Re: Row Migration/Rowchaining

I'm interpreting the stat as #4 in Dan's list.

Finn

On 4/11/08, Dan Norris <dannorris_at_dannorris.com> wrote:
>
> My interpretation of this information is one or more of the following:
>
> - You have other chained rows in tables that are not analyzed (and
> therefore wouldn't be listed in your dba_tables query). If this is the case,
> then v$sysstat is including reads of chained rows in tables that are not yet
> analyzed.
> - If you're estimating stats, dba_tables won't have accurate
> chain_cnt--definitely not for migrated rows. Check sample_size in dba_tables
> to be sure.
> - There were other chained rows that are now gone.
> - Or, you really have touched those 101 rows 2.3 million times since
> instance startup.
>
> Dan
>
> maheswara.rao_at_ubs.com wrote:
>
> Thank you Dan and Joe.
>
> I checked dba_tables. The query result shows 101 rows.
>
> >From v$sysstat, I am getting 2,327,441.
>
> Does v$sysstat contains other info when query for 'table fetch continued row'?
>
> Please see below queries.
>
> 1 SELECT owner, table_name, chain_cnt
> 2 FROM dba_tables
> 3* WHERE chain_cnt > 0
> SQL> /
>
> OWNER TABLE_NAME CHAIN_CNT
> ------------------------------ ------------------------------ ----------
> REPORTER REP_AUDIT_SEVERITY 18
> REPORTER REP_AUDIT_ACK 83
>
> = = = =
>
> SQL> SELECT name, value
> FROM v$sysstat
> WHERE name = 'table fetch continued row';
>
> NAME VALUE
> ---------------------------------- --------
> table fetch continued row 2327441
>
>
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