Re: Accounting of zero-filled buffers in EXPLAIN (BUFFERS)

On 2018-04-30 14:59:31 +1200, Thomas Munro wrote:
> Hi,
> 
> In EXPLAIN (BUFFERS), there are two kinds of cache misses that show up
> as "reads" when in fact they are not reads at all:
> 
> 1.  Relation extension, which in fact writes a zero-filled block.
> 2.  The RBM_ZERO_* modes, which provoke neither read nor write.

Just for understanding: 2) can never happen for buffers showing up in
EXPLAIN, right?

I'm not saying you shouldn't fix the accounting...

Greetings,

Andres Freund