// @file dur.cpp durability in the storage engine (crash-safeness / journaling)
/**
* Copyright (C) 2009 10gen Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see .
*/
/*
phases:
PREPLOGBUFFER
we will build an output buffer ourself and then use O_DIRECT
we could be in read lock for this
for very large objects write directly to redo log in situ?
WRITETOJOURNAL
we could be unlocked (the main db lock that is...) for this, with sufficient care, but there is some complexity
have to handle falling behind which would use too much ram (going back into a read lock would suffice to stop that).
for now (1.7.5/1.8.0) we are in read lock which is not ideal.
WRITETODATAFILES
apply the writes back to the non-private MMF after they are for certain in redo log
REMAPPRIVATEVIEW
we could in a write lock quickly flip readers back to the main view, then stay in read lock and do our real
remapping. with many files (e.g., 1000), remapping could be time consuming (several ms), so we don't want
to be too frequent.
there could be a slow down immediately after remapping as fresh copy-on-writes for commonly written pages will
be required. so doing these remaps fractionally is helpful.
mutexes:
READLOCK dbMutex
LOCK groupCommitMutex
PREPLOGBUFFER()
READLOCK mmmutex
commitJob.reset()
UNLOCK dbMutex // now other threads can write
WRITETOJOURNAL()
WRITETODATAFILES()
UNLOCK mmmutex
UNLOCK groupCommitMutex
on the next write lock acquisition for dbMutex: // see MongoMutex::_acquiredWriteLock()
REMAPPRIVATEVIEW()
@see https://docs.google.com/drawings/edit?id=1TklsmZzm7ohIZkwgeK6rMvsdaR13KjtJYMsfLr175Zc
*/
#include "mongo/pch.h"
#include
#include "mongo/db/client.h"
#include "mongo/db/cmdline.h"
#include "mongo/db/commands/fsync.h"
#include "mongo/db/commands/server_status.h"
#include "mongo/db/dur.h"
#include "mongo/db/dur_commitjob.h"
#include "mongo/db/dur_journal.h"
#include "mongo/db/dur_recover.h"
#include "mongo/db/dur_stats.h"
#include "mongo/server.h"
#include "mongo/util/concurrency/race.h"
#include "mongo/util/mongoutils/hash.h"
#include "mongo/util/mongoutils/str.h"
#include "mongo/util/stacktrace.h"
#include "mongo/util/timer.h"
using namespace mongoutils;
namespace mongo {
namespace dur {
void assertNothingSpooled();
void unspoolWriteIntents();
void PREPLOGBUFFER(JSectHeader& outParm, AlignedBuilder&);
void WRITETOJOURNAL(JSectHeader h, AlignedBuilder& uncompressed);
void WRITETODATAFILES(const JSectHeader& h, AlignedBuilder& uncompressed);
/** declared later in this file
only used in this file -- use DurableInterface::commitNow() outside
*/
static void groupCommit(Lock::GlobalWrite *lgw = 0);
CommitJob& commitJob = *(new CommitJob()); // don't destroy
Stats stats;
void Stats::S::reset() {
memset(this, 0, sizeof(*this));
}
Stats::Stats() {
_a.reset();
_b.reset();
curr = &_a;
_intervalMicros = 3000000;
}
Stats::S * Stats::other() {
return curr == &_a ? &_b : &_a;
}
string _CSVHeader();
string Stats::S::_CSVHeader() {
return "cmts jrnMB\twrDFMB\tcIWLk\tearly\tprpLgB wrToJ\twrToDF\trmpPrVw";
}
string Stats::S::_asCSV() {
stringstream ss;
ss <<
setprecision(2) <<
_commits << '\t' << fixed <<
_journaledBytes / 1000000.0 << '\t' <<
_writeToDataFilesBytes / 1000000.0 << '\t' <<
_commitsInWriteLock << '\t' <<
_earlyCommits << '\t' <<
(unsigned) (_prepLogBufferMicros/1000) << '\t' <<
(unsigned) (_writeToJournalMicros/1000) << '\t' <<
(unsigned) (_writeToDataFilesMicros/1000) << '\t' <<
