title: PostgreSQL column size vs table size
body: <p>I am trying to get only one table size, and then size of each row.
  While I was using</p>
  <pre><code>SELECT pg_table_size(*mytable*) as DATA;
  </code></pre>
  <p>I get 393216 bytes.</p>
  <p>Using</p>
  <pre><code>SELECT (SUM(pg_column_size(t) - 24)) FROM *mytable* AS t;
  </code></pre>
  <p>(as written here <a href="https://stackoverflow.com/questions/34222996/how-to-get-each-row-size-of-a-particular-table-in-postgresql">How to get each row size of a particular table in postgresql..?</a>)</p>
  <p>I get 560669 bytes.</p>
  <p>560669 vs 393216 bytes - which one is real?</p>