/**
* Copyright (C) 2012 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 .
*
* 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.
*/
#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kCommand
#include "mongo/platform/basic.h"
#include "mongo/db/commands/mr.h"
#include
#include "mongo/client/connpool.h"
#include "mongo/client/parallel.h"
#include "mongo/db/auth/authorization_session.h"
#include "mongo/db/catalog/collection.h"
#include "mongo/db/catalog/collection_catalog_entry.h"
#include "mongo/db/catalog/database_holder.h"
#include "mongo/db/catalog/document_validation.h"
#include "mongo/db/clientcursor.h"
#include "mongo/db/commands.h"
#include "mongo/db/db.h"
#include "mongo/db/db_raii.h"
#include "mongo/db/dbhelpers.h"
#include "mongo/db/service_context.h"
#include "mongo/db/index/index_descriptor.h"
#include "mongo/db/instance.h"
#include "mongo/db/matcher/matcher.h"
#include "mongo/db/namespace_string.h"
#include "mongo/db/op_observer.h"
#include "mongo/db/operation_context_impl.h"
#include "mongo/db/query/get_executor.h"
#include "mongo/db/query/query_planner.h"
#include "mongo/db/range_preserver.h"
#include "mongo/db/repl/replication_coordinator_global.h"
#include "mongo/s/catalog/catalog_cache.h"
#include "mongo/s/chunk_manager.h"
#include "mongo/s/collection_metadata.h"
#include "mongo/s/config.h"
#include "mongo/s/d_state.h"
#include "mongo/s/grid.h"
#include "mongo/s/shard_key_pattern.h"
#include "mongo/s/stale_exception.h"
#include "mongo/scripting/engine.h"
#include "mongo/stdx/mutex.h"
#include "mongo/util/log.h"
#include "mongo/util/scopeguard.h"
namespace mongo {
using boost::scoped_ptr;
using boost::shared_ptr;
using std::unique_ptr;
using std::endl;
using std::set;
using std::string;
using std::stringstream;
using std::vector;
namespace mr {
AtomicUInt32 Config::JOB_NUMBER;
JSFunction::JSFunction( const std::string& type , const BSONElement& e ) {
_type = type;
_code = e._asCode();
if ( e.type() == CodeWScope )
_wantedScope = e.codeWScopeObject();
}
void JSFunction::init( State * state ) {
_scope = state->scope();
verify( _scope );
_scope->init( &_wantedScope );
_func = _scope->createFunction( _code.c_str() );
uassert( 13598 , str::stream() << "couldn't compile code for: " << _type , _func );
// install in JS scope so that it can be called in JS mode
_scope->setFunction(_type.c_str(), _code.c_str());
}
void JSMapper::init( State * state ) {
_func.init( state );
_params = state->config().mapParams;
}
/**
* Applies the map function to an object, which should internally call emit()
*/
void JSMapper::map( const BSONObj& o ) {
Scope * s = _func.scope();
verify( s );
if (s->invoke(_func.func(), &_params, &o, 0, true))
uasserted(9014, str::stream() << "map invoke failed: " << s->getError());
}
/**
* Applies the finalize function to a tuple obj (key, val)
* Returns tuple obj {_id: key, value: newval}
*/
BSONObj JSFinalizer::finalize( const BSONObj& o ) {
Scope * s = _func.scope();
Scope::NoDBAccess no = s->disableDBAccess( "can't access db inside finalize" );
s->invokeSafe( _func.func() , &o, 0 );
// don't want to use o.objsize() to size b
// since there are many cases where the point of finalize
// is converting many fields to 1
BSONObjBuilder b;
b.append( o.firstElement() );
s->append( b , "value" , "__returnValue" );
return b.obj();
}
void JSReducer::init( State * state ) {
_func.init( state );
}
/**
* Reduces a list of tuple objects (key, value) to a single tuple {"0": key, "1": value}
*/
BSONObj JSReducer::reduce( const BSONList& tuples ) {
if (tuples.size() <= 1)
return tuples[0];
BSONObj key;
int endSizeEstimate = 16;
_reduce( tuples , key , endSizeEstimate );
BSONObjBuilder b(endSizeEstimate);
b.appendAs( key.firstElement() , "0" );
_func.scope()->append( b , "1" , "__returnValue" );
return b.obj();
}
/**
* Reduces a list of tuple object (key, value) to a single tuple {_id: key, value: val}
* Also applies a finalizer method if present.
*/
BSONObj JSReducer::finalReduce( const BSONList& tuples , Finalizer * finalizer ) {
BSONObj res;
BSONObj key;
if (tuples.size() == 1) {
// 1 obj, just use it
key = tuples[0];
BSONObjBuilder b(key.objsize());
BSONObjIterator it(key);
b.appendAs( it.next() , "_id" );
b.appendAs( it.next() , "value" );
res = b.obj();
}
else {
// need to reduce
int endSizeEstimate = 16;
_reduce( tuples , key , endSizeEstimate );
BSONObjBuilder b(endSizeEstimate);
b.appendAs( key.firstElement() , "_id" );
_func.scope()->append( b , "value" , "__returnValue" );
res = b.obj();
}
if ( finalizer ) {
res = finalizer->finalize( res );
}
return res;
}
/**
* actually applies a reduce, to a list of tuples (key, value).
