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102 lines
3.4 KiB
C++
102 lines
3.4 KiB
C++
// @file dur_journal.h
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/**
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* Copyright (C) 2010 10gen Inc.
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License, version 3,
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* as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#pragma once
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#include "../util/logfile.h"
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namespace mongo {
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namespace dur {
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/** the writeahead journal for durability */
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class Journal {
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public:
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string dir; // set by journalMakeDir() during initialization
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Journal();
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/** call during startup by journalMakeDir() */
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void init();
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/** check if time to rotate files. assure a file is open.
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done separately from the journal() call as we can do this part
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outside of lock.
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thread: durThread()
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*/
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void rotate();
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/** write to journal
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*/
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void journal(const AlignedBuilder& b);
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boost::filesystem::path getFilePathFor(int filenumber) const;
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unsigned long long lastFlushTime() const { return _lastFlushTime; }
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void cleanup();
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// Rotate after reaching this data size in a journal (j._<n>) file
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// We use a smaller size for 32 bit as the journal is mmapped during recovery (only)
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// Note if you take a set of datafiles, including journal files, from 32->64 or vice-versa, it must
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// work. (and should as-is)
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static const unsigned long long DataLimit = (sizeof(void*)==4) ? 256 * 1024 * 1024 : 1 * 1024 * 1024 * 1024;
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unsigned long long curFileId() const { return _curFileId; }
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void assureLogFileOpen() {
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mutex::scoped_lock lk(_curLogFileMutex);
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if( _curLogFile == 0 )
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_open();
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}
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private:
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/** open a journal file to journal operations to. */
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void open();
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void _open();
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void closeCurrentJournalFile();
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void removeUnneededJournalFiles();
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unsigned long long _written; // bytes written so far to the current journal (log) file
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unsigned _nextFileNumber;
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mutex _curLogFileMutex;
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LogFile *_curLogFile; // use _curLogFileMutex
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unsigned long long _curFileId; // current file id see JHeader::fileId
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struct JFile {
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string filename;
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unsigned long long lastEventTimeMs;
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};
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// files which have been closed but not unlinked (rotated out) yet
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// ordered oldest to newest
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list<JFile> _oldJournalFiles; // use _curLogFileMutex
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// lsn related
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static void preFlush();
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static void postFlush();
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unsigned long long _preFlushTime;
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unsigned long long _lastFlushTime; // data < this time is fsynced in the datafiles (unless hard drive controller is caching)
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bool _writeToLSNNeeded;
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void updateLSNFile();
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};
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}
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}
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