Re: vacuum, performance, and MVCC

> On 6/24/06, Mark Woodward <pgsql@mohawksoft.com> wrote:
>> > On 6/24/06, Mark Woodward <pgsql@mohawksoft.com> wrote:
>> >> In the scenario, as previously outlined:
>> >>
>> >> ver001->verN->...->ver003->ver2->|
>> >>   ^-----------------------------/
>> >
>> > So you want to always keep an old version around?
>>
>> Prior to vacuum, it will be there anyway, and after vacuum, the new
>> version will become ver001.
>
> So you do intend to move verN into ver001's slot?  What about the
> other conditions you had mentioned where you have to follow
> PostgreSQL's current behavior?  How are you going to have a pointer
> chain in that case?

Who said anything about moving anything. When vacuum comes along, it
cleans out previous versions of rows. Very little will change.