Re: Clarification on pg_basebackup

Selon "Campbell, Lance" <lance(at)illinois(dot)edu>:

PostgreSQL 9.3
Would someone be able to clarify if one should use the -X option with
pg_basebackup when your intention is to include all WAL files created? There
are two scenarios. The first scenario listed below makes sense using the -X
option. Bus scenario #2 has me a little confused. I don't want to cause any
issues when restoring.

1) Use pg_basebackup for a fully standalone restorable snapshot of the
database using the -X parameter. When a failure occurs you restore the
database to that exact point in time.

2) You restore from a pg_basebackup and you also apply all of the WAL
files since the last pg_basebackup. Do you want to use the -X option when
doing the pg_basebackup if your intention is to have all of the WAL files
since you backed up last? Or does it matter. Would PostgreSQL just ignore
the duplicate WAL files that were created by the -X option during the
pg_basebackup?

Thanks for your clarification. This is a hard scenario to test.

Thanks,

Lance Campbell<http://illinois.edu/person/lance>
Software Architect
Web Services at Public Affairs
217-333-0382
[University of Illinois at Urbana-Champaign logo]<http://illinois.edu/>

For security, I will do both i.e pg_basebackup -X + continuous WAL archiving.
Reason : you never know what could happen with your WAL archiving process.
At least with -X you will have a "restartable" backup.

Regards

Gilles