summaryrefslogtreecommitdiff
path: root/s/balancer_policy.cpp
diff options
context:
space:
mode:
Diffstat (limited to 's/balancer_policy.cpp')
-rw-r--r--s/balancer_policy.cpp189
1 files changed, 0 insertions, 189 deletions
diff --git a/s/balancer_policy.cpp b/s/balancer_policy.cpp
deleted file mode 100644
index bd1763d6b2e..00000000000
--- a/s/balancer_policy.cpp
+++ /dev/null
@@ -1,189 +0,0 @@
-// balancer_policy.cpp
-
-/**
-* Copyright (C) 2010 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 "config.h"
-
-#include "../client/dbclient.h"
-#include "../util/stringutils.h"
-#include "../util/unittest.h"
-
-#include "balancer_policy.h"
-
-namespace mongo {
-
- // limits map fields
- BSONField<long long> LimitsFields::currSize( "currSize" );
- BSONField<bool> LimitsFields::hasOpsQueued( "hasOpsQueued" );
-
- BalancerPolicy::ChunkInfo* BalancerPolicy::balance( const string& ns,
- const ShardToLimitsMap& shardToLimitsMap,
- const ShardToChunksMap& shardToChunksMap,
- int balancedLastTime ) {
- pair<string,unsigned> min("",numeric_limits<unsigned>::max());
- pair<string,unsigned> max("",0);
- vector<string> drainingShards;
-
- bool maxOpsQueued = false;
-
- for (ShardToChunksIter i = shardToChunksMap.begin(); i!=shardToChunksMap.end(); ++i ) {
-
- // Find whether this shard's capacity or availability are exhausted
- const string& shard = i->first;
- BSONObj shardLimits;
- ShardToLimitsIter it = shardToLimitsMap.find( shard );
- if ( it != shardToLimitsMap.end() ) shardLimits = it->second;
- const bool maxedOut = isSizeMaxed( shardLimits );
- const bool draining = isDraining( shardLimits );
- const bool opsQueued = hasOpsQueued( shardLimits );
-
-
- // Is this shard a better chunk receiver then the current one?
- // Shards that would be bad receiver candidates:
- // + maxed out shards
- // + draining shards
- // + shards with operations queued for writeback
- const unsigned size = i->second.size();
- if ( ! maxedOut && ! draining && ! opsQueued ) {
- if ( size < min.second ) {
- min = make_pair( shard , size );
- }
- }
- else if ( opsQueued ) {
- LOG(1) << "won't send a chunk to: " << shard << " because it has ops queued" << endl;
- }
- else if ( maxedOut ) {
- LOG(1) << "won't send a chunk to: " << shard << " because it is maxedOut" << endl;
- }
-
-
- // Check whether this shard is a better chunk donor then the current one.
- // Draining shards take a lower priority than overloaded shards.
- if ( size > max.second ) {
- max = make_pair( shard , size );
- maxOpsQueued = opsQueued;
- }
- if ( draining && (size > 0)) {
- drainingShards.push_back( shard );
- }
- }
-
- // If there is no candidate chunk receiver -- they may have all been maxed out,
- // draining, ... -- there's not much that the policy can do.
- if ( min.second == numeric_limits<unsigned>::max() ) {
- log() << "no available shards to take chunks" << endl;
- return NULL;
- }
-
- if ( maxOpsQueued ) {
- log() << "biggest shard " << max.first << " has unprocessed writebacks, waiting for completion of migrate" << endl;
- return NULL;
- }
-
- LOG(1) << "collection : " << ns << endl;
- LOG(1) << "donor : " << max.second << " chunks on " << max.first << endl;
- LOG(1) << "receiver : " << min.second << " chunks on " << min.first << endl;
- if ( ! drainingShards.empty() ) {
- string drainingStr;
- joinStringDelim( drainingShards, &drainingStr, ',' );
- LOG(1) << "draining : " << ! drainingShards.empty() << "(" << drainingShards.size() << ")" << endl;
- }
-
- // Solving imbalances takes a higher priority than draining shards. Many shards can
- // be draining at once but we choose only one of them to cater to per round.
- const int imbalance = max.second - min.second;
- const int threshold = balancedLastTime ? 2 : 8;
- string from, to;
- if ( imbalance >= threshold ) {
- from = max.first;
- to = min.first;
-
- }
- else if ( ! drainingShards.empty() ) {
- from = drainingShards[ rand() % drainingShards.size() ];
- to = min.first;
-
- }
- else {
- // Everything is balanced here!
- return NULL;
- }
-
- const vector<BSONObj>& chunksFrom = shardToChunksMap.find( from )->second;
- const vector<BSONObj>& chunksTo = shardToChunksMap.find( to )->second;
- BSONObj chunkToMove = pickChunk( chunksFrom , chunksTo );
- log() << "chose [" << from << "] to [" << to << "] " << chunkToMove << endl;
-
- return new ChunkInfo( ns, to, from, chunkToMove );
- }
-
- BSONObj BalancerPolicy::pickChunk( const vector<BSONObj>& from, const vector<BSONObj>& to ) {
- // It is possible for a donor ('from') shard to have less chunks than a receiver one ('to')
- // if the donor is in draining mode.
-
- if ( to.size() == 0 )
- return from[0];
-
- if ( from[0]["min"].Obj().woCompare( to[to.size()-1]["max"].Obj() , BSONObj() , false ) == 0 )
- return from[0];
-
- if ( from[from.size()-1]["max"].Obj().woCompare( to[0]["min"].Obj() , BSONObj() , false ) == 0 )
- return from[from.size()-1];
-
- return from[0];
- }
-
- bool BalancerPolicy::isSizeMaxed( BSONObj limits ) {
- // If there's no limit information for the shard, assume it can be a chunk receiver
- // (i.e., there's not bound on space utilization)
- if ( limits.isEmpty() ) {
- return false;
- }
-
- long long maxUsage = limits[ ShardFields::maxSize.name() ].Long();
- if ( maxUsage == 0 ) {
- return false;
- }
-
- long long currUsage = limits[ LimitsFields::currSize.name() ].Long();
- if ( currUsage < maxUsage ) {
- return false;
- }
-
- return true;
- }
-
- bool BalancerPolicy::isDraining( BSONObj limits ) {
- BSONElement draining = limits[ ShardFields::draining.name() ];
- if ( draining.eoo() || ! draining.trueValue() ) {
- return false;
- }
-
- return true;
- }
-
- bool BalancerPolicy::hasOpsQueued( BSONObj limits ) {
- BSONElement opsQueued = limits[ LimitsFields::hasOpsQueued.name() ];
- if ( opsQueued.eoo() || ! opsQueued.trueValue() ) {
- return false;
- }
- return true;
- }
-
-} // namespace mongo
generated by cgit v1.2.3 (git 2.39.1) at 2026-09-11 11:57:43 +0000