Re: Hot Standby query cancellation and Streaming Replication integration

Greg Stark <gsstark@mit.edu> writes:
> On Fri, Feb 26, 2010 at 9:19 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> 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?

> What extra entries?

Locks, just for starters.  I haven't read enough of the code yet to know
what else Simon added.  In the past it's not been necessary to record
any transient information in WAL, but now we'll have to.
        regards, tom lane