Re: vacuum, performance, and MVCC - Mailing list pgsql-hackers

From Mark Woodward
Subject Re: vacuum, performance, and MVCC
Date
Msg-id 18564.24.91.171.78.1151151250.squirrel@mail.mohawksoft.com
Whole thread Raw
In response to Re: vacuum, performance, and MVCC  (Jan Wieck <JanWieck@Yahoo.com>)
Responses Re: vacuum, performance, and MVCC  (Martijn van Oosterhout <kleptog@svana.org>)
Re: vacuum, performance, and MVCC  (Heikki Linnakangas <hlinnaka@iki.fi>)
List pgsql-hackers
> On 6/23/2006 3:10 PM, Mark Woodward wrote:
>
>> This is NOT an "in-place" update. The whole MVCC strategy of keeping old
>> versions around doesn't change. The only thing that does change is one
>> level of indirection. Rather than keep references to all versions of all
>> rows in indexes, keep only a reference to the first or "key" row of each
>> row, and have the first version of a row form the head of a linked list
>> to
>> subsequent versions of each row. The list will be in decending order.
>
> Where exactly do you intend to keep all those links (for a table with N
> indexes)?
>

I'm probably mistaken, but aren't there already forward references in
tuples to later versions? If so, I'm only sugesting reversing the order
and referencing the latest version.


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