C++ ShardingState::resetVersion方法代码示例

//.........这里部分代码省略.........
                }
                return true;
            }

        }

        // step 4

        // this is because of a weird segfault I saw and I can't see why this should ever be set
        massert( 13647 , str::stream() << "context should be empty here, is: " << cc().getContext()->ns() , cc().getContext() == 0 );

        Lock::GlobalWrite setShardVersionLock; // TODO: can we get rid of this??

        if ( oldVersion.isSet() && ! globalVersion.isSet() ) {
            // this had been reset
            info->setVersion( ns , ShardChunkVersion( 0, OID() ) );
        }

        if ( ! version.isSet() && ! globalVersion.isSet() ) {
            // this connection is cleaning itself
            info->setVersion( ns , ShardChunkVersion( 0, OID() ) );
            return true;
        }

        if ( ! version.isSet() && globalVersion.isSet() ) {
            if ( ! authoritative ) {
                result.appendBool( "need_authoritative" , true );
                result.append( "ns" , ns );
                globalVersion.addToBSON( result, "globalVersion" );
                errmsg = "dropping needs to be authoritative";
                return false;
            }
            log() << "wiping data for: " << ns << endl;
            globalVersion.addToBSON( result, "beforeDrop" );
            // only setting global version on purpose
            // need clients to re-find meta-data
            shardingState.resetVersion( ns );
            info->setVersion( ns , ShardChunkVersion( 0, OID() ) );
            return true;
        }

        if ( version < oldVersion ) {
            errmsg = "this connection already had a newer version of collection '" + ns + "'";
            result.append( "ns" , ns );
            version.addToBSON( result, "newVersion" );
            globalVersion.addToBSON( result, "globalVersion" );
            return false;
        }

        if ( version < globalVersion ) {
            while ( shardingState.inCriticalMigrateSection() ) {
                dbtemprelease r;
                sleepmillis(2);
                OCCASIONALLY log() << "waiting till out of critical section" << endl;
            }
            errmsg = "shard global version for collection is higher than trying to set to '" + ns + "'";
            result.append( "ns" , ns );
            version.addToBSON( result, "version" );
            globalVersion.addToBSON( result, "globalVersion" );
            result.appendBool( "reloadConfig" , true );
            return false;
        }

        if ( ! globalVersion.isSet() && ! authoritative ) {
            // Needed b/c when the last chunk is moved off a shard, the version gets reset to zero, which
            // should require a reload.
            // TODO: Maybe a more elegant way of doing this
            while ( shardingState.inCriticalMigrateSection() ) {
                dbtemprelease r;
                sleepmillis(2);
                OCCASIONALLY log() << "waiting till out of critical section for version reset" << endl;
            }

            // need authoritative for first look
            result.append( "ns" , ns );
            result.appendBool( "need_authoritative" , true );
            errmsg = "first time for collection '" + ns + "'";
            return false;
        }

        Timer relockTime;
        {
            dbtemprelease unlock;

            ShardChunkVersion currVersion = version;
            if ( ! shardingState.trySetVersion( ns , currVersion ) ) {
                errmsg = str::stream() << "client version differs from config's for collection '" << ns << "'";
                result.append( "ns" , ns );
                version.addToBSON( result, "version" );
                globalVersion.addToBSON( result, "globalVersion" );
                return false;
            }
        }
        if ( relockTime.millis() >= ( cmdLine.slowMS - 10 ) ) {
            log() << "setShardVersion - relocking slow: " << relockTime.millis() << endl;
        }

        info->setVersion( ns , version );
        return true;
    }

        bool run(const string& , BSONObj& cmdObj, string& errmsg, BSONObjBuilder& result, bool) {

            lastError.disableForCommand();
            ShardedConnectionInfo* info = ShardedConnectionInfo::get( true );

            bool authoritative = cmdObj.getBoolField( "authoritative" );

            string configdb = cmdObj["configdb"].valuestrsafe();
            {
                // configdb checking
                if ( configdb.size() == 0 ) {
                    errmsg = "no configdb";
                    return false;
                }

                if ( shardingState.enabled() ) {
                    if ( configdb != shardingState.getConfigServer() ) {
                        errmsg = "specified a different configdb!";
                        return false;
                    }
                }
                else {
                    if ( ! authoritative ) {
                        result.appendBool( "need_authoritative" , true );
                        errmsg = "first setShardVersion";
                        return false;
                    }
                    shardingState.enable( configdb );
                    configServer.init( configdb );
                }
            }

            if ( cmdObj["shard"].type() == String ) {
                shardingState.gotShardName( cmdObj["shard"].String() );
                shardingState.gotShardHost( cmdObj["shardHost"].String() );
            }

