Improving query performance


Improving query performance


I am selecting columns from a table having 80 columns,when i select all columns from the table it is hitting performance.If i select 4 columns from that table it is working fine.

if we increase datablock size will performance increses and what will be maximum block size.
and please suggest me any other way to improve the performance.


Re: Improving query performance

Are these 4 columns part of an index ? (Covered queries are generally faster since they are read directly from the index subtable).

The other questions is how wide these 80 columns are, it can be too much data to be pushed across network.

Check for large char(n) columns etc (which might be so to help aid compression).