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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Hi Gabriele,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">I had the same issue when my search_primary_node_timeout had a bad value. With a value at 300, it work fine for me.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">If it can help …<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Regards,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Christophe<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">De :</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> pgpool-general-bounces@pgpool.net [mailto:pgpool-general-bounces@pgpool.net]
<b>De la part de</b> Gabriele Monfardini<br>
<b>Envoyé :</b> mercredi 21 septembre 2016 16:12<br>
<b>À :</b> pgpool-general@pgpool.net<br>
<b>Objet :</b> [pgpool-general: 5006] Failover command not invoked by secondary pgpool after its promotion to primary in HA<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Hi all,<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">I have the following setup: 2 identical virtual machines with pgpool 3.5.4 and postgresql 9.5.4 and CentOS 7.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">The first one, let's call it A, has master postgresql and primary pgpool.<o:p></o:p></p>
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<p class="MsoNormal">The second one, let's call it B, has slave postgresql (in hot standby) and secondary pgpool.<o:p></o:p></p>
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<p class="MsoNormal">I think this setup is pretty common.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">The two pgpool are configured with a delegate ip, watchdog, health check on both backends and a failover command.<o:p></o:p></p>
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<p class="MsoNormal">The setup seems to work correctly at first.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">The problem is that, to assess failover, we try bringing down the network on vm A.<o:p></o:p></p>
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<p class="MsoNormal">This should cause the following:<o:p></o:p></p>
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<li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l0 level1 lfo1">
pgpool on B should react becoming primary pgpool and adding delegate ip to its ethernet device<o:p></o:p></li><li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l0 level1 lfo1">
pgpool, after the configured number of attempts to connect to master database on A should promote postgresql on B using the configured failover_command.<o:p></o:p></li></ul>
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<p class="MsoNormal">First point was successful, second one was not.<o:p></o:p></p>
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<p class="MsoNormal">After attempting to connect to postgresql on A appears a message that notify that backend on A is declared down, but no failover command was issued and SHOW pool_nodes shows postgresql on A as online.<o:p></o:p></p>
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<p class="MsoNormal">Moreover attempts to connect to postgresql on A continue forever.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Note that restarting pgpool fixes all problems. <o:p></o:p></p>
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<p class="MsoNormal">It declares itself primary since it cannot reach its counterpart on A, brings up delegate ip and after configured number of attempts promotes postgresql on B as new master.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">So this definitely seems a bug, and indeed a tichet was already be opened for it.<o:p></o:p></p>
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<p class="MsoNormal"><a href="http://www.pgpool.net/mantisbt/view.php?id=227&history=1">http://www.pgpool.net/mantisbt/view.php?id=227&history=1</a><o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">My question is the following: our setup and in particular having two nodes with one pgpool and one postgresql is ideal or is it advisable to arrange services in more nodes or differently?<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">IMHO the probability that one node goes down entirely or becomes unreachable is bigger than a failure of the sole postgresql service.<o:p></o:p></p>
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<p class="MsoNormal">Thus, due to this bug, we risk to have no high avaiability at all and to be left with a read-only database.<o:p></o:p></p>
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<p class="MsoNormal">Obviously our client is not very happy with that since we have a more complex setup with little advantages.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Is there any news on bug resolution timing?<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Is there any workaround that I can use to mitigate the impact?<o:p></o:p></p>
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<p class="MsoNormal">For instance, I may setup pgpools in order to have primary on B.<o:p></o:p></p>
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<p class="MsoNormal">Getting rid of pgpool promotion probably does trigger postgresql failover.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">What is your opinion?<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Best regards,<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Gabriele Monfardini<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">-----<o:p></o:p></p>
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<p class="MsoNormal">Gabriele Monfardini<br>
LdP Progetti GIS<o:p></o:p></p>
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<p class="MsoNormal">tel: 0577.531049<br>
email: <a href="mailto:monfardini@ldpgis.it" target="_blank">monfardini@ldpgis.it</a><o:p></o:p></p>
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