Re: [PATCH 8/8] Introduce wal decoding via catalog timetravel

Robert Haas <robertmhaas@gmail.com> writes:
> On Wed, Oct 10, 2012 at 7:02 PM, Peter Geoghegan <peter@2ndquadrant.com> wrote:
>> The purpose of ApplyCache/transaction reassembly is to reassemble
>> interlaced records, and organise them by XID, so that the consumer
>> client code sees only streams (well, lists) of records split by XID.

> I think I've mentioned it before, but in the interest of not being
> seen to critique the bikeshed only after it's been painted: this
> design gives up something very important that exists in our current
> built-in replication solution, namely pipelining.

Isn't there an even more serious problem, namely that this assumes
*all* transactions are serializable?  What happens when they aren't?
Or even just that the effective commit order is not XID order?
        regards, tom lane