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?
masterKey.SetSeed(seed.begin(), seed.size());
    
    
    masterKey.Derive(accountKey, BIP32_HARDENED_KEY_LIMIT);
    
    assert(internal ? CanSupportFeature(FEATURE_HD_SPLIT) : true);
    accountKey.Derive(chainChildKey, BIP32_HARDENED_KEY_LIMIT+(internal ? 1 : 0));
    
    do {
        
        
        
        if (internal) {
            chainChildKey.Derive(childKey, hdChain.nInternalChainCounter | BIP32_HARDENED_KEY_LIMIT);
            metadata.hdKeypath = "m/0'/1'/" + std::to_string(hdChain.nInternalChainCounter) + "'";
            hdChain.nInternalChainCounter++;
        }
        else {
            chainChildKey.Derive(childKey, hdChain.nExternalChainCounter | BIP32_HARDENED_KEY_LIMIT);
            metadata.hdKeypath = "m/0'/0'/" + std::to_string(hdChain.nExternalChainCounter) + "'";
            hdChain.nExternalChainCounter++;
        }
    } while (HaveKey(childKey.key.GetPubKey().GetID()));
    secret = childKey.key;
    metadata.hd_seed_id = hdChain.seed_id;
    
    if (!batch.WriteHDChain(hdChain))
        throw std::runtime_error(std::string(__func__) + ": Writing HD chain model failed");
}
bool CWallet::AddKeyPubKeyWithDB(WalletBatch &batch, const CKey& secret, const CPubKey &pubkey)