* After the call, tuples will hold a single tuple {"0": key, "1": value}
*/
void JSReducer::_reduce( const BSONList& tuples , BSONObj& key , int& endSizeEstimate ) {
uassert( 10074 , "need values" , tuples.size() );
int sizeEstimate = ( tuples.size() * tuples.begin()->getField( "value" ).size() ) + 128;
// need to build the reduce args: ( key, [values] )
BSONObjBuilder reduceArgs( sizeEstimate );
boost::scoped_ptr valueBuilder;
unsigned n = 0;
for ( ; nlen() + ee.size() > BSONObjMaxUserSize ) {
verify( n > 1 ); // if not, inf. loop
break;
}
valueBuilder->append( ee );
}
verify(valueBuilder);
valueBuilder->done();
BSONObj args = reduceArgs.obj();
Scope * s = _func.scope();
s->invokeSafe(_func.func(), &args, 0);
++numReduces;
if ( s->type( "__returnValue" ) == Array ) {
uasserted( 10075 , "reduce -> multiple not supported yet");
return;
}
endSizeEstimate = key.objsize() + ( args.objsize() / tuples.size() );
if ( n == tuples.size() )
return;
// the input list was too large, add the rest of elmts to new tuples and reduce again
// note: would be better to use loop instead of recursion to avoid stack overflow
BSONList x;
for ( ; n < tuples.size(); n++ ) {
x.push_back( tuples[n] );
}
BSONObjBuilder temp( endSizeEstimate );
temp.append( key.firstElement() );
s->append( temp , "1" , "__returnValue" );
x.push_back( temp.obj() );
_reduce( x , key , endSizeEstimate );
}
Config::Config( const string& _dbname , const BSONObj& cmdObj )
{
dbname = _dbname;
ns = dbname + "." + cmdObj.firstElement().valuestrsafe();
verbose = cmdObj["verbose"].trueValue();
jsMode = cmdObj["jsMode"].trueValue();
splitInfo = 0;
if (cmdObj.hasField("splitInfo")) {
splitInfo = cmdObj["splitInfo"].Int();
}
jsMaxKeys = 500000;
reduceTriggerRatio = 10.0;
maxInMemSize = 500 * 1024;
uassert( 13602 , "outType is no longer a valid option" , cmdObj["outType"].eoo() );
outputOptions = parseOutputOptions(dbname, cmdObj);
shardedFirstPass = false;
if (cmdObj.hasField("shardedFirstPass") && cmdObj["shardedFirstPass"].trueValue()){
massert(16054,
"shardedFirstPass should only use replace outType",
outputOptions.outType == REPLACE);
shardedFirstPass = true;
}
if ( outputOptions.outType != INMEMORY ) { // setup temp collection name
tempNamespace = str::stream()
<< (outputOptions.outDB.empty() ? dbname : outputOptions.outDB)
<< ".tmp.mr."
<< cmdObj.firstElement().String()
<< "_"
<< JOB_NUMBER.fetchAndAdd(1);
incLong = tempNamespace + "_inc";
}
{
// scope and code
if ( cmdObj["scope"].type() == Object )
scopeSetup = cmdObj["scope"].embeddedObjectUserCheck();
mapper.reset( new JSMapper( cmdObj["map"] ) );
reducer.reset( new JSReducer( cmdObj["reduce"] ) );
if ( cmdObj["finalize"].type() && cmdObj["finalize"].trueValue() )
finalizer.reset( new JSFinalizer( cmdObj["finalize"] ) );
if ( cmdObj["mapparams"].type() == Array ) {
mapParams = cmdObj["mapparams"].embeddedObjectUserCheck();
}
}
{
// query options
BSONElement q = cmdObj["query"];
if ( q.type() == Object )
filter = q.embeddedObjectUserCheck();
else
uassert( 13608 , "query has to be blank or an Object" , ! q.trueValue() );
BSONElement s = cmdObj["sort"];
if ( s.type() == Object )
sort = s.embeddedObjectUserCheck();
else
uassert( 13609 , "sort has to be blank or an Object" , ! s.trueValue() );
if ( cmdObj["limit"].isNumber() )
limit = cmdObj["limit"].numberLong();
else
limit = 0;
}
}
/**
* Clean up the temporary and incremental collections
*/
void State::dropTempCollections() {
_db.dropCollection(_config.tempNamespace);
// Always forget about temporary namespaces, so we don't cache lots of them
ShardConnection::forgetNS( _config.tempNamespace );
if (_useIncremental) {
// We don't want to log the deletion of incLong as it isn't replicated. While
// harmless, this would lead to a scary looking warning on the secondaries.
bool shouldReplicateWrites = _txn->writesAreReplicated();
_txn->setReplicatedWrites(false);
ON_BLOCK_EXIT(&OperationContext::setReplicatedWrites, _txn, shouldReplicateWrites);
ScopedTransaction scopedXact(_txn, MODE_IX);
Lock::DBLock lk(_txn->lockState(),
nsToDatabaseSubstring(_config.incLong),
MODE_X);
if (Database* db = dbHolder().get(_txn, _config.incLong)) {
WriteUnitOfWork wunit(_txn);
db->dropCollection(_txn, _config.incLong);
wunit.commit();
}
ShardConnection::forgetNS( _config.incLong );
}
}
/**
* Create temporary collection, set up indexes
*/
void State::prepTempCollection() {
if ( ! _onDisk )
return;
dropTempCollections();
if (_useIncremental) {
// Create the inc collection and make sure we have index on "0" key.
// Intentionally not replicating the inc collection to secondaries.
bool shouldReplicateWrites = _txn->writesAreReplicated();
_txn->setReplicatedWrites(false);
ON_BLOCK_EXIT(&OperationContext::setReplicatedWrites, _txn, shouldReplicateWrites);
OldClientWriteContext incCtx(_txn, _config.incLong);
WriteUnitOfWork wuow(_txn);
Collection* incColl = incCtx.getCollection();
invariant(!incColl);
CollectionOptions options;
options.setNoIdIndex();
options.temp = true;
incColl = incCtx.db()->createCollection(_txn, _config.incLong, options);
invariant(incColl);
BSONObj indexSpec = BSON( "key" << BSON( "0" << 1 ) << "ns" << _config.incLong
<< "name" << "_temp_0" );
Status status = incColl->getIndexCatalog()->createIndexOnEmptyCollection(_txn,
indexSpec);
if ( !status.isOK() ) {
uasserted( 17305 , str::stream() << "createIndex failed for mr incLong ns: " <<
_config.incLong << " err: " << status.code() );
}
wuow.commit();
}
CollectionOptions finalOptions;
vector indexesToInsert;
{
// copy indexes and collection options into temporary storage
OldClientWriteContext finalCtx(_txn, _config.outputOptions.finalNamespace);
Collection* const finalColl = finalCtx.getCollection();
if ( finalColl ) {
finalOptions = finalColl->getCatalogEntry()->getCollectionOptions(_txn);
IndexCatalog::IndexIterator ii =
finalColl->getIndexCatalog()->getIndexIterator( _txn, true );
// Iterate over finalColl's indexes.
while ( ii.more() ) {
IndexDescriptor* currIndex = ii.next();
BSONObjBuilder b;
b.append( "ns" , _config.tempNamespace );
// Copy over contents of the index descriptor's infoObj.
