Database.h

//------------------------------------------------------------------------------
/*
    This file is part of rippled: https://github.com/ripple/rippled
    Copyright (c) 2012, 2017 Ripple Labs Inc.
 
    Permission to use, copy, modify, and/or distribute this software for any
    purpose  with  or without fee is hereby granted, provided that the above
    copyright notice and this permission notice appear in all copies.
 
    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
    ANY  SPECIAL ,  DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
//==============================================================================
 
#ifndef RIPPLE_NODESTORE_DATABASE_H_INCLUDED
#define RIPPLE_NODESTORE_DATABASE_H_INCLUDED
 
#include <ripple/basics/KeyCache.h>
#include <ripple/basics/TaggedCache.h>
#include <ripple/core/Stoppable.h>
#include <ripple/nodestore/Backend.h>
#include <ripple/nodestore/NodeObject.h>
#include <ripple/nodestore/Scheduler.h>
#include <ripple/nodestore/impl/Tuning.h>
#include <ripple/protocol/SystemParameters.h>
 
#include <thread>
 
namespace ripple {
 
class Ledger;
 
namespace NodeStore {
 
class Database : public Stoppable
{
public:
    Database() = delete;
 
    Database(
        std::string name,
        Stoppable& parent,
        Scheduler& scheduler,
        int readThreads,
        Section const& config,
        beast::Journal j);
 
    virtual ~Database();
 
    virtual std::string
    getName() const = 0;
 
    virtual void
    import(Database& source) = 0;
 
    virtual std::int32_t
    getWriteLoad() const = 0;
 
    virtual void
    store(
        NodeObjectType type,
        Blob&& data,
        uint256 const& hash,
        std::uint32_t seq) = 0;
 
    virtual std::shared_ptr<NodeObject>
    fetch(uint256 const& hash, std::uint32_t seq) = 0;
 
    virtual bool
    asyncFetch(
        uint256 const& hash,
        std::uint32_t seq,
        std::shared_ptr<NodeObject>& object) = 0;
 
    virtual bool
    storeLedger(std::shared_ptr<Ledger const> const& srcLedger) = 0;
 
    void
    waitReads();
 
    virtual int
    getDesiredAsyncReadCount(std::uint32_t seq) = 0;
 
    virtual float
    getCacheHitRate() = 0;
 
    virtual void
    tune(int size, std::chrono::seconds age) = 0;
 
    virtual void
    sweep() = 0;
 
    std::uint32_t
    getStoreCount() const
    {
        return storeCount_;
    }
 
    std::uint32_t
    getFetchTotalCount() const
    {
        return fetchTotalCount_;
    }
 
    std::uint32_t
    getFetchHitCount() const
    {
        return fetchHitCount_;
    }
 
    std::uint32_t
    getStoreSize() const
    {
        return storeSz_;
    }
 
    std::uint32_t
    getFetchSize() const
    {
        return fetchSz_;
    }
 
    int
    fdRequired() const
    {
        return fdRequired_;
    }
 
    void
    onStop() override;
 
    void
    onChildrenStopped() override;
 
    std::uint32_t
    earliestLedgerSeq() const
    {
        return earliestLedgerSeq_;
    }
 
protected:
    beast::Journal const j_;
    Scheduler& scheduler_;
    int fdRequired_{0};
 
    void
    stopThreads();
 
    void
    storeStats(size_t sz)
    {
        ++storeCount_;
        storeSz_ += sz;
    }
 
    // Called by the public asyncFetch function
    void
    asyncFetch(
        uint256 const& hash,
        std::uint32_t seq,
        std::shared_ptr<TaggedCache<uint256, NodeObject>> const& pCache,
        std::shared_ptr<KeyCache<uint256>> const& nCache);
 
    // Called by the public fetch function
    std::shared_ptr<NodeObject>
    fetchInternal(uint256 const& hash, std::shared_ptr<Backend> backend);
 
    // Called by the public import function
    void
    importInternal(Backend& dstBackend, Database& srcDB);
 
    std::shared_ptr<NodeObject>
    doFetch(
        uint256 const& hash,
        std::uint32_t seq,
        TaggedCache<uint256, NodeObject>& pCache,
        KeyCache<uint256>& nCache,
        bool isAsync);
 
    // Called by the public storeLedger function
    bool
    storeLedger(
        Ledger const& srcLedger,
        std::shared_ptr<Backend> dstBackend,
        std::shared_ptr<TaggedCache<uint256, NodeObject>> dstPCache,
        std::shared_ptr<KeyCache<uint256>> dstNCache,
        std::shared_ptr<Ledger const> next);
 
private:
    std::atomic<std::uint32_t> storeCount_{0};
    std::atomic<std::uint32_t> fetchTotalCount_{0};
    std::atomic<std::uint32_t> fetchHitCount_{0};
    std::atomic<std::uint32_t> storeSz_{0};
    std::atomic<std::uint32_t> fetchSz_{0};
 
    std::mutex readLock_;
    std::condition_variable readCondVar_;
    std::condition_variable readGenCondVar_;
 
    // reads to do
    std::map<
        uint256,
        std::tuple<
            std::uint32_t,
            std::weak_ptr<TaggedCache<uint256, NodeObject>>,
            std::weak_ptr<KeyCache<uint256>>>>
        read_;
 
    // last read
    uint256 readLastHash_;
 
    std::vector<std::thread> readThreads_;
    bool readShut_{false};
 
    // current read generation
    uint64_t readGen_{0};
 
    // The default is 32570 to match the XRP ledger network's earliest
    // allowed sequence. Alternate networks may set this value.
    std::uint32_t const earliestLedgerSeq_;
 
    virtual std::shared_ptr<NodeObject>
    fetchFrom(uint256 const& hash, std::uint32_t seq) = 0;
 
    virtual void
    for_each(std::function<void(std::shared_ptr<NodeObject>)> f) = 0;
 
    void
    threadEntry();
};
 
}  // namespace NodeStore
}  // namespace ripple
 
#endif