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</style></head><body><div class="document" id="bus-alt-connection"><h1 class="title">Bus Alt Connection</h1>
<!-- !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!! This file is generated by oca-gen-addon-readme !!!! changes will be overwritten. !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! --><p><a class="reference external" href="https://odoo-community.org/page/development-status"><img alt="Beta" src="https://img.shields.io/badge/maturity-Beta-yellow.png" /></a> <a class="reference external" href="http://www.gnu.org/licenses/agpl-3.0-standalone.html"><img alt="License: AGPL-3" src="https://img.shields.io/badge/licence-AGPL--3-blue.png" /></a> <a class="reference external" href="https://github.com/OCA/server-tools/tree/12.0/bus_alt_connection"><img alt="OCA/server-tools" src="https://img.shields.io/badge/github-OCA%2Fserver--tools-lightgray.png?logo=github" /></a> <a class="reference external" href="https://translation.odoo-community.org/projects/server-tools-12-0/server-tools-12-0-bus_alt_connection"><img alt="Translate me on Weblate" src="https://img.shields.io/badge/weblate-Translate%20me-F47D42.png" /></a> <a class="reference external" href="https://runbot.odoo-community.org/runbot/149/12.0"><img alt="Try me on Runbot" src="https://img.shields.io/badge/runbot-Try%20me-875A7B.png" /></a></p><p>This module makes it possible to use <a class="reference external" href="https://pgbouncer.github.io/">PgBouncer</a> as a connection poolerfor odoo.</p><div class="section" id="why-isn-t-odoo-s-connection-pooling-good-enough"><h1>Why isn’t odoo’s connection pooling good enough?</h1><p>Odoo’s builtin connection pooling works at process level: each Odoo processhas its own <a class="reference external" href="https://github.com/odoo/odoo/blob/12.0/odoo/sql_db.py#L525">ConnectionPool</a>, limited to <tt class="docutils literal">db_maxconn</tt>.</p><p>It does the job of re-using open connections available in the pool.But it never closes these connections, <a class="reference external" href="https://github.com/odoo/odoo/blob/12.0/odoo/sql_db.py#L593">unless reaching db_maxconn</a>.</p><p>In practice, we observe that each odoo worker will end upwith up to 3 open connection in its pool.With 10 http workers, that’s up to 30 connection continuously open justfor one single instance.</p></div><div class="section" id="here-comes-pgbouncer"><h1>Here comes PgBouncer</h1><p>PgBouncer will help to limit this number of open connections,by sharing a pool of connections at the instance level, betweenall workers. Odoo workers will still have up to 3 open connections,but these will be connections to PgBouncer, that on its side willclose unnecessary connections to pg.</p><p>This has proven to help performances on Odoo deployments withmultiple instances.</p><p>It allows you to define how resources should be shared,according to your priorities, e.g. :</p><ul class="simple"><li>key odoo instance on host A can open up to 30 connections</li><li>while odoo instance on host B, dedicated to reports,can open up to 10 connections only</li></ul><p>And most importantly, it helps you to ensure that<tt class="docutils literal">max_connections</tt> will never be reached on pg server side.</p></div><div class="section" id="why-is-this-module-needed"><h1>Why is this module needed?</h1><p>When configuring PgBouncer, you can choose between 2 transaction pooling modes:</p><ul class="simple"><li><cite>pool_mode = session</cite></li><li><cite>pool_mode = transaction</cite></li></ul><p>If we choose <cite>pool_mode = session</cite>, then one server connection will be tiedto a given odoo process until its death, which is exactly what we’re tryingto change. Thus, to release the server connection once the transaction iscomplete, we use <cite>pool_mode = transaction</cite>.</p><p>This works fine, except for Odoo’s longpolling features that relieson the <a class="reference external" href="https://www.postgresql.org/docs/9.6/static/sql-notify.html">LISTEN/NOTIFY</a> mechanism from pg, which is <a class="reference external" href="https://wiki.postgresql.org/wiki/PgBouncer">not compatible</a> with thatmode.