On 11/01/14 13:25, Stephen Frost wrote:

* Adrian Klaver (adrian.kla...@gmail.com) wrote:
A) Change the existing sync mode to allow the master and standby
fall out of sync should a standby fall over.

I'm not sure that anyone is argueing for this..

B) Create a new mode that does this without changing the existing sync mode.

My two cents would be to implement B. Sync to me is a contract that
master and standby are in sync at any point in time. Anything else
should be called something else. Then it is up to the documentation
to clearly point out the benefits/pitfalls. If you want to implement
something as important as replication without reading the docs then
the results are on you.

The issue is that there are folks who are argueing, essentially, that
"B" is worthless, wrong, and no one should want it and therefore we
shouldn't have it.

We have some people who clearly do want it (and seemed to have provided sensible arguments about why it might be worthwhile), and the others who say they should not.

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

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



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