On Fri, Sep 26, 2014 at 2:02 PM, Robert Haas <robertmh...@gmail.com> wrote:
> On Fri, Sep 26, 2014 at 1:22 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: > > Robert Haas <robertmh...@gmail.com> writes: > >> If we want the narrowest possible fix for this, I think it's "complain > >> if a non-zero value would round to zero". That fixes the original > >> complaint and changes absolutely nothing else. But I think that's > >> kind of wussy. Yeah, rounding 29 seconds down to a special magic > >> value of 0 is more surprising than rounding 30 seconds up to a minute, > >> but the latter is still surprising. We're generally not averse to > >> tighter validation, so why here? > > > > So in other words, if I set "shared_buffers = 100KB", you are proposing > > that that be rejected because it's not an exact multiple of 8KB? > > Absolutely. And if anyone is inconvenienced by that, then they should > upgrade to a 386. Seriously, who is going to set a value of > shared_buffers that is not measured in MB? And if they do, why > shouldn't we complain if we can't honor the value exactly? If they > really put in a value that small, it's not stupid to think that the > difference between 96kB and 104kB is significant. Honestly, the most > likely explanation for that value is that it's a developer doing > testing. > Related thought - why don't we allow the user to specify "1.5MB" as a valid value? Since we don't the rounding on the 8kb stuff makes sense because not everyone wants to choose between 1MB and 2MB. A difference of 1 minute is not as noticeable. In the thread Tom linked to earlier the whole idea of a unit being "8kb" (instead "1 block") is problematic and this is just another symptom of that. David J.