</p><p>To be more precise, <cite>NOTIFY</cite> statements are properly transfered by PgBouncerin that mode; only the <cite>LISTEN</cite> statement isn’t (because it needs to keep theserver connection open).</p><p>So for the unique “listening” connection per instance that requires thisstatement (<a class="reference external" href="https://github.com/odoo/odoo/blob/12.0/addons/bus/models/bus.py#L166">here</a>), we need odoo to connect directly to the pg server, bypassingPgBouncer.</p><p>That’s what this module implements, by overriding the relevant methodof the <a class="reference external" href="https://github.com/odoo/odoo/blob/12.0/addons/bus/models/bus.py#L105">Dispatcher</a>.</p><p><strong>Table of contents</strong></p></div><div class="section" id="installation"><h1>Installation</h1><p>You don’t need to install this module in the database(s) to enable it.</p><p>But you need to load it server-wide:</p><ul class="simple"><li>By starting Odoo with <tt class="docutils literal"><span class="pre">--load=web,bus_alt_connection</span></tt></li><li>Or by updating its configuration file:</li></ul><pre class="code ini literal-block"><span class="k">[options]</span><span class="na">(...)</span><span class="na">server_wide_modules</span> <span class="o">=</span> <span class="s">web,bus_alt_connection</span></pre></div><div class="section" id="configuration"><h1>Configuration</h1><p>You need to define how to connect directly to the database:</p><ul><li><p class="first">Either by defining environment variables:</p><blockquote><ul class="simple"><li><tt class="docutils literal"><span class="pre">IMDISPATCHER_DB_HOST=db-01</span></tt></li><li><tt class="docutils literal">IMDISPATCHER_DB_PORT=5432</tt></li></ul></blockquote></li><li><p class="first">Or in Odoo’s configuration file:</p></li></ul><pre class="code ini literal-block"><span class="k">[options]</span><span class="na">(...)</span><span class="na">imdispatcher_db_host</span> <span class="o">=</span> <span class="s">db-01</span><span class="na">imdispatcher_db_port</span> <span class="o">=</span> <span class="s">5432</span></pre></div><div class="section" id="bug-tracker"><h1>Bug Tracker</h1><p>Bugs are tracked on <a class="reference external" href="https://github.com/OCA/server-tools/issues">GitHub Issues</a>.In case of trouble, please check there if your issue has already been reported.If you spotted it first, help us smashing it by providing a detailed and welcomed<a class="reference external" href="https://github.com/OCA/server-tools/issues/new?body=module:%20bus_alt_connection%0Aversion:%2012.0%0A%0A**Steps%20to%20reproduce**%0A-%20...%0A%0A**Current%20behavior**%0A%0A**Expected%20behavior**">feedback</a>.</p><p>Do not contact contributors directly about support or help with technical issues.</p></div><div class="section" id="credits"><h1>Credits</h1><div class="section" id="authors"><h2>Authors</h2><ul class="simple"><li>Trobz</li></ul></div><div class="section" id="contributors"><h2>Contributors</h2><ul class="simple"><li>Nils Hamerlinck <<a class="reference external" href="mailto:nils@trobz.com">nils@trobz.com</a>></li></ul></div><div class="section" id="maintainers"><h2>Maintainers</h2><p>This module is maintained by the OCA.</p><a class="reference external image-reference" href="https://odoo-community.org"><img alt="Odoo Community Association" src="https://odoo-community.org/logo.png" /></a><p>OCA, or the Odoo Community Association, is a nonprofit organization whosemission is to support the collaborative development of Odoo features andpromote its widespread use.</p><p>This module is part of the <a class="reference external" href="https://github.com/OCA/server-tools/tree/12.0/bus_alt_connection">OCA/server-tools</a> project on GitHub.</p><p>You are welcome to contribute. To learn how please visit <a class="reference external" href="https://odoo-community.org/page/Contribute">https://odoo-community.org/page/Contribute</a>.</p></div></div></div></body></html>
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