Druid was implemented at Conviva to improve their streaming analytics capabilities. Previously they used Hadoop batch jobs and Spark streaming, but saw challenges with reliability and performance like query timeouts. With Druid they saw improvements through optimizations like data locality tuning, additional query tiers, and Kubernetes improvements on Google Cloud. This helped add a "9" to their reliability. However, challenges remained around cost, high cardinality queries, and rapid disaster recovery which they continue working to address.