On 10/23/2012 04:13 PM, Tom Lane wrote:
[ hadn't been following this thread, sorry ]
Hannu Krosing <ha...@2ndquadrant.com> writes:
My RFC was for a proposal to skip writing the unneeded info in local
tables and put it _only_ in WAL.
This concept seems fundamentally broken. What will happen if the master
crashes immediately after emitting the WAL record? It will replay it
locally, that's what, and thus you have uncertainty about whether the
master will contain the data or not.
I agree that emitting a record indistinguishable from current insert
record would probably be a bad idea as it would require the WAL
replay to examine the table description to find that the corresponding
table does not accept local data .
It surely would be better to use a special record type so crash
recovery on the master knows not to replay it.
The syntax and mechanics of what would essentially be a simple QUEUEing
feature being declared and defined in a similar way to a table were chosen
for 2 reasons -
* familiarity - easy to adapt
* most structure can be shared with tables & views - easy to implement
--------------------
Hannu
regards, tom lane
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