Re: Proposal for CSN based snapshots

On Fri, May 30, 2014 at 2:38 PM, Heikki Linnakangas
<hlinnakangas@vmware.com> wrote:
> (forgot to answer this question)
>
> On 05/30/2014 06:27 PM, Andres Freund wrote:
>>
>> On 2014-05-30 17:59:23 +0300, Heikki Linnakangas wrote:
>>>
>>> * I expanded pg_clog to 64-bits per XID, but people suggested keeping
>>> pg_clog as is, with two bits per commit, and adding a new SLRU for the
>>> commit LSNs beside it. Probably will need to do something like that to
>>> avoid
>>> bloating the clog.
>>
>>
>> It also influences how on-disk compatibility is dealt with. So: How are
>> you planning to deal with on-disk compatibility?
>
>
> Have pg_upgrade read the old clog and write it out in the new format.

That doesn't address Bruce's concern about CLOG disk consumption.

-- 
Robert Haas
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