Re: pgsql: Fast promote mode skips checkpoint at end of recovery.

On Tue, Jan 29, 2013 at 9:07 AM, Simon Riggs <simon(at)2ndquadrant(dot)com> wrote:
> Fast promote mode skips checkpoint at end of recovery.
> pg_ctl promote -m fast will skip the checkpoint at end of recovery so that we
> can achieve very fast failover when the apply delay is low. Write new WAL record
> XLOG_END_OF_RECOVERY to allow us to switch timeline correctly for downstream log
> readers. If we skip synchronous end of recovery checkpoint we request a normal
> spread checkpoint so that the window of re-recovery is low.

When I tested this feature, I encountered the following FATAL message.

FATAL: highest timeline 1 of the primary is behind recovery timeline 2

Is this an intentional behavior or bug? What I did in my test is:

1. Set up one master (A), one standby (B), one cascade standby (C)
2. After running pgbench -i -s 10, I promoted the standby (B) with fast mode
3. Then, I shut down the server (B) with immediate mode after it has been
brought up to the master before end-of-recovery checkpoint has not been
completed.
4. Restart the server (B).
5. After the standby (C) established the replication connection with (B),
I got the above FATAL messages repeatedly.

Promoting (B) increments the timeline ID to 2 and generates the timeline
history file. But after restarting (B), its timeline ID is reset to 1
unexpectedly.
This seems to be the cause of the problem.

To address this problem, we should switch to new timeline ID whenever
we read the XLOG_END_OF_RECOVERY even if it's a crash recovery?

Regards,

--
Fujii Masao