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/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 ledgerSeq) = 0;
 
    /* Check if two ledgers are in the same database
 
        If these two sequence numbers map to the same database,
        the result of a fetch with either sequence number would
        be identical.
 
        @param s1 The first sequence number
        @param s2 The second sequence number
 
        @return 'true' if both ledgers would be in the same DB
 
    */
    virtual bool
    isSameDB(std::uint32_t s1, std::uint32_t s2) = 0;
 
    virtual void
    sync() = 0;
 
    std::shared_ptr<NodeObject>
    fetchNodeObject(
        uint256 const& hash,
        std::uint32_t ledgerSeq = 0,
        FetchType fetchType = FetchType::synchronous);
 
    void
    asyncFetch(
        uint256 const& hash,
        std::uint32_t ledgerSeq,
        std::function<void(std::shared_ptr<NodeObject> const&)>&& callback);
 
    virtual bool
    storeLedger(std::shared_ptr<Ledger const> const& srcLedger) = 0;
 
    virtual void
    sweep() = 0;
 
    virtual Backend&
    getBackend() = 0;
 
    std::uint64_t
    getStoreCount() const
    {
        return storeCount_;
    }
 
    std::uint32_t
    getFetchTotalCount() const
    {
        return fetchTotalCount_;
    }
 
    std::uint32_t
    getFetchHitCount() const
    {
        return fetchHitCount_;
    }
 
    std::uint64_t
    getStoreSize() const
    {
        return storeSz_;
    }
 
    std::uint32_t
    getFetchSize() const
    {
        return fetchSz_;
    }
 
    void
    getCountsJson(Json::Value& obj);
 
    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};
 
    std::atomic<std::uint32_t> fetchHitCount_{0};
    std::atomic<std::uint32_t> fetchSz_{0};
 
    void
    stopReadThreads();
 
    void
    storeStats(std::uint64_t count, std::uint64_t sz)
    {
        assert(count <= sz);
        storeCount_ += count;
        storeSz_ += sz;
    }
 
    // Called by the public asyncFetch function
    void
    asyncFetch(uint256 const& hash, std::uint32_t ledgerSeq);
 
    // Called by the public import function
    void
    importInternal(Backend& dstBackend, Database& srcDB);
 
    // Called by the public storeLedger function
    bool
    storeLedger(Ledger const& srcLedger, std::shared_ptr<Backend> dstBackend);
 
    void
    updateFetchMetrics(uint64_t fetches, uint64_t hits, uint64_t duration)
    {
        fetchTotalCount_ += fetches;
        fetchHitCount_ += hits;
        fetchDurationUs_ += duration;
    }
 
private:
    std::atomic<std::uint64_t> storeCount_{0};
    std::atomic<std::uint64_t> storeSz_{0};
    std::atomic<std::uint64_t> fetchTotalCount_{0};
    std::atomic<std::uint64_t> fetchDurationUs_{0};
    std::atomic<std::uint64_t> storeDurationUs_{0};
 
    std::mutex readLock_;
    std::condition_variable readCondVar_;
 
    // reads to do
    std::map<
        uint256,
        std::vector<std::pair<
            std::uint32_t,
            std::function<void(std::shared_ptr<NodeObject> const&)>>>>
        read_;
 
    // last read
    uint256 readLastHash_;
 
    std::vector<std::thread> readThreads_;
    bool readShut_{false};
 
    // 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>
    fetchNodeObject(
        uint256 const& hash,
        std::uint32_t ledgerSeq,
        FetchReport& fetchReport) = 0;
 
    virtual void
    for_each(std::function<void(std::shared_ptr<NodeObject>)> f) = 0;
 
    void
    threadEntry();
};
 
}  // namespace NodeStore
}  // namespace ripple
 
#endif