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David Williams wrote:
> I assume he means a dirty block in the table is a data (as opposite to
> index)
> block which has changed since the last index rebuild. Presumably if the
> number (and hence percentage) of
>
> a) new blocks (i.e. rows put into the index in a sub-optimal manner)
> b) deleted blocks which leave sub-optimal free space in an index
> i.e. leave free space in a block which could be occupied by other
> index entries using optimal placement.
> c) updated blocks which have have rows moved and hence non-optimal
> placment of index entries.
>
Assuming you are correct ... and that involves a lot of assuming ... you are misusing the phrase "dirty block". I have no idea how a row can be put into an index in a sub-optimal manner or even what "sub-optimal" actually means. I can't see what is sub-optimal about free space in an index block? Is that space less optimal than having no space when an insert comes along with a block that belongs in the block, etc.?
In short ... we have a huge amount of imprecise language being bandied about by people who have yet to produce demos that supports their contentions.
Which means to me that those of us trying to learn from these "experts" are still in the dark. So lets stop making assumptions and get clarifications and demos.
-- Daniel Morgan http://www.outreach.washington.edu/ext/certificates/oad/oad_crs.asp http://www.outreach.washington.edu/ext/certificates/aoa/aoa_crs.asp damorgan_at_x.washington.edu (replace 'x' with a 'u' to reply)Received on Sun May 09 2004 - 17:33:07 CDT