[Pgpool-general] stopping/adding a node causes pgpool to return error to all running sqls

[ilias seperis]

Hello again,

Thanks for the info.
Just out of curiosity, I had a quick look into the source code and noticed that the status of nodes are kept in "Req_info" (shm).
Since all forked pgpools can access this shm, why you need to restart them?
(I don't mean to judge you or anything, obviously there is a reason. I was just wondering what would that be.)
I know that this is beyond the scope of this list, so please forgive me:)

Thanks
ilias


>________________________________
>From: Toshihiro Kitagawa <kitagawa at sraoss.co.jp>
>To: ilias seperis <ilisepe1 at yahoo.com>
>Cc: "pgpool-general at pgfoundry.org" <pgpool-general at pgfoundry.org>
>Sent: Friday, July 1, 2011 11:20 AM
>Subject: Re: [Pgpool-general] stopping/adding a node causes pgpool to return error to all running sqls
>
>On Wed, 29 Jun 2011 09:57:09 -0700 (PDT)
>ilias seperis <ilisepe1 at yahoo.com> wrote:
>
>> Hello,
>> 
>> I've just installed pgpool-II 2.3.2.1 with 2 nodes and I wanted to test what would happen if one of my backends would have failed.
>> So I gave a few select sqls to pgpool and I checked (with top) that the select sqls were distributed to both my nodes, so I was happy:-)
>> 
>> But after stopping the 2nd node, I expected to get a failure result only from those sqls that were running on the 2nd node (since I had just stopped it).
>> To my surprise I got error result from all my sqls!
>> Is this normal?
>> (Pgpool works fine afterwards (with node2 kicked-out of course).)
>> I also noticed that the same thing happens (running sqls fail) while adding node2 (pcp_attach_node 1 node1 9898 ilias 1234 1).
>> Again, is this normal?
>
>Both are normal.
>pgpool-II restarts all child processes when failover or failback occurs.
>
>