(unsigned) (_remapPrivateViewMicros/1000);
return ss.str();
}
//int getAgeOutJournalFiles();
BSONObj Stats::S::_asObj() {
BSONObjBuilder b;
b <<
"commits" << _commits <<
"journaledMB" << _journaledBytes / 1000000.0 <<
"writeToDataFilesMB" << _writeToDataFilesBytes / 1000000.0 <<
"compression" << _journaledBytes / (_uncompressedBytes+1.0) <<
"commitsInWriteLock" << _commitsInWriteLock <<
"earlyCommits" << _earlyCommits <<
"timeMs" <<
BSON( "dt" << _dtMillis <<
"prepLogBuffer" << (unsigned) (_prepLogBufferMicros/1000) <<
"writeToJournal" << (unsigned) (_writeToJournalMicros/1000) <<
"writeToDataFiles" << (unsigned) (_writeToDataFilesMicros/1000) <<
"remapPrivateView" << (unsigned) (_remapPrivateViewMicros/1000)
);
if( cmdLine.journalCommitInterval != 0 )
b << "journalCommitIntervalMs" << cmdLine.journalCommitInterval;
return b.obj();
}
BSONObj Stats::asObj() {
return other()->_asObj();
}
void Stats::rotate() {
unsigned long long now = curTimeMicros64();
unsigned long long dt = now - _lastRotate;
if( dt >= _intervalMicros && _intervalMicros ) {
// rotate
curr->_dtMillis = (unsigned) (dt/1000);
_lastRotate = now;
curr = other();
curr->reset();
}
}
void* NonDurableImpl::writingPtr(void *x, unsigned len) {
cc().writeHappened();
return x;
}
void NonDurableImpl::declareWriteIntent(void *, unsigned) {
cc().writeHappened();
}
void assertLockedForCommitting();
static DurableImpl* durableImpl = new DurableImpl();
static NonDurableImpl* nonDurableImpl = new NonDurableImpl();
DurableInterface* DurableInterface::_impl = nonDurableImpl;
void DurableInterface::enableDurability() {
verify(_impl == nonDurableImpl);
_impl = durableImpl;
}
void DurableInterface::disableDurability() {
verify(_impl == durableImpl);
massert(13616, "can't disable durability with pending writes", !commitJob.hasWritten());
_impl = nonDurableImpl;
}
bool DurableImpl::commitNow() {
stats.curr->_earlyCommits++;
groupCommit(0);
return true;
}
bool DurableImpl::awaitCommit() {
commitJob._notify.awaitBeyondNow();
return true;
}
/** Declare that a file has been created
Normally writes are applied only after journaling, for safety. But here the file
is created first, and the journal will just replay the creation if the create didn't
happen because of crashing.
*/
void DurableImpl::createdFile(const std::string& filename, unsigned long long len) {
shared_ptr op( new FileCreatedOp(filename, len) );
commitJob.noteOp(op);
}
void* DurableImpl::writingPtr(void *x, unsigned len) {
void *p = x;
declareWriteIntent(p, len);
return p;
}
/** declare intent to write
@param ofs offset within buf at which we will write
@param len the length at ofs we will write
@return new buffer pointer.
*/
void* DurableImpl::writingAtOffset(void *buf, unsigned ofs, unsigned len) {
char *p = (char *) buf;
declareWriteIntent(p+ofs, len);
return p;
}
void* DurableImpl::writingRangesAtOffsets(void *buf, const vector< pair< long long, unsigned > > &ranges ) {
char *p = (char *) buf;
for( vector< pair< long long, unsigned > >::const_iterator i = ranges.begin();
i != ranges.end(); ++i ) {
declareWriteIntent( p + i->first, i->second );
}
return p;
}
bool DurableImpl::aCommitIsNeeded() const {
DEV commitJob._nSinceCommitIfNeededCall = 0;
return commitJob.bytes() > UncommittedBytesLimit;
}
void assertLockedForCommitting() {
char t = Lock::isLocked();
if( t == 'R' || t == 'W' )
return;
// 'w' case we upgrade to exclusive (X).
