Re: confusing checkpoint_flush_after / bgwriter_flush_after

Hello Tomas,

>>> While the 9.6 cat is out of the bag, I think we can fix this quite
>>> easily - use "-1" to specify the default value should be used, and use
>>> that in the sample file. This won't break any user configuration.
>> 
>> Although I understand the issue, I'm not sure about -1 as a special
>> value to mean the default.
>
> Why? We use wal_buffers=-1 to use the default (depending on the size of 
> shared_buffers), for example.

Indeed. Just my 0.02€:

ISTM that the use of -1 is not very consistent, as it may mean:
 - default: autovacuum_work_mem, wal_buffers
 - disable: temp_file_limit, old_snapshot_limit,     max_standby_*_delay, log_min_duration_statement

And sometimes disable is the default, but not always:-) Basically I'm not 
sure that adding some more confusion around that helps much...

-- 
Fabien.