In the log I see things like:

    2017-09-13 03:54:33 init message: Rescanning...
    2017-09-13 03:54:33 Rescanning last 68616 blocks (from block 416339)...
    2017-09-13 03:54:40 AddToWallet xxxxx  update
    2017-09-13 03:55:33 Still rescanning. At block 418849. Progress=0.549138

I would be interested to see the wallet file name on each of these log lines.

Would there be any interest in merging such a PR?
int ret = m_batch.ReadAtCursor(pcursor, ssKey, ssValue);
            if (ret == DB_NOTFOUND)
                break;
            else if (ret != 0)
            {
                LogPrintf("Error reading next record from wallet database\n");
                return DBErrors::CORRUPT;
            }
            std::string strType;
            ssKey >> strType;
            if (strType == "tx") {
                uint256 hash;
                ssKey >> hash;
                CWalletTx wtx(nullptr , MakeTransactionRef());
                ssValue >> wtx;
                vTxHash.push_back(hash);
                vWtx.push_back(wtx);
            }
        }
        pcursor->close();
    }
    catch (const boost::thread_interrupted&) {
        throw;
    }
    catch (...) {
        result = DBErrors::CORRUPT;
    }
    return result;
}
DBErrors WalletBatch::ZapSelectTx(std::vector<uint256>& vTxHashIn, std::vector<uint256>& vTxHashOut)