SERVER-23609 Make top chunk split use the balancer to move chunks

Moves all direct access to balancer structures out of the top chunk split
optimization code and changes it to an explicit call to the balancer.

1 files changed, 0 insertions, 134 deletions

diff --git a/src/mongo/s/balance.h b/src/mongo/s/balance.h
deleted file mode 100644
index 41c0349716a..00000000000
--- a/src/mongo/s/balance.h
+++ /dev/null
@@ -1,134 +0,0 @@
-/**
- *    Copyright (C) 2016 MongoDB 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.
- */
-
-#pragma once
-
-#include <string>
-#include <vector>
-
-#include "mongo/s/balancer/balancer_chunk_selection_policy.h"
-#include "mongo/util/background.h"
-#include "mongo/util/timer.h"
-
-namespace mongo {
-
-class ClusterStatistics;
-class MigrationSecondaryThrottleOptions;
-class OperationContext;
-template <typename T>
-class StatusWith;
-
-/**
- * The balancer is a background task that tries to keep the number of chunks across all
- * servers of the cluster even. Although every mongos will have one balancer running, only one
- * of them will be active at the any given point in time. The balancer uses a distributed lock
- * for that coordination.
- *
- * The balancer does act continuously but in "rounds". At a given round, it would decide if
- * there is an imbalance by checking the difference in chunks between the most and least
- * loaded shards. It would issue a request for a chunk migration per round, if it found so.
- */
-class Balancer : public BackgroundJob {
-public:
-    Balancer();
-    ~Balancer();
-
-    /**
-     * Retrieves the per-service instance of the Balancer.
-     */
-    static Balancer* get(OperationContext* operationContext);
-
-    ClusterStatistics* getClusterStatistics() const {
-        return _clusterStats.get();
-    }
-
-private:
-    // BackgroundJob methods implementation
-
-    void run() override;
-
-    std::string name() const override {
-        return "Balancer";
-    }
-
-    /**
-     * Checks that the balancer can connect to all servers it needs to do its job.
-     *
-     * @return true if balancing can be started
-     *
-     * This method throws on a network exception
-     */
-    bool _init(OperationContext* txn);
-
-    /**
-     * Marks this balancer as being live on the config server(s).
-     */
-    void _ping(OperationContext* txn, bool waiting);
-
-    /**
-     * Returns true if all the servers listed in configdb as being shards are reachable and are
-     * distinct processes (no hostname mixup).
-     */
-    bool _checkOIDs(OperationContext* txn);
-
-    /**
-     * Iterates through all chunks in all collections and ensures that no chunks straddle tag
-     * boundary. If any do, they will be split.
-     */
-    Status _enforceTagRanges(OperationContext* txn);
-
-    /**
-     * Issues chunk migration request, one at a time.
-     *
-     * @param candidateChunks possible chunks to move
-     * @param writeConcern detailed write concern. NULL means the default write concern.
-     * @param waitForDelete wait for deletes to complete after each chunk move
-     * @return number of chunks effectively moved
-     */
-    int _moveChunks(OperationContext* txn,
-                    const BalancerChunkSelectionPolicy::MigrateInfoVector& candidateChunks,
-                    const MigrationSecondaryThrottleOptions& secondaryThrottle,
-                    bool waitForDelete);
-
-    // hostname:port of my mongos
-    std::string _myid;
-
-    // Time the Balancer started running
-    Timer _timer;
-
-    // number of moved chunks in last round
-    int _balancedLastTime;
-
-    // Balancer policy
-    std::unique_ptr<BalancerChunkSelectionPolicy> _chunkSelectionPolicy;
-
-    // Source for cluster statistics
-    std::unique_ptr<ClusterStatistics> _clusterStats;
-};
-
-}  // namespace mongo