Re: Hard limit on WAL space used (because PANIC sucks)

Andres Freund <andres@2ndquadrant.com> writes:
> On 2014-01-21 19:23:57 -0500, Tom Lane wrote:
>> I'm not suggesting that we stop providing that information!  I'm just
>> saying that we perhaps don't need to store it all in one WAL record,
>> if instead we put the onus on WAL replay to be able to reconstruct what
>> it needs from a series of WAL records.

> That'd likely require something similar to the incomplete actions used
> in btrees (and until recently in more places). I think that is/was a
> disaster I really don't want to extend.

I don't think that's a comparable case.  Incomplete actions are actions
to be taken immediately, and which the replayer then has to complete
somehow if it doesn't find the rest of the action in the WAL sequence.
The only thing to be done with the records I'm proposing is to remember
their contents (in some fashion) until it's time to apply them.  If you
hit end of WAL you don't really have to do anything.
        regards, tom lane