Re: Interrupted streaming replication - Mailing list pgsql-general

On 12/07/2015 06:04 AM, Tony Nelson wrote:
> Thank you very much, this is working perfectly.  I copied a couple over
> and the server applied them, and is waiting for the next set.

To prevent this sort of thing in the future I would still take a look at
the restore_command, for the following reason:

http://www.postgresql.org/docs/9.1/interactive/warm-standby.html#STREAMING-REPLICATION

"If you use streaming replication without file-based continuous
archiving, you have to set wal_keep_segments in the master to a value
high enough to ensure that old WAL segments are not recycled too early,
while the standby might still need them to catch up. If the standby
falls behind too much, it needs to be reinitialized from a new base
backup. If you set up a WAL archive that's accessible from the standby,
wal_keep_segments is not required as the standby can always use the
archive to catch up."

A belt and suspenders approach where streaming is the default and WAL
archive recovery is the backup.

>
> Tony
>
> *From:*Melvin Davidson [mailto:melvin6925@gmail.com]
> *Sent:* Monday, December 07, 2015 8:59 AM
> *To:* Tony Nelson
> *Cc:* Andreas Kretschmer; pgsql-general@postgresql.org
> *Subject:* Re: [GENERAL] Interrupted streaming replication
>
> As long as you have 00000001000000890000002C and the subsequent WALs in
> your archive directory, then you should
> be able to simply scp them to you second slave's pg_xlog directory.
>
> On Mon, Dec 7, 2015 at 8:50 AM, Tony Nelson <tnelson@starpoint.com
> <mailto:tnelson@starpoint.com>> wrote:
>
>
>
>  > -----Original Message-----
>  > Tony Nelson <tnelson@starpoint.com <mailto:tnelson@starpoint.com>> wrote:
>  >
>  > > 2015-12-07 08:24:50 EST FATAL:  requested WAL segment
>  > > 00000001000000890000002C has already been removed
>  > >
>  > >
>  > >
>  > > Can I simply copy the file from my archive directory back to the WAL
>  > directory?
>  >
>  > I'm afraid that won't work, because of the master knows nothing about
> this
>  > copy and can't stream its content.
>  >
>  > Maybe you can create/update your recovery.conf, see restore_command.
>  >
>  >
>  > for the future: increase wal_keep_segments, or better: use
> replication slots
>  > (since 9.4 a really good feature to prevent such errors).
>  >
>  >
>
> Thank you.  I'm still running 9.1, but I'll look into 9.4.  Fortunately
> my database is small so doing a new base backup is not the end of the
> world.  It's been a long time since I've set this up, so I'm going to
> have to go through a refresher course on exactly what I need to do.
>
> Thanks for your help.
>
> Tony
>
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> *Melvin Davidson*
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>
> ------------------------------------------------------------------------
> Since 1982, Starpoint Solutions has been a trusted source of human
> capital and solutions. We are committed to our clients, employees,
> environment, community and social concerns. We foster an inclusive
> culture based on trust, respect, honesty and solid performance. Learn
> more about Starpoint and our social responsibility at
> http://www.starpoint.com/social_responsibility
>
> ------------------------------------------------------------------------
> This email message from Starpoint Solutions LLC is for the sole use of
> the intended recipient(s) and may contain confidential and privileged
> information. Any unauthorized review, use, disclosure or distribution is
> prohibited. If you are not the intended recipient, please contact the
> sender by reply email and destroy all copies of the original message.
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--
Adrian Klaver
adrian.klaver@aklaver.com