How to find bottlenecks in an existing database?

Question

SQL Server

Hello. At the interview for the position of a developer, a programmer was asked a question.
Your first day at work. You have MS SQL SERVER 2012
There is a database in production, it has a table for 5 million records.
It has no indexes. Requests are made to it: select, update, delete, insert.
What will you do with this database to improve performance?
My answer.
Run a profiler and monitor queries that are running for a long time. Looked at the query plan and would create indexes for a heavy query.
How would you answer?

Answer 1

This is a question from a series of tricks)
Like "what do they do first: pee or poop?" (they go to the toilet, then take off their pants)
To begin with, it is worth studying the organizational "history" of the base, for example, who steers it, who is responsible for it, who makes and whether backups are made, whether backups are restored on the test site. And only then you can play around on the test with severity, plans and prepare proposals for upgrading the base, with estimates of downtime and performance failures ...
By the way, base-brakes and a profiler - often like with Schrödinger's cat - profiling can lay a base on performance ... yes , ms did a lot to protect herself from being shot in the legs, but...