Questions $3-5$

For each SQL query below, do the following:

a$)$ Write a query for the pg class table to get the number of pages and tuples in each

relation. Show the query and the results. No need to repeat answers if a table is used

multiple times in the questions below. That is$,$ for each question, just get information

about "new" tables.

b$)$ List two types of join algorithms that could be used for the query.

c$)$ Using the formulas provided in the slides, calculate the cost of doing each type of

join listed in b$.$ Note: Keep in mind number of scans is a number of times of

scanning; therefore, it needs to be in integer.

d$)$ Use EXPLAIN to identify which join algorithm PostgreSQL uses.

e$)$ Report if your calculation of which join is cheapest matches PostgreSQL's choice or

not

$8)$

Use work mem $/8$k to find # of buffer pages available to join $($Documentation:

Resource Consumption$)$