Delete takes ages! Help!!!!!!!!

Question

I am running a stored procedure from shell script as a sceduled task in crontab. This SP is run every Monday at 3 in the morning.
The scenario is;
I am working on GSM Prepaid Service for a telecom company. I have a log table which maintains the history when subscribers recharge their account through prepaid voucher cards to keep track of the used voucher pins. The log is maitained for 7 days only.
I have approx. 1 million records every week, which I delete through stored procedure in a batch of 20000 rows each. This takes around 75 minutes and puts lot of load on the server, as there are also many other scheduled tasks running in parallel.
Can anyone help me troubleshoot this problem.

Answer 1

Hi,
The most important in partitioned table is the choice of partition clause. What is the desc of your table, index, PK and you need to know the main query about this table.
Assuming that delete previous week records is the main job, you can create partition on week number, for example, you can have 2 partitions (0 and 1) with mod2 on week number :
SQL> select mod(to_char(sysdate,'IW'),2) from dual; --this week
MOD(TO_CHAR(SYSDATE,'IW'),2)
                           0
SQL> select mod(to_char(sysdate+5,'IW'),2) from dual;--next week
MOD(TO_CHAR(SYSDATE+5,'IW'),2)
                             1
SQL> Replace sysdate by your date column.
Only one problem with this one, it's when a year has 53 weeks, the 53th week of the current year and the 1st week of the next year goes in the same partition... this is not the case in 2005/2006.
You can too precreate a partition for each week number from 1 to 53. There are too many possibilities.
I advise you to read doc : http://download-west.oracle.com/docs/cd/B10501_01/server.920/a96540/statements_73a.htm#2101280
and
http://download-west.oracle.com/docs/cd/B10501_01/server.920/a96540/statements_32a.htm#2100180
You can export your table, drop table, create your partitioned table and import.
Nicolas.