RE: Row chaining

From: DENNIS WILLIAMS <DWILLIAMS_at_LIFETOUCH.COM>
Date: Tue, 11 Mar 2003 07:49:06 -0800
Message-ID: <F001.00566134.20030311074906@fatcity.com>

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.
dwilliams_at_lifetouch.com

-----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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Author: DENNIS WILLIAMS
  INET: DWILLIAMS_at_LIFETOUCH.COM

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