/
mr.cpp
1675 lines (1426 loc) · 69.1 KB
/
mr.cpp
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// mr.cpp
/**
* 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 <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.
*/
#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kCommand
#include "mongo/platform/basic.h"
#include "mongo/db/commands/mr.h"
#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/database_holder.h"
#include "mongo/db/catalog/index_catalog.h"
#include "mongo/db/clientcursor.h"
#include "mongo/db/commands.h"
#include "mongo/db/db.h"
#include "mongo/db/dbhelpers.h"
#include "mongo/db/instance.h"
#include "mongo/db/index/index_descriptor.h"
#include "mongo/db/matcher/matcher.h"
#include "mongo/db/query/get_executor.h"
#include "mongo/db/query/query_planner.h"
#include "mongo/db/repl/oplog.h"
#include "mongo/db/repl/repl_coordinator_global.h"
#include "mongo/db/range_preserver.h"
#include "mongo/db/namespace_string.h"
#include "mongo/db/operation_context_impl.h"
#include "mongo/db/storage_options.h"
#include "mongo/scripting/engine.h"
#include "mongo/s/collection_metadata.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/util/log.h"
#include "mongo/util/scopeguard.h"
namespace mongo {
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<BSONArrayBuilder> valueBuilder;
unsigned n = 0;
for ( ; n<tuples.size(); n++ ) {
BSONObjIterator j(tuples[n]);
BSONElement keyE = j.next();
if ( n == 0 ) {
reduceArgs.append( keyE );
key = keyE.wrap();
valueBuilder.reset(new BSONArrayBuilder( reduceArgs.subarrayStart( "tuples" ) ));
}
BSONElement ee = j.next();
uassert( 13070 , "value too large to reduce" , ee.size() < ( BSONObjMaxUserSize / 2 ) );
// If adding this element to the array would cause it to be too large, break. The
// remainder of the tuples will be processed recursively at the end of this
// function.
if ( valueBuilder->len() + 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() {
// Dropping the tempNamespace must be logged as that collection is replicated.
_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.
ScopedTransaction(_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.
Client::WriteContext 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();
}
vector<BSONObj> indexesToInsert;
{
// copy indexes into temporary storage
Client::WriteContext finalCtx(_txn, _config.outputOptions.finalNamespace);
Collection* const finalColl = finalCtx.getCollection();
if ( finalColl ) {
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
Client::WriteContext tempCtx(_txn, _config.tempNamespace);
WriteUnitOfWork wuow(_txn);
uassert(ErrorCodes::NotMaster, "no longer master",
repl::getGlobalReplicationCoordinator()->
canAcceptWritesForDatabase(nsToDatabase(_config.tempNamespace.c_str())));
Collection* tempColl = tempCtx.getCollection();
invariant(!tempColl);
CollectionOptions options;
options.temp = true;
tempColl = tempCtx.db()->createCollection(_txn, _config.tempNamespace, options);
// Log the createCollection operation.
BSONObjBuilder b;
b.append( "create", nsToCollectionSubstring( _config.tempNamespace ));
b.appendElements( options.toBSON() );
string logNs = nsToDatabase( _config.tempNamespace ) + ".$cmd";
repl::logOp(_txn, "c", logNs.c_str(), b.obj());
for ( vector<BSONObj>::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";
repl::logOp(_txn, "i", logNs.c_str(), *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( // 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; // ignore versioning here
return db.count( ns, query, options, limit, skip );
}
//
// End SERVER-6116
//
long long State::postProcessCollectionNonAtomic(
OperationContext* txn, CurOp* op, ProgressMeterHolder& pm) {
if ( _config.outputOptions.finalNamespace == _config.tempNamespace )
return _safeCount( _db, _config.outputOptions.finalNamespace );
if (_config.outputOptions.outType == Config::REPLACE ||
_safeCount(_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
op->setMessage("m/r: merge post processing",
"M/R Merge Post Processing Progress",
_safeCount(_db, _config.tempNamespace, BSONObj()));
auto_ptr<DBClientCursor> cursor = _db.query(_config.tempNamespace , BSONObj());
while (cursor->more()) {
ScopedTransaction(_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;
op->setMessage("m/r: reduce post processing",
"M/R Reduce Post Processing Progress",
_safeCount(_db, _config.tempNamespace, BSONObj()));
auto_ptr<DBClientCursor> 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;
{
Client::Context tx(txn, _config.outputOptions.finalNamespace);
Collection* coll =
tx.db()->getCollection(_txn, _config.outputOptions.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( _db, _config.outputOptions.finalNamespace );
}
/**
* Insert doc in collection. This should be replicated.
*/
void State::insert( const string& ns , const BSONObj& o ) {
verify( _onDisk );
Client::WriteContext ctx(_txn, ns );
WriteUnitOfWork wuow(_txn);
uassert(ErrorCodes::NotMaster, "no longer master",
repl::getGlobalReplicationCoordinator()->
canAcceptWritesForDatabase(nsToDatabase(ns.c_str())));
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() );
repl::logOp(_txn, "i", ns.c_str(), bo);
wuow.commit();
}
/**
* Insert doc into the inc collection. This should not be replicated.
*/
void State::_insertToInc( BSONObj& o ) {
verify( _onDisk );
Client::WriteContext ctx(_txn, _config.incLong );
WriteUnitOfWork wuow(_txn);
Collection* coll = getCollectionOrUassert(ctx.db(), _config.incLong);
uassertStatusOK( coll->insertDocument( _txn, o, true ).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( _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 = ClientBasic::getCurrent()->getAuthorizationSession()
->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, const StringData& ns) {
Collection* out = db ? db->getCollection(_txn, 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<BSONObj&>(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 );
{
Client::WriteContext 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<AutoGetCollectionForRead> ctx(new AutoGetCollectionForRead(_txn, _config.incLong));
BSONObj prev;
BSONList all;
verify(pm == op->setMessage("m/r: (3/3) final reduce to collection",