fassertFailed( 16110 );
}
bool NOINLINE_DECL DurableImpl::_aCommitIsNeeded() {
switch (Lock::isLocked()) {
case '\0': {
DEV log() << "commitIfNeeded but we are unlocked that is ok but why do we get here" << endl;
Lock::GlobalRead r;
if( commitJob.bytes() < UncommittedBytesLimit ) {
// someone else beat us to it
return false;
}
commitNow();
return true;
}
case 'w': {
if( Lock::atLeastReadLocked("local") ) {
error() << "can't commitNow from commitIfNeeded, as we are in local db lock" << endl;
printStackTrace();
dassert(false); // this will make _DEBUG builds terminate. so we will notice in buildbot.
return false;
}
if( Lock::atLeastReadLocked("admin") ) {
error() << "can't commitNow from commitIfNeeded, as we are in admin db lock" << endl;
printStackTrace();
dassert(false);
return false;
}
LOG(1) << "commitIfNeeded upgrading from shared write to exclusive write state"
<< endl;
Lock::DBWrite::UpgradeToExclusive ex;
if (ex.gotUpgrade()) {
commitNow();
}
return true;
}
case 'W':
case 'R':
commitNow();
return true;
case 'r':
return false;
default:
fassertFailed(16434); // unknown lock type
}
}
/** we may need to commit earlier than normal if data are being written at
very high rates.
note you can call this unlocked, and that is a good idea as if you are in
say, a 'w' lock state, we can't do the commit
@param force force a commit now even if seemingly not needed - ie the caller may
know something we don't such as that files will be closed
perf note: this function is called a lot, on every lock_w() ... and usually returns right away
*/
bool DurableImpl::commitIfNeeded(bool force) {
unspoolWriteIntents();
DEV commitJob._nSinceCommitIfNeededCall = 0;
if( likely( commitJob.bytes() < UncommittedBytesLimit && !force ) ) {
return false;
}
return _aCommitIsNeeded();
}
/** Used in _DEBUG builds to check that we didn't overwrite the last intent
that was declared. called just before writelock release. we check a few
bytes after the declared region to see if they changed.
@see MongoMutex::_releasedWriteLock
SLOW
*/
#if 0
void DurableImpl::debugCheckLastDeclaredWrite() {
static int n;
++n;
verify(debug && cmdLine.dur);
if (commitJob.writes().empty())
return;
const WriteIntent &i = commitJob.lastWrite();
size_t ofs;
MongoMMF *mmf = privateViews.find(i.start(), ofs);
if( mmf == 0 )
return;
size_t past = ofs + i.length();
if( mmf->length() < past + 8 )
return; // too close to end of view
char *priv = (char *) mmf->getView();
char *writ = (char *) mmf->view_write();
unsigned long long *a = (unsigned long long *) (priv+past);
unsigned long long *b = (unsigned long long *) (writ+past);
if( *a != *b ) {
for( set::iterator it(commitJob.writes().begin()), end((commitJob.writes().begin())); it != end; ++it ) {
const WriteIntent& wi = *it;
char *r1 = (char*) wi.start();
char *r2 = (char*) wi.end();
if( r1 <= (((char*)a)+8) && r2 > (char*)a ) {
//log() << "it's ok " << wi.p << ' ' << wi.len << endl;
return;
}
}
log() << "journal data after write area " << i.start() << " does not agree" << endl;
log() << " was: " << ((void*)b) << " " << hexdump((char*)b, 8) << endl;
log() << " now: " << ((void*)a) << " " << hexdump((char*)a, 8) << endl;
log() << " n: " << n << endl;
log() << endl;
}
}
#endif
// Functor to be called over all MongoFiles
class validateSingleMapMatches {
public:
validateSingleMapMatches(unsigned long long& bytes) :_bytes(bytes) {}
void operator () (MongoFile *mf) {
if( mf->isMongoMMF() ) {
