Consider partitioning strategies for sent_notifications

Due to the ongoing increased load issues on the primary, we need to take action to reduce the load. One of the solutions we're considering is partitioning tables > 100GB. As a very large table, sent_notifications has been selected as a candidate. For more information on available strategies, please review our docs

We'd like to answer the following questions:

• Does sent_notifications have a key that would be easy to partition on?
• What strategy seems like the best bet for partitioning this table?
• Are there other strategies we'd like to consider to reduce the size of sent_notifications?