Re: The age() of a column?

Ron <ronljohnsonjr@gmail.com> writes:
> What does it mean, and where is it documented?

age(xid) returns the difference between the given xid and the current xid.
It's not terribly well documented, but psql's \df gives some info:

regression=# \df+ age
   Schema   | Name | Result data type |                   Argument data types                    | Type | Volatility |
Parallel |  Owner   | Security | Access privileges | Language |                                 Source code
                    |                             Description                  
...
 pg_catalog | age  | integer          | xid                                                      | func | stable     |
restricted| postgres | invoker  |                   | internal | xid_age
                     | age of a transaction ID, in transactions before current transaction 

The only reference I could find in the SGML docs is in the maintenance
chapter.

            regards, tom lane