MongoMMF *mmf = (MongoMMF*) mf;
const unsigned char *p = (const unsigned char *) mmf->getView();
const unsigned char *w = (const unsigned char *) mmf->view_write();
if (!p || !w) return; // File not fully opened yet
_bytes += mmf->length();
verify( mmf->length() == (unsigned) mmf->length() );
if (memcmp(p, w, (unsigned) mmf->length()) == 0)
return; // next file
unsigned low = 0xffffffff;
unsigned high = 0;
log() << "DurParanoid mismatch in " << mmf->filename() << endl;
int logged = 0;
unsigned lastMismatch = 0xffffffff;
for( unsigned i = 0; i < mmf->length(); i++ ) {
if( p[i] != w[i] ) {
if( lastMismatch != 0xffffffff && lastMismatch+1 != i )
log() << endl; // separate blocks of mismatches
lastMismatch= i;
if( ++logged < 60 ) {
if( logged == 1 )
log() << "ofs % 628 = 0x" << hex << (i%628) << endl; // for .ns files to find offset in record
stringstream ss;
ss << "mismatch ofs:" << hex << i << "\tfilemap:" << setw(2) << (unsigned) w[i] << "\tprivmap:" << setw(2) << (unsigned) p[i];
if( p[i] > 32 && p[i] <= 126 )
ss << '\t' << p[i];
log() << ss.str() << endl;
}
if( logged == 60 )
log() << "..." << endl;
if( i < low ) low = i;
if( i > high ) high = i;
}
}
if( low != 0xffffffff ) {
std::stringstream ss;
ss << "journal error warning views mismatch " << mmf->filename() << ' ' << (hex) << low << ".." << high << " len:" << high-low+1;
log() << ss.str() << endl;
log() << "priv loc: " << (void*)(p+low) << ' ' << endl;
//vector& _intents = commitJob.wi()._intents;
//(void) _intents; // mark as unused. Useful for inspection in debugger
// should we abort() here so this isn't unnoticed in some circumstances?
massert(13599, "Written data does not match in-memory view. Missing WriteIntent?", false);
}
}
}
private:
unsigned long long& _bytes;
};
/** (SLOW) diagnostic to check that the private view and the non-private view are in sync.
*/
void debugValidateAllMapsMatch() {
if( ! (cmdLine.durOptions & CmdLine::DurParanoid) )
return;
unsigned long long bytes = 0;
Timer t;
MongoFile::forEach(validateSingleMapMatches(bytes));
OCCASIONALLY log() << "DurParanoid map check " << t.millis() << "ms for " << (bytes / (1024*1024)) << "MB" << endl;
}
extern size_t privateMapBytes;
static void _REMAPPRIVATEVIEW() {
// todo: Consider using ProcessInfo herein and watching for getResidentSize to drop. that could be a way
// to assure very good behavior here.
static unsigned startAt;
static unsigned long long lastRemap;
LOG(4) << "journal REMAPPRIVATEVIEW" << endl;
verify( Lock::isW() );
verify( !commitJob.hasWritten() );
// we want to remap all private views about every 2 seconds. there could be ~1000 views so
// we do a little each pass; beyond the remap time, more significantly, there will be copy on write
// faults after remapping, so doing a little bit at a time will avoid big load spikes on
// remapping.
unsigned long long now = curTimeMicros64();
double fraction = (now-lastRemap)/2000000.0;
if( cmdLine.durOptions & CmdLine::DurAlwaysRemap )
fraction = 1;
lastRemap = now;
#if defined(_WIN32) || defined(__sunos__)
// Note that this negatively affects performance.
// We must grab the exclusive lock here because remapPrivateView() on Windows and
// Solaris need to grab it as well, due to the lack of an atomic way to remap a
// memory mapped file.
// See SERVER-5723 for performance improvement.
// See SERVER-5680 to see why this code is necessary on Windows.
// See SERVER-8795 to see why this code is necessary on Solaris.
