Re: Patch: raise default for max_wal_segments to 1GB

On 03/03/2015 08:21 PM, Josh Berkus wrote:
> On 03/03/2015 10:15 AM, Josh Berkus wrote:
>> On 03/02/2015 11:25 PM, Heikki Linnakangas wrote:
>>> I propose that we remove the comment from max_wal_size, and also remove
>>> the "in milliseconds" from wal_receiver_timeout and
>>> autovacuum_vacuum_cost_delay.
>>
>> +1
>>
>
> Actually, let's be consistent about this.  It makes no sense to remove
> unit comments from some settings which accept ms but not others.
>
> Do we want to remove unit comments from all settings which accept
> "MB,GB" or "ms,s,min"?  There's more than a few.  I'd be in favor of
> this, but seems like (a) it should be universal, and (b) its own patch.

I think it's a good rule that if the commented-out default in the sample 
file does not contain a unit, then the base unit is in the comment. 
Otherwise it's not. For example:

#shared_buffers = 32MB            # min 128kB                # (change requires restart)

The base unit is BLCKSZ, i.e. 8k, but usually people will usually use 
MB/GB. And that is evident from the default value, 32MB, so there's no 
need to mention it in the comment.

#tcp_keepalives_idle = 0        # TCP_KEEPIDLE, in seconds;                # 0 selects the system default

Here it's not obvious what the unit should be from the default itself. 
So the comment says it's "in seconds".

- Heikki