<div dir="ltr">Hey,<div><br></div><div>So there is no way of manually taking a postgresql node out of a pool without interrupting traffic to all other postgresql nodes?</div><div><br></div><div>Cheers,<br></div></div><div class="gmail_extra">
<br clear="all"><div><div style="color:#b8276a;font:bold 14px Arial,Helvetica,sans-serif">
<br>
<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>
<span style="color:#a9a9a9">______________________________________</span><br>
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<br><br><div class="gmail_quote">On Fri, Jul 25, 2014 at 3:07 PM, Tatsuo Ishii <span dir="ltr"><<a href="mailto:ishii@postgresql.org" target="_blank">ishii@postgresql.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div class="">I cannot imagine how you maintenance the database while a user<br>
connects to the database:-)<br>
<br>
BTW I'm not sure if this is usefull for you or not,<br>
but... pcp_detach_node accepts -g option which force pcp_detach_node<br>
wait until all clients exit.<br>
<br>
</div><div class="">Best regards,<br>
--<br>
Tatsuo Ishii<br>
SRA OSS, Inc. Japan<br>
English: <a href="http://www.sraoss.co.jp/index_en.php" target="_blank">http://www.sraoss.co.jp/index_en.php</a><br>
Japanese:<a href="http://www.sraoss.co.jp" target="_blank">http://www.sraoss.co.jp</a><br>
<br>
</div><div class="">> Cool,<br>
><br>
> Thanks Tatsuo.<br>
><br>
> Is there a way of taking a postgresql node out of a pool without causing<br>
> connections to other postgresql nodes to drop?<br>
><br>
> This would be used in a situation such as database maintenance.<br>
><br>
> Cheers,<br>
><br>
><br>
> James Sewell,<br>
> PostgreSQL Team Lead / Solutions Architect<br>
> ______________________________________<br>
><br>
><br>
</div><div class="">> Level 2, 50 Queen St, Melbourne VIC 3000<br>
><br>
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<div class="HOEnZb"><div class="h5">><br>
><br>
><br>
> On Fri, Jul 25, 2014 at 2:43 PM, Tatsuo Ishii <<a href="mailto:ishii@postgresql.org">ishii@postgresql.org</a>> wrote:<br>
><br>
>> > Hey all,<br>
>> ><br>
>> > This is a seemingly a pretty bad problem which I uncovered as part of my<br>
>> > last post, so the start of the message will be similar.<br>
>> ><br>
>> > I have two pgpool nodes which I am using a TCP load balancer to spread<br>
>> > between. I am using watchdog to synchronise PostgreSQL node information<br>
>> > between the two and an external HA solution (with ALLOW_TO_FAILOVER).<br>
>> ><br>
>> > If I start both my pgpool nodes up I get the following initial state:<br>
>> ><br>
>> > postgres=# show pool_nodes;<br>
>> > node_id | hostname | port | status | lb_weight | role<br>
>> > ---------+-------------+------+--------+-----------+---------<br>
>> > 0 | 10.10.10.1 | 5432 | 2 | 0.500000 | standby<br>
>> > 1 | 10.10.10.2 | 5432 | 2 | 0.500000 | primary<br>
>> > (2 rows)<br>
>> ><br>
>> > Now I open a PSQL connection and do the following:<br>
>> ><br>
>> > postgres=# SELECT inet_server_addr();<br>
>> > inet_server_addr<br>
>> > ------------------<br>
>> > 10.10.10.2<br>
>> > (1 row)<br>
>> ><br>
>> > This shows I am connected to the primary.<br>
>> ><br>
>> > I can run this multiple times and I will always be connected to the<br>
>> > primary, as long as I don't close the psql session.<br>
>> ><br>
>> > Then from another window I run the following command:<br>
>> ><br>
>> > pcp_detach_node 1 load_balancer 9898 postgres postgres 0<br>
>> ><br>
>> > And in the same PSQL session run the command again:<br>
>> ><br>
>> > postgres=# SELECT inet_server_addr();<br>
>> > SSL SYSCALL error: EOF detected<br>
>> > The connection to the server was lost. Attempting reset: Succeeded.<br>
>> ><br>
>> > This is strange. Why has my master connection been severed?<br>
>><br>
>> It's an expected behavior of pcp_detach_node, which causes failover<br>
>> and all existing sessions are disconnected.<br>
>><br>
>> Best regards,<br>
>> --<br>
>> Tatsuo Ishii<br>
>> SRA OSS, Inc. Japan<br>
>> English: <a href="http://www.sraoss.co.jp/index_en.php" target="_blank">http://www.sraoss.co.jp/index_en.php</a><br>
>> Japanese:<a href="http://www.sraoss.co.jp" target="_blank">http://www.sraoss.co.jp</a><br>
>><br>
><br>
</div></div><div class="HOEnZb"><div class="h5">> --<br>
><br>
><br>
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