Thread: SR: pg_xlog

SR: pg_xlog

From
salah jubeh
Date:
Hello,

I have a question regarding streaming replication:

When  pg_xlog needs to be shipped in streaming replication and when not?  I have faced a different issues in two existing setups, in the first setup, when shipping the pg_xlogs  a time line issue has arisen, and in another setup, when not shipping the log files i get -the database system is starting up- Fatal error.

Regards

Re: SR: pg_xlog

From
Albe Laurenz
Date:
salah jubeh wrote:
> I have a question regarding streaming replication:
> 
> When  pg_xlog needs to be shipped in streaming replication and when not?  I have faced a different
> issues in two existing setups, in the first setup, when shipping the pg_xlogs  a time line issue has
> arisen, and in another setup, when not shipping the log files i get -the database system is starting
> up- Fatal error.

You don't need log shipping for streaming replication as such.

The time line problem should be solved in PostgreSQL 9.3.

But it is still a good idea to use log shipping:
As you describe, you will usually need archived WALs to start replication,
unless the base backup is really recent.
Another case is when there is an interruption or the standby cannot
replicate fast enough.  Then replication will fall behind and might
need WAL archives to catch up.

Yours,
Laurenz Albe