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?
FeeCalculation feeCalc;
    CAmount nFeeNeeded;
    int nBytes;
    {
        std::set<CInputCoin> setCoins;
        LOCK2(cs_main, cs_wallet);
        {
            std::vector<COutput> vAvailableCoins;
            AvailableCoins(vAvailableCoins, true, &coin_control);
            CoinSelectionParams coin_selection_params; 
            
            
            
            CScript scriptChange;
            
            if (!boost::get<CNoDestination>(&coin_control.destChange)) {
                scriptChange = GetScriptForDestination(coin_control.destChange);
            } else { 
                
                
                
                
                
                
                
                if (IsWalletFlagSet(WALLET_FLAG_DISABLE_PRIVATE_KEYS)) {
                    strFailReason = _("Can't generate a change-address key. Private keys are disabled for this wallet.");
                    return false;
                }
                CPubKey vchPubKey;