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?
if (setKeyPool.empty()) {
        return GetTime();
    }
    CKeyPool keypool;
    int64_t nIndex = *(setKeyPool.begin());
    if (!batch.ReadPool(nIndex, keypool)) {
        throw std::runtime_error(std::string(__func__) + ": read oldest key in keypool failed");
    }
    assert(keypool.vchPubKey.IsValid());
    return keypool.nTime;
}
int64_t CWallet::GetOldestKeyPoolTime()
{
    LOCK(cs_wallet);
    WalletBatch batch(*database);
    
    int64_t oldestKey = GetOldestKeyTimeInPool(setExternalKeyPool, batch);
    if (IsHDEnabled() && CanSupportFeature(FEATURE_HD_SPLIT)) {
        oldestKey = std::max(GetOldestKeyTimeInPool(setInternalKeyPool, batch), oldestKey);
        if (!set_pre_split_keypool.empty()) {
            oldestKey = std::max(GetOldestKeyTimeInPool(set_pre_split_keypool, batch), oldestKey);
        }
    }
    return oldestKey;
}
std::map<CTxDestination, CAmount> CWallet::GetAddressBalances()