Re: Nicer error when connecting to standby with hot_standby=off

On 2021/03/23 3:59, James Coleman wrote:
> Are you saying we should only change the message for a single case:
> the case where we'd otherwise allow connections but EnableHotStandby
> is false?

No. Let me clarify my opinion.

At PM_STARTUP, "the database system is starting up" should be logged
whatever the setting of hot_standby is. This is the same as the original
behavior. During crash recovery, this message is output. Also at archive
recovery or standby server, until the startup process sends
PMSIGNAL_RECOVERY_STARTED, this message is logged.

At PM_RECOVERY, originally "the database system is starting up" was logged
whatever the setting of hot_standby is. My opinion is the same as our
consensus, i.e., "the database system is not accepting connections" and
"Hot standby mode is disabled." are logged if hot_standby is disabled.
"the database system is not accepting connections" and "Consistent
recovery state has not been yet reached." are logged if hot_standby is
enabled.

After the consistent recovery state is reached, if hot_standby is disabled,
the postmaster state is still PM_RECOVERY. So "Hot standby mode is disabled."
is still logged in this case. This is also different behavior from the original.
If hot_standby is enabled, read-only connections can be accepted because
the consistent state is reached. So no message needs to be logged.

Therefore for now what we've not reached the consensus is what message
should be logged at PM_STARTUP. I'm thinking it's better to log
"the database system is starting up" in that case because of the reasons
that I explained upthread.

Thought?

Regards,

--
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION