Interestingly there's a little snippet in the 9i doco that says that ANALYZE
may disappear in future.... I'll be keen to know how Oracle intend to work
out chained rows when that happens...
--
==============================
Connor McDonald
http://www.oracledba.co.uk
"Some days you're the pigeon, some days you're the statue..."
"Jonathan Lewis" <jonathan_at_jlcomp.demon.co.uk> wrote in message
news:993584161.27747.0.nnrp-14.9e984b29_at_news.demon.co.uk...
>
> MONITOR simply collects in real time
> the number of changes you make to
> the table - it does NOT write any stats
> back to the USER_TABLES columns.
>
> If your user_tables.num_rows says
> 1,000,000, and you do 50,000 inserts
> on the table, then user_tables.num_rows
> will still say 1,000,000; but there will
> be a row in view USER_MODIFICATIONS
> for that table with
> user_modifications.inserts = 50,000
>
> The CBO and the ANALYZE command
> will not make any use of that value -
> it simply acts as a flag to the dbms_stats
> procedure to suggest that the table has
> changed a lot since the last analyze.
>
>
> dbms_stats collects (if I recall correctly)
> the current number of rows physically in
> the table, the number of blocks, the
> number of free blocks, and the average
> free space per block; (it misses a couple
> that the ANALYZE command gathers),
> and a few figures about each column
> such as number of nulls, high and low
> values, number of distinct values.
>
> --
> Jonathan Lewis
>
> Host to The Co-operative Oracle Users' FAQ
> http://www.jlcomp.demon.co.uk/faq/ind_faq.html
>
> Author of:
> Practical Oracle 8i: Building Efficient Databases
> See http://www.jlcomp.demon.co.uk/book_rev.html
>
> Seminars on getting the best out of Oracle
> See http://www.jlcomp.demon.co.uk/seminar.html
>
>
>
>
>
>
> Brian Tkatch wrote in message <3b3894c2.319452859_at_news.alt.net>...
> >Then what statistics does DBMS_STATS gather that MONITORING does not?
> >I think that is what I do not understand
> >
>
>
>
Received on Tue Jun 26 2001 - 16:47:09 CDT
