I wrote:
> Simon Riggs <simon@2ndQuadrant.com> writes:
>> In some cases, but my wish is also to minimise WAL volume as much as
>> possible.
> I'm with Greg on this one: baroque bit-squeezing schemes are a bad idea.
Wait a minute ... why are we even having this conversation? XLogRecord
has at least two entirely-wasted bytes right now, due to alignment.
It is entirely not sane to consider messing with xl_prev in preference
to using that space.
regards, tom lane