path: root/src/mongo/db/repl/rs.cpp

/**
*    Copyright (C) 2008 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 <http://www.gnu.org/licenses/>.
*
*    As a special exception, the copyright holders give permission to link the
*    code of portions of this program with the OpenSSL library under certain
*    conditions as described in each individual source file and distribute
*    linked combinations including the program with the OpenSSL library. You
*    must comply with the GNU Affero General Public License in all respects for
*    all of the code used other than as permitted herein. If you modify file(s)
*    with this exception, you may extend this exception to your version of the
*    file(s), but you are not obligated to do so. If you do not wish to do so,
*    delete this exception statement from your version. If you delete this
*    exception statement from all source files in the program, then also delete
*    it in the license file.
*/

#include "mongo/platform/basic.h"

#include "mongo/base/owned_pointer_vector.h"
#include "mongo/base/status.h"
#include "mongo/db/auth/authorization_manager.h"
#include "mongo/db/auth/authorization_session.h"
#include "mongo/db/client.h"
#include "mongo/db/dbhelpers.h"
#include "mongo/db/instance.h"
#include "mongo/db/repl/bgsync.h"
#include "mongo/db/repl/connections.h"
#include "mongo/db/repl/oplog.h"
#include "mongo/db/repl/replication_server_status.h"  // replSettings
#include "mongo/db/repl/rs.h"
#include "mongo/db/server_parameters.h"
#include "mongo/platform/bits.h"
#include "mongo/s/d_logic.h"
#include "mongo/util/net/sock.h"

using namespace std;

namespace mongo {
    
    using namespace bson;

#ifdef MONGO_PLATFORM_64
    const int ReplSetImpl::replWriterThreadCount = 16;
    const int ReplSetImpl::replPrefetcherThreadCount = 16;
#else
    const int ReplSetImpl::replWriterThreadCount = 2;
    const int ReplSetImpl::replPrefetcherThreadCount = 2;
#endif

    bool replSet = false;
    ReplSet *theReplSet = 0;

    // This is a bitmask with the first bit set. It's used to mark connections that should be kept
    // open during stepdowns
    const unsigned ScopedConn::keepOpen = 1;

    bool isCurrentlyAReplSetPrimary() {
        return theReplSet && theReplSet->isPrimary();
    }

    void replset::sethbmsg(const string& s, const int level) {
        if (theReplSet) {
            theReplSet->sethbmsg(s, level);
        }
    }

    void ReplSetImpl::sethbmsg(const std::string& s, int logLevel) {
        static time_t lastLogged;
        _hbmsgTime = time(0);

        if( s == _hbmsg ) {
            // unchanged
            if( _hbmsgTime - lastLogged < 60 )
                return;
        }

        unsigned sz = s.size();
        if( sz >= 256 )
            memcpy(_hbmsg, s.c_str(), 255);
        else {
            _hbmsg[sz] = 0;
            memcpy(_hbmsg, s.c_str(), sz);
        }
        if( !s.empty() ) {
            lastLogged = _hbmsgTime;
            LOG(logLevel) << "replSet " << s << rsLog;
        }
    }

    void ReplSetImpl::goStale(const Member* stale, const BSONObj& oldest) {
        log() << "replSet error RS102 too stale to catch up, at least from " << stale->fullName() << rsLog;
        log() << "replSet our last optime : " << lastOpTimeWritten.toStringLong() << rsLog;
        log() << "replSet oldest at " << stale->fullName() << " : " << oldest["ts"]._opTime().toStringLong() << rsLog;
        log() << "replSet See http://dochub.mongodb.org/core/resyncingaverystalereplicasetmember" << rsLog;

        // reset minvalid so that we can't become primary prematurely
        setMinValid(oldest);

        sethbmsg("error RS102 too stale to catch up");
        changeState(MemberState::RS_RECOVERING);
    }

    void ReplSetImpl::assumePrimary() {
        LOG(2) << "replSet assuming primary" << endl;
        verify( iAmPotentiallyHot() );

        // Wait for replication to stop and buffer to be consumed
        LOG(1) << "replSet waiting for replication to finish before becoming primary" << endl;
        replset::BackgroundSync::get()->stopReplicationAndFlushBuffer();

        // Lock here to prevent stepping down & becoming primary from getting interleaved
        Lock::GlobalWrite lk;

