Understanding simple queries and the cost model

In this section, we will get started with indexes. To understand how things work, some test data is needed. The following code snippet shows how data can easily be created:

test=# DROP TABLE IF EXISTS t_test;
 DROP TABLE
test=# CREATE TABLE t_test (id serial, name text);
CREATE TABLE
test=# INSERT INTO t_test (name) SELECT 'hans'
   FROM generate_series(1, 2000000);
INSERT 0 2000000
test=# INSERT INTO t_test (name) SELECT 'paul'
   FROM generate_series(1, 2000000);
INSERT 0 2000000

In the first line, a simple table is created. Two columns are used; the first is an auto-increment column that continually creates numbers, and the second is a column that will be filled with static values.

The generate_series function will generate numbers from 1 to 2 million, so in this example, 2 million static values for hans and 2 million static values for paul are created.

All in all, 4 million...