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// repl_block.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/>.
*/
#include "pch.h"
#include "repl.h"
#include "repl_block.h"
#include "instance.h"
#include "dbhelpers.h"
#include "../util/background.h"
#include "../util/mongoutils/str.h"
#include "replutil.h"
//#define REPLDEBUG(x) log() << "replBlock: " << x << endl;
#define REPLDEBUG(x)
namespace mongo {
using namespace mongoutils;
class SlaveTracking : public BackgroundJob { // SERVER-4328 todo review
public:
string name() const { return "SlaveTracking"; }
static const char * NS;
struct Ident {
Ident(const BSONObj& r, const string& h, const string& n) {
BSONObjBuilder b;
b.appendElements( r );
b.append( "host" , h );
b.append( "ns" , n );
obj = b.obj();
}
bool operator<( const Ident& other ) const {
return obj["_id"].OID() < other.obj["_id"].OID();
}
BSONObj obj;
};
SlaveTracking() : _mutex("SlaveTracking") {
_dirty = false;
_started = false;
_currentlyUpdatingCache = false;
}
void run() {
Client::initThread( "slaveTracking" );
DBDirectClient db;
while ( ! inShutdown() ) {
sleepsecs( 1 );
if ( ! _dirty )
continue;
if ( inShutdown() )
return;
list< pair<BSONObj,BSONObj> > todo;
{
scoped_lock mylk(_mutex);
for ( map<Ident,OpTime>::iterator i=_slaves.begin(); i!=_slaves.end(); i++ ) {
BSONObjBuilder temp;
temp.appendTimestamp( "syncedTo" , i->second.asDate() );
todo.push_back( pair<BSONObj,BSONObj>( i->first.obj.getOwned() ,
BSON( "$set" << temp.obj() ).getOwned() ) );
}
_dirty = false;
}
_currentlyUpdatingCache = true;
for ( list< pair<BSONObj,BSONObj> >::iterator i=todo.begin(); i!=todo.end(); i++ ) {
db.update( NS , i->first , i->second , true );
}
_currentlyUpdatingCache = false;
}
}
void reset() {
if ( _currentlyUpdatingCache )
return;
scoped_lock mylk(_mutex);
_slaves.clear();
}
void update( const BSONObj& rid , const string& host , const string& ns , OpTime last ) {
REPLDEBUG( host << " " << rid << " " << ns << " " << last );
Ident ident(rid,host,ns);
scoped_lock mylk(_mutex);
_slaves[ident] = last;
_dirty = true;
if (theReplSet && theReplSet->isPrimary()) {
theReplSet->ghost->updateSlave(ident.obj["_id"].OID(), last);
}
if ( ! _started ) {
// start background thread here since we definitely need it
_started = true;
go();
}
}
bool opReplicatedEnough( OpTime op , BSONElement w ) {
RARELY {
REPLDEBUG( "looking for : " << op << " w=" << w );
}
if (w.isNumber()) {
return replicatedToNum(op, w.numberInt());
}
if (!theReplSet) {
return false;
}
string wStr = w.String();
if (wStr == "majority") {
// use the entire set, including arbiters, to prevent writing
// to a majority of the set but not a majority of voters
return replicatedToNum(op, theReplSet->config().getMajority());
}
map<string,ReplSetConfig::TagRule*>::const_iterator it = theReplSet->config().rules.find(wStr);
uassert(14830, str::stream() << "unrecognized getLastError mode: " << wStr,
it != theReplSet->config().rules.end());
return op <= (*it).second->last;
}
bool replicatedToNum(OpTime& op, int w) {
if ( w <= 1 || ! _isMaster() )
return true;
w--; // now this is the # of slaves i need
scoped_lock mylk(_mutex);
for ( map<Ident,OpTime>::iterator i=_slaves.begin(); i!=_slaves.end(); i++) {
OpTime s = i->second;
if ( s < op ) {
continue;
}
if ( --w == 0 )
return true;
}
return w <= 0;
}
unsigned getSlaveCount() const {
scoped_lock mylk(_mutex);
return _slaves.size();
}
// need to be careful not to deadlock with this
mutable mongo::mutex _mutex;
map<Ident,OpTime> _slaves;
bool _dirty;
bool _started;
bool _currentlyUpdatingCache; // this is not thread safe, but ok for our purposes
} slaveTracking;
const char * SlaveTracking::NS = "local.slaves";
void updateSlaveLocation( CurOp& curop, const char * ns , OpTime lastOp ) {
if ( lastOp.isNull() )
return;
verify( str::startsWith(ns, "local.oplog.") );
Client * c = curop.getClient();
verify(c);
BSONObj rid = c->getRemoteID();
if ( rid.isEmpty() )
return;
slaveTracking.update( rid , curop.getRemoteString( false ) , ns , lastOp );
if (theReplSet && !theReplSet->isPrimary()) {
// we don't know the slave's port, so we make the replica set keep
// a map of rids to slaves
log(2) << "percolating " << lastOp.toString() << " from " << rid << endl;
theReplSet->ghost->send( boost::bind(&GhostSync::percolate, theReplSet->ghost, rid, lastOp) );
}
}
bool opReplicatedEnough( OpTime op , BSONElement w ) {
return slaveTracking.opReplicatedEnough( op , w );
}
bool opReplicatedEnough( OpTime op , int w ) {
return slaveTracking.replicatedToNum( op , w );
}
void resetSlaveCache() {
slaveTracking.reset();
}
unsigned getSlaveCount() {
return slaveTracking.getSlaveCount();
}
}
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