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?
else
        {
            nWatchCreditCached = pwallet->GetCredit(*tx, ISMINE_WATCH_ONLY);
            fWatchCreditCached = true;
            credit += nWatchCreditCached;
        }
    }
    return credit;
}
CAmount CWalletTx::GetImmatureCredit(bool fUseCache) const
{
    if (IsCoinBase() && GetBlocksToMaturity() > 0 && IsInMainChain())
    {
        if (fUseCache && fImmatureCreditCached)
            return nImmatureCreditCached;
        nImmatureCreditCached = pwallet->GetCredit(*tx, ISMINE_SPENDABLE);
        fImmatureCreditCached = true;
        return nImmatureCreditCached;
    }
    return 0;
}
CAmount CWalletTx::GetAvailableCredit(bool fUseCache, const isminefilter& filter) const
{
    if (pwallet == nullptr)
        return 0;
    
    if (IsCoinBase() && GetBlocksToMaturity() > 0)
        return 0;
    CAmount* cache = nullptr;
    bool* cache_used = nullptr;