        // Make sure that new OpTimes are higher than existing ones even with clock skew
        DBDirectClient c;
        BSONObj lastOp = c.findOne( "local.oplog.rs", Query().sort(reverseNaturalObj), NULL, QueryOption_SlaveOk );
        if ( !lastOp.isEmpty() ) {
            OpTime::setLast( lastOp[ "ts" ].date() );
        }

        changeState(MemberState::RS_PRIMARY);
    }

    void ReplSetImpl::changeState(MemberState s) { box.change(s, _self); }

    bool ReplSetImpl::setMaintenanceMode(const bool inc) {
        lock replLock(this);
        // Lock here to prevent state from changing between checking the state and changing it
        Lock::GlobalWrite writeLock;

        if (box.getState().primary()) {
            return false;
        }

        if (inc) {
            log() << "replSet going into maintenance mode (" << _maintenanceMode << " other tasks)" << rsLog;

            _maintenanceMode++;
            changeState(MemberState::RS_RECOVERING);
        }
        else if (_maintenanceMode > 0) {
            _maintenanceMode--;
            // no need to change state, syncTail will try to go live as a secondary soon

            log() << "leaving maintenance mode (" << _maintenanceMode << " other tasks)" << rsLog;
        }
        else {
            return false;
        }

        fassert(16844, _maintenanceMode >= 0);
        return true;
    }

    Member* ReplSetImpl::getMostElectable() {
        lock lk(this);

        Member *max = 0;
        set<unsigned>::iterator it = _electableSet.begin();
        while ( it != _electableSet.end() ) {
            const Member *temp = findById(*it);
            if (!temp) {
                log() << "couldn't find member: " << *it << endl;
                set<unsigned>::iterator it_delete = it;
                it++;
                _electableSet.erase(it_delete);
                continue;
            }
            if (!max || max->config().priority < temp->config().priority) {
                max = (Member*)temp;
            }
            it++;
        }

        return max;
    }

    void ReplSetImpl::relinquish() {
        {
            Lock::GlobalWrite lk; // so we are synchronized with _logOp()

            LOG(2) << "replSet attempting to relinquish" << endl;
            if( box.getState().primary() ) {
                log() << "replSet relinquishing primary state" << rsLog;
                changeState(MemberState::RS_SECONDARY);

                // close sockets that were talking to us so they don't blithly send many writes that
                // will fail with "not master" (of course client could check result code, but in
                // case they are not)
                log() << "replSet closing client sockets after relinquishing primary" << rsLog;
                MessagingPort::closeAllSockets(ScopedConn::keepOpen);
            }
            else if( box.getState().startup2() ) {
                // This block probably isn't necessary
                changeState(MemberState::RS_RECOVERING);
                return;
            }
        }

        // now that all connections were closed, strip this mongod from all sharding details
        // if and when it gets promoted to a primary again, only then it should reload the sharding state
        // the rationale here is that this mongod won't bring stale state when it regains primaryhood
        shardingState.resetShardingState();
    }

    /* look freshly for who is primary - includes relinquishing ourself. */
    void ReplSetImpl::forgetPrimary() {
        if( box.getState().primary() )
            relinquish();
        else {
            box.setOtherPrimary(0);
        }
    }

    // for the replSetStepDown command
    bool ReplSetImpl::_stepDown(int secs) {
        lock lk(this);
        if( box.getState().primary() ) {
            elect.steppedDown = time(0) + secs;
            log() << "replSet info stepping down as primary secs=" << secs << rsLog;
            relinquish();
            return true;
        }
        return false;
    }

    bool ReplSetImpl::_freeze(int secs) {
        lock lk(this);
        /* note if we are primary we remain primary but won't try to elect ourself again until
           this time period expires.
           */
        if( secs == 0 ) {
            elect.steppedDown = 0;
            log() << "replSet info 'unfreezing'" << rsLog;
        }
        else {
            if( !box.getState().primary() ) {
                elect.steppedDown = time(0) + secs;
                log() << "replSet info 'freezing' for " << secs << " seconds" << rsLog;
            }
            else {
                log() << "replSet info received freeze command but we are primary" << rsLog;
            }
        }
        return true;
    }

    void ReplSetImpl::msgUpdateHBInfo(HeartbeatInfo h) {
        for( Member *m = _members.head(); m; m=m->next() ) {
            if( m->id() == h.id() ) {
                m->_hbinfo.updateFromLastPoll(h);
                return;
            }
        }
    }

