BODS Long_to_Varchar function performance issue

Dear BODS Group members,

Good Day!

Am facing an performance issue in SAP BODS.

We have an job which has oracle table(oracle 11g) as source and loads it to the BW targets.

In the source table we have an column desc with data type Long and loading it to BW target with column zz_desc of data type varchar(250).

So we mapped this columns with the function long_to_varchar(des) to zz_desc

But, while running the job its running very very slow especially for this long_to_vrachar function and it's taking 16 hours for just 1.5 million records(i tested with one to one map it loaded in 10 mins).

The ds version is 4.2 and the os platform is unix.

1. i tried to increase the arrray fetch size and rows per limit to 5000 and also increased number of loaders but, no luck
2. also tried with the degree of parallelism no luck
3. tried with almost all optimising options no luck
4. also changed target to some template table and tried same issue no luck

Job design

Source(oracle table)--->query(Long_to_varchar function)--->target(BW datsource)

Anyone please help me on this.

Regards,
Prasanna