delete is getting hung when there is a huge data in table

Hi,

I am facing an issue with the deletion of huge data.
We have a cronscript which is used to delete the data of last 3 months from one of the tables.
Data in the table is large (8872597 as you can see the count below) since it is from last 3 months.

fm_db_Server3=# select count(*) from audittraillogentry ;


count
---------
8872597
(1 row)

Now issue is that when this script for the deletion of data is launched , it is taking more than 7 days and doing nothing i.e not a single row has been deleted.

Then we stopped the script,terminated the database sessions by using SELECT pg_terminate_backend(proc pid) and run the following command

delete from audittraillogentry where intime <= to_timestamp('2015-01-30 23:59:59.999', 'YYYY/MM/DD-HH24:MI:SS.FF3') OR outtime <= to_timestamp('2015-01-30 23:59:59.999', 'YYYY/MM/DD-HH24:MI:SS.FF3');
still this delete operation is not working and not a single row has been deleted from the table.

Now i have following questions -

1. If postgreSQL has some limitations for deletion of large data?
2. If i should run the vacumm, after stopping the cron script ? because probably to get the "smaller" table?
3. if dropping the indexes can help here? now sure.
4.if i should think about partitioning , if there is any limitation while delaing with large data in postgreSQL?

regards
Mitu

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