Re: Chained vs. migrated rows - Any easy way to tell the


would it be save to run
DBMS_SPACE.OBJECT_SPACE_USAGE to check for chain_pcent > 0 without disturbing DBMS_STATS at all?

just a guess - never tried yet.
And I also doesn't see a valid answer for the question between chained and migrated rows there.

br.
 Martin

--
Martin Berger  http://berxblog.blogspot.com

Am 06.11.2008 um 10:35 schrieb Christian Antognini:

Hi Joel

The difference between dba_tables.chain_cnt and what is contained
in chained_rows table now is still a mystery.  Stats are collected
nightly.

DBMS_STATS doesn't compute the value chain_cnt. Therefore, there are two
possibilities:
1) dba_tables.chain_cnt = 0
2) dba_tables.chain_cnt > 0

If 1, either the table doesn't contain chained/migrated rows or ANALYZE
was never used to compute statistics for it.

If 2, at some time in the past the statistics were compute with ANALYZE.
Since DBMS_STATS doesn't compute it, you see the value at the time of
the last execution of ANALYZE.

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