psql -h localhost -U pony pg_guts

\timing

SELECT * FROM projects WHERE id = 1337;
SELECT * FROM projects WHERE name = 'Manhattan';
EXPLAIN SELECT * FROM projects WHERE name = 'Manhattan';

CREATE INDEX projects_name ON projects(name);
EXPLAIN SELECT * FROM projects WHERE name = 'Manhattan';
SELECT * FROM projects WHERE name = 'Manhattan';

SELECT COUNT(*) FROM projects WHERE priority = 'low';
CREATE INDEX projects_priority ON projects(priority);
SELECT COUNT(*) FROM projects WHERE priority = 'low';
EXPLAIN SELECT COUNT(*) FROM projects WHERE priority = 'low';
SELECT DISTINCT priority FROM projects;

EXPLAIN SELECT * FROM projects WHERE priority = 'low' AND created_at > '2016-01-29';
CREATE INDEX projects_priority_created_at ON projects(priority, created_at);
EXPLAIN SELECT * FROM projects WHERE priority = 'low' AND created_at > '2016-01-29';
SELECT * FROM projects WHERE priority = 'low' AND created_at > '2016-01-29';

EXPLAIN SELECT * FROM projects WHERE priority = 'low' AND created_at > '2016-01-29';
SELECT * FROM projects WHERE priority = 'low' AND created_at > '2016-01-29';

EXPLAIN SELECT * FROM projects WHERE priority = 'low';  
EXPLAIN SELECT * FROM projects WHERE created_at > '2016-01-29';