    void ReplSetImpl::msgUpdateHBRecv(unsigned id, time_t newTime) {
        for (Member *m = _members.head(); m; m = m->next()) {
            if (m->id() == id) {
                m->_hbinfo.lastHeartbeatRecv = newTime;
                return;
            }
        }
    }

    list<HostAndPort> ReplSetImpl::memberHostnames() const {
        list<HostAndPort> L;
        L.push_back(_self->h());
        for( Member *m = _members.head(); m; m = m->next() )
            L.push_back(m->h());
        return L;
    }

    void ReplSetImpl::_fillIsMasterHost(const Member *m, vector<string>& hosts, vector<string>& passives, vector<string>& arbiters) {
        verify( m );
        if( m->config().hidden )
            return;

        if( m->potentiallyHot() ) {
            hosts.push_back(m->h().toString());
        }
        else if( !m->config().arbiterOnly ) {
            if( m->config().slaveDelay ) {
                /* hmmm - we don't list these as they are stale. */
            }
            else {
                passives.push_back(m->h().toString());
            }
        }
        else {
            arbiters.push_back(m->h().toString());
        }
    }

    void ReplSetImpl::_fillIsMaster(BSONObjBuilder& b) {
        lock lk(this);
        
        const StateBox::SP sp = box.get();
        bool isp = sp.state.primary();
        b.append("setName", name());
        b.append("setVersion", version());
        b.append("ismaster", isp);
        b.append("secondary", sp.state.secondary());
        {
            vector<string> hosts, passives, arbiters;
            _fillIsMasterHost(_self, hosts, passives, arbiters);

            for( Member *m = _members.head(); m; m = m->next() ) {
                verify( m );
                _fillIsMasterHost(m, hosts, passives, arbiters);
            }

            if( hosts.size() > 0 ) {
                b.append("hosts", hosts);
            }
            if( passives.size() > 0 ) {
                b.append("passives", passives);
            }
            if( arbiters.size() > 0 ) {
                b.append("arbiters", arbiters);
            }
        }

        if( !isp ) {
            const Member *m = sp.primary;
            if( m )
                b.append("primary", m->h().toString());
        }
        else {
            b.append("primary", _self->fullName());
        }

        if( myConfig().arbiterOnly )
            b.append("arbiterOnly", true);
        if( myConfig().priority == 0 && !myConfig().arbiterOnly)
            b.append("passive", true);
        if( myConfig().slaveDelay )
            b.append("slaveDelay", myConfig().slaveDelay);
        if( myConfig().hidden )
            b.append("hidden", true);
        if( !myConfig().buildIndexes )
            b.append("buildIndexes", false);
        if( !myConfig().tags.empty() ) {
            BSONObjBuilder a;
            for( map<string,string>::const_iterator i = myConfig().tags.begin(); i != myConfig().tags.end(); i++ )
                a.append((*i).first, (*i).second);
            b.append("tags", a.done());
        }
        b.append("me", myConfig().h.toString());
    }

    /** @param cfgString <setname>/<seedhost1>,<seedhost2> */

    void parseReplsetCmdLine(const std::string& cfgString,
                             string& setname,
                             vector<HostAndPort>& seeds,
                             set<HostAndPort>& seedSet ) {
        const char *p = cfgString.c_str();
        const char *slash = strchr(p, '/');
        if( slash )
            setname = string(p, slash-p);
        else
            setname = p;
        uassert(13093, "bad --replSet config string format is: <setname>[/<seedhost1>,<seedhost2>,...]", !setname.empty());

        if( slash == 0 )
            return;

        p = slash + 1;
        while( 1 ) {
            const char *comma = strchr(p, ',');
            if( comma == 0 ) comma = strchr(p,0);
            if( p == comma )
                break;
            {
                HostAndPort m;
                try {
                    m = HostAndPort( string(p, comma-p) );
                }
                catch(...) {
                    uassert(13114, "bad --replSet seed hostname", false);
                }
                uassert(13096, "bad --replSet command line config string - dups?", seedSet.count(m) == 0 );
                seedSet.insert(m);
                //uassert(13101, "can't use localhost in replset host list", !m.isLocalHost());
                if( m.isSelf() ) {
                    LOG(1) << "replSet ignoring seed " << m.toString() << " (=self)" << rsLog;
                }
                else
                    seeds.push_back(m);
                if( *comma == 0 )
                    break;
                p = comma + 1;
            }
        }
    }

    void ReplSetImpl::init(ReplSetCmdline& replSetCmdline) {
        mgr = new Manager(this);
        ghost = new GhostSync(this);

