The size of my table is not growing

I couldn't see any growth in table size down to a single byte when I added 1 million rows in the table during the last days. I'm using this query: ~~~pgsql select table_name, pg_relation_size(quote_ident(table_name)) as data_size from information_schema.tables where table_schema = SOME_SCHEMA and table_name = SOME_TABLE; ~~~ And it returns the same result all these days. What could cause this unexpected result?