The BUFFER_HIT and BUFFER_MISS probes seem pretty darn redundant

Tom Lane wrote:

Whilst cleaning up the dtrace probe documentation, I realized that
there is nothing the aforementioned probes tell you that you can't find
out (with a lot more data besides) from the final argument of the
BUFFER_READ_DONE probe. Furthermore, tallying them as-is would be
misleading since you couldn't distinguish true reads from relation
extension requests. I think we should just remove them.

Agreed. The found flag from BUFFER_READ_DONE will serve the same
purpose. As always, thanks for offering great solutions!

-Robert