Reading Bulk data from CSV and writring into another csv
<p>I had one csv file of 1 cr lines of data.From this file i have to read data from csv and using first field i need do check conditions with in my db and from that Db took one key and append all prevoius data and write to another csv .which ever i read from CSV i written code for this but it takes days of time to read and write for one 2 lakhs line of data .Here i am using single thread to do this all. 
sample code is i follwoed below steps.
1).reading data from CSF.
2).Read first field from csv and checking condition(in this i am checking  5 conditions). 
3).And written into CSV.    </p>