        _cfg = 0;
        memset(_hbmsg, 0, sizeof(_hbmsg));
        strcpy( _hbmsg , "initial startup" );
        lastH = 0;
        changeState(MemberState::RS_STARTUP);

        _seeds = &replSetCmdline.seeds;

        LOG(1) << "replSet beginning startup..." << rsLog;

        loadConfig();

        unsigned sss = replSetCmdline.seedSet.size();
        for( Member *m = head(); m; m = m->next() ) {
            replSetCmdline.seedSet.erase(m->h());
        }
        for( set<HostAndPort>::iterator i = replSetCmdline.seedSet.begin(); i != replSetCmdline.seedSet.end(); i++ ) {
            if( i->isSelf() ) {
                if( sss == 1 ) {
                    LOG(1) << "replSet warning self is listed in the seed list and there are no other seeds listed did you intend that?" << rsLog;
                }
            }
            else {
                log() << "replSet warning command line seed " << i->toString() << " is not present in the current repl set config" << rsLog;
            }
        }

        // Figure out indexPrefetch setting
        std::string& prefetch = replSettings.rsIndexPrefetch;
        if (!prefetch.empty()) {
            IndexPrefetchConfig prefetchConfig = PREFETCH_ALL;
            if (prefetch == "none")
                prefetchConfig = PREFETCH_NONE;
            else if (prefetch == "_id_only")
                prefetchConfig = PREFETCH_ID_ONLY;
            else if (prefetch == "all")
                prefetchConfig = PREFETCH_ALL;
            else
                warning() << "unrecognized indexPrefetch setting: " << prefetch << endl;
            setIndexPrefetchConfig(prefetchConfig);
        }
    }

    ReplSetImpl::ReplSetImpl() :
        elect(this),
        _forceSyncTarget(0),
        _blockSync(false),
        _hbmsgTime(0),
        _self(0),
        _maintenanceMode(0),
        mgr(0),
        ghost(0),
        _writerPool(replWriterThreadCount),
        _prefetcherPool(replPrefetcherThreadCount),
        oplogVersion(0),
        _indexPrefetchConfig(PREFETCH_ALL) {
    }

    ReplSet::ReplSet() {
    }

    ReplSet* ReplSet::make(ReplSetCmdline& replSetCmdline) {
        auto_ptr<ReplSet> ret(new ReplSet());
        ret->init(replSetCmdline);
        return ret.release();
    }

    void ReplSetImpl::loadLastOpTimeWritten(bool quiet) {
        Lock::DBRead lk(rsoplog);
        BSONObj o;
        if( Helpers::getLast(rsoplog, o) ) {
            lastH = o["h"].numberLong();
            lastOpTimeWritten = o["ts"]._opTime();
            uassert(13290, "bad replSet oplog entry?", quiet || !lastOpTimeWritten.isNull());
        }
    }

    /* call after constructing to start - returns fairly quickly after launching its threads */
    void ReplSetImpl::_go() {
        {
            boost::unique_lock<boost::mutex> lk(rss.mtx);
            while (!rss.indexRebuildDone) {
                rss.cond.wait(lk);
            }
        }
        try {
            loadLastOpTimeWritten();
        }
        catch(std::exception& e) {
            log() << "replSet error fatal couldn't query the local " << rsoplog << " collection.  Terminating mongod after 30 seconds." << rsLog;
            log() << e.what() << rsLog;
            sleepsecs(30);
            dbexit( EXIT_REPLICATION_ERROR );
            return;
        }

        changeState(MemberState::RS_STARTUP2);
        startThreads();
        newReplUp(); // oplog.cpp
    }

    ReplSetImpl::StartupStatus ReplSetImpl::startupStatus = PRESTART;
    DiagStr ReplSetImpl::startupStatusMsg;
    ReplicationStartSynchronizer ReplSetImpl::rss;

    extern BSONObj *getLastErrorDefault;

    void ReplSetImpl::setSelfTo(Member *m) {
        // already locked in initFromConfig
        _self = m;
        _id = m->id();
        _config = m->config();
        if( m ) _buildIndexes = m->config().buildIndexes;
        else _buildIndexes = true;
    }

