When users write a query and then move to the explore view, the table view reders but once they try to click a `Bar Chart - Distribution` type viz the explore blanks out. The only way to get back the current state is copying the link and reloading the page.
Steps to Reproduce: 1. Goto this link https://superset.lyft.net/superset/sqllab?id=1531 2. Run the query 3. Click `Explore` btn 4. Change viz type to 'Distribution Bar Chart` 5. Set metrics = `SUM(ride_count`) and series = 'venue_name` StackTrack: {“error”: “The datasource associated with this chart no longer exists”, “stacktrace”: “Traceback (most recent call last):\n File \“/srv/venvs/service/trusty/service_venv_python3.6/lib/python3.6/site-packages/superset/views/core.py\“, line 1158, in explore_json\n datasource_id, datasource_type, form_data)\n File \“/srv/venvs/service/trusty/service_venv_python3.6/lib/python3.6/site-packages/superset/views/core.py\“, line 1217, in datasource_info\n ‘The datasource associated with this chart no longer exists’)\nException: The datasource associated with this chart no longer exists\n”}  [ Full content available at: https://github.com/apache/incubator-superset/issues/5947 ] This message was relayed via gitbox.apache.org for [email protected]
