2018-05-08

Notes about postgresql

How to generate and insert test data?

For example, my table is like: create table (time timestamp, value double precision, sensor integer). If I want to insert some test data, I can use function generate_series. Following sql will insert 5000 rows:

    insert into test (time, sensor, value) select now(), i, random() from generate_series(1, 5000) s(i)

How to view disk usage?

View table size

     select pg_size_pretty(pg_relation_size('pressure_01'))

View database size

     select pg_size_pretty(pg_database_size('pressure_01'))