Re: Proper way to restore from a basebackup without the WAL-files?

[Gustav Karlsson <gustav.karlsson@xxxxxxx>]

Thanks everyone for your answers and pointing me to relevant documentation! I will attempt to do a dump and restore immediately after pg_resetxlog and see where that leaves me.

It is indeed a one off for us. Generally we have a complete WAL-history.

Regards,

Gustav

On Dec 15, 2015, at 7:58 PM, Keith <keith@xxxxxxxxxxx> wrote:

On Tue, Dec 15, 2015 at 1:19 PM, Kevin Grittner <kgrittn@xxxxxxxxx> wrote:

On Tue, Dec 15, 2015 at 11:47 AM, John Scalia <jayknowsunix@xxxxxxxxx> wrote:

> If you absolutely must use the pg_basebackup as your source and I'm assuming
> you have a tarball without any of WAL files, you could expand the tarball
> into you data directory, and use pg_resetxlog to "fool" the master into
> starting up. I only say "fool" as it just builds you a blank WAL file which
> this system can use as its integrity check and properly start.

Please note that this will generally leave you with a corrupted
cluster; you would be well advised to follow the advice in the
documentation:

http://www.postgresql.org/docs/9.4/interactive/app-pgresetxlog.html

| After running this command, it should be possible to start the
| server, but bear in mind that the database might contain
| inconsistent data due to partially-committed transactions. You
| should immediately dump your data, run initdb, and reload. After
| reload, check for inconsistencies and repair as needed.

--
Kevin Grittner
EDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

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Hopefully this is just a one-off occurrence where you needed to do this. The best thing long term would be to ensure you're backing up the WAL files along with pg_basebackup. Use the -X option with pg_basebackup so you have a consistent backup that can be started on its own. Or make sure you're backing up your WAL files another way (archive_command on master, pg_receivexlogs, etc).