Simon Riggs <simon(at)2ndquadrant(dot)com> writes:
> Why do we have a WAL record for CLOG page extension?
Think of it as being a substitute for a full-page image, or perhaps the
init-bit in heap-insert records is the closest analogy. Your patch is
unworkable because it provides no means for recovering from
corrupt-on-disk clog pages.
regards, tom lane