BSONObjIterator j( currIndex->infoObj() );
while ( j.more() ) {
BSONElement e = j.next();
if ( str::equals( e.fieldName() , "_id" ) ||
str::equals( e.fieldName() , "ns" ) )
continue;
b.append( e );
}
indexesToInsert.push_back( b.obj() );
}
}
}
{
// create temp collection and insert the indexes from temporary storage
OldClientWriteContext tempCtx(_txn, _config.tempNamespace);
WriteUnitOfWork wuow(_txn);
NamespaceString tempNss(_config.tempNamespace);
uassert(ErrorCodes::NotMaster, "no longer master",
repl::getGlobalReplicationCoordinator()->canAcceptWritesFor(tempNss));
Collection* tempColl = tempCtx.getCollection();
invariant(!tempColl);
CollectionOptions options = finalOptions;
options.temp = true;
tempColl = tempCtx.db()->createCollection(_txn, _config.tempNamespace, options);
for ( vector::iterator it = indexesToInsert.begin();
it != indexesToInsert.end(); ++it ) {
Status status =
tempColl->getIndexCatalog()->createIndexOnEmptyCollection(_txn, *it);
if (!status.isOK()) {
if (status.code() == ErrorCodes::IndexAlreadyExists) {
continue;
}
uassertStatusOK(status);
}
// Log the createIndex operation.
string logNs = nsToDatabase( _config.tempNamespace ) + ".system.indexes";
getGlobalServiceContext()->getOpObserver()->onCreateIndex(_txn, logNs, *it);
}
wuow.commit();
}
}
/**
* For inline mode, appends results to output object.
* Makes sure (key, value) tuple is formatted as {_id: key, value: val}
*/
void State::appendResults( BSONObjBuilder& final ) {
if ( _onDisk ) {
if (!_config.outputOptions.outDB.empty()) {
BSONObjBuilder loc;
if ( !_config.outputOptions.outDB.empty())
loc.append( "db" , _config.outputOptions.outDB );
if ( !_config.outputOptions.collectionName.empty() )
loc.append( "collection" , _config.outputOptions.collectionName );
final.append("result", loc.obj());
}
else {
if ( !_config.outputOptions.collectionName.empty() )
final.append( "result" , _config.outputOptions.collectionName );
}
if ( _config.splitInfo > 0 ) {
// add split points, used for shard
BSONObj res;
BSONObj idKey = BSON( "_id" << 1 );
if (!_db.runCommand("admin",
BSON("splitVector" << _config.outputOptions.finalNamespace
<< "keyPattern" << idKey
<< "maxChunkSizeBytes" << _config.splitInfo),
res)) {
uasserted( 15921 , str::stream() << "splitVector failed: " << res );
}
if ( res.hasField( "splitKeys" ) )
final.append( res.getField( "splitKeys" ) );
}
return;
}
if (_jsMode) {
ScriptingFunction getResult = _scope->createFunction(
"var map = _mrMap;"
"var result = [];"
"for (key in map) {"
" result.push({_id: key, value: map[key]});"
"}"
"return result;");
_scope->invoke(getResult, 0, 0, 0, false);
BSONObj obj = _scope->getObject("__returnValue");
final.append("results", BSONArray(obj));
return;
}
uassert( 13604 , "too much data for in memory map/reduce" , _size < BSONObjMaxUserSize );
BSONArrayBuilder b( (int)(_size * 1.2) ); // _size is data size, doesn't count overhead and keys
for ( InMemory::iterator i=_temp->begin(); i!=_temp->end(); ++i ) {
BSONObj key = i->first;
BSONList& all = i->second;
verify( all.size() == 1 );
BSONObjIterator vi( all[0] );
vi.next();
BSONObjBuilder temp( b.subobjStart() );
temp.appendAs( key.firstElement() , "_id" );
temp.appendAs( vi.next() , "value" );
temp.done();
}
BSONArray res = b.arr();
final.append( "results" , res );
}
/**
* Does post processing on output collection.
* This may involve replacing, merging or reducing.
*/
long long State::postProcessCollection(
OperationContext* txn, CurOp* op, ProgressMeterHolder& pm) {
if ( _onDisk == false || _config.outputOptions.outType == Config::INMEMORY )
return numInMemKeys();
if (_config.outputOptions.outNonAtomic)
return postProcessCollectionNonAtomic(txn, op, pm);
invariant( !txn->lockState()->isLocked() );
ScopedTransaction transaction(txn, MODE_X);
Lock::GlobalWrite lock(txn->lockState()); // TODO(erh): this is how it was, but seems it doesn't need to be global
return postProcessCollectionNonAtomic(txn, op, pm);
}
//
// For SERVER-6116 - can't handle version errors in count currently
//
/**
* Runs count and disables version errors.
*
* TODO: make count work with versioning
*/
unsigned long long _safeCount( Client* client,
// Can't be const b/c count isn't
/* const */ DBDirectClient& db,
const string &ns,
const BSONObj& query = BSONObj(),
int options = 0,
int limit = 0,
int skip = 0 )
{
ShardForceVersionOkModeBlock ignoreVersion(client); // ignore versioning here
return db.count( ns, query, options, limit, skip );
}
//
// End SERVER-6116
//
long long State::postProcessCollectionNonAtomic(
OperationContext* txn, CurOp* op, ProgressMeterHolder& pm) {
auto client = txn->getClient();
if ( _config.outputOptions.finalNamespace == _config.tempNamespace )
return _safeCount( client, _db, _config.outputOptions.finalNamespace );
if (_config.outputOptions.outType == Config::REPLACE ||
_safeCount(client, _db, _config.outputOptions.finalNamespace) == 0) {
ScopedTransaction transaction(txn, MODE_X);
Lock::GlobalWrite lock(txn->lockState()); // TODO(erh): why global???
// replace: just rename from temp to final collection name, dropping previous collection
_db.dropCollection( _config.outputOptions.finalNamespace );
BSONObj info;
if ( ! _db.runCommand( "admin"
, BSON( "renameCollection" << _config.tempNamespace <<
"to" << _config.outputOptions.finalNamespace <<
"stayTemp" << _config.shardedFirstPass )
, info ) ) {
uasserted( 10076 , str::stream() << "rename failed: " << info );
}
_db.dropCollection( _config.tempNamespace );
}
else if ( _config.outputOptions.outType == Config::MERGE ) {
// merge: upsert new docs into old collection
{
const auto count = _safeCount(client, _db, _config.tempNamespace, BSONObj());
stdx::lock_guard lk(*txn->getClient());
op->setMessage_inlock("m/r: merge post processing",
"M/R Merge Post Processing Progress",
count);
}
unique_ptr cursor = _db.query(_config.tempNamespace , BSONObj());
while (cursor->more()) {
ScopedTransaction scopedXact(_txn, MODE_IX);
Lock::DBLock lock(_txn->lockState(),
nsToDatabaseSubstring(_config.outputOptions.finalNamespace),
MODE_X);
BSONObj o = cursor->nextSafe();
Helpers::upsert( _txn, _config.outputOptions.finalNamespace , o );
pm.hit();
}
_db.dropCollection( _config.tempNamespace );
pm.finished();
}
else if ( _config.outputOptions.outType == Config::REDUCE ) {
// reduce: apply reduce op on new result and existing one
BSONList values;
{
const auto count = _safeCount(client, _db, _config.tempNamespace, BSONObj());
stdx::lock_guard lk(*txn->getClient());
op->setMessage_inlock("m/r: reduce post processing",
"M/R Reduce Post Processing Progress",
count);
}
unique_ptr cursor = _db.query( _config.tempNamespace , BSONObj() );
while ( cursor->more() ) {
ScopedTransaction transaction(txn, MODE_X);
Lock::GlobalWrite lock(txn->lockState()); // TODO(erh) why global?
