SharePoint 2013 Search index partition and Query processing component is in bad status and search is not working

SharePoint 2013 Search index partition and Query processing component is in bad status and search is not working

Cause
- This happens when search controller host service is manually started
- noderunner is taking more memory on server its crashing

Workaround:
- Reset index and do full crawl.
- wait until full crawl completes to see change in status of index partition and query processing component to Green.