LockMongoFilesExclusive lk;
#else
LockMongoFilesShared lk;
#endif
set& files = MongoFile::getAllFiles();
unsigned sz = files.size();
if( sz == 0 )
return;
{
// be careful not to use too much memory if the write rate is
// extremely high
double f = privateMapBytes / ((double)UncommittedBytesLimit);
if( f > fraction ) {
fraction = f;
}
privateMapBytes = 0;
}
unsigned ntodo = (unsigned) (sz * fraction);
if( ntodo < 1 ) ntodo = 1;
if( ntodo > sz ) ntodo = sz;
const set::iterator b = files.begin();
const set::iterator e = files.end();
set::iterator i = b;
// skip to our starting position
for( unsigned x = 0; x < startAt; x++ ) {
i++;
if( i == e ) i = b;
}
unsigned startedAt = startAt;
startAt = (startAt + ntodo) % sz; // mark where to start next time
Timer t;
for( unsigned x = 0; x < ntodo; x++ ) {
dassert( i != e );
if( (*i)->isMongoMMF() ) {
MongoMMF *mmf = (MongoMMF*) *i;
verify(mmf);
if( mmf->willNeedRemap() ) {
mmf->willNeedRemap() = false;
mmf->remapThePrivateView();
}
i++;
if( i == e ) i = b;
}
}
LOG(2) << "journal REMAPPRIVATEVIEW done startedAt: " << startedAt << " n:" << ntodo << ' ' << t.millis() << "ms" << endl;
}
/** We need to remap the private views periodically. otherwise they would become very large.
Call within write lock. See top of file for more commentary.
*/
void REMAPPRIVATEVIEW() {
Timer t;
_REMAPPRIVATEVIEW();
stats.curr->_remapPrivateViewMicros += t.micros();
}
// this is a pseudo-local variable in the groupcommit functions
// below. however we don't truly do that so that we don't have to
// reallocate, and more importantly regrow it, on every single commit.
static AlignedBuilder __theBuilder(4 * 1024 * 1024);
static bool _groupCommitWithLimitedLocks() {
unspoolWriteIntents(); // in case we were doing some writing ourself (likely impossible with limitedlocks version)
AlignedBuilder &ab = __theBuilder;
verify( ! Lock::isLocked() );
// do we need this to be greedy, so that it can start working fairly soon?
// probably: as this is a read lock, it wouldn't change anything if only reads anyway.
// also needs to stop greed. our time to work before clearing lk1 is not too bad, so
// not super critical, but likely 'correct'. todo.
scoped_ptr lk1( new Lock::GlobalRead() );
SimpleMutex::scoped_lock lk2(commitJob.groupCommitMutex);
commitJob.commitingBegin(); // increments the commit epoch for getlasterror j:true
if( !commitJob.hasWritten() ) {
// getlasterror request could have came after the data was already committed
commitJob.committingNotifyCommitted();
return true;
}
JSectHeader h;
PREPLOGBUFFER(h,ab); // need to be in readlock (writes excluded) for this
LockMongoFilesShared lk3;
unsigned abLen = ab.len();
commitJob.committingReset(); // must be reset before allowing anyone to write
DEV verify( !commitJob.hasWritten() );
// release the readlock -- allowing others to now write while we are writing to the journal (etc.)
lk1.reset();
// ****** now other threads can do writes ******
WRITETOJOURNAL(h, ab);
verify( abLen == ab.len() ); // a check that no one touched the builder while we were doing work. if so, our locking is wrong.
// data is now in the journal, which is sufficient for acknowledging getLastError.
// (ok to crash after that)
commitJob.committingNotifyCommitted();
// note the higher-up-the-chain locking of filesLockedFsync is important here,
// as we are not in Lock::GlobalRead anymore. private view readers won't see
// anything as we do this, but external viewers of the datafiles will see them
// mutating.
WRITETODATAFILES(h, ab);
verify( abLen == ab.len() ); // check again wasn't modded
ab.reset();
// can't : d.dbMutex._remapPrivateViewRequested = true;
// (writes have happened we released)
return true;
}
/** @return true if committed; false if lock acquisition timed out (we only try for a read lock herein and only wait for a certain duration). */
bool groupCommitWithLimitedLocks() {
try {
return _groupCommitWithLimitedLocks();
}
catch(DBException& e ) {
log() << "dbexception in groupCommitLL causing immediate shutdown: " << e.toString() << endl;
mongoAbort("dur1");
}
catch(std::ios_base::failure& e) {
log() << "ios_base exception in groupCommitLL causing immediate shutdown: " << e.what() << endl;
mongoAbort("dur2");
}
catch(std::bad_alloc& e) {
log() << "bad_alloc exception in groupCommitLL causing immediate shutdown: " << e.what() << endl;
mongoAbort("dur3");
}
catch(std::exception& e) {
log() << "exception in dur::groupCommitLL causing immediate shutdown: " << e.what() << endl;
mongoAbort("dur4");
}
return false;
}
static void _groupCommit(Lock::GlobalWrite *lgw) {
LOG(4) << "_groupCommit " << endl;
// We are 'R' or 'W'
assertLockedForCommitting();
unspoolWriteIntents(); // in case we were doing some writing ourself
{
AlignedBuilder &ab = __theBuilder;
// we need to make sure two group commits aren't running at the same time
// (and we are only read locked in the dbMutex, so it could happen)
SimpleMutex::scoped_lock lk(commitJob.groupCommitMutex);
commitJob.commitingBegin();
if( !commitJob.hasWritten() ) {
// getlasterror request could have came after the data was already committed
commitJob.committingNotifyCommitted();
}
else {
JSectHeader h;
PREPLOGBUFFER(h,ab);
// todo : write to the journal outside locks, as this write can be slow.
