VersionedSegment.h

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/*
// $Id: //open/dev/fennel/segment/VersionedSegment.h#15 $
// Fennel is a library of data storage and processing components.
// Copyright (C) 2005-2009 The Eigenbase Project
// Copyright (C) 2005-2009 SQLstream, Inc.
// Copyright (C) 2005-2009 LucidEra, Inc.
// Portions Copyright (C) 1999-2009 John V. Sichi
//
// This program is free software; you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by the Free
// Software Foundation; either version 2 of the License, or (at your option)
// any later version approved by The Eigenbase Project.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

#ifndef Fennel_VersionedSegment_Included
#define Fennel_VersionedSegment_Included

#include "fennel/segment/DelegatingSegment.h"
#include "fennel/synch/SynchObj.h"
#include "fennel/cache/FuzzyCheckpointSet.h"
#include "fennel/common/PseudoUuid.h"

#include <boost/crc.hpp>

FENNEL_BEGIN_NAMESPACE

class WALSegment;

class FENNEL_SEGMENT_EXPORT VersionedSegment
    : public DelegatingSegment
{
    friend class SegmentFactory;

    bool inRecovery;
    PseudoUuid onlineUuid;
    SegVersionNum versionNumber;
    PageId oldestLogPageId;
    PageId newestLogPageId;
    PageId lastCheckpointLogPageId;
    StrictMutex mutex;
    SharedSegment logSegment;
    WALSegment *pWALSegment;
    FuzzyCheckpointSet fuzzyCheckpointSet;

    // TODO:  use a 64-bit crc instead
    boost::crc_32_type crcComputer;

    PageMap dataToLogMap;

    explicit VersionedSegment(
        SharedSegment dataSegment,
        SharedSegment logSegment,
        PseudoUuid const &onlineUuid,
        SegVersionNum versionNumber);

    uint64_t computeChecksum(void const *pPageData);

public:
    virtual ~VersionedSegment();

    void recover(
        SharedSegment pDelegatingSegment,
        PageId firstLogPageId,
        SegVersionNum versionNumber = MAXU);

    void recover(
        SharedSegment pDelegatingSegment,
        PageId firstLogPageId,
        SegVersionNum versionNumber,
        PseudoUuid const &onlineUuid);

    void prepareOnlineRecovery();

    PageId getRecoveryPageId() const;

    PageId getOnlineRecoveryPageId() const;

    SegVersionNum getPageVersion(CachePage &page);

    SegVersionNum getVersionNumber() const;

    SharedSegment getLogSegment() const;

    void deallocateCheckpointedLog(CheckpointType checkpointType);

    // implement the Segment interface
    virtual void deallocatePageRange(PageId startPageId,PageId endPageId);
    virtual void delegatedCheckpoint(
        Segment &delegatingSegment,CheckpointType checkpointType);

    // implement the MappedPageListener interface
    virtual void notifyPageDirty(CachePage &page,bool bDataValid);
    virtual bool canFlushPage(CachePage &page);
};

FENNEL_END_NAMESPACE

#endif

// End VersionedSegment.h

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