copy_plain and copy_indexed are empty tables with the same columns as visits. copy_plain has no index. copy_indexed has four indexes. visits has an index on ms, and members has an index on email.

Each statement in the Result tab shows how many milliseconds it took.

1. Copy every row of visits into copy_plain.
2. Copy every row of visits into copy_indexed.
3. Which table took longer to fill?
4. Show the plan of SELECT * FROM visits WHERE ms > 100. About 96 % of the visits match. Does the plan use visits_ms_idx? Answer yes or no.
5. Show the plan of SELECT * FROM members WHERE lower(email) = 'user77@example.com'.
6. Make that plan use an index. Then show the plan again.