Re: [RFC] CREATE QUEUE (log-only table) for londiste/pgQ ccompatibility

On 10/23/2012 04:13 PM, Tom Lane wrote:
> [ hadn't been following this thread, sorry ]
>
> Hannu Krosing <hannu@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
>
>