Re: LRU and full table scans

On Wed, 2002-02-27 at 13:09, Mike Mascari wrote:

On general a discussion has been taking place regarding cached query
plans and how MySQL invented them.

IMHO the discussion was about cached queries not query plans.

Of course, this is totally false. I
remembered a nice paragraph in the Oracle docs as to the process by
which Oracle uses shared SQL areas to share the execution plan of
identical statements, flushing the area whenever a dependent object was
modified. In searching for the reference, however, I stumbled an
interesting fact. Unlike normal queries where blocks are added to the
MRU end of an LRU list, full table scans add the blocks to the LRU end
of the LRU list.

This seems really elegant solution , much better than not caching at all
and much better than flushing the whole cache by a large table scan

I was wondering, in the light of the discussion of
using LRU-K, if PostgreSQL does, or if anyone has tried, this technique?

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Hannu