Re: [PATCHES] Bitmapscan changes

Grzegorz Jaskiewicz wrote:
>
> On Mar 19, 2007, at 11:16 AM, Heikki Linnakangas wrote:
>
>> Grzegorz Jaskiewicz wrote:
>>> On Mar 16, 2007, at 10:12 PM, Heikki Linnakangas wrote:
>>>> You'll obviously need to run it with the patch applied. I'd suggest
>>>> to enable stats_block_level to see the effect on buffer cache
>>>> hit/miss ratio.
>>> groupeditems-42-pghead.patch.gz is enough, or it needs
>>> maintain_cluster_order_v5.patch ??
>>
>> No, it won't make a difference unless you're inserting to the table,
>> and the inserts are not in cluster order.
> well, that's okay than. I see really good improvement in terms of speed
> and db size (which reflects obviously in i/o performance).
> Let me know if further testing can be done. I would happily see it in
> mainline.
>

Right. My understanding is that the clustered index will gradually
degrade to a normal btree, is that correct heikki?

We could of course resolve this by doing a reindex.

The other item I think this would be great for is fairly static tables.
Think about tables that are children of partitions that haven't been
touched in 6 months. Why are we wasting space with them?

Anyway, from a "feature" perspective I can't see any negative. I can not
speak from a code injection (into core) perspective.

Joshua D. Drake

>
>
> --Grzegorz Jaskiewicz
>
> C/C++ freelance for hire
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