Re: warning message in standby

On Thu, Jun 10, 2010 at 12:49 PM, Greg Stark <gsstark(at)mit(dot)edu> wrote:
> On Thu, Jun 10, 2010 at 5:13 PM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>> At this point you should have a working HS/SR setup.  Now:
>>
>> 8. shut the slave down
>> 9. move recovery.conf out of the way
>> 10. restart the slave - it will do recovery and enter normal running
>> 11. make some database changes
>> 12. stop the slave
>> 13. put recovery.conf back
>> 14. restart the slave
>> 15. make a bunch of changes on the master
>>
>> When the slave then tries to replay, you then get something like:
>>
>> WARNING:  invalid record length at 0/4005330
>> WARNING:  invalid record length at 0/4005330
>> WARNING:  invalid record length at 0/4005330
>>
>
> Woah, why does this procedure lead to this situation? I would hope
> there's nothing a user could do which would cause it short of invoking
> dd to corrupt the WAL files.
>
> At precisely which step of the procedure did the user do something
> wrong?

13.

> Is there any reason we can't detect that they've done it and
> throw a specific error message saying the configuration is invalid?

I'm not sure how we'd go about doing that, but I agree it would be nice.

--
Robert Haas
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