Re: Strange optimization - xmin,xmax compression :)

On Dec 17, 2010, at 8:46 PM, Robert Haas wrote:
> 2010/12/6 pasman pasmański <pasman(dot)p(at)gmail(dot)com>:
>> hello.
>>
>> i tested how are distributed values xmin,xmax on pages.
>> in my tables . typically there are no more than 80 records
>> on pages.
>>
>> maybe its possible to compress xmin & xmax values to
>> 1 byte/per record (+table of transactions per page)?
>> its reduce the space when more than 1 record is
>> from the same transaction.
>
> Not a bad idea, but not easy to implement, I think.

Another option that would help even more for data warehousing would be storing the XIDs at the table level, because you'll typically have a very limited number of transactions per table.

But as Robert mentioned, this is not easy to implement. The community would probably need to see some pretty compelling performance numbers to even consider it.
--
Jim C. Nasby, Database Architect jim(at)nasby(dot)net
512.569.9461 (cell) http://jim.nasby.net