<div dir="ltr">Hi,<br><br> As per the docs:<br><ul><li> <b>Limiting Exceeding Connections</b>
</li></ul>
<dl><dd> There is a limit on the maximum number of concurrent
connections with PostgreSQL, and connections are rejected after this
many connections. Setting the maximum number of connections, however,
increases resource consumption and affect system performance. pgpool-II
also has a limit on the maximum number of connections, but <b>extra
connections will be queued instead of returning an error immediately.</b></dd></dl><p></p><p>So one would expect the application to wait indefinitely if the connection parameter pair (user, database) that it is requesting is not yet available, but I see that the application connections are terminated immediately. Here's how I tested this on version 3.1.3 and master branch ( 3.2.0 RC3, commit id: 1c584a84).</p>
.) Start a single Postgres database instance (version PostgreSQL 9.1.4)<br>.) Create 2 databases : test and test2<br>.) Start pgpool as follows: (config files attached)<br><br>inst/bin/pgpool -f ~/Downloads/pgpool.conf -F ~/Downloads/pcp.conf -a ~/Downloads/pool_hba.conf<br>
<br>.) In one terminal, run psql clients, one at a time, to connect to 'test' database, over pgpool:<br><br><span style="font-family:courier new,monospace">export PGHOST=localhost PGPORT=9999 PGDATABASE=test PGUSER=postgres</span><br style="font-family:courier new,monospace">
<span style="font-family:courier new,monospace">while sleep 1; do psql -c "select datname, now()::timestamp(0), count(*) from pg_stat_activity group by datname"; done</span><br style="font-family:courier new,monospace">
<br>.) In other terminal, run psql clients, one at a time,, to connect to 'test2' database over pgpool:<br><br><span style="font-family:courier new,monospace">export PGHOST=localhost PGPORT=9999 PGDATABASE=test2 PGUSER=postgres</span><br style="font-family:courier new,monospace">
<span style="font-family:courier new,monospace">while sleep 1; do psql -c "select datname, now()::timestamp(0), count(*) from pg_stat_activity group by datname"; done</span><br style="font-family:courier new,monospace">
<br>After a few seconds, in the second terminal, when the total connections on Postgres server have all been exhausted, I see the psql connections failing:<br><br><br><span style="font-family:courier new,monospace"> datname | now | count </span><br style="font-family:courier new,monospace">
<span style="font-family:courier new,monospace">---------+---------------------+-------</span><br style="font-family:courier new,monospace"><span style="font-family:courier new,monospace"> test | 2012-07-31 11:17:49 | 75</span><br style="font-family:courier new,monospace">
<span style="font-family:courier new,monospace"> test2 | 2012-07-31 11:17:49 | 25</span><br style="font-family:courier new,monospace"><span style="font-family:courier new,monospace">(2 rows)</span><br style="font-family:courier new,monospace">
<br style="font-family:courier new,monospace"><span style="font-family:courier new,monospace">psql: psql: psql: psql: psql: psql: psql: psql: psql: psql: psql: psql: psql: psql: psql: psql: psql: psql: psql: psql: ^C</span><br style="font-family:courier new,monospace">
<span style="font-family:courier new,monospace">gurjeet@work:~/dev/POSTGRES T111809 (pg_9.1_stable)$ </span><br style="font-family:courier new,monospace"><br clear="all">Given that pgpool advertises that 'extra connections will be queued instead of returning an error immediately", I think we should treat this as a bug, unless there's something wrong with my configuration.<br>
<br>Best regards,<br>-- <br><div dir="ltr">Gurjeet Singh<br>EnterpriseDB Corporation<br>The Enterprise PostgreSQL Company<br></div><br>
</div>