Re: The age() of a column?

On 11/28/18 7:32 PM, Ron wrote:
> What does it mean, and where is it documented?  The only place in the 

https://www.postgresql.org/docs/10/routine-vacuuming.html

"The age column measures the number of transactions from the cutoff XID 
to the current transaction's XID."

> docs I see reference to age() is 
> https://www.postgresql.org/docs/9.6/functions-datetime.html and this 
> doesn't seem to fit that use case.
> 
> Thanks
> 
> TAPb=# select COALESCE(ta.schemaname, 'pg_toast') || '.' || cl.relname,
>         cl.relfrozenxid,
>         age(cl.relfrozenxid)
> from pg_class cl FULL JOIN pg_tables ta
>      ON ta.tablename = cl.relname
> where not cl.relfrozenxid = xid '0'
>    --and age(cl.relfrozenxid) > 4000000
> order by 1
> limit 30;
>             ?column?            | relfrozenxid |   age
> -------------------------------+--------------+---------
> cds.ach_return_batch           |     58569152 | 2111005
> cds.ach_return_detail          |     58569152 | 2111005
> cds.all_day_event              |     58569152 | 2111005
> cds.all_day_event_trigger      |     58569152 | 2111005
> [snip]
> cds.bank_ftp                   |     58569152 | 2111005
> cds.bank_health_care_job       |     58569152 | 2111005
> cds.bank_inbound_file          |     58569152 | 2111005
> cds.bank_input_format          |     58569152 | 2111005
> (30 rows)
> 
> 


-- 
Adrian Klaver
adrian.klaver@aklaver.com