BSONObj temp = cursor->nextSafe();
BSONObj old;
bool found;
{
const std::string& finalNamespace = _config.outputOptions.finalNamespace;
OldClientContext tx(txn, finalNamespace);
Collection* coll = getCollectionOrUassert(tx.db(), finalNamespace);
found = Helpers::findOne(_txn,
coll,
temp["_id"].wrap(),
old,
true);
}
if ( found ) {
// need to reduce
values.clear();
values.push_back( temp );
values.push_back( old );
Helpers::upsert(_txn,
_config.outputOptions.finalNamespace,
_config.reducer->finalReduce(values,
_config.finalizer.get()));
}
else {
Helpers::upsert( _txn, _config.outputOptions.finalNamespace , temp );
}
pm.hit();
}
pm.finished();
}
return _safeCount( txn->getClient(), _db, _config.outputOptions.finalNamespace );
}
/**
* Insert doc in collection. This should be replicated.
*/
void State::insert( const string& ns , const BSONObj& o ) {
verify( _onDisk );
OldClientWriteContext ctx(_txn, ns );
WriteUnitOfWork wuow(_txn);
NamespaceString nss(ns);
uassert(ErrorCodes::NotMaster, "no longer master",
repl::getGlobalReplicationCoordinator()->canAcceptWritesFor(nss));
Collection* coll = getCollectionOrUassert(ctx.db(), ns);
BSONObjBuilder b;
if ( !o.hasField( "_id" ) ) {
b.appendOID( "_id", NULL, true );
}
b.appendElements(o);
BSONObj bo = b.obj();
uassertStatusOK( coll->insertDocument( _txn, bo, true ).getStatus() );
wuow.commit();
}
/**
* Insert doc into the inc collection. This should not be replicated.
*/
void State::_insertToInc( BSONObj& o ) {
verify( _onDisk );
OldClientWriteContext ctx(_txn, _config.incLong );
WriteUnitOfWork wuow(_txn);
Collection* coll = getCollectionOrUassert(ctx.db(), _config.incLong);
bool shouldReplicateWrites = _txn->writesAreReplicated();
_txn->setReplicatedWrites(false);
ON_BLOCK_EXIT(&OperationContext::setReplicatedWrites, _txn, shouldReplicateWrites);
uassertStatusOK(coll->insertDocument(_txn, o, true, false).getStatus());
wuow.commit();
}
State::State(OperationContext* txn, const Config& c) :
_config(c),
_db(txn),
_useIncremental(true),
_txn(txn),
_size(0),
_dupCount(0),
_numEmits(0) {
_temp.reset( new InMemory() );
_onDisk = _config.outputOptions.outType != Config::INMEMORY;
}
bool State::sourceExists() {
return _db.exists( _config.ns );
}
long long State::incomingDocuments() {
return _safeCount( _txn->getClient(), _db, _config.ns , _config.filter , QueryOption_SlaveOk , (unsigned) _config.limit );
}
State::~State() {
if ( _onDisk ) {
try {
dropTempCollections();
}
catch ( std::exception& e ) {
error() << "couldn't cleanup after map reduce: " << e.what() << endl;
}
}
if (_scope && !_scope->isKillPending() && _scope->getError().empty()) {
// cleanup js objects
try {
ScriptingFunction cleanup =
_scope->createFunction("delete _emitCt; delete _keyCt; delete _mrMap;");
_scope->invoke(cleanup, 0, 0, 0, true);
}
catch (const DBException &) {
// not important because properties will be reset if scope is reused
LOG(1) << "MapReduce terminated during state destruction" << endl;
}
}
}
/**
* Initialize the mapreduce operation, creating the inc collection
*/
void State::init() {
// setup js
const string userToken = AuthorizationSession::get(ClientBasic::getCurrent())
->getAuthenticatedUserNamesToken();
_scope.reset(globalScriptEngine->getPooledScope(
_txn, _config.dbname, "mapreduce" + userToken).release());
if ( ! _config.scopeSetup.isEmpty() )
_scope->init( &_config.scopeSetup );
_config.mapper->init( this );
_config.reducer->init( this );
if ( _config.finalizer )
_config.finalizer->init( this );
_scope->setBoolean("_doFinal", _config.finalizer.get() != 0);
switchMode(_config.jsMode); // set up js-mode based on Config
// global JS map/reduce hashmap
// we use a standard JS object which means keys are only simple types
// we could also add a real hashmap from a library and object comparison methods
// for increased performance, we may want to look at v8 Harmony Map support
// _scope->setObject("_mrMap", BSONObj(), false);
ScriptingFunction init = _scope->createFunction(
"_emitCt = 0;"
"_keyCt = 0;"
"_dupCt = 0;"
"_redCt = 0;"
"if (typeof(_mrMap) === 'undefined') {"
" _mrMap = {};"
"}");
_scope->invoke(init, 0, 0, 0, true);
// js function to run reduce on all keys
// redfunc = _scope->createFunction("for (var key in hashmap) { print('Key is ' + key); list = hashmap[key]; ret = reduce(key, list); print('Value is ' + ret); };");
_reduceAll = _scope->createFunction(
"var map = _mrMap;"
"var list, ret;"
"for (var key in map) {"
" list = map[key];"
" if (list.length != 1) {"
" ret = _reduce(key, list);"
" map[key] = [ret];"
" ++_redCt;"
" }"
"}"
"_dupCt = 0;");
massert(16717, "error initializing JavaScript reduceAll function",
_reduceAll != 0);
_reduceAndEmit = _scope->createFunction(
"var map = _mrMap;"
"var list, ret;"
"for (var key in map) {"
" list = map[key];"
" if (list.length == 1)"
" ret = list[0];"
" else {"
" ret = _reduce(key, list);"
" ++_redCt;"
" }"
" emit(key, ret);"
"}"
"delete _mrMap;");
massert(16718, "error initializing JavaScript reduce/emit function",
_reduceAndEmit != 0);
_reduceAndFinalize = _scope->createFunction(
"var map = _mrMap;"
"var list, ret;"
"for (var key in map) {"
" list = map[key];"
" if (list.length == 1) {"
" if (!_doFinal) { continue; }"
" ret = list[0];"
" }"
" else {"
" ret = _reduce(key, list);"
" ++_redCt;"
" }"
" if (_doFinal)"
" ret = _finalize(key, ret);"
" map[key] = ret;"
"}");
massert(16719, "error creating JavaScript reduce/finalize function",
_reduceAndFinalize != 0);
_reduceAndFinalizeAndInsert = _scope->createFunction(
"var map = _mrMap;"
