[check_postgres] check_postgres.pl checkpoint values

[Ashish Jaiswal]

Hello.

I have setup in which is getting replicated by WAL files. I found out 
the postgres plugin is the one which I can use

./check_postgres.pl --action=checkpoint --datadir 
/var/lib/postgresql/8.3/main/ --assume-prod --warning=8
POSTGRES_CHECKPOINT OK:  Last checkpoint was -53844 seconds ago | 
age=-53844;8 mode=MASTER

Can anyone explain why there is negative value I'm getting.

Let me know if anything extra if needed

-- 
Regards,
Ashish Jaiswal
System Admin