I have written two programs to deal with this:
1) a plsql procedure that shows all the LIO for a chained row system wide.
This works like sar:
ser serveroutput on
execute oraperf.analyze_lio(10, 1);
2) an object row chainer analyzer, this will find which SQL statements and
what objects have LIOs for row chaining and how much.
Program 1 will be available from Oraperf.com
Anjo.
On Tuesday 11 March 2003 07:49, you wrote:
> ak
> Smart-alek answer: Apply one of the methods to eliminate migrated rows,
> and if the problem doesn't go away, you know you have some chained rows ;-)
> Chained rows are a little difficult to diagnose. Look at the value for
> avg_row_len - is it near the db_block_size? I haven't tried this, but if
> you really want to go to the trouble, you could create a table named
> CHAINED_ROWS, run ANALYZE . . . LIST CHAINED ROWS. The create a SQL
> statement that will execute the VSIZE function on each column and sum the
> values. Then run this statement on each rowid in CHAINED_ROWS. Now you see
> the reason for my initial suggestion.
> I would suggest that you not get too paranoid about getting CHAINED_ROWS
> to zero. But if your wait statistics starts to show "table fetch continued
> row" as significant, you definitely need to fix the problem.
>
>
>
> Dennis Williams
> DBA, 40%OCP, 100% DBA
> Lifetouch, Inc.
> [EMAIL PROTECTED]
>
> -----Original Message-----
> Sent: Tuesday, March 11, 2003 9:14 AM
> To: Multiple recipients of list ORACLE-L
>
>
> I see some values >0 for chaint_cnt in dba_tables . How do I know if this
> is chained rows or migrated rows ?
> Any hits .
>
> Thanks,
> ak
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