"var list, ret;"
"for (var key in map) {"
" list = map[key];"
" if (list.length == 1)"
" ret = list[0];"
" else {"
" ret = _reduce(key, list);"
" ++_redCt;"
" }"
" if (_doFinal)"
" ret = _finalize(key, ret);"
" _nativeToTemp({_id: key, value: ret});"
"}");
massert(16720, "error initializing JavaScript functions",
_reduceAndFinalizeAndInsert != 0);
}
void State::switchMode(bool jsMode) {
_jsMode = jsMode;
if (jsMode) {
// emit function that stays in JS
_scope->setFunction("emit",
"function(key, value) {"
" if (typeof(key) === 'object') {"
" _bailFromJS(key, value);"
" return;"
" }"
" ++_emitCt;"
" var map = _mrMap;"
" var list = map[key];"
" if (!list) {"
" ++_keyCt;"
" list = [];"
" map[key] = list;"
" }"
" else"
" ++_dupCt;"
" list.push(value);"
"}");
_scope->injectNative("_bailFromJS", _bailFromJS, this);
}
else {
// emit now populates C++ map
_scope->injectNative( "emit" , fast_emit, this );
}
}
void State::bailFromJS() {
LOG(1) << "M/R: Switching from JS mode to mixed mode" << endl;
// reduce and reemit into c++
switchMode(false);
_scope->invoke(_reduceAndEmit, 0, 0, 0, true);
// need to get the real number emitted so far
_numEmits = _scope->getNumberInt("_emitCt");
_config.reducer->numReduces = _scope->getNumberInt("_redCt");
}
Collection* State::getCollectionOrUassert(Database* db, StringData ns) {
Collection* out = db ? db->getCollection(ns) : NULL;
uassert(18697, "Collection unexpectedly disappeared: " + ns.toString(),
out);
return out;
}
/**
* Applies last reduce and finalize on a list of tuples (key, val)
* Inserts single result {_id: key, value: val} into temp collection
*/
void State::finalReduce( BSONList& values ) {
if ( !_onDisk || values.size() == 0 )
return;
BSONObj res = _config.reducer->finalReduce( values , _config.finalizer.get() );
insert( _config.tempNamespace , res );
}
BSONObj _nativeToTemp( const BSONObj& args, void* data ) {
State* state = (State*) data;
BSONObjIterator it(args);
state->insert(state->_config.tempNamespace, it.next().Obj());
return BSONObj();
}
// BSONObj _nativeToInc( const BSONObj& args, void* data ) {
// State* state = (State*) data;
// BSONObjIterator it(args);
// const BSONObj& obj = it.next().Obj();
// state->_insertToInc(const_cast(obj));
// return BSONObj();
// }
/**
* Applies last reduce and finalize.
* After calling this method, the temp collection will be completed.
* If inline, the results will be in the in memory map
*/
void State::finalReduce(CurOp * op , ProgressMeterHolder& pm ) {
if (_jsMode) {
// apply the reduce within JS
if (_onDisk) {
_scope->injectNative("_nativeToTemp", _nativeToTemp, this);
_scope->invoke(_reduceAndFinalizeAndInsert, 0, 0, 0, true);
return;
}
else {
_scope->invoke(_reduceAndFinalize, 0, 0, 0, true);
return;
}
}
if ( ! _onDisk ) {
// all data has already been reduced, just finalize
if ( _config.finalizer ) {
long size = 0;
for ( InMemory::iterator i=_temp->begin(); i!=_temp->end(); ++i ) {
BSONObj key = i->first;
BSONList& all = i->second;
verify( all.size() == 1 );
BSONObj res = _config.finalizer->finalize( all[0] );
all.clear();
all.push_back( res );
size += res.objsize();
}
_size = size;
}
return;
}
// use index on "0" to pull sorted data
verify( _temp->size() == 0 );
BSONObj sortKey = BSON( "0" << 1 );
{
OldClientWriteContext incCtx(_txn, _config.incLong );
WriteUnitOfWork wuow(_txn);
Collection* incColl = getCollectionOrUassert(incCtx.db(), _config.incLong );
bool foundIndex = false;
IndexCatalog::IndexIterator ii =
incColl->getIndexCatalog()->getIndexIterator( _txn, true );
// Iterate over incColl's indexes.
while ( ii.more() ) {
IndexDescriptor* currIndex = ii.next();
BSONObj x = currIndex->infoObj();
if ( sortKey.woCompare( x["key"].embeddedObject() ) == 0 ) {
foundIndex = true;
break;
}
}
verify( foundIndex );
wuow.commit();
}
scoped_ptr ctx(new AutoGetCollectionForRead(_txn, _config.incLong));
BSONObj prev;
BSONList all;
{
const auto count = _db.count(_config.incLong, BSONObj(), QueryOption_SlaveOk);
stdx::lock_guard lk(*_txn->getClient());
verify(pm == op->setMessage_inlock("m/r: (3/3) final reduce to collection",
"M/R: (3/3) Final Reduce Progress",
count));
}
const NamespaceString nss(_config.incLong);
const WhereCallbackReal whereCallback(_txn, nss.db());
CanonicalQuery* cqRaw;
verify(CanonicalQuery::canonicalize(_config.incLong,
BSONObj(),
sortKey,
BSONObj(),
&cqRaw,
whereCallback).isOK());
std::unique_ptr cq(cqRaw);
Collection* coll = getCollectionOrUassert(ctx->getDb(), _config.incLong);
invariant(coll);
PlanExecutor* rawExec;
verify(getExecutor(_txn,
coll,
cq.release(),
PlanExecutor::YIELD_AUTO,
&rawExec,
QueryPlannerParams::NO_TABLE_SCAN).isOK());
scoped_ptr exec(rawExec);
// iterate over all sorted objects
BSONObj o;
PlanExecutor::ExecState state;
while (PlanExecutor::ADVANCED == (state = exec->getNext(&o, NULL))) {
o = o.getOwned(); // we will be accessing outside of the lock
pm.hit();
if ( o.woSortOrder( prev , sortKey ) == 0 ) {
// object is same as previous, add to array
all.push_back( o );
if ( pm->hits() % 100 == 0 ) {
_txn->checkForInterrupt();
}
continue;
}
exec->saveState();
ctx.reset();
// reduce a finalize array
finalReduce( all );
ctx.reset(new AutoGetCollectionForRead(_txn, _config.incLong));
all.clear();
prev = o;
all.push_back( o );
if (!exec->restoreState(_txn)) {
break;
}
_txn->checkForInterrupt();
}
ctx.reset();
// reduce and finalize last array
finalReduce( all );
ctx.reset(new AutoGetCollectionForRead(_txn, _config.incLong));
pm.finished();
}
/**
* Attempts to reduce objects in the memory map.
