Re: ARC patent - Mailing list pgsql-hackers

From Manfred Koizar
Subject Re: ARC patent
Date
Msg-id qo42v01e2jlesq1f7at1h92b47943rfeu8@email.aon.at
Whole thread Raw
In response to Re: ARC patent  (Hannu Krosing <hannu@tm.ee>)
Responses Re: ARC patent
Re: ARC patent
List pgsql-hackers
On Fri, 21 Jan 2005 02:31:40 +0200, Hannu Krosing <hannu@tm.ee> wrote:
>2) Another simple, but nondeterministic, hack would be using randomness,
>i.e. 
>
>  2.1) select a random buffer in LR side half (or 30% or 60%) of 
>       for replacement. 
>
>  2.2) dont last accessed pages to top of LRU list immediately, 
>       just push them uphill some amount, either random, or 
>       perhaps 1/2 the way to top at each access.

Sounds good, but how do find the middle of a linked list?  Or the other
way round:  Given a list element, how do you find out its position in a
linked list?  So the only approach that is easily implementable is

2.3) If a sequential scan hint flag is set, put the buffer into the    free list at a random position.

ServusManfred


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