Using the Sakila Database darr, run an explain query plan for the following queries. For each query, what operation has the most impact on

performance? Propose an optimization for each query $($ex$.$ adding an index, changing the order of items in the SQL$)$ that you think will

improve the performance of the query.

A$.$

select title, description, name

from film

join language on film.language$\_$id $=$ language.language$\_$id

limit $300$

B$.$

select customer$\_$id

from rental

join inventory on rental.inventory$\_$id $=$ inventory.inventory$\_$id

join film on inventory.film$\_$id $=$ film.film$\_$id

where film.title $=$ 'MONTEZUMA COMMAND'

C$.$ select first$\_$name, last$\_$name, sum$($amount$)$

from customer

join payment on customer.customer$\_$id $=$ payment.customer$\_$id

group by customer.customer$\_$id$,$ first$\_$name, last$\_$name

D$.$ select distinct actor.$*$

from actor

join film$\_$actor on actor.actor$\_$id $=$ film$\_$actor.actor$\_$id

join film on film$\_$actor.film$\_$id $=$ film.film$\_$id

where film. rental$\_$rate $=\mathrm{.}99$

E$.$ select first$\_$name, last$\_$name, address, city, country, postal$\_$code, phone

from customer

join address on customer.address$\_$id $=$ address.address$\_$id

join city on address.city$\_$id $=$ city.city$\_$id

join country on city. country$\_$id $=$ country. country$\_$id

where customer$\_$id in $($select customer$\_$id from rental where return$\_$date is null$)$