MongoDB BI Connector: null pointer dereference

A database user able to create a view in a namespace that MongoDB Connector for BI samples can cause the schema-sampling routine to stop functioning by defining a view whose evaluation reliably fails. The sampling logic classifies the resulting server message as transient and, after the configured retries are exhausted, proceeds without a valid result, ending the schema refresh routine. The mongosqld process continues running without a usable schema, so SQL clients are unable to obtain results until an operator removes the view or excludes its namespace from sampling.