// however, be careful then about remapprivateview as that cannot be done
// if new writes are then pending in the private maps.
WRITETOJOURNAL(h, ab);
// data is now in the journal, which is sufficient for acknowledging getLastError.
// (ok to crash after that)
commitJob.committingNotifyCommitted();
WRITETODATAFILES(h, ab);
debugValidateAllMapsMatch();
commitJob.committingReset();
ab.reset();
}
}
// REMAPPRIVATEVIEW
//
// remapping private views must occur after WRITETODATAFILES otherwise
// we wouldn't see newly written data on reads.
//
DEV verify( !commitJob.hasWritten() );
if( !Lock::isW() ) {
// REMAPPRIVATEVIEW needs done in a write lock (as there is a short window during remapping when each view
// might not exist) thus we do it later.
//
// if commitIfNeeded() operations are not in a W lock, you could get too big of a private map
// on a giant operation. for now they will all be W.
//
// If desired, perhaps this can be eliminated on posix as it may be that the remap is race-free there.
//
// For durthread, lgw is set, and we can upgrade to a W lock for the remap. we do this way as we don't want
// to be in W the entire time we were committing about (in particular for WRITETOJOURNAL() which takes time).
if( lgw ) {
LOG(4) << "_groupCommit upgrade" << endl;
lgw->upgrade();
REMAPPRIVATEVIEW();
}
}
else {
stats.curr->_commitsInWriteLock++;
// however, if we are already write locked, we must do it now -- up the call tree someone
// may do a write without a new lock acquisition. this can happen when MongoMMF::close() calls
// this method when a file (and its views) is about to go away.
//
REMAPPRIVATEVIEW();
}
}
/** locking: in read lock when called
or, for early commits (commitIfNeeded), in write lock
@param lwg set if the durcommitthread *only* -- then we will upgrade the lock
to W so we can remapprivateview. only durcommitthread as more than one
thread upgrading would potentially deadlock
@see MongoMMF::close()
*/
static void groupCommit(Lock::GlobalWrite *lgw) {
try {
_groupCommit(lgw);
}
catch(DBException& e ) {
log() << "dbexception in groupCommit causing immediate shutdown: " << e.toString() << endl;
mongoAbort("gc1");
}
catch(std::ios_base::failure& e) {
log() << "ios_base exception in groupCommit causing immediate shutdown: " << e.what() << endl;
mongoAbort("gc2");
}
catch(std::bad_alloc& e) {
log() << "bad_alloc exception in groupCommit causing immediate shutdown: " << e.what() << endl;
mongoAbort("gc3");
}
catch(std::exception& e) {
log() << "exception in dur::groupCommit causing immediate shutdown: " << e.what() << endl;
mongoAbort("gc4");
}
LOG(4) << "groupCommit end" << endl;
}
static void durThreadGroupCommit() {
SimpleMutex::scoped_lock flk(filesLockedFsync);
const int N = 10;
static int n;
if( privateMapBytes < UncommittedBytesLimit && ++n % N && (cmdLine.durOptions&CmdLine::DurAlwaysRemap)==0 ) {
// limited locks version doesn't do any remapprivateview at all, so only try this if privateMapBytes
// is in an acceptable range. also every Nth commit, we do everything so we can do some remapping;
// remapping a lot all at once could cause jitter from a large amount of copy-on-writes all at once.
if( groupCommitWithLimitedLocks() )
return;
}
// we get a write lock, downgrade, do work, upgrade, finish work.