    /** @param reconf true if this is a reconfiguration and not an initial load of the configuration.
        @return true if ok; throws if config really bad; false if config doesn't include self
    */
    bool ReplSetImpl::initFromConfig(ReplSetConfig& c, bool reconf) {
        /* NOTE: haveNewConfig() writes the new config to disk before we get here.  So
                 we cannot error out at this point, except fatally.  Check errors earlier.
                 */
        lock lk(this);

        if( getLastErrorDefault || !c.getLastErrorDefaults.isEmpty() ) {
            // see comment in dbcommands.cpp for getlasterrordefault
            getLastErrorDefault = new BSONObj( c.getLastErrorDefaults );
        }

        list<ReplSetConfig::MemberCfg*> newOnes;
        // additive short-cuts the new config setup. If we are just adding a
        // node/nodes and nothing else is changing, this is additive. If it's
        // not a reconfig, we're not adding anything
        bool additive = reconf;
        bool updateConfigs = false;
        {
            unsigned nfound = 0;
            int me = 0;
            for( vector<ReplSetConfig::MemberCfg>::iterator i = c.members.begin(); i != c.members.end(); i++ ) {
                
                ReplSetConfig::MemberCfg& m = *i;
                if( m.h.isSelf() ) {
                    me++;
                }
                
                if( reconf ) {
                    const Member *old = findById(m._id);
                    if( old ) {
                        nfound++;
                        verify( (int) old->id() == m._id );
                        if (!old->config().isSameIgnoringTags(m)) {
                            additive = false;
                        }
                        if (!updateConfigs && old->config() != m) {
                            updateConfigs = true;
                        }
                    }
                    else {
                        newOnes.push_back(&m);
                    }
                }
            }
            if( me == 0 ) { // we're not in the config -- we must have been removed
                if (state().shunned()) {
                    // already took note of our ejection from the set
                    // so just sit tight and poll again
                    return false;
                }

                _members.orphanAll();

                // kill off rsHealthPoll threads (because they Know Too Much about our past)
                endOldHealthTasks();

                // close sockets to force clients to re-evaluate this member
                MessagingPort::closeAllSockets(0);

                // take note of our ejection
                changeState(MemberState::RS_SHUNNED);

                // go into holding pattern
                log() << "replSet info self not present in the repl set configuration:" << rsLog;
                log() << c.toString() << rsLog;

                loadConfig();  // redo config from scratch
                return false; 
            }
            uassert( 13302, "replSet error self appears twice in the repl set configuration", me<=1 );

            // if we found different members that the original config, reload everything
            if( reconf && config().members.size() != nfound )
                additive = false;
        }

        // If we are changing chaining rules, we don't want this to be an additive reconfig so that
        // the primary can step down and the sync targets change.
        // TODO: This can be removed once SERVER-5208 is fixed.
        if (reconf && config().chainingAllowed() != c.chainingAllowed()) {
            additive = false;
        }

        _cfg = new ReplSetConfig(c);
        dassert( &config() == _cfg ); // config() is same thing but const, so we use that when we can for clarity below
        verify( config().ok() );
        verify( _name.empty() || _name == config()._id );
        _name = config()._id;
        verify( !_name.empty() );
        // this is a shortcut for simple changes
        if( additive ) {
            log() << "replSet info : additive change to configuration" << rsLog;
            for( list<ReplSetConfig::MemberCfg*>::const_iterator i = newOnes.begin(); i != newOnes.end(); i++ ) {
                ReplSetConfig::MemberCfg *m = *i;
                Member *mi = new Member(m->h, m->_id, m, false);

                /** we will indicate that new members are up() initially so that we don't relinquish our
                    primary state because we can't (transiently) see a majority.  they should be up as we
                    check that new members are up before getting here on reconfig anyway.
                    */
                mi->get_hbinfo().health = 0.1;

                _members.push(mi);
                startHealthTaskFor(mi);
            }

            if (updateConfigs) {
                // for logging
                string members = "";

                // not setting _self to 0 as other threads use _self w/o locking
                int me = 0;
                for(vector<ReplSetConfig::MemberCfg>::const_iterator i = config().members.begin();
                    i != config().members.end(); i++) {
                    const ReplSetConfig::MemberCfg& m = *i;
                    Member *mi;
                    members += (members == "" ? "" : ", ") + m.h.toString();
                    if (m.h.isSelf()) {
                        verify(me++ == 0);
                        mi = new Member(m.h, m._id, &m, true);
                        if (!reconf) {
                            log() << "replSet I am " << m.h.toString() << rsLog;
                        }
                        setSelfTo(mi);
                    }
                    else {
                        mi = new Member(m.h, m._id, &m, false);
                        _members.push(mi);
                    }
                }
            }

