<div dir="ltr">Hello,<div><br></div><div>Can anyone comment on if this is expected behavior?</div><div><br></div><div>I can't seem to produce a configuration where a short network outage to the standby node doesn't result in one of the following happening:</div><div><br></div><div>a) No new connections being accepted to the master until the node returns</div><div>b) (Eventually) The standby node being marked as status=3 and never being returned to service</div><div><br></div><div>Is there a way round this?</div><div><br></div><div>It can be tested by setting up PGPool then running /sbin/iptables -A INPUT -p tcp --destination-port 5432 -j DROP on the standby and trying to connect.</div><div><br></div><div>Cheers,</div><div><br></div><div><br></div></div><div class="gmail_extra"><br clear="all"><div><div class="gmail_signature"><div style="color:#b8276a;font:bold 14px Arial,Helvetica,sans-serif">
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<span style="color:#323b62">James Sewell,</span><br>
<span style="color:#a9a9a9"><span style="font:12px Arial,Helvetica,sans-serif">PostgreSQL Team Lead / Solutions Architect </span></span><br>
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<br><div class="gmail_quote">On Tue, Mar 29, 2016 at 3:36 PM, James Sewell <span dir="ltr"><<a href="mailto:james.sewell@lisasoft.com" target="_blank">james.sewell@lisasoft.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Hi All,<div><br></div><div>I'm running pgpool-II version 3.3.4 (tokakiboshi) with two 9.3.1.3 nodes.</div><div><br></div><div>I have the following in my config file:</div><div><br></div><div><div><font face="monospace, monospace"># - Backend Connection Settings -</font></div><div><font face="monospace, monospace"><br></font></div><div><font face="monospace, monospace">backend_hostname0 = '10.51.9.125'</font></div><div><font face="monospace, monospace">backend_port0 = 5432</font></div><div><font face="monospace, monospace">backend_weight0 = 1</font></div><div><font face="monospace, monospace">backend_data_directory0 = '/apps/pg_data/data'</font></div><div><font face="monospace, monospace">backend_flag0 = 'ALLOW_TO_FAILOVER'</font></div><div><font face="monospace, monospace"><br></font></div><div><font face="monospace, monospace">backend_hostname1 = '10.51.10.116'</font></div><div><font face="monospace, monospace">backend_port1 = 5432</font></div><div><font face="monospace, monospace">backend_weight1 = 1</font></div><div><font face="monospace, monospace">backend_data_directory1 = '/apps/pg_data/data'</font></div><div><font face="monospace, monospace">backend_flag1 = 'ALLOW_TO_FAILOVER'</font></div><div><font face="monospace, monospace"><br></font></div><div><font face="monospace, monospace">...</font></div><div><font face="monospace, monospace"><br></font></div><div><div style="font-family:monospace,monospace">master_slave_mode = on </div><div style="font-family:monospace,monospace">master_slave_sub_mode = 'stream'</div><div style="font-family:monospace,monospace"><br></div><div style="font-family:monospace,monospace">...</div><div style="font-family:monospace,monospace"><br></div><div><div style="font-family:monospace,monospace">health_check_period = 5</div><div style="font-family:monospace,monospace">health_check_timeout = 10</div><div style="font-family:monospace,monospace">health_check_max_retries = 5</div><div style="font-family:monospace,monospace">health_check_retry_delay = 1</div><div style="font-family:monospace,monospace"><br></div><div style="font-family:monospace,monospace">...</div><div style="font-family:monospace,monospace"><br></div><div style="font-family:monospace,monospace">fail_over_on_backend_error = off</div><div style="font-family:monospace,monospace"><br></div><div><font face="arial, helvetica, sans-serif">This mostly works as expected. I am using a third party clustering solution which uses pcp_detach_node for fencing - although I don't think that is relevant here.</font></div><div><br></div><div>I get the following node info when up:</div><div><br></div><div><div><font face="monospace, monospace">node_id | hostname | port | status | lb_weight | role</font></div><div><font face="monospace, monospace">---------+--------------+------+--------+-----------+---------</font></div><div><font face="monospace, monospace"> 0 | 10.51.9.125 | 5432 | 2 | 0.500000 | primary</font></div><div><font face="monospace, monospace"> 1 | 10.51.10.116 | 5432 | 3 | 0.500000 | standby</font></div><div><font face="monospace, monospace">(2 rows)</font></div></div><div><br></div><div><font face="arial, helvetica, sans-serif">The problem comes when my standby node becomes unavailable - let's say I shut it down.</font></div><div><font face="arial, helvetica, sans-serif"><br></font></div><div><font face="arial, helvetica, sans-serif">Now until all my health checks have failed I am not able to connect to the database:</font></div><div><font face="arial, helvetica, sans-serif"><br></font></div><div><div><font face="monospace, monospace">-bash-4.1$ psql</font></div><div><font face="monospace, monospace">psql.bin: -bash-4.1$</font></div><div><font face="monospace, monospace"><br></font></div><div><font face="arial, helvetica, sans-serif">My network is pretty temperamental, so I actually would like to lengthen the time to failure - but this means I get a complete outage every time my network flutters?</font></div><div><font face="arial, helvetica, sans-serif"><br></font></div><div><font face="arial, helvetica, sans-serif">I could also change the setting of </font><span style="font-family:monospace,monospace">fail_over_on_backend_error</span><span style="font-family:monospace,monospace"> </span><font face="arial, helvetica, sans-serif">but then although the failure is immediate there is no coming back without intervention once my server is set to a status of 3.</font></div></div><div><font face="arial, helvetica, sans-serif"><br></font></div><div><font face="arial, helvetica, sans-serif">Is there a way of avoiding this behavior and allowing traffic to continue to be processed on my functioning master when the standby is in question?</font></div><div><font face="arial, helvetica, sans-serif"><br></font></div><div><font face="arial, helvetica, sans-serif">Cheers,</font></div></div></div><div><div><div><div><div style="color:rgb(184,39,106);font-style:normal;font-variant:normal;font-weight:bold;font-stretch:normal;font-size:14px;line-height:normal;font-family:Arial,Helvetica,sans-serif">
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<span style="color:rgb(50,59,98)">James Sewell,</span><br>
<span style="color:rgb(169,169,169)"><span style="font-style:normal;font-variant:normal;font-weight:normal;font-stretch:normal;font-size:12px;line-height:normal;font-family:Arial,Helvetica,sans-serif">PostgreSQL Team Lead / Solutions Architect </span></span><br>
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