Row chaining and migration

Summary 

You can identify if you have Row Chaining and Migration in your database with the following query.

SELECT a.name, b.value
  FROM v$statname a, v$mystat b
 WHERE a.statistic# = b.statistic#
   AND lower(a.name) = 'table fetch continued row';

If it returns a value>0 then you have a Row Chaining or Migration. If you check column chain_cnt of view dba_tables then you can see the tables which have chains.

select owner, table_name, pct_free, pct_used, last_analyzed, avg_row_len, num_rows, chain_cnt, chain_cnt/num_rows Pct
from dba_tables
where owner not in ('SYS','SYSTEM')
and table_name not in (select table_name from dba_tab_columns 
where data_type in ('RAW','LONG RAW'))
and chain_cnt > 0 
order by chain_cnt desc;