Simon Riggs <simon(at)2ndQuadrant(dot)com> wrote:
> In this release? Maybe? In later releases? Yes.
>
> If it blocks your excellent contribution in this release, then
> from me, "no". If you can achieve this in this release, yes.
> However, if this is difficult or complex, then I would rather say
> "not yet" quickly now, than spend months working out the
> weirdnesses and possibly still get them wrong.
We already have a mechanism for generating a good snapshot, the hard
part (for me at least) would be to get that snapshot over to the hot
standby and have it use the latest one on a request for a
serializable transaction. I have no experience with WAL file
output, and don't know what it would take for hot standby to use it
as I describe.
I agree it's pretty late in the cycle, but I'm going through all the
loose ends and found this one -- which has been hanging out on the
Wiki page as an R&D item for over a full year without discussion.
:-( If we provide the snapshots (which we can safely and easily
do), can someone else who knows what they're doing with WAL and HS
get the rest of it safely into the release? That seems to me to be
the only way it can still happen for 9.1.
If not, I agree this can be 9.2 material. We just have to decide
how to document it and answer the questions near the bottom of my
initial post of the thread.
-Kevin