            // if we aren't creating new members, we may have to update the
            // groups for the current ones
            _cfg->updateMembers(_members);

            return true;
        }

        // start with no members.  if this is a reconfig, drop the old ones.
        _members.orphanAll();

        endOldHealthTasks();
        
        // Clear out our memory of who might have been syncing from us.
        // Any incoming handshake connections after this point will be newly registered.
        ghost->clearCache();

        int oldPrimaryId = -1;
        {
            const Member *p = box.getPrimary();
            if( p )
                oldPrimaryId = p->id();
        }
        forgetPrimary();

        // not setting _self to 0 as other threads use _self w/o locking
        int me = 0;

        // For logging
        string members = "";

        for( vector<ReplSetConfig::MemberCfg>::const_iterator i = config().members.begin(); i != config().members.end(); i++ ) {
            const ReplSetConfig::MemberCfg& m = *i;
            Member *mi;
            members += ( members == "" ? "" : ", " ) + m.h.toString();
            if( m.h.isSelf() ) {
                verify( me++ == 0 );
                mi = new Member(m.h, m._id, &m, true);
                if (!reconf) {
                    log() << "replSet I am " << m.h.toString() << rsLog;
                }
                setSelfTo(mi);

                if( (int)mi->id() == oldPrimaryId )
                    box.setSelfPrimary(mi);
            }
            else {
                mi = new Member(m.h, m._id, &m, false);
                _members.push(mi);
                if( (int)mi->id() == oldPrimaryId )
                    box.setOtherPrimary(mi);
            }
        }

        if( me == 0 ){
            log() << "replSet warning did not detect own host in full reconfig, members " << members << " config: " << c << rsLog;
        }
        else {
            // Do this after we've found ourselves, since _self needs
            // to be set before we can start the heartbeat tasks
            for( Member *mb = _members.head(); mb; mb=mb->next() ) {
                startHealthTaskFor( mb );
            }
        }
        return true;
    }

    // Our own config must be the first one.
    bool ReplSetImpl::_loadConfigFinish(vector<ReplSetConfig*>& cfgs) {
        int v = -1;
        ReplSetConfig *highest = 0;
        int myVersion = -2000;
        int n = 0;
        for( vector<ReplSetConfig*>::iterator i = cfgs.begin(); i != cfgs.end(); i++ ) {
            ReplSetConfig* cfg = *i;
            DEV { LOG(1) << n+1 << " config shows version " << cfg->version << rsLog; }
            if( ++n == 1 ) myVersion = cfg->version;
            if( cfg->ok() && cfg->version > v ) {
                highest = cfg;
                v = cfg->version;
            }
        }
        verify( highest );

        if( !initFromConfig(*highest) )
            return false;

        if( highest->version > myVersion && highest->version >= 0 ) {
            log() << "replSet got config version " << highest->version << " from a remote, saving locally" << rsLog;
            highest->saveConfigLocally(BSONObj());
        }
        return true;
    }

    void ReplSetImpl::loadConfig() {
        startupStatus = LOADINGCONFIG;
        startupStatusMsg.set("loading " + rsConfigNs + " config (LOADINGCONFIG)");
        LOG(1) << "loadConfig() " << rsConfigNs << endl;

        while( 1 ) {
            try {
                OwnedPointerVector<ReplSetConfig> configs;
                try {
                    configs.mutableVector().push_back(ReplSetConfig::makeDirect());
                }
                catch(DBException& e) {
                    log() << "replSet exception loading our local replset configuration object : " << e.toString() << rsLog;
                }
                for( vector<HostAndPort>::const_iterator i = _seeds->begin(); i != _seeds->end(); i++ ) {
                    try {
                        configs.mutableVector().push_back( ReplSetConfig::make(*i) );
                    }
                    catch( DBException& e ) {
                        log() << "replSet exception trying to load config from " << *i << " : " << e.toString() << rsLog;
                    }
                }
                {
                    scoped_lock lck( replSettings.discoveredSeeds_mx );
                    if( replSettings.discoveredSeeds.size() > 0 ) {
                        for (set<string>::iterator i = replSettings.discoveredSeeds.begin(); 
                             i != replSettings.discoveredSeeds.end(); 
                             i++) {
                            try {
                                configs.mutableVector().push_back( ReplSetConfig::make(HostAndPort(*i)) );
                            }
                            catch( DBException& ) {
                                LOG(1) << "replSet exception trying to load config from discovered seed " << *i << rsLog;
                                replSettings.discoveredSeeds.erase(*i);
                            }
                        }
                    }
                }

