SQL & PL/SQL

i am new to oracle i am writing a stored procedure of about 1600 lines when i compiled the stored procedure
it is giving me warnings AND not any error and got compiled successfully which i write below

warnings
Warning(6,2): PLW-07203: parameter 'P_RN' may benefit from use of the NOCOPY compiler hint
Warning(168,72): PLW-07204: conversion away from column type may result in sub-optimal query plan
Warning(169,48): PLW-07204: conversion away from column type may result in sub-optimal query plan
.
.
.
.
.
.
.
.
.
.
Warning(1,1): Only first 20 issues are reported -- coming at last


and when check the status of the stored procedure by running the below query
informing that object is INVALID
select status from all_objects where object_name='USP_GENERATERUNNINGNUMBER';

and as far as i know that if warnings come and no error then it means procedure has been
compiled successfully and becomes VALID

please help me somebody