Re: Re: Hot Standby query cancellation and Streaming Replication integration

Tom Lane wrote:
> I don't see a "substantial additional burden" there.  What I would
> imagine is needed is that the slave transmits a single number back
> --- its current oldest xmin --- and the walsender process publishes
> that number as its transaction xmin in its PGPROC entry on the master.
>   

That is exactly the core idea I was trying to suggest in my rambling 
message.  Just that small additional bit of information transmitted and 
published to the master via that route, and it's possible to optimize 
this problem in a way not available now.  And it's a way that I believe 
will feel more natural to some users who may not be well served by any 
of the existing tuning possibilities.

-- 
Greg Smith  2ndQuadrant US  Baltimore, MD
PostgreSQL Training, Services and Support
greg@2ndQuadrant.com   www.2ndQuadrant.us