Enhancement of the datasource is taking lot of time

Hi Experts,

we enhanced the datasource 0employee_attr almost 35 fileds but every thing fine when we are loading it taking almost 20hrs . these reports are using every day .how to reduce the loading time .iam not written any routines i thought its happened in R/3 side because lot of select statement.can any one suggest me on this issue.

Regards

sivaraju