Re: 64-bit XIDs again

Josh Berkus <josh@agliodbs.com> writes:
> On 07/31/2015 02:46 PM, Heikki Linnakangas wrote:
>> Well, sure, if you don't want the clog to grow arbitrarily large, then
>> you need to freeze. And most people would want to freeze regularly, to
>> keep the clog size in check. The point is that you wouldn't *have* to do
>> so at any particular time. You would never be up against the wall, in
>> the "you must freeze now or your database will shut down" situation.

> Well, we still have to freeze *eventually*.  Just not for 122,000 years
> at current real transaction rates.  In 2025, though, we'll be having
> this conversation again because of people doing 100 billion transactions
> per second. ;-)

Well, we'd wrap the 64-bit WAL position counters well before we wrap
64-bit TIDs ... and there is no code to support wraparound in WAL LSNs.
        regards, tom lane