One 400GB table, One query - Need Tuning Ideas (SQL2005)

Question

I have a single large table which I would like to optimize. I\'m using MS-SQL 2005 server. I\'ll try to describe how it is used and if anyone has any suggestions I would appreci

Answer 1

Help me understand more about the table. if your PK is k1,k2, you shouldn't have to select by any other column to get a completely unique record.

Do you mean to say that k1 through 7 is the PK? If so, declare it as such and it will be a clustered index. Query performance should improve dramatically.

The order by is adding a lot of overhead. Consider finding a better option that can return a smaller set of data. Knowing why you need around a million records returned might help me provide a better solution.

Edit: I get the sense that I'm not alone in my suspicion that the best place to start optimizing is in your physical table design. Do you have any control over this? Not knowing what each column stores, I can't offer very specific ideas but a very general approach follows: Put K1,3,4,5 & 6 (k2 appears to be directly related to the values in your table) in its own table with a single unique int as the PK. Then create a FK relationship back to this table. You PK on the main table would then include this field, k2 & k7. Now your query will optimizer will perform a rather inexpensive lookup in your new table, return a single record and then perform an index seek into your main table by PK only.