Re: Switching timeline over streaming replication

On Wednesday, November 21, 2012 11:36 PM Heikki Linnakangas wrote:
> On 20.11.2012 15:33, Amit Kapila wrote:
> > Defect-2:
> >      1. start primary A
> >      2. start standby B following A
> >      3. start cascade standby C following B.
> >      4. Start another standby D following C.
> >      5. Execute the following commands in the primary A.
> >             create table tbl(f int);
> >             insert into tbl values(generate_series(1,1000));
> >      6. Promote standby B.
> >      7. Execute the following commands in the primary B.
> >             insert into tbl values(generate_series(1001,2000));
> >             insert into tbl values(generate_series(2001,3000));
> >
> >      The following logs are observed on standby C:
> >
> >      LOG:  restarted WAL streaming at position 0/7000000 on tli 2
> >      ERROR:  requested WAL segment 000000020000000000000007 has
> > already been removed
> >      LOG:  record with zero length at 0/7028190
> >      LOG:  record with zero length at 0/7048540
> >      LOG:  out-of-sequence timeline ID 1 (after 2) in log segment
> > 000000020000000000000007, offset 0
> 
> I propose the attached patch (against 9.2) to fix that. This should be
> backpatched to 9.0, where standby_mode was introduced. The code was the
> same in 8.4, too, but AFAICS there was no problem there because 8.4
> never tried to re-open the same WAL segment after replaying some of it.

Fixed.

With Regards,
Amit Kapila.