We've a very large table and I'm thinking to partition it. Either one of these 3 main columns(appid, date or loan_custid) are used in the WHERE clause of the queries.
I've never implemented partitioning before, so my question is should I partition it by the date or appid or loan_custid?
Partitioning is a VERY COMPLEX subsystem and it is VERY easy to get things messed up. Without professional guidance you are very unlikely to be successful in your endeavor. I have come across MANY clients and forum posters that attempted partitioning without proper help and were disappointed or worse. Some questions/recommendations:
1) WHY do you think you need to partition the table? You mention columns that are in a WHERE clause, making me believe you want to use partitioning as a "go fast" button. That is NOT what it was designed for!! It was built primarily to facilitate large table management and especially loading.
2) What is the data loading process for this table?
3) What is the exact and full create-table script for this table (including triggers, keys, indexes)?
4) I STRONGLY recommend you get a professional on board to help you understand your system and whether or not you NEED partitioning and then help you implement, maintain, monitor it correctly. It is quite possible that you simply need to TUNE your existing queries against this table or do other stuff to make things "go fast"!!
Kevin G. Boles
SQL Server Consultant
SQL MVP 2007-2012
TheSQLGuru at GMail