Re: New trigger option of pg_standby - Mailing list pgsql-hackers

From Andreas Pflug
Subject Re: New trigger option of pg_standby
Date
Msg-id 49EDD9D8.9020102@pse-consulting.de
Whole thread Raw
In response to Re: New trigger option of pg_standby  (Fujii Masao <masao.fujii@gmail.com>)
Responses Re: New trigger option of pg_standby  (Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>)
List pgsql-hackers
Fujii Masao wrote:
> Hi,
>
> On Tue, Apr 21, 2009 at 8:28 PM, Heikki Linnakangas
> <heikki.linnakangas@enterprisedb.com> wrote:
>   
>> Simon Riggs wrote:
>>     
>>> If you do this, then you would have to change the procedure written into
>>> the 8.3 docs also. Docs aren't backpatchable.
>>>
>>> What you propose is *better* than raw pg_standby is now, but still not
>>> enough in all cases, as I think you know.
>>>       
>> No, I don't. What is the case where it doesn't work?
>>     
>
> It's the case which I described as the 2nd comment to your
> proposal.
>
> 1. pg_standby tries to restore a non-existent file
> 1-1. remove the trigger file
> 1-2. pg_standby exits with non-zero code
> 2. the startup process tries to read it from pg_xlog
> 2-1. it is applied
> 3. the startup process tries to restore the next file using pg_standby
>   
I'm a little confused. After pg_standby returned non-zero as indication
for end-of-recovery, the startup process shouldn't request another file
from pg_standby, right? Which means 3. should never happen (unless the
startup process stalls and restarts, in which case I find it normal that
another trigger required).

Regards,
Andreas


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