Tunning Pro*C code

Question

Hi,
I have a pro*c program which reads data from txt file and load this into database. It also have some select sql statements to validate data before loading. I have to tune this pro*c program. The database optimization mode is Cost based i.e. first_rows. I am checking each SQL statement using explain plan in sql*plus.
Pro*c code take time when it perform insert operation. The select statements have realy low cost as they are well tuned. cost is like 2,3,7 ,8 etc..
execution plan for Insert statements shows cost = 90 , 40 , 60 etc.
I couldn't under stand why insertion cost is so much...?
The more data in txt file the more time it takes to load. can some body advice me in this regards?
Thanks in advance.
Regards
Ravi

Answer 1

Hi,
If inserts are taking a lot of time (more time and more cost may not be the same), my primary conclusion is, there are too many indexes on the table you are inserting. Check if that is the case?
If that the case,
a) Check if all those indexes are really required, get rid of any if possible
b) If you are adding data to the same table frequently (like daily or 4 times a day), partition the table and create local index. Also, you can have the partitions for each day, that would help in case of a daily load
c) Check if you can further tune the SELECTs and let the inserts take their time
d) If its not a frequent load, drop some heavy indexes ( with 3 to 8 columns ) before the load and create them after load (or disable them and rebuild). This will make your space usage efficiant also
Best of luck.