Thread: not finding rows using ctid

On 08/07/2014 12:40 PM, AI Rumman wrote:
>
> Hi,
>
> I am getting the logs as follows:
>
> LOG:  process 32145 acquired ExclusiveLock on tuple (153420,5) of
> relation 663326 of database 475999 after 1123.028 ms
>
>
> But, when I am executing sqls to find the row on that table using the
> ctid = '(153420,5)', I get no rows.
>
>
> Any idea, why?

http://www.postgresql.org/docs/9.3/static/ddl-system-columns.html
"ctid

     The physical location of the row version within its table. Note
that although the ctid can be used to locate the row version very
quickly, a row's ctid will change if it is updated or moved by VACUUM
FULL. Therefore ctid is useless as a long-term row identifier. The OID,
or even better a user-defined serial number, should be used to identify
logical rows."

Something changed the row between the time you saw it in the log and the
time you did the query.

>
>
> Thanks.
>


--
Adrian Klaver
adrian.klaver@aklaver.com

On 08/07/2014 02:14 PM, AI Rumman wrote:
> I didn't execute any Vacuum Full and I tried to get the row after 3
> hours of the issue.

Also, "...a row's ctid will change if it is updated..."

>
> Thanks.
>




--
Adrian Klaver
adrian.klaver@aklaver.com