I'm trying to analyze fees in the blockchain and I wrote a script in Python using bitcoinrpc library and getrawtransaction RPC call. However, getrawtransaction does not print vin values, only corresponding txids so I had to read all those transactions and extract the values from vout of the parent transactions. The script works but is very slow, each block takes a few minutes to process.

Is there a faster way to do it? I want a local solution (I can patch Bitcoin Core if necessary) but downloading e.g. from blockchain.info will not work because they have limits on the number of queries.