[pgpool-general: 6147] Re: What happens when node is assigned as shutdown

Tatsuo Ishii ishii at sraoss.co.jp
Tue Jun 26 23:47:06 JST 2018


Thank you for the clarification. In addition to this, even if
load_balance_node is on, a session whose load balancing node is the
standy, then the pgpool connection will not be disrupted by the
failover happening on the standby.

> Note that if standby node fails and if load_balance_node is off, then the pgpool connection will not be disrupted by the failover happening on the standby (at least with recent version of pgpool): this is documented in the doc and I can confirm that it is working in my tests.
> In all other cases the backend connection will be disconnected and I suppose the client will receive an error and the query result will be lost
> Pierre 
>     On Tuesday, June 26, 2018, 3:35:41 PM GMT+2, Mariel Cherkassky <mariel.cherkassky at gmail.com> wrote:  
>  The moment the pool assign the shutdown status to a specific node all active session to that node are closed immediatly ?
> 2018-06-26 16:11 GMT+03:00 Tatsuo Ishii <ishii at sraoss.co.jp>:
>> Hi,
>> I wanted to understand what happens to a session that was opened from the
>> pool to   one of the nodes in my cluster (query that is taking x time).
>> Suddenly there was a network conflict between the pool node and the
>> database node and the pool change the status of the database node to
>> shutdown(the node is slave). What happens to the query that runned ? What
>> happens to the session that was open ?
> The session will be closed. This is pretty much similar when you
> directly connect to PostgreSQL.
>> Will the output of the query will
>> come back to the user ?
> Though it really depends on the timing of failure, probably the output
> of the query will not come bacl to the user in most cases.
> Best regards,
> --
> Tatsuo Ishii
> SRA OSS, Inc. Japan
> English: http://www.sraoss.co.jp/index_ en.php
> Japanese:http://www.sraoss.co. jp
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