Re: Standalone synchronous master

Mark Kirkwood <mark.kirkwood@catalyst.net.nz> writes [slightly rearranged]
> My 2c is:

> The current behavior in CAP theorem speak is 'Cap' - i.e focused on 
> consistency at the expense of availability. A reasonable thing to want.

> The other behavior being asked for is 'cAp' - i.e focused on 
> availability. Also a reasonable configuration to want.

> I think an option to control whether we operate 'Cap' or 'cAp' 
> (defaulting to the current 'Cap' I guess) is probably the best solution.

The above is all perfectly reasonable.  The argument that's not been made
to my satisfaction is that the proposed patch is a good implementation of
'cAp'-optimized behavior.  In particular,

> ... Now the desire to 
> use sync rather than async is to achieve as much consistency as 
> possible, which is also reasonable.

I don't think that the existing sync mode is designed to do that, and
simply lobotomizing it as proposed doesn't get you there.  I think we
need a replication mode that's been designed *from the ground up*
with cAp priorities in mind.  There may end up being only a few actual
differences in behavior --- but I fear that some of those differences
will be crucial.
        regards, tom lane