Re: warning message in standby - Mailing list pgsql-hackers

From Greg Stark
Subject Re: warning message in standby
Date
Msg-id AANLkTiks4k9WqAZCMFH5Uq_xxC6u_NkkhS7PZY3ve9cF@mail.gmail.com
Whole thread Raw
In response to Re: warning message in standby  (Robert Haas <robertmhaas@gmail.com>)
Responses Re: warning message in standby  (Robert Haas <robertmhaas@gmail.com>)
List pgsql-hackers
On Thu, Jun 10, 2010 at 5:13 PM, Robert Haas <robertmhaas@gmail.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? Is there any reason we can't detect that they've done it and
throw a specific error message saying the configuration is invalid?

--
greg


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