                if (!replSettings.reconfig.isEmpty()) {
                    try {
                        configs.mutableVector().push_back(ReplSetConfig::make(replSettings.reconfig,
                                                                       true));
                    }
                    catch( DBException& re) {
                        log() << "replSet couldn't load reconfig: " << re.what() << rsLog;
                        replSettings.reconfig = BSONObj();
                    }
                }

                int nok = 0;
                int nempty = 0;
                for( vector<ReplSetConfig*>::iterator i = configs.mutableVector().begin();
                     i != configs.mutableVector().end(); i++ ) {
                    if( (*i)->ok() )
                        nok++;
                    if( (*i)->empty() )
                        nempty++;
                }
                if( nok == 0 ) {

                    if( nempty == (int) configs.mutableVector().size() ) {
                        startupStatus = EMPTYCONFIG;
                        startupStatusMsg.set("can't get " + rsConfigNs + " config from self or any seed (EMPTYCONFIG)");
                        log() << "replSet can't get " << rsConfigNs << " config from self or any seed (EMPTYCONFIG)" << rsLog;
                        static unsigned once;
                        if( ++once == 1 ) {
                            log() << "replSet info you may need to run replSetInitiate -- rs.initiate() in the shell -- if that is not already done" << rsLog;
                        }
                        if( _seeds->size() == 0 ) {
                            LOG(1) << "replSet info no seed hosts were specified on the --replSet command line" << rsLog;
                        }
                    }
                    else {
                        startupStatus = EMPTYUNREACHABLE;
                        startupStatusMsg.set("can't currently get " + rsConfigNs + " config from self or any seed (EMPTYUNREACHABLE)");
                        log() << "replSet can't get " << rsConfigNs << " config from self or any seed (yet)" << rsLog;
                    }

                    sleepsecs(1);
                    continue;
                }

                if( !_loadConfigFinish(configs.mutableVector()) ) {
                    log() << "replSet info Couldn't load config yet. Sleeping 20sec and will try again." << rsLog;
                    sleepsecs(20);
                    continue;
                }
            }
            catch(DBException& e) {
                startupStatus = BADCONFIG;
                startupStatusMsg.set("replSet error loading set config (BADCONFIG)");
                log() << "replSet error loading configurations " << e.toString() << rsLog;
                log() << "replSet error replication will not start" << rsLog;
                sethbmsg("error loading set config");
                _fatal();
                throw;
            }
            break;
        }
        startupStatusMsg.set("? started");
        startupStatus = STARTED;
    }

    void ReplSetImpl::_fatal() {
        box.set(MemberState::RS_FATAL, 0);
        log() << "replSet error fatal, stopping replication" << rsLog;
    }

    void ReplSet::haveNewConfig(ReplSetConfig& newConfig, bool addComment) {
        bo comment;
        if( addComment )
            comment = BSON( "msg" << "Reconfig set" << "version" << newConfig.version );

        newConfig.saveConfigLocally(comment);

        try {
            if (initFromConfig(newConfig, true)) {
                log() << "replSet replSetReconfig new config saved locally" << rsLog;
            }
        }
        catch(DBException& e) {
            log() << "replSet error unexpected exception in haveNewConfig() : " << e.toString() << rsLog;
            _fatal();
        }
        catch(...) {
            log() << "replSet error unexpected exception in haveNewConfig()" << rsLog;
            _fatal();
        }
    }

    void Manager::msgReceivedNewConfig(BSONObj o) {
        log() << "replset msgReceivedNewConfig version: " << o["version"].toString() << rsLog;
        scoped_ptr<ReplSetConfig> config(ReplSetConfig::make(o));
        if( config->version > rs->config().version )
            theReplSet->haveNewConfig(*config, false);
        else {
            log() << "replSet info msgReceivedNewConfig but version isn't higher " <<
                  config->version << ' ' << rs->config().version << rsLog;
        }
    }

