Re: Hot Standby query cancellation and Streaming Replication integration

Greg Stark <gsstark@mit.edu> writes:
> Why shouldn't it have any queries at walreceiver startup? It has any
> xlog segments that were copied from the master and any it can find in
> the archive, it could easily reach a consistent point long before it
> needs to connect to the master. If you really want to protect your
> master from any additional overhead you don't currently need to
> configure a streaming connection at all, you can just use the file
> shipping interface.

There's *definitely* not going to be enough information in the WAL
stream coming from a master that doesn't think it has HS slaves.
We can't afford to record all that extra stuff in installations for
which it's just useless overhead.  BTW, has anyone made any attempt
to measure the performance hit that the patch in its current form is
creating via added WAL entries?
        regards, tom lane