I added an S3 storage plugin and was able to query files successfully. I modified the config to remove my security keys. I might have also updated my build to 1.7.0 (from 1.6.0).
After the change, I was unable to execute any queries. "Show schemas" and all other queries hang and no error message was thrown. Log indicates an issue with loading the S3 classes.
Log snippets (relevant log attached):
After updating the S3 plugin with complete config, I was able to resolve the issue.