This is to track the regression introduced in master, which needs fixing for 0.14. See #9240, #9371, etc.
{
private:
    uint32_t nCheckFrequency; 
    unsigned int nTransactionsUpdated;
    CBlockPolicyEstimator* minerPolicyEstimator;
    uint64_t totalTxSize;      
    uint64_t cachedInnerUsage; 
    mutable int64_t lastRollingFeeUpdate;
    mutable bool blockSinceLastRollingFeeBump;
    mutable double rollingMinimumFeeRate; 
    void trackPackageRemoved(const CFeeRate& rate);
public:
    static const int ROLLING_FEE_HALFLIFE = 60 * 60 * 12; 
    typedef boost::multi_index_container<
        CTxMemPoolEntry,
        boost::multi_index::indexed_by<
            
            boost::multi_index::hashed_unique<mempoolentry_txid, SaltedTxidHasher>,
            
            boost::multi_index::ordered_non_unique<