            {
                // setting up ids
                if ( cmdObj["serverID"].type() != jstOID ) {
                    // TODO: fix this
                    //errmsg = "need serverID to be an OID";
                    //return 0;
                }
                else {
                    OID clientId = cmdObj["serverID"].__oid();
                    if ( ! info->hasID() ) {
                        info->setID( clientId );
                    }
                    else if ( clientId != info->getID() ) {
                        errmsg = "server id has changed!";
                        return 0;
                    }
                }
            }

            unsigned long long version = extractVersion( cmdObj["version"] , errmsg );

            if ( errmsg.size() ) {
                return false;
            }

            string ns = cmdObj["setShardVersion"].valuestrsafe();
            if ( ns.size() == 0 ) {
                errmsg = "need to speciy fully namespace";
                return false;
            }

            const ConfigVersion oldVersion = info->getVersion(ns);
            const ConfigVersion globalVersion = shardingState.getVersion(ns);

            if ( oldVersion > 0 && globalVersion == 0 ) {
                // this had been reset
                info->setVersion( ns , 0 );
            }

            if ( version == 0 && globalVersion == 0 ) {
                // this connection is cleaning itself
                info->setVersion( ns , 0 );
                return true;
            }

            if ( version == 0 && globalVersion > 0 ) {
                if ( ! authoritative ) {
                    result.appendBool( "need_authoritative" , true );
                    result.append( "ns" , ns );
                    result.appendTimestamp( "globalVersion" , globalVersion );
                    result.appendTimestamp( "oldVersion" , oldVersion );
                    errmsg = "dropping needs to be authoritative";
                    return false;
                }
                log() << "wiping data for: " << ns << endl;
                result.appendTimestamp( "beforeDrop" , globalVersion );
                // only setting global version on purpose
                // need clients to re-find meta-data
                shardingState.resetVersion( ns );
                info->setVersion( ns , 0 );
                return true;
            }

//.........这里部分代码省略.........

        bool run(const string& , BSONObj& cmdObj, string& errmsg, BSONObjBuilder& result, bool) {

            // Steps
            // 1. check basic config
            // 2. extract params from command
            // 3. fast check
            // 4. slow check (LOCKS)
            
            // step 1

            lastError.disableForCommand();
            ShardedConnectionInfo* info = ShardedConnectionInfo::get( true );

            bool authoritative = cmdObj.getBoolField( "authoritative" );
            
            // check config server is ok or enable sharding
            if ( ! checkConfigOrInit( cmdObj["configdb"].valuestrsafe() , authoritative , errmsg , result ) )
                return false;

            // check shard name/hosts are correct
            if ( cmdObj["shard"].type() == String ) {
                shardingState.gotShardName( cmdObj["shard"].String() );
                shardingState.gotShardHost( cmdObj["shardHost"].String() );
            }
            
            // make sure we have the mongos id for writebacks
            if ( ! checkMongosID( info , cmdObj["serverID"] , errmsg ) )
                return false;

            // step 2
            
            string ns = cmdObj["setShardVersion"].valuestrsafe();
            if ( ns.size() == 0 ) {
                errmsg = "need to speciy namespace";
                return false;
            }

            const ConfigVersion version = extractVersion( cmdObj["version"] , errmsg );
            if ( errmsg.size() )
                return false;
            
            // step 3

            const ConfigVersion oldVersion = info->getVersion(ns);
            const ConfigVersion globalVersion = shardingState.getVersion(ns);

            result.appendTimestamp( "oldVersion" , oldVersion );
            
            if ( globalVersion > 0 && version > 0 ) {
                // this means there is no reset going on an either side
                // so its safe to make some assuptions

                if ( version == globalVersion ) {
                    // mongos and mongod agree!
                    if ( oldVersion != version ) {
                        assert( oldVersion < globalVersion );
                        info->setVersion( ns , version );
                    }
                    return true;
                }
                
            }

            // step 4
            
            // this is because of a weird segfault I saw and I can't see why this should ever be set
            massert( 13647 , str::stream() << "context should be empty here, is: " << cc().getContext()->ns() , cc().getContext() == 0 ); 
        
            dblock setShardVersionLock; // TODO: can we get rid of this??
            
            if ( oldVersion > 0 && globalVersion == 0 ) {
                // this had been reset
                info->setVersion( ns , 0 );
            }

            if ( version == 0 && globalVersion == 0 ) {
                // this connection is cleaning itself
                info->setVersion( ns , 0 );
                return true;
            }

            if ( version == 0 && globalVersion > 0 ) {
                if ( ! authoritative ) {
                    result.appendBool( "need_authoritative" , true );
                    result.append( "ns" , ns );
                    result.appendTimestamp( "globalVersion" , globalVersion );
                    errmsg = "dropping needs to be authoritative";
                    return false;
                }
                log() << "wiping data for: " << ns << endl;
                result.appendTimestamp( "beforeDrop" , globalVersion );
                // only setting global version on purpose
                // need clients to re-find meta-data
                shardingState.resetVersion( ns );
                info->setVersion( ns , 0 );
                return true;
            }

            if ( version < oldVersion ) {
                errmsg = "this connection already had a newer version of collection '" + ns + "'";
//.........这里部分代码省略.........