title: How to set up synchronous streaming replication in postgres?
body: <p>I am trying to set up synchronous replication with Postgres 9.1, but I cannot get it to work. I was able to configure streaming replication, but not synchronous.
  I hope I have not missed anything obvious. I have read carefully many sections of ch 17, 18, 14, 25, 26 and 29 in the admin guide.</p>
  
  <p>I am running ubuntu 12.04 and my master postgresql.conf has these, among all the other standard settings:</p>
  
  <pre><code>listen_addresses = '*'              # what IP address(es) to listen on;
  wal_level = archive                 # minimal, archive, or hot_standby
  archive_mode = on                   # allows archiving to be done
  archive_command = 'test ! -f /data/pgWalArchive/%f &amp;&amp; cp %p /data/pgWalArchive/%f'
  wal_keep_segments = 100             # in logfile segments, 16MB each; 0 disables ??? What should this be ???? 
  max_wal_senders = 3                 # max number of walsender processes
  </code></pre>
  
  <p>My pg_hba.conf has this, in addition to the standard stuff:</p>
  
  <pre><code>host    all             all             XX.6.35.0/24            md5
  host    replication     postgres        XX.6.35.0/24            md5
  </code></pre>
  
  <p>My master db has just one sequence, so it is tiny. I successfully created a backup of the master in the primary and restored it:</p>
  
  <pre><code>sudo -u postgres pg_basebackup -D ~/backup -F tar -x -z -l ~/backup/base1 -v -h XX.6.35.51 -U postgres
  </code></pre>
  
  <p>I also copied the WAL archive files to the standby. My standby recovery.conf file has this:</p>
  
  <pre><code>restore_command = '/usr/lib/postgresql/9.1/bin/pg_standby /data/pgWalArchive %f %p %r'
  archive_cleanup_command = '/usr/lib/postgresql/9.1/bin/pg_archivecleanup /data/pgWalArchive %r'
  standby_mode = on
  primary_conninfo = 'host=XX.6.35.51 port=5432' # e.g. 'host=masterIpAddressOrName port=5432'
  </code></pre>
  
  <p>Both servers start up with no problems and the logs seem ok. My standby has this:</p>
  
  <pre><code>2012-06-08 10:23:51 MDT LOG:  shutting down
  2012-06-08 10:23:51 MDT LOG:  database system is shut down
  2012-06-08 10:23:53 MDT LOG:  database system was shut down in recovery at 2012-06-08 10:23:51 MDT
  2012-06-08 10:23:53 MDT LOG:  entering standby mode
  2012-06-08 10:23:53 MDT LOG:  consistent recovery state reached at 0/1D000078
  2012-06-08 10:23:53 MDT LOG:  record with zero length at 0/1D000078
  2012-06-08 10:23:53 MDT LOG:  streaming replication successfully connected to primary
  2012-06-08 10:23:53 MDT LOG:  incomplete startup packet
  2012-06-08 10:23:54 MDT FATAL:  the database system is starting up
  2012-06-08 10:23:54 MDT FATAL:  the database system is starting up
  2012-06-08 10:23:55 MDT FATAL:  the database system is starting up
  2012-06-08 10:23:55 MDT FATAL:  the database system is starting up
  2012-06-08 10:23:56 MDT FATAL:  the database system is starting up
  2012-06-08 10:23:56 MDT FATAL:  the database system is starting up
  2012-06-08 10:23:57 MDT FATAL:  the database system is starting up
  2012-06-08 10:23:57 MDT FATAL:  the database system is starting up
  2012-06-08 10:23:58 MDT FATAL:  the database system is starting up
  2012-06-08 10:23:58 MDT FATAL:  the database system is starting up
  2012-06-08 10:23:59 MDT FATAL:  the database system is starting up
  2012-06-08 10:23:59 MDT LOG:  incomplete startup packet
  2012-06-08 10:24:40 MDT LOG:  redo starts at 0/1D000078
  </code></pre>
  
  <p>The problem is that when I issue statements against the master, they hang forever. Am I missing something?</p>