Cassandra queries review

[chinmoy12c]

Action Items:

• [x] Query based on timestamp only on the broadcast report and filter in code.
• [ ] Review and document the usage of other Cassandra queries and figure out if they can be cached or avoided.

[chinmoy12c]

Sheet to keep track of queries: https://docs.google.com/spreadsheets/d/13f8TOblzObdmOPI41CJ6cuE_rNe07oXXc4hUKBz1vZ8/edit#gid=0

[karntrehan]

To pick changes mentioned here as a separate ticket.