the Completed state without throwing any exceptions or giving any other indication that not all the data was read. (This can be verified via running a SELECT COUNT(*) query on the source table and comparing it with the the Rows Read metric of the respective table in Database Reader's Table Information monitoring metric.) This is due to BigQuery's Storage Read API having a maximum session timeout of six hours. To avoid this, try increasing the Parallel Threads property value of the target. On restart, set Database Reader's Restart Behavior on IL Interruption property to Replace target table or Truncate target table (see Fast Snapshot Recovery during initial load).

If you receive an exception when using the Query property with a valid query, try including the parameter QueryPassthrough=true in the connection URL.