    /* forked as a thread during startup
       it can run quite a while looking for config.  but once found,
       a separate thread takes over as ReplSetImpl::Manager, and this thread
       terminates.
    */
    void startReplSets(ReplSetCmdline *replSetCmdline) {
        Client::initThread("rsStart");
        try {
            verify( theReplSet == 0 );
            if( replSetCmdline == 0 ) {
                verify(!replSet);
                return;
            }
            replLocalAuth();
            (theReplSet = ReplSet::make(*replSetCmdline))->go();
        }
        catch(std::exception& e) {
            log() << "replSet caught exception in startReplSets thread: " << e.what() << rsLog;
            if( theReplSet )
                theReplSet->fatal();
        }
        cc().shutdown();
    }

    void ReplSet::shutdown() {
        replset::BackgroundSync::shutdown();
    }

    void replLocalAuth() {
        if (!AuthorizationManager::isAuthEnabled())
            return;
        cc().getAuthorizationSession()->grantInternalAuthorization();
    }

    const char* ReplSetImpl::_initialSyncFlagString = "doingInitialSync";
    const BSONObj ReplSetImpl::_initialSyncFlag(BSON(_initialSyncFlagString << true));

    void ReplSetImpl::clearInitialSyncFlag() {
        Lock::DBWrite lk( "local" );
        Helpers::putSingleton("local.replset.minvalid", BSON( "$unset" << _initialSyncFlag ));
    }

    void ReplSetImpl::setInitialSyncFlag() {
        Lock::DBWrite lk( "local" );
        Helpers::putSingleton("local.replset.minvalid", BSON( "$set" << _initialSyncFlag ));
    }

    bool ReplSetImpl::getInitialSyncFlag() {
        Lock::DBRead lk ( "local" );
        BSONObj mv;
        if (Helpers::getSingleton("local.replset.minvalid", mv)) {
            return mv[_initialSyncFlagString].trueValue();
        }
        return false;
    }

    void ReplSetImpl::setMinValid(BSONObj obj) {
        BSONObjBuilder builder;
        BSONObjBuilder subobj(builder.subobjStart("$set"));
        subobj.appendTimestamp("ts", obj["ts"].date());
        subobj.done();
        Lock::DBWrite lk( "local" );
        Helpers::putSingleton("local.replset.minvalid", builder.obj());
    }

    OpTime ReplSetImpl::getMinValid() {
        Lock::DBRead lk("local.replset.minvalid");
        BSONObj mv;
        if (Helpers::getSingleton("local.replset.minvalid", mv)) {
            return mv["ts"]._opTime();
        }
        return OpTime();
    }

    void ReplSetImpl::registerSlave(const BSONObj& rid, const int memberId) {
        // To prevent race conditions with clearing the cache at reconfig time,
        // we lock the replset mutex here.
        {
            lock lk(this);
            ghost->associateSlave(rid, memberId);
        }
        syncSourceFeedback.associateMember(rid, memberId);
    }

    class ReplIndexPrefetch : public ServerParameter {
    public:
        ReplIndexPrefetch()
            : ServerParameter( ServerParameterSet::getGlobal(), "replIndexPrefetch" ) {
        }

        virtual ~ReplIndexPrefetch() {
        }

        const char * _value() {
            if (!theReplSet)
                return "uninitialized";
            ReplSetImpl::IndexPrefetchConfig ip = theReplSet->getIndexPrefetchConfig();
            switch (ip) {
            case ReplSetImpl::PREFETCH_NONE:
                return "none";
            case ReplSetImpl::PREFETCH_ID_ONLY:
                return "_id_only";
            case ReplSetImpl::PREFETCH_ALL:
                return "all";
            default:
                return "invalid";
            }
        }

        virtual void append( BSONObjBuilder& b, const string& name ) {
            b.append( name, _value() );
        }

        virtual Status set( const BSONElement& newValueElement ) {
            if (!theReplSet) {
                return Status( ErrorCodes::BadValue, "replication is not enabled" );
            }

            std::string prefetch = newValueElement.valuestrsafe();
            return setFromString( prefetch );
        }

        virtual Status setFromString( const string& prefetch ) {
            log() << "changing replication index prefetch behavior to " << prefetch << endl;

            ReplSetImpl::IndexPrefetchConfig prefetchConfig;

            if (prefetch == "none")
                prefetchConfig = ReplSetImpl::PREFETCH_NONE;
            else if (prefetch == "_id_only")
                prefetchConfig = ReplSetImpl::PREFETCH_ID_ONLY;
            else if (prefetch == "all")
                prefetchConfig = ReplSetImpl::PREFETCH_ALL;
            else {
                return Status( ErrorCodes::BadValue,
                               str::stream() << "unrecognized indexPrefetch setting: " << prefetch );
            }

            theReplSet->setIndexPrefetchConfig(prefetchConfig);
            return Status::OK();
        }

    } replIndexPrefetch;
}