コード例 #1
0
ファイル: balancer_policy.cpp プロジェクト: ardneh/mongo
 void DistributionStatus::populateShardInfoMap(const vector<Shard> allShards,
                                               ShardInfoMap* shardInfo) {
     for (vector<Shard>::const_iterator it = allShards.begin();
             it != allShards.end(); ++it ) {
         const Shard& shard = *it;
         ShardStatus status = shard.getStatus();
         shardInfo->insert(make_pair(shard.getName(),
                                     ShardInfo(shard.getMaxSize(),
                                               status.mapped(),
                                               shard.isDraining(),
                                               status.hasOpsQueued(),
                                               shard.tags(),
                                               status.mongoVersion())));
     }
 }
コード例 #2
0
    void Balancer::_doBalanceRound( DBClientBase& conn, vector<CandidateChunkPtr>* candidateChunks ) {
        verify( candidateChunks );

        //
        // 1. Check whether there is any sharded collection to be balanced by querying
        // the ShardsNS::collections collection
        //

        auto_ptr<DBClientCursor> cursor = conn.query(CollectionType::ConfigNS, BSONObj());
        vector< string > collections;
        while ( cursor->more() ) {
            BSONObj col = cursor->nextSafe();

            // sharded collections will have a shard "key".
            if ( ! col[CollectionType::keyPattern()].eoo() &&
                 ! col[CollectionType::noBalance()].trueValue() ){
                collections.push_back( col[CollectionType::ns()].String() );
            }
            else if( col[CollectionType::noBalance()].trueValue() ){
                LOG(1) << "not balancing collection " << col[CollectionType::ns()].String()
                       << ", explicitly disabled" << endl;
            }

        }
        cursor.reset();

        if ( collections.empty() ) {
            LOG(1) << "no collections to balance" << endl;
            return;
        }

        //
        // 2. Get a list of all the shards that are participating in this balance round
        // along with any maximum allowed quotas and current utilization. We get the
        // latter by issuing db.serverStatus() (mem.mapped) to all shards.
        //
        // TODO: skip unresponsive shards and mark information as stale.
        //

        vector<Shard> allShards;
        Shard::getAllShards( allShards );
        if ( allShards.size() < 2) {
            LOG(1) << "can't balance without more active shards" << endl;
            return;
        }
        
        ShardInfoMap shardInfo;
        for ( vector<Shard>::const_iterator it = allShards.begin(); it != allShards.end(); ++it ) {
            const Shard& s = *it;
            ShardStatus status = s.getStatus();
            shardInfo[ s.getName() ] = ShardInfo( s.getMaxSize(),
                                                  status.mapped(),
                                                  s.isDraining(),
                                                  status.hasOpsQueued(),
                                                  s.tags(),
                                                  status.mongoVersion()
                                                  );
        }

        OCCASIONALLY warnOnMultiVersion( shardInfo );

        //
        // 3. For each collection, check if the balancing policy recommends moving anything around.
        //

        for (vector<string>::const_iterator it = collections.begin(); it != collections.end(); ++it ) {
            const string& ns = *it;

            map< string,vector<BSONObj> > shardToChunksMap;
            cursor = conn.query(ChunkType::ConfigNS,
                                QUERY(ChunkType::ns(ns)).sort(ChunkType::min()));

            set<BSONObj> allChunkMinimums;

            while ( cursor->more() ) {
                BSONObj chunk = cursor->nextSafe().getOwned();
                vector<BSONObj>& chunks = shardToChunksMap[chunk[ChunkType::shard()].String()];
                allChunkMinimums.insert( chunk[ChunkType::min()].Obj() );
                chunks.push_back( chunk );
            }
            cursor.reset();

            if (shardToChunksMap.empty()) {
                LOG(1) << "skipping empty collection (" << ns << ")";
                continue;
            }

            for ( vector<Shard>::iterator i=allShards.begin(); i!=allShards.end(); ++i ) {
                // this just makes sure there is an entry in shardToChunksMap for every shard
                Shard s = *i;
                shardToChunksMap[s.getName()].size();
            }

            DistributionStatus status( shardInfo, shardToChunksMap );

            // load tags
            conn.ensureIndex(TagsType::ConfigNS,
                             BSON(TagsType::ns() << 1 << TagsType::min() << 1),
                             true);

            cursor = conn.query(TagsType::ConfigNS,
                                QUERY(TagsType::ns(ns)).sort(TagsType::min()));

            vector<TagRange> ranges;

            while ( cursor->more() ) {
                BSONObj tag = cursor->nextSafe();
                TagRange tr(tag[TagsType::min()].Obj().getOwned(),
                            tag[TagsType::max()].Obj().getOwned(),
                            tag[TagsType::tag()].String());
                ranges.push_back(tr);
                uassert(16356,
                        str::stream() << "tag ranges not valid for: " << ns,
                        status.addTagRange(tr) );

            }
            cursor.reset();

            DBConfigPtr cfg = grid.getDBConfig( ns );
            if ( !cfg ) {
                warning() << "could not load db config to balance " << ns << " collection" << endl;
                continue;
            }

            // This line reloads the chunk manager once if this process doesn't know the collection
            // is sharded yet.
            ChunkManagerPtr cm = cfg->getChunkManagerIfExists( ns, true );
            if ( !cm ) {
                warning() << "could not load chunks to balance " << ns << " collection" << endl;
                continue;
            }

            // loop through tags to make sure no chunk spans tags; splits on tag min. for all chunks
            bool didAnySplits = false;
            for ( unsigned i = 0; i < ranges.size(); i++ ) {
                BSONObj min = ranges[i].min;

                min = cm->getShardKey().extendRangeBound( min, false );

                if ( allChunkMinimums.count( min ) > 0 )
                    continue;

                didAnySplits = true;

                log() << "ns: " << ns << " need to split on "
                      << min << " because there is a range there" << endl;

                ChunkPtr c = cm->findIntersectingChunk( min );

                vector<BSONObj> splitPoints;
                splitPoints.push_back( min );

                BSONObj res;
                if ( !c->multiSplit( splitPoints, res ) ) {
                    error() << "split failed: " << res << endl;
                }
                else {
                    LOG(1) << "split worked: " << res << endl;
                }
                break;
            }

            if ( didAnySplits ) {
                // state change, just wait till next round
                continue;
            }

            CandidateChunk* p = _policy->balance( ns, status, _balancedLastTime );
            if ( p ) candidateChunks->push_back( CandidateChunkPtr( p ) );
        }
    }