* A new memory map will be created to hold the results.
* If applicable, objects with unique key may be dumped to inc collection.
* Input and output objects are both {"0": key, "1": val}
*/
void State::reduceInMemory() {
if (_jsMode) {
// in js mode the reduce is applied when writing to collection
return;
}
unique_ptr n( new InMemory() ); // for new data
long nSize = 0;
_dupCount = 0;
for ( InMemory::iterator i=_temp->begin(); i!=_temp->end(); ++i ) {
BSONList& all = i->second;
if ( all.size() == 1 ) {
// only 1 value for this key
if ( _onDisk ) {
// this key has low cardinality, so just write to collection
_insertToInc( *(all.begin()) );
}
else {
// add to new map
nSize += _add(n.get(), all[0]);
}
}
else if ( all.size() > 1 ) {
// several values, reduce and add to map
BSONObj res = _config.reducer->reduce( all );
nSize += _add(n.get(), res);
}
}
// swap maps
_temp.reset( n.release() );
_size = nSize;
}
/**
* Dumps the entire in memory map to the inc collection.
*/
void State::dumpToInc() {
if ( ! _onDisk )
return;
for ( InMemory::iterator i=_temp->begin(); i!=_temp->end(); i++ ) {
BSONList& all = i->second;
if ( all.size() < 1 )
continue;
for ( BSONList::iterator j=all.begin(); j!=all.end(); j++ )
_insertToInc( *j );
}
_temp->clear();
_size = 0;
}
/**
* Adds object to in memory map
*/
void State::emit( const BSONObj& a ) {
_numEmits++;
_size += _add(_temp.get(), a);
}
int State::_add(InMemory* im, const BSONObj& a) {
BSONList& all = (*im)[a];
all.push_back( a );
if (all.size() > 1) {
++_dupCount;
}
return a.objsize() + 16;
}
void State::reduceAndSpillInMemoryStateIfNeeded() {
// Make sure no DB locks are held, because this method manages its own locking and
// write units of work.
invariant(!_txn->lockState()->isLocked());
if (_jsMode) {
// try to reduce if it is beneficial
int dupCt = _scope->getNumberInt("_dupCt");
int keyCt = _scope->getNumberInt("_keyCt");
if (keyCt > _config.jsMaxKeys) {
// too many keys for JS, switch to mixed
_bailFromJS(BSONObj(), this);
// then fall through to check map size
}
else if (dupCt > (keyCt * _config.reduceTriggerRatio)) {
// reduce now to lower mem usage
Timer t;
_scope->invoke(_reduceAll, 0, 0, 0, true);
LOG(3) << " MR - did reduceAll: keys=" << keyCt << " dups=" << dupCt
<< " newKeys=" << _scope->getNumberInt("_keyCt") << " time="
<< t.millis() << "ms" << endl;
return;
}
}
if (_jsMode)
return;
if (_size > _config.maxInMemSize || _dupCount > (_temp->size() * _config.reduceTriggerRatio)) {
// attempt to reduce in memory map, if memory is too high or we have many duplicates
long oldSize = _size;
Timer t;
reduceInMemory();
LOG(3) << " MR - did reduceInMemory: size=" << oldSize << " dups=" << _dupCount
<< " newSize=" << _size << " time=" << t.millis() << "ms" << endl;
// if size is still high, or values are not reducing well, dump
if ( _onDisk && (_size > _config.maxInMemSize || _size > oldSize / 2) ) {
dumpToInc();
LOG(3) << " MR - dumping to db" << endl;
}
}
}
/**
* emit that will be called by js function
*/
BSONObj fast_emit( const BSONObj& args, void* data ) {
uassert( 10077 , "fast_emit takes 2 args" , args.nFields() == 2 );
uassert( 13069 , "an emit can't be more than half max bson size" , args.objsize() < ( BSONObjMaxUserSize / 2 ) );
State* state = (State*) data;
if ( args.firstElement().type() == Undefined ) {
BSONObjBuilder b( args.objsize() );
b.appendNull( "" );
BSONObjIterator i( args );
i.next();
b.append( i.next() );
state->emit( b.obj() );
}
else {
state->emit( args );
}
return BSONObj();
}
/**
* function is called when we realize we cant use js mode for m/r on the 1st key
*/
BSONObj _bailFromJS( const BSONObj& args, void* data ) {
State* state = (State*) data;
state->bailFromJS();
// emit this particular key if there is one
if (!args.isEmpty()) {
fast_emit(args, data);
}
return BSONObj();
}
/**
* This class represents a map/reduce command executed on a single server
*/
class MapReduceCommand : public Command {
public:
MapReduceCommand() : Command("mapReduce", false, "mapreduce") {}
virtual bool slaveOk() const {
return repl::getGlobalReplicationCoordinator()->getReplicationMode() !=
repl::ReplicationCoordinator::modeReplSet;
}
virtual bool slaveOverrideOk() const { return true; }
virtual void help( stringstream &help ) const {
help << "Run a map/reduce operation on the server.\n";
help << "Note this is used for aggregation, not querying, in MongoDB.\n";
help << "http://dochub.mongodb.org/core/mapreduce";
}
virtual bool isWriteCommandForConfigServer() const { return false; }
virtual void addRequiredPrivileges(const std::string& dbname,
const BSONObj& cmdObj,
std::vector* out) {
addPrivilegesRequiredForMapReduce(this, dbname, cmdObj, out);
}
bool run(OperationContext* txn,
const string& dbname,
BSONObj& cmd,
int,
string& errmsg,
BSONObjBuilder& result) {
Timer t;
boost::optional maybeDisableValidation;
if (shouldBypassDocumentValidationForCommand(cmd))
maybeDisableValidation.emplace(txn);
auto client = txn->getClient();
if (client->isInDirectClient()) {
return appendCommandStatus(result,
Status(ErrorCodes::IllegalOperation,
"Cannot run mapReduce command from eval()"));
}
CurOp* op = CurOp::get(txn);
Config config( dbname , cmd );
LOG(1) << "mr ns: " << config.ns << endl;
uassert( 16149 , "cannot run map reduce without the js engine", globalScriptEngine );
CollectionMetadataPtr collMetadata;
// Prevent sharding state from changing during the MR.
