hard20 pts · first answer countsquery-tuningpostgresql

Estimates wrong for city and zip code

WHERE city = 'Dubai' AND zip = '00000' is estimated at 3 rows but returns 90,000, leading to a nested loop. The columns are strongly correlated. What helps the planner most?

A.Raise random_page_costB.CREATE STATISTICS ... (dependencies, ndistinct) ON city, zip FROM the table, then ANALYZEC.Rebuild all indexes on the tableD.Increase max_connections

← Prepared statement slows down later Index-only scan still reads the table →