Q. How can u generate sequence of values in which target has more than 2billion of records.(but with sequence generator u can generate upto 2 biliion only)?

Answer-1:
by using unconnected lookup transformation u can check condtion ie counter >0 it will be allways true,
or you can use oracle sequence or stored procedure

Answer-2:
generate a sequance values through sequesnce generator and connet it to the target get the max value of it every time from unconnected lookup and set this value(maxvalue) to
mapping variable so that the last max value will be stored in repository. Once the sequance generator is reached its max value say 2billion , set the property reset to 1 so
that sequence generator will start again to produce sequance numbers .

and in experession write the logic like
new_seq=max(mapping_variable+sequence_generator (value)
then it is like 2million+1...2......(seq_gen)

every time sequance generator will reset to 1 after
reaching its max value