title: WARNING: concurrent delete in progress within table while creating index in big table in Postgres 9.2
body: <p>I have a problem while creating index on a big table which is 53 GB, so I tried to create this index  many times
  the code is </p>
  
  <pre><code>do $$
  begin
   if not exists (select * from pg_class where relname = 'index_usage_id_idx')       then
       create  index index_usage_id_idx on mytable (usage_id);
   end if; 
  end $$;
  </code></pre>
  
  <p>I got many logs in pg_log directory with errors below  while creating index which does not stop and expose logs with more than 200 GB so that i am running out of free space</p>
  
  <p><strong>2014-01-17 11:39:40  CONTEXT:  SQL statement "create  index index_usage_id_idx on mytable (usage_id)"<br/>
  PL/pgSQL function inline_code_block line 46 at SQL statement<br/>
  2014-01-17 11:39:40  WARNING:  concurrent delete in progress within table "mytable"</strong></p>
  
  <p>Why is it trying to concurrent delete something?</p>