Re: Run end-of-recovery checkpoint in non-wait mode or skip it entirely for faster server availability?

On Fri, Mar 25, 2022 at 3:40 AM Bharath Rupireddy
<bharath(dot)rupireddyforpostgres(at)gmail(dot)com> wrote:
> Since the server spins up checkpointer process [1] while the startup
> process performs recovery, isn't it a good idea to make
> end-of-recovery completely optional for the users or at least run it
> in non-wait mode so that the server will be available faster. The next
> checkpointer cycle will take care of performing the EOR checkpoint
> work, if user chooses to skip the EOR or the checkpointer will run EOR
> checkpoint in background, if user chooses to run it in the non-wait
> mode (without CHECKPOINT_WAIT flag). Of course by choosing this
> option, users must be aware of the fact that the extra amount of
> recovery work that needs to be done if a crash happens from the point
> EOR gets skipped or runs in non-wait mode until the next checkpoint.
> But the advantage that users get is the faster server availability.

I think that we should remove end-of-recovery checkpoints completely
and instead use the end-of-recovery WAL record (cf.
CreateEndOfRecoveryRecord). However, when I tried to do that, I ran
into some problems:

http://postgr.es/m/CA+TgmobrM2jvkiccCS9NgFcdjNSgAvk1qcAPx5S6F+oJT3D2mQ@mail.gmail.com

The second problem described in that email has subsequently been
fixed, I believe, but the first one remains.

--
Robert Haas
EDB: http://www.enterprisedb.com