[GENERAL] optimising the pl/pgsql function

Hello,

We are running a pretty big plsql function, we are fetching data from
some tables based on certain conditions. And using that data in a for loop
within the function.
the problem we are facing is when the no of records are more the function
ction is taking too much time, is there a solution to this problem? Can we
replace the for loop with something else?