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?
{
    AssertLockHeld(cs_wallet); 
    return setExternalKeyPool.size() + set_pre_split_keypool.size();
}
void CWallet::LoadKeyPool(int64_t nIndex, const CKeyPool &keypool)
{
    AssertLockHeld(cs_wallet);
    if (keypool.m_pre_split) {
        set_pre_split_keypool.insert(nIndex);
    } else if (keypool.fInternal) {
        setInternalKeyPool.insert(nIndex);
    } else {
        setExternalKeyPool.insert(nIndex);
    }
    m_max_keypool_index = std::max(m_max_keypool_index, nIndex);
    m_pool_key_to_index[keypool.vchPubKey.GetID()] = nIndex;
    
    
    
    CKeyID keyid = keypool.vchPubKey.GetID();
    if (mapKeyMetadata.count(keyid) == 0)
        mapKeyMetadata[keyid] = CKeyMetadata(keypool.nTime);
}
bool CWallet::TopUpKeyPool(unsigned int kpSize)