title: Unable to extend postgresql database with timescaledb
body: <p>I have created a PostgreSQL cluster with 3 nodes using Patroni.</p>
  
  <p>I am using Ubuntu 18.04, Postgresql-10 and Timescaledb 1.4.2.</p>
  
  <p>In <code>postgresql.conf</code> file I have included <code>shared_preload_libraries = 'timescaledb'</code></p>
  
  <p>When extend the <code>postresql</code> with <code>timescaledb</code> using the command </p>
  
  <pre class="lang-sql prettyprint-override"><code>CREATE EXTENSION IF NOT EXISTS timescaledb CASCADE; 
  </code></pre>
  
  <p>it gives the error</p>
  
  <blockquote>
    <p>ERROR:  cache lookup failed for function 1</p>
  </blockquote>