Hi Team,
The OTBI Report export to excel or csv limited to 250k rows.This Limit is very small for business requirements .It's better to provide some configuration to increase this limitation in OTBI atleast to the limit that excel provides.
You can look at this SR (SR 3-33765290921 - Potential for extension of number of rows exported in Excel through OTBI Analysis) for more details.
Regards,
Elston