<div dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Jan 25, 2017 at 12:11 PM, Ahsan Hadi <span dir="ltr"><<a href="mailto:ahsan.hadi@enterprisedb.com" target="_blank">ahsan.hadi@enterprisedb.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote"><span class="gmail-">On Wed, Jan 25, 2017 at 9:22 AM, Tatsuo Ishii <span dir="ltr"><<a href="mailto:ishii@sraoss.co.jp" target="_blank">ishii@sraoss.co.jp</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><span>> You can also understand "auto-failover" as preserving the connection. Right<br>
> now if you have a connection with a master and a stand-by node, the pgpool<br>
> "show pool_nodes" gives you this...<br>
><br>
> [ec2-user@ip-172-25-1-32 bin]$ ./edb-psql edb -p 9999 -U ec2-user<br>
><br>
> edb-psql (9.6.1.6, server 9.5.3.8)<br>
><br>
> Type "help" for help.<br>
><br>
> edb=# show pool_nodes;<br>
><br>
> node_id | hostname | port | status | lb_weight | role | select_cnt |<br>
> load_balance_node | replication_delay<br>
><br>
> ---------+-------------+------<wbr>+--------+-----------+--------<wbr>-+------------+---------------<wbr>----+-------------------<br>
><br>
> 0 | 172.25.1.33 | 5444 | up | 0.500000 | primary | 0 |<br>
> false | 0<br>
><br>
> 1 | 172.25.1.34 | 5444 | up | 0.500000 | standby | 0 |<br>
> true | 0<br>
> (2 rows)<br>
><br>
> if you bring down the stand-by node, the health-check will kick in and if<br>
> you run the same query again it will fail.<br>
<br>
</span>That's only happens if the client uses the standby.<br></blockquote><div><br></div></span><div>Correct...After the feature you added to 3.6, if a standby fails that is not being used by the client, the client won't be affected. That was good step in the right direction. The next step is that if the stand-by fails and the master is still available the client is still not affected, that's what i am proposing...</div><span class="gmail-"><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<span><br>
> What i mean by auto-failover is if the master (primary server) is<br>
> available, the auto-failover feature should failover to the master instead<br>
> of throwing an error.<br>
><br>
> Does that make sense?<br>
<br>
</span>To make it possible we need to think about followings:<br>
<br>
1) We need to migrate all the session properties set in the previous<br>
session to the new master connection.<br>
<br>
2) If the client was receiving data row from Pgpool-II, it's hard to<br>
continue it in the new session.<br>
<br>
3) If the client was in the middle of a transaction, it's hard to<br>
continue it in the new session.<br>
<br>
These are not trivial, and I think it's not worth the problem, to be<br>
honest.<br></blockquote><div><br></div></span><div>Well i think it is debatable whether the feature is worth the effort of not. It affects an application continuity to work if we don't have the complete auto-failover feature. Do you think it becomes less complex of we don't provide 3 in the first phase?</div></div></div></div></blockquote><div><br></div><div>Btw this is similar functionality that <span style="font-size:12.8px">Oracle offers called Transparent Application Failover (TAF)...</span> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><span class="gmail-"><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div class="gmail-m_4151120540417437195HOEnZb"><div class="gmail-m_4151120540417437195h5"><br>
Best regards,<br>
--<br>
Tatsuo Ishii<br>
SRA OSS, Inc. Japan<br>
English: <a href="http://www.sraoss.co.jp/index_en.php" rel="noreferrer" target="_blank">http://www.sraoss.co.jp/index_<wbr>en.php</a><br>
Japanese:<a href="http://www.sraoss.co.jp" rel="noreferrer" target="_blank">http://www.sraoss.co.<wbr>jp</a><br>
</div></div></blockquote></span></div><br><br clear="all"><span class="gmail-"><div><br></div>-- <br><div class="gmail-m_4151120540417437195gmail_signature">Ahsan Hadi<br>Snr Director Product Development<br>EnterpriseDB Corporation<br>The Enterprise Postgres Company<br><br>Phone: <a href="tel:(051)%208358874" value="+92518358874" target="_blank">+92-51-8358874</a> <br>Mobile: <a href="tel:0333%205162114" value="+923335162114" target="_blank">+92-333-5162114</a><br><br>Website: <a href="http://www.enterprisedb.com" target="_blank">www.enterprisedb.com</a><br>EnterpriseDB Blog: <a href="http://blogs.enterprisedb.com/" target="_blank">http://blogs.enterprisedb.com/</a><br>Follow us on Twitter: <a href="http://www.twitter.com/enterprisedb" target="_blank">http://www.twitter.com/<wbr>enterprisedb</a><br><br>This e-mail message (and any attachment) is intended for the use of the individual or entity to whom it is addressed. This message contains information from EnterpriseDB Corporation that may be privileged, confidential, or exempt from disclosure under applicable law. If you are not the intended recipient or authorized to receive this for the intended recipient, any use, dissemination, distribution, retention, archiving, or copying of this communication is strictly prohibited. If you have received this e-mail in error, please notify the sender immediately by reply e-mail and delete this message.</div>
</span></div></div>
</blockquote></div><br><br clear="all"><div><br></div>-- <br><div class="gmail_signature">Ahsan Hadi<br>Snr Director Product Development<br>EnterpriseDB Corporation<br>The Enterprise Postgres Company<br><br>Phone: +92-51-8358874 <br>Mobile: +92-333-5162114<br><br>Website: <a href="http://www.enterprisedb.com" target="_blank">www.enterprisedb.com</a><br>EnterpriseDB Blog: <a href="http://blogs.enterprisedb.com/" target="_blank">http://blogs.enterprisedb.com/</a><br>Follow us on Twitter: <a href="http://www.twitter.com/enterprisedb" target="_blank">http://www.twitter.com/enterprisedb</a><br><br>This e-mail message (and any attachment) is intended for the use of the individual or entity to whom it is addressed. This message contains information from EnterpriseDB Corporation that may be privileged, confidential, or exempt from disclosure under applicable law. If you are not the intended recipient or authorized to receive this for the intended recipient, any use, dissemination, distribution, retention, archiving, or copying of this communication is strictly prohibited. If you have received this e-mail in error, please notify the sender immediately by reply e-mail and delete this message.</div>
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