<div dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Feb 25, 2016 at 7:18 AM, Brandon Ridler <span dir="ltr"><<a href="mailto:brandonr@motiga.com" target="_blank">brandonr@motiga.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div dir="ltr">Hello,<div><br></div><div>I've scoured the site and the interwebs with out being able to find information in regards to what I'm seeing and am hoping I can be pointed in the right direction, or given an explanation as to why it appears every connection to pgpool is resulting in a connection to every backend I have. My general setup when compared to a default is:<br></div><div><br></div><div>1. I have 3 backends, all weight 1.</div><div>2. I have master/slave mode enabled with stream.</div><div>3. I have load_balancing on.</div><div>4. I have connection_cache off.</div><div>5. I have connection_life_time set to 60.</div><div>6. I have watchdog enabled and configured.</div><div><br></div><div>I'm using 3.5.0 pgpool2 running on an ubuntu 14.0.4 inside a docker container. I also tried 3.3.2 from the ubuntu apt repos.</div><div><br></div><div>It doesn't matter if it's our custom app, an established app like ejabberd, or me using psql to connect to it, it will always make connections to all backends listed. I'd like to know if that is expected behavior but haven't found anything in the docs to confirm or deny this other than a reference to when your making transactions.</div></div></blockquote><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div dir="ltr"><div><br></div><div>Assuming the above is correct, I tried to use the connection_life_time value. Thinking that if the front-end connection to pgpool is idle, and thus the backend is idle, that at least pgpool would close the backend and re-establish it if anything came down from the apps.</div></div></blockquote><div><br></div><div><div>Yes It is expected by pgpool-II to make connections with all configured backend nodes And for the second part, the connection_life_time only disconnects the idle cached backend connections. While the backend connection which is in use by the front-end even if the front-end is idle is not considered as idle by pgpool-II. To disconnect the idle frontend connections you can set the client_idle_limit config parameter.</div></div><div><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div dir="ltr"><div>Can you please let me know if I'm misunderstanding the intent of pgpool here or if there's a configuration that I may be overlooking. I thought when I originally set up pgpool a month ago that I saw like 300 connection to pgpool and only 50-60 connections to each of the backends.</div></div></blockquote><div><br></div><div style=""><font color="#000000" face="sans-serif"><span style="line-height:19.2px">When the connection cache is enabled on pgpool-II, then pgpool-II does not close the backend connection even when the client application disconnects. Each connection is identified by database_name and user_name values of the connection, So when the client connection request arrives to the pgpool-II child and that child already have a cached connection with the same credentials(same database_name and user_name pair), then no new backed connection is opened by the pgpool-II while pgpool-II hooks the incoming client connection with that already cached backend connection. Only when the database_name and user_name pair of incoming client connection does not exist in the connection cache pgpool-II opens a new backend connection.</span></font></div><div style=""><font color="#000000" face="sans-serif"><span style="line-height:19.2px">The number of backend connection cached by a pgpool-II child can be configured by the <i>max_pool</i> config paramete. And theoretically PostgreSQL server can have up to (max_pool*num_init_children) opened connection when the connection cache is enabled, even when no client is connected to pgpool-II</span></font><br></div><div style=""><font color="#000000" face="sans-serif"><span style="font-size:12.8px;line-height:19.2px"><br></span></font></div><div style=""><font color="#000000" face="sans-serif"><span style="font-size:12.8px;line-height:19.2px">Regards</span></font></div><div style=""><font color="#000000" face="sans-serif"><span style="font-size:12.8px;line-height:19.2px">Muhammad Usama</span></font></div><div style="font-size:12.8px"><span style="font-size:small"> </span><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div dir="ltr"><div><br></div><div>Regards,</div><div>Brandon</div></div>
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