Re: when the startup process doesn't (logging startup delays)

On Mon, Sep 27, 2021 at 9:32 AM Justin Pryzby <pryzby(at)telsasoft(dot)com> wrote:
> >>It also looks pretty silly to say that if you set the value to 10s, something
> >>will happen every 10s. What else would anyone expect to happen?
>
> @Robert: that's consistent with existing documentation, even though it might
> seem obvious and silly to us.
>
> | For example, if you set this to 250ms then all automatic vacuums and analyzes that run 250ms or longer will be logged
> | For example, if you set it to 250ms then all SQL statements that run 250ms or longer will be logged

Fair enough, but I still don't like it much. I tried my hand at
rewriting this and came up with the attached:

+ Sets the amount of time after which the startup process will log
+ a message about a long-running operation that is still in progress,
+ as well as the interval between further progress messages for that
+ operation. This setting is applied separately to each operation.
+ For example, if syncing the data directory takes 25 seconds and
+ thereafter resetting unlogged relations takes 8 seconds, and if this
+ setting has the default value of 10 seconds, then a messages will be
+ logged for syncing the data directory after it has been in progress
+ for 10 seconds and again after it has been in progress for 20 seconds,
+ but nothing will be logged for resetting unlogged operations.
+ A setting of <literal>0</literal> disables the feature.

I prefer this to Nitin's version because I think it could be unclear
to someone that the value applies separately to each operation,
whereas I don't think we need to document that we can't guarantee that
the messages will be perfectly on time - that's true of every kind of
scheduled event in pretty much every computer system - or what happens
if the system clock goes backwards. Those are things we should try to
get right, as well as we can anyway, but we don't need to tell the
user that we got them right.

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