Bruce Momjian <bruce@momjian.us> writes:
> Matthew Wakeling wrote:
>> Does it really take that long to zero out 8kB of RAM? I thought CPUs were
>> really quick at doing that!
> Yea, that was my assumption too.
You have to write the page (to be sure there is space for it on disk)
not only zero it.
This design is kind of a holdover, though, from back when we had one
ever-growing clog file. Today I'd be inclined to think about managing
it more like pg_xlog, ie, have some background process pre-create a
whole segment file at a time.
regards, tom lane