I haven't checked yet how Oracle estimates the
row size of rows that go into the hash (build) table
of a hash join. Perhaps the avg_row_length is used
as a guideline at this point.
--
Regards
Jonathan Lewis
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"Mark D Powell" <Mark.Powell_at_eds.com> wrote in message
news:2687bb95.0307100541.10a6a305_at_posting.google.com...
>
> First, I am not sure when avg_row_len is used, but I believe that
all
> statistics gathered by dbms_stats, unlike some of those gathered by
> the analyze commad (such as chained rows), are used by the CBO. The
> use may be indirect in that some statistics may be used in
calculating
> other statistics that are directly used. For some reason I think
the
> use of avg_row_len is in estimating logical IO, but I would not bank
> on that.
>
Received on Thu Jul 10 2003 - 15:16:39 CDT
