[pgpool-general: 4934] Re: Load balancing issue

[Vlad Novikov]

Hi Lucas,

I checked the log and found no failover entries. Here's how that happens. I
start two postgres backends (master-slave streaming replication) and
pgpool-II instance. Then I attach both of the nodes and initially all the
clients get connected to master only. I see that with ps ax | grep
postgres. After some time new clients start getting connected to the hot
standby node while older clients are still connected to master. Again, I
see that with ps ax | grep postgres. In that case both master and hot
standby have pgpool-II connected. That's what concerns me the most. If
there was a failover event, master would've been detached and there would
be no pgpool-II connections there.

Vlad

On Sat, Aug 20, 2016 at 1:25 AM, Lucas Luengas <lucasluengas at gmail.com>
wrote:

> Hello.
>
> Have you checked pgpool log file?  Maybe a failover happened?
>
> On Fri, Aug 19, 2016 at 10:48 PM, Vlad Novikov <xou.slackware at gmail.com>
> wrote:
>
>> Hello,
>>
>> I'm have setup pgpool-II with 2 backends in streaming mode (see
>> configuration file attached). In particular, I have load_balance_mode = off
>> to make sure that in this pool all connections will be established to
>> streaming master only. However, over some time I see pgpool-II establishing
>> connections to hot standby server. As a result client applications start
>> failing as they cannot write to the database they're connected to. So far
>> the only solution for me is to keep the hot standby detached (which is not
>> a good idea in terms of automated failover).
>> Pgpool-II starts behaving like this at about 100 clients connected.
>> PostgreSQL max_connections is set to 900 and with hot standby detached
>> there are no connection issues reported (all clients can connect to the
>> backend with no issues).
>> I use pgpool-II and PostgreSQL provided by PostgreSQL official repository.
>> PostgreSQL 9.4.9
>> pgpool-II 3.5.3
>> OS: CentOS 7.2
>>
>> Is there anything I need to change in the configuration file to make all
>> clients connect to master only when both backends are attached? From what I
>> understand that is expected with load_balance_mode = off.
>>
>> Regards,
>> Vlad
>>
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>>
>>
>
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