Re: Fixed xloginsert_locks for 9.4

On 10/03/2014 09:42 PM, Bruce Momjian wrote:
> On Fri, Oct  3, 2014 at 03:30:35PM -0300, Arthur Silva wrote:
>>      > Every GUC add complexity to the system because people have to understand
>>      > it to know if they should tune it.  No GUC is zero-cost.
>>
>>      Please see my blog post about the cost of adding GUCs:
>>
>>              http://momjian.us/main/blogs/pgblog/2009.html#January_10_2009
>>
>> That's true Bruce (nice post, it was a good reading).
>> But how can we ignore 25%+ improvements (from 8 to 24)?
>> At very least we should delivery some pretty good defaults.
>
> Well, checkpoint_segments was a similar case where we couldn't give good
> tuning advice so we went with a server log file warning if it needed to
> be increased --- this might be a similar case.

I have no idea how to decide at runtime whether it should be increased 
or not. If that was feasible, we probably could make it tune itself on 
the fly - it's not like checkpoint_segments where you need more disk 
space if you increase it.

I stand by my decision to make it a #define, at least until someone 
voices their objection in the form of a documentation patch.

- Heikki