All migrations will automatically be wrapped in a transaction. There are
queries that you can’t execute inside a transaction. Adding index
concurrently is one of them, we have to disable the transaction. I
missed this in the earlier PR. #11831
This PR adds a composite index (:account_id, :content_type, :created_at)
on the table messages.
This index is added as a temporary fix for performance issues in the
CSAT responses controller where we query messages with account_id,
content_type and created_at. The current implementation
(account.message.input_csat.count) times out with millions of messages.
TODO: Create a dedicated csat_survey table and add entries when surveys
are sent, then query this table instead of the entire messages table for
better performance.
