generate postgres data

http://bonesmoses.org/2016/07/15/pg-phriday-a-postgres-persepctive-on-mongodb/
CREATE TABLE sensor_log (
  id            SERIAL NOT NULL PRIMARY KEY,
  location      VARCHAR NOT NULL,
  reading       BIGINT NOT NULL,
  reading_date  TIMESTAMP NOT NULL
);
 
\timing
 
INSERT INTO sensor_log (id, location, reading, reading_date)
SELECT s.id, s.id % 1000, s.id % 100,
       CURRENT_DATE - ((s.id * 10) || 's')::INTERVAL
  FROM generate_series(1, 1000000) s(id);
 
TIME: 7236.906 ms
 
CREATE INDEX idx_sensor_log_date
    ON sensor_log (reading_date);
 
TIME: 804.044 ms