Re: Should we increase the default vacuum_cost_limit?

On Sat, Mar 9, 2019 at 11:14 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>
> BTW ... I noticed while fooling with this that GUC's out-of-range
> messages can be confusing:
>
> regression=# set vacuum_cost_delay = '1s';
> ERROR:  1000 is outside the valid range for parameter "vacuum_cost_delay" (0 .. 100)
>
> One's immediate reaction to that is "I put in 1, not 1000".  I think
> it'd be much clearer if we included the unit we'd converted to, thus:
>
> ERROR:  1000 ms is outside the valid range for parameter "vacuum_cost_delay" (0 .. 100)
>
> (Notice that this also implicitly tells what units the range limits
> are being quoted in.

I like it!

> A small problem with this idea is that GUC_UNIT_[X]BLOCK variables don't
> really have a natural unit name.  If we follow the lead of pg_settings,
> such errors would look something like
>
> ERROR:  1000 8kB is outside the valid range for ...
>
> I can't think of a better idea, though, and it'd still be clearer than
> what happens now.
>
> Barring objections I'll go make this happen.

No objection here.