RE: Row Migration/Rowchaining

From: <>
Date: Fri, 11 Apr 2008 15:33:49 -0400
Message-ID: <>

Thank you Dan and Joe.

I checked dba_tables. The query result shows 101 rows.

From v$sysstat, I am getting 2,327,441.

Does v$sysstat contains other info when query for 'table fetch continued row'?

Please see below queries.

  1 SELECT owner, table_name, chain_cnt   2 FROM dba_tables
  3* WHERE chain_cnt > 0
SQL> /

OWNER                          TABLE_NAME                      CHAIN_CNT

------------------------------ ------------------------------ ----------
  • = = =

SQL> SELECT name, value

       FROM v$sysstat
       WHERE name = 'table fetch continued row';

NAME                               VALUE

---------------------------------- --------
table fetch continued row 2327441 ________________________________________
From: Dan Norris [] Sent: Friday, April 11, 2008 3:23 PM
Cc: Rao, Maheswara; Subject: Re: Row Migration/Rowchaining

For the purposes of statistics, chained and migrated rows are the same. So, chain_cnt would show a count of all chained rows which includes all migrated rows.

You could also do:

analyze table <tablename> list chained rows;

which would put the rows into the table INVALID_ROWS which is created by the OH/rdbms/admin/utlvalid.sql script (you'd have to run that script to create the table first).

I believe that you can do the analyze on any table and statistics will not be computed, but just the chained rows will be listed into the INVALID_ROWS table. Of course, a FTS will be required to find the chained rows, so beware of the I/O impact of running such a command.

Dan wrote:

This will show you the table for chained rows, not sure if it covers migrated or not, anyone else?

 select owner, table_name, chain_cnt from dba_tables where chain_cnt > 0;

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-- Received on Fri Apr 11 2008 - 14:33:49 CDT

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