unique_ptr rangePreserver;
{
AutoGetCollectionForRead ctx(txn, config.ns);
Collection* collection = ctx.getCollection();
if (collection) {
rangePreserver.reset(new RangePreserver(collection));
}
// Get metadata before we check our version, to make sure it doesn't increment
// in the meantime. Need to do this in the same lock scope as the block.
if (shardingState.needCollectionMetadata(client, config.ns)) {
collMetadata = shardingState.getCollectionMetadata( config.ns );
}
}
bool shouldHaveData = false;
BSONObjBuilder countsBuilder;
BSONObjBuilder timingBuilder;
State state( txn, config );
if ( ! state.sourceExists() ) {
errmsg = "ns doesn't exist";
return false;
}
if (state.isOnDisk()) {
// this means that it will be doing a write operation, make sure we are on Master
// ideally this check should be in slaveOk(), but at that point config is not known
NamespaceString nss(config.ns);
if (!repl::getGlobalReplicationCoordinator()->canAcceptWritesFor(nss)) {
errmsg = "not master";
return false;
}
}
try {
state.init();
state.prepTempCollection();
ON_BLOCK_EXIT_OBJ(state, &State::dropTempCollections);
int progressTotal = 0;
bool showTotal = true;
if ( state.config().filter.isEmpty() ) {
progressTotal = state.incomingDocuments();
}
else {
showTotal = false;
// Set an arbitrary total > 0 so the meter will be activated.
progressTotal = 1;
}
stdx::unique_lock lk(*txn->getClient());
ProgressMeter& progress( op->setMessage_inlock("m/r: (1/3) emit phase",
"M/R: (1/3) Emit Progress",
progressTotal ));
lk.unlock();
progress.showTotal(showTotal);
ProgressMeterHolder pm(progress);
// See cast on next line to 32 bit unsigned
wassert(config.limit < 0x4000000);
long long mapTime = 0;
long long reduceTime = 0;
long long numInputs = 0;
{
// We've got a cursor preventing migrations off, now re-establish our
// useful cursor.
const NamespaceString nss(config.ns);
// Need lock and context to use it
scoped_ptr scopedXact(
new ScopedTransaction(txn, MODE_IS));
scoped_ptr scopedAutoDb(new AutoGetDb(txn, nss.db(), MODE_S));
const WhereCallbackReal whereCallback(txn, nss.db());
CanonicalQuery* cqRaw;
if (!CanonicalQuery::canonicalize(config.ns,
config.filter,
config.sort,
BSONObj(),
&cqRaw,
whereCallback).isOK()) {
uasserted(17238, "Can't canonicalize query " + config.filter.toString());
return 0;
}
std::unique_ptr cq(cqRaw);
Database* db = scopedAutoDb->getDb();
Collection* coll = state.getCollectionOrUassert(db, config.ns);
invariant(coll);
PlanExecutor* rawExec;
if (!getExecutor(txn,
coll,
cq.release(),
PlanExecutor::YIELD_AUTO,
&rawExec).isOK()) {
uasserted(17239, "Can't get executor for query "
+ config.filter.toString());
return 0;
}
scoped_ptr exec(rawExec);
Timer mt;
// go through each doc
BSONObj o;
while (PlanExecutor::ADVANCED == exec->getNext(&o, NULL)) {
// check to see if this is a new object we don't own yet
// because of a chunk migration
if ( collMetadata ) {
ShardKeyPattern kp( collMetadata->getKeyPattern() );
if (!collMetadata->keyBelongsToMe(kp.extractShardKeyFromDoc(o))) {
continue;
}
}
// do map
if ( config.verbose ) mt.reset();
config.mapper->map( o );
if ( config.verbose ) mapTime += mt.micros();
// Check if the state accumulated so far needs to be written to a
// collection. This may yield the DB lock temporarily and then
// acquire it again.
//
numInputs++;
if (numInputs % 100 == 0) {
Timer t;
// TODO: As an optimization, we might want to do the save/restore
// state and yield inside the reduceAndSpillInMemoryState method, so
// it only happens if necessary.
exec->saveState();
scopedAutoDb.reset();
scopedXact.reset();
state.reduceAndSpillInMemoryStateIfNeeded();
scopedXact.reset(new ScopedTransaction(txn, MODE_IS));
scopedAutoDb.reset(new AutoGetDb(txn, nss.db(), MODE_S));
exec->restoreState(txn);
// Need to reload the database, in case it was dropped after we
// released the lock
db = scopedAutoDb->getDb();
if (db == NULL) {
// Database was deleted after we freed the lock
StringBuilder sb;
sb << "Database "
<< nss.db()
<< " was deleted in the middle of the reduce job.";
uasserted(28523, sb.str());
}
reduceTime += t.micros();
txn->checkForInterrupt();
}
pm.hit();
if (config.limit && numInputs >= config.limit)
break;
}
}
pm.finished();
txn->checkForInterrupt();
// update counters
countsBuilder.appendNumber("input", numInputs);
countsBuilder.appendNumber( "emit" , state.numEmits() );
if ( state.numEmits() )
shouldHaveData = true;
timingBuilder.appendNumber( "mapTime" , mapTime / 1000 );
timingBuilder.append( "emitLoop" , t.millis() );
{
stdx::lock_guard lk(*txn->getClient());
op->setMessage_inlock("m/r: (2/3) final reduce in memory",
"M/R: (2/3) Final In-Memory Reduce Progress");
}
Timer rt;
// do reduce in memory
// this will be the last reduce needed for inline mode
state.reduceInMemory();
// if not inline: dump the in memory map to inc collection, all data is on disk
state.dumpToInc();
// final reduce
state.finalReduce(op , pm );
reduceTime += rt.micros();
countsBuilder.appendNumber( "reduce" , state.numReduces() );
timingBuilder.appendNumber("reduceTime", reduceTime / 1000);
timingBuilder.append( "mode" , state.jsMode() ? "js" : "mixed" );
long long finalCount = state.postProcessCollection(txn, op, pm);
state.appendResults( result );
timingBuilder.appendNumber( "total" , t.millis() );
result.appendNumber( "timeMillis" , t.millis() );
countsBuilder.appendNumber( "output" , finalCount );
if ( config.verbose ) result.append( "timing" , timingBuilder.obj() );
result.append( "counts" , countsBuilder.obj() );
if ( finalCount == 0 && shouldHaveData ) {
result.append( "cmd" , cmd );
errmsg = "there were emits but no data!";
return false;
}
}
catch( SendStaleConfigException& e ){
log() << "mr detected stale config, should retry" << causedBy(e) << endl;
throw e;
}
// TODO: The error handling code for queries is v. fragile,
// *requires* rethrow AssertionExceptions - should probably fix.
