Re: effective_cache_size vs units

Gregory Stark wrote:
> 
> "Kenneth Marshall" <ktm@it.is.rice.edu> writes:
> 
> > My one comment is that a little 'b' is used to indicate bits normally
> > and a capital 'B' is used to indicate bytes. So
> >        kb = '1024 bits'
> >        kB = '1024 bytes'
> > I do think that whether or not the k/m/g is upper case or lower case
> > is immaterial.
> 
> Yes, well, no actually there are standard capitalizations for the k and M and
> G. A lowercase g is a gram and a lowercase m means "milli-".

I will have 150 grams of shared memory, please.

> But I think that only gets you as far as concluding that Postgres ought to
> consistently use kB MB and GB in its own output. Which afaik it does.
> 
> To reach a conclusion about whether it should restrict valid user input
> similarly you would have to make some sort of argument about what problems it
> could lead to if we allow users to be sloppy.
> 
> I could see such an argument being made but it requires a lot of speculation
> about hypothetical future parameters and future problems. When we have known
> real problems today.
> 
> And yes, btw, the case sensitivity of these units had already surprised and
> bothered me earlier and I failed to mention it at the time.

Agreed.  However, I see 'ms' as milliseconds, so perhaps the M vs. m is
already in use.  I think we at least need to document the case
sensitivity and improve the error message.

--  Bruce Momjian   bruce@momjian.us EnterpriseDB    http://www.enterprisedb.com
 + If your life is a hard drive, Christ can be your backup. +