Re: Is it correct to update db state in control file as "shutting down" during end-of-recovery checkpoint?

On 12/7/21, 8:42 PM, "Bharath Rupireddy" <bharath.rupireddyforpostgres@gmail.com> wrote:
> On Wed, Dec 8, 2021 at 9:49 AM Bossart, Nathan <bossartn@amazon.com> wrote:
>> I think that's alright.  The only other small suggestion I have would
>> be to say "during end-of-recovery checkpoint" instead of "while in
>> end-of-recovery checkpoint."
>
> "while in" is being used by DB_IN_CRASH_RECOVERY and
> DB_IN_ARCHIVE_RECOVERY messages. I don't think it's a good idea to
> deviate from that and use "during".

Fair enough.  I don't have a strong opinion about this.

>> Another option we might want to consider is to just skip updating the
>> state entirely for end-of-recovery checkpoints.  The state would
>> instead go straight from DB_IN_CRASH_RECOVERY to DB_IN_PRODUCTION.  I
>> don't know if it's crucial to have a dedicated control file state for
>> end-of-recovery checkpoints.
>
> Please note that end-of-recovery can take a while in production
> systems (we have observed such things working with our customers) and
> anything can happen during that period of time. The end-of-recovery
> checkpoint is not something that gets finished momentarily. Therefore,
> having a separate db state in the control file is useful.

Is there some useful distinction between the states for users?  ISTM
that users will be waiting either way, and I don't know that an extra
control file state will help all that much.  The main reason I bring
up this option is that the list of states is pretty short and appears
to be intended to indicate the high-level status of the server.  Most
of the states are over 20 years old, and the newest one is over 10
years old, so I don't think new states can be added willy-nilly.

Of course, I could be off-base and others might agree that this new
state would be nice to have.

Nathan