catch ( AssertionException& e ){
log() << "mr failed, removing collection" << causedBy(e) << endl;
throw e;
}
catch ( std::exception& e ){
log() << "mr failed, removing collection" << causedBy(e) << endl;
throw e;
}
catch ( ... ) {
log() << "mr failed for unknown reason, removing collection" << endl;
throw;
}
return true;
}
} mapReduceCommand;
/**
* This class represents a map/reduce command executed on the output server of a sharded env
*/
class MapReduceFinishCommand : public Command {
public:
void help(stringstream& h) const { h << "internal"; }
MapReduceFinishCommand() : Command( "mapreduce.shardedfinish" ) {}
virtual bool slaveOk() const {
return repl::getGlobalReplicationCoordinator()->getReplicationMode() !=
repl::ReplicationCoordinator::modeReplSet;
}
virtual bool slaveOverrideOk() const { return true; }
virtual bool isWriteCommandForConfigServer() const { return false; }
virtual void addRequiredPrivileges(const std::string& dbname,
const BSONObj& cmdObj,
std::vector* out) {
ActionSet actions;
actions.addAction(ActionType::internal);
out->push_back(Privilege(ResourcePattern::forClusterResource(), actions));
}
bool run(OperationContext* txn,
const string& dbname,
BSONObj& cmdObj,
int,
string& errmsg,
BSONObjBuilder& result) {
boost::optional maybeDisableValidation;
if (shouldBypassDocumentValidationForCommand(cmdObj))
maybeDisableValidation.emplace(txn);
ShardedConnectionInfo::addHook();
// legacy name
string shardedOutputCollection = cmdObj["shardedOutputCollection"].valuestrsafe();
verify( shardedOutputCollection.size() > 0 );
string inputNS;
if ( cmdObj["inputDB"].type() == String ) {
inputNS = cmdObj["inputDB"].String() + "." + shardedOutputCollection;
}
else {
inputNS = dbname + "." + shardedOutputCollection;
}
CurOp * op = CurOp::get(txn);
Config config( dbname , cmdObj.firstElement().embeddedObjectUserCheck() );
State state(txn, config);
state.init();
// no need for incremental collection because records are already sorted
state._useIncremental = false;
config.incLong = config.tempNamespace;
BSONObj shardCounts = cmdObj["shardCounts"].embeddedObjectUserCheck();
BSONObj counts = cmdObj["counts"].embeddedObjectUserCheck();
stdx::unique_lock lk(*txn->getClient());
ProgressMeterHolder pm(op->setMessage_inlock("m/r: merge sort and reduce",
"M/R Merge Sort and Reduce Progress"));
lk.unlock();
set servers;
{
// parse per shard results
BSONObjIterator i(shardCounts);
while (i.more()) {
BSONElement e = i.next();
servers.insert(e.fieldName());
}
}
state.prepTempCollection();
ON_BLOCK_EXIT_OBJ(state, &State::dropTempCollections);
BSONList values;
if (!config.outputOptions.outDB.empty()) {
BSONObjBuilder loc;
if ( !config.outputOptions.outDB.empty())
loc.append( "db" , config.outputOptions.outDB );
if ( !config.outputOptions.collectionName.empty() )
loc.append( "collection" , config.outputOptions.collectionName );
result.append("result", loc.obj());
}
else {
if ( !config.outputOptions.collectionName.empty() )
result.append( "result" , config.outputOptions.collectionName );
}
auto status = grid.catalogCache()->getDatabase(dbname);
if (!status.isOK()) {
return appendCommandStatus(result, status.getStatus());
}
shared_ptr confOut = status.getValue();
vector chunks;
if ( confOut->isSharded(config.outputOptions.finalNamespace) ) {
ChunkManagerPtr cm = confOut->getChunkManager(
config.outputOptions.finalNamespace);
// Fetch result from other shards 1 chunk at a time. It would be better to do
// just one big $or query, but then the sorting would not be efficient.
const string shardName = shardingState.getShardName();
const ChunkMap& chunkMap = cm->getChunkMap();
for ( ChunkMap::const_iterator it = chunkMap.begin(); it != chunkMap.end(); ++it ) {
ChunkPtr chunk = it->second;
if (chunk->getShardId() == shardName) {
chunks.push_back(chunk);
}
}
}
long long inputCount = 0;
unsigned int index = 0;
BSONObj query;
BSONArrayBuilder chunkSizes;
while (true) {
ChunkPtr chunk;
if (chunks.size() > 0) {
chunk = chunks[index];
BSONObjBuilder b;
b.appendAs(chunk->getMin().firstElement(), "$gte");
b.appendAs(chunk->getMax().firstElement(), "$lt");
query = BSON("_id" << b.obj());
// chunkSizes.append(min);
}
// reduce from each shard for a chunk
BSONObj sortKey = BSON( "_id" << 1 );
ParallelSortClusteredCursor cursor(servers, inputNS,
Query(query).sort(sortKey), QueryOption_NoCursorTimeout);
cursor.init();
int chunkSize = 0;
while ( cursor.more() || !values.empty() ) {
BSONObj t;
if (cursor.more()) {
t = cursor.next().getOwned();
++inputCount;
if ( values.size() == 0 ) {
values.push_back( t );
continue;
}
if ( t.woSortOrder( *(values.begin()) , sortKey ) == 0 ) {
values.push_back( t );
continue;
}
}
BSONObj res = config.reducer->finalReduce( values , config.finalizer.get());
chunkSize += res.objsize();
if (state.isOnDisk())
state.insert( config.tempNamespace , res );
else
state.emit(res);
values.clear();
if (!t.isEmpty())
values.push_back( t );
}
if (chunk) {
chunkSizes.append(chunk->getMin());
chunkSizes.append(chunkSize);
}
if (++index >= chunks.size())
break;
}
// Forget temporary input collection, if output is sharded collection
ShardConnection::forgetNS( inputNS );
result.append( "chunkSizes" , chunkSizes.arr() );
long long outputCount = state.postProcessCollection(txn, op, pm);
state.appendResults( result );
BSONObjBuilder countsB(32);
countsB.append("input", inputCount);
countsB.append("reduce", state.numReduces());
countsB.append("output", outputCount);
result.append( "counts" , countsB.obj() );
return 1;
}
} mapReduceFinishCommand;
}
}