<div dir="ltr">I have been using your scenario (2 PSQL nodes with Postgis in replication mode). I can say pgpool is stable (it hasn't failed in 2 years). Recovery is manual (needs to execute one command from administrator) but you don't have to do anything extra. The dificulty laid in its initial configuration (I had to tweak 3 scripts a lot).<div><br><div>Besides that, replication mode didn't work for us:</div><div><br></div><div>1.) From time to time pgpool detects data mismatch between nodes (pgool got more results in a query from 1 node than the other), so it dettaches the node. I guess there is some PSQL function which runs inside DDBB and gets different results on both nodes. PostGIS maybe?</div><div><br></div><div>2.) When reattaching the node (doing 'online recovery') everything works fine, but if I create new objects (DDBB, tables, etc) both nodes use different OID's for each object. When pgpool detects this difference it dettaches one node. I guess they are getting different OID because the reattached node is in another PSQL "timeline" from activde node after recovery.</div><div><br></div><div>3.) If I don't create new objects, after a few days there is the same mismatch about getting different number of results from some query.</div><div><br></div><div>(There is a workaroung for number 2, which is to shutdown and restart the active node. Now I can execute online recovery to reattach failed node.)</div><div><br></div><div>At the end I am using master-slave with PSQL's synchronus replication which doesn't suffer from these anomalies.</div><div><br></div><div><br></div><div><br></div></div></div><div class="gmail_extra"><br><div class="gmail_quote">On 14 September 2015 at 15:31, VILLARD, Pierre <span dir="ltr"><<a href="mailto:pierre.villard@capgemini.com" target="_blank">pierre.villard@capgemini.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hi,<br>
<br>
I am comfortable with standalone PostgreSQL but, so far, I never used PgPool to switch to a multi-instance installation. In order to improve the read-only performances on my system, I am considering to switch to a two (or more) nodes installation of PostgreSQL with the native replication of PostgreSQL and the use of PgPool. I am also using a lot PostGIS with my PostgreSQL installation and I am accessing this database through Java code using a JDBC/Hibernate layer.<br>
<br>
Unfortunately, I received a bad feedback about this approach. According to this feedback, PgPool would not be very stable, the load balancing would not be mature and the recovering on a failure would be manual and very complex.<br>
<br>
I have to admit that this feedback slowed things down... I need to have something really robust regarding my context of application.<br>
<br>
Do you have feedbacks on your side regarding my approach ? Some advice ?<br>
<br>
Pierre<br>
This message contains information that may be privileged or confidential and is the property of the Capgemini Group. It is intended only for the person to whom it is addressed. If you are not the intended recipient, you are not authorized to read, print, retain, copy, disseminate, distribute, or use this message or any part thereof. If you receive this message in error, please notify the sender immediately and delete all copies of this message.<br>
<br>
_______________________________________________<br>
pgpool-general mailing list<br>
<a href="mailto:pgpool-general@pgpool.net">pgpool-general@pgpool.net</a><br>
<a href="http://www.pgpool.net/mailman/listinfo/pgpool-general" rel="noreferrer" target="_blank">http://www.pgpool.net/mailman/listinfo/pgpool-general</a><br>
</blockquote></div><br></div>