// getting a write lock is helpful also as we need to be greedy and not be starved here
// note our "stopgreed" parm -- to stop greed by others while we are working. you can't write
// anytime soon anyway if we are journaling for a while, that was the idea.
Lock::GlobalWrite w(/*stopgreed:*/true);
w.downgrade();
groupCommit(&w);
}
/** called when a MongoMMF is closing -- we need to go ahead and group commit in that case before its
views disappear
*/
void closingFileNotification() {
if (!cmdLine.dur)
return;
if( Lock::isLocked() ) {
getDur().commitIfNeeded(true);
}
else {
verify( inShutdown() );
if( commitJob.hasWritten() ) {
log() << "journal warning files are closing outside locks with writes pending" << endl;
}
}
}
extern int groupCommitIntervalMs;
boost::filesystem::path getJournalDir();
void durThread() {
Client::initThread("journal");
bool samePartition = true;
try {
const string dbpathDir = boost::filesystem::path(dbpath).string();
samePartition = onSamePartition(getJournalDir().string(), dbpathDir);
}
catch(...) {
}
while( !inShutdown() ) {
RACECHECK
unsigned ms = cmdLine.journalCommitInterval;
if( ms == 0 ) {
// use default
ms = samePartition ? 100 : 30;
}
unsigned oneThird = (ms / 3) + 1; // +1 so never zero
try {
stats.rotate();
// commit sooner if one or more getLastError j:true is pending
sleepmillis(oneThird);
for( unsigned i = 1; i <= 2; i++ ) {
if( commitJob._notify.nWaiting() )
break;
if( commitJob.bytes() > UncommittedBytesLimit / 2 )
break;
sleepmillis(oneThird);
}
//DEV log() << "privateMapBytes=" << privateMapBytes << endl;
durThreadGroupCommit();
}
catch(std::exception& e) {
log() << "exception in durThread causing immediate shutdown: " << e.what() << endl;
mongoAbort("exception in durThread");
}
}
cc().shutdown();
}
void recover();
void releasingWriteLock() {
unspoolWriteIntents();
}
void preallocateFiles();
/** at startup, recover, and then start the journal threads */
void startup() {
if( !cmdLine.dur )
return;
#if defined(_DURABLEDEFAULTON)
DEV {
if( time(0) & 1 ) {
cmdLine.durOptions |= CmdLine::DurAlwaysCommit;
log() << "_DEBUG _DURABLEDEFAULTON : forcing DurAlwaysCommit mode for this run" << endl;
}
if( time(0) & 2 ) {
cmdLine.durOptions |= CmdLine::DurAlwaysRemap;
log() << "_DEBUG _DURABLEDEFAULTON : forcing DurAlwaysRemap mode for this run" << endl;
}
}
#endif
DurableInterface::enableDurability();
journalMakeDir();
try {
recover();
}
catch(DBException& e) {
log() << "dbexception during recovery: " << e.toString() << endl;
throw;
}
catch(std::exception& e) {
log() << "std::exception during recovery: " << e.what() << endl;
throw;
}
catch(...) {
log() << "exception during recovery" << endl;
throw;
}
preallocateFiles();
boost::thread t(durThread);
}
void DurableImpl::syncDataAndTruncateJournal() {
verify( Lock::isW() );
// a commit from the commit thread won't begin while we are in the write lock,
// but it may already be in progress and the end of that work is done outside
// (dbMutex) locks. This line waits for that to complete if already underway.
{
SimpleMutex::scoped_lock lk(commitJob.groupCommitMutex);
}
commitNow();
MongoFile::flushAll(true);
journalCleanup();
verify(!haveJournalFiles()); // Double check post-conditions
}
class DurSSS : public ServerStatusSection {
public:
DurSSS() : ServerStatusSection( "dur" ){}
virtual bool includeByDefault() const { return true; }
BSONObj generateSection(const BSONElement& configElement) const {
if ( ! cmdLine.dur )
return BSONObj();
return dur::stats.asObj();
}
} durSSS;
} // namespace dur
} // namespace mongo