Reduce AutocompleteController#users call for reviewer dropdown from Sidebar and issuable form
See: Mar-25-2021_15-46-35
It seems to me that we're sending AutocompleteController#users
requests too quickly and unnecessarily.
I think we can reduce the number of request by simply increasing the delay after user's input.
Also, I think we can avoid prefilling initial dropdown list as they are often useless if you have more than 20 users.
This is the historical requests for AutocompleteController#users over the last 7 days
- Postgres slow query count: 14,758 - https://log.gprd.gitlab.net/app/discover#/?_g=h@daebe85&_a=h@45c7c37
- Rails request count: 3,275,620 - https://log.gprd.gitlab.net/goto/007bdb23f392231aa937116fc711d44d
- Slow query ratio: 0.45%
I think we could reduce the total request by half or more by doing this.