Hawkin
/
arangodb
mirror of https://gitee.com/bigwinds/arangodb
1
0
Fork 0
Code Issues Projects Releases Wiki Activity
arangodb/arangod/Aql/Query.cpp

1516 lines
50 KiB
C++
Raw Blame History

////////////////////////////////////////////////////////////////////////////////
/// DISCLAIMER
///
/// Copyright 2014-2016 ArangoDB GmbH, Cologne, Germany
/// Copyright 2004-2014 triAGENS GmbH, Cologne, Germany
///
/// Licensed under the Apache License, Version 2.0 (the "License");
/// you may not use this file except in compliance with the License.
/// You may obtain a copy of the License at
///
/// http://www.apache.org/licenses/LICENSE-2.0
///
/// Unless required by applicable law or agreed to in writing, software
/// distributed under the License is distributed on an "AS IS" BASIS,
/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
/// See the License for the specific language governing permissions and
/// limitations under the License.
///
/// Copyright holder is ArangoDB GmbH, Cologne, Germany
///
/// @author Jan Steemann
////////////////////////////////////////////////////////////////////////////////
#include "Query.h"
#include "Aql/AqlItemBlock.h"
#include "Aql/AqlTransaction.h"
#include "Aql/ExecutionBlock.h"
#include "Aql/ExecutionEngine.h"
#include "Aql/ExecutionPlan.h"
#include "Aql/Optimizer.h"
#include "Aql/Parser.h"
#include "Aql/PlanCache.h"
#include "Aql/QueryCache.h"
#include "Aql/QueryList.h"
#include "Aql/QueryProfile.h"
#include "Aql/QueryRegistry.h"
#include "Basics/Exceptions.h"
#include "Basics/StringUtils.h"
#include "Basics/VelocyPackHelper.h"
#include "Basics/fasthash.h"
#include "Basics/system-functions.h"
#include "Cluster/ServerState.h"
#include "Graph/Graph.h"
#include "Graph/GraphManager.h"
#include "Logger/LogMacros.h"
#include "Logger/Logger.h"
#include "Logger/LoggerStream.h"
#include "RestServer/AqlFeature.h"
#include "StorageEngine/TransactionCollection.h"
#include "StorageEngine/TransactionState.h"
#include "Transaction/Methods.h"
#include "Transaction/StandaloneContext.h"
#include "Transaction/V8Context.h"
#include "Utils/CollectionNameResolver.h"
#include "Utils/ExecContext.h"
#include "V8/JavaScriptSecurityContext.h"
#include "V8/v8-vpack.h"
#include "V8Server/V8DealerFeature.h"
#include "VocBase/LogicalCollection.h"
#include "VocBase/vocbase.h"
#include <velocypack/Iterator.h>
#ifndef USE_PLAN_CACHE
#undef USE_PLAN_CACHE
#endif
using namespace arangodb;
using namespace arangodb::aql;
namespace {
static std::atomic<TRI_voc_tick_t> nextQueryId(1);
}
/// @brief creates a query
Query::Query(bool contextOwnedByExterior, TRI_vocbase_t& vocbase,
QueryString const& queryString, std::shared_ptr<VPackBuilder> const& bindParameters,
std::shared_ptr<VPackBuilder> const& options, QueryPart part)
: _id(Query::nextId()),
_resourceMonitor(),
_resources(&_resourceMonitor),
_vocbase(vocbase),
_context(nullptr),
_queryString(queryString),
_bindParameters(bindParameters),
_options(options),
_collections(&vocbase),
_trx(nullptr),
_startTime(TRI_microtime()),
_queryHash(DontCache),
_contextOwnedByExterior(contextOwnedByExterior),
_killed(false),
_isModificationQuery(false),
_preparedV8Context(false),
_queryHashCalculated(false),
_state(QueryExecutionState::ValueType::INVALID_STATE),
_part(part),
_executionPhase(ExecutionPhase::INITIALIZE),
_sharedState(std::make_shared<SharedQueryState>()) {
if (_contextOwnedByExterior) {
// copy transaction options from global state into our local query options
TransactionState* state = transaction::V8Context::getParentState();
if (state != nullptr) {
_queryOptions.transactionOptions = state->options();
}
}
// populate query options
if (_options != nullptr) {
_queryOptions.fromVelocyPack(_options->slice());
}
ProfileLevel level = _queryOptions.profile;
if (level >= PROFILE_LEVEL_TRACE_1) {
LOG_TOPIC("22a70", INFO, Logger::QUERIES) << TRI_microtime() - _startTime << " "
<< "Query::Query queryString: " << _queryString
<< " this: " << (uintptr_t)this;
} else {
LOG_TOPIC("11160", DEBUG, Logger::QUERIES)
<< TRI_microtime() - _startTime << " "
<< "Query::Query queryString: " << _queryString << " this: " << (uintptr_t)this;
}
if (bindParameters != nullptr && !bindParameters->isEmpty() &&
!bindParameters->slice().isNone()) {
if (level >= PROFILE_LEVEL_TRACE_1) {
LOG_TOPIC("8c9fc", INFO, Logger::QUERIES)
<< "bindParameters: " << bindParameters->slice().toJson();
} else {
LOG_TOPIC("16a3f", DEBUG, Logger::QUERIES)
<< "bindParameters: " << bindParameters->slice().toJson();
}
}
if (options != nullptr && !options->isEmpty() && !options->slice().isNone()) {
if (level >= PROFILE_LEVEL_TRACE_1) {
LOG_TOPIC("8979d", INFO, Logger::QUERIES)
<< "options: " << options->slice().toJson();
} else {
LOG_TOPIC("0b7cb", DEBUG, Logger::QUERIES)
<< "options: " << options->slice().toJson();
}
}
_resourceMonitor.setMemoryLimit(_queryOptions.memoryLimit);
if (!AqlFeature::lease()) {
THROW_ARANGO_EXCEPTION(TRI_ERROR_SHUTTING_DOWN);
}
}
/// @brief creates a query from VelocyPack
Query::Query(bool contextOwnedByExterior, TRI_vocbase_t& vocbase,
std::shared_ptr<VPackBuilder> const& queryStruct,
std::shared_ptr<VPackBuilder> const& options, QueryPart part)
: _id(Query::nextId()),
_resourceMonitor(),
_resources(&_resourceMonitor),
_vocbase(vocbase),
_context(nullptr),
_queryString(),
_queryBuilder(queryStruct),
_options(options),
_collections(&vocbase),
_trx(nullptr),
_startTime(TRI_microtime()),
_queryHash(DontCache),
_contextOwnedByExterior(contextOwnedByExterior),
_killed(false),
_isModificationQuery(false),
_preparedV8Context(false),
_queryHashCalculated(false),
_state(QueryExecutionState::ValueType::INVALID_STATE),
_part(part),
_executionPhase(ExecutionPhase::INITIALIZE),
_sharedState(std::make_shared<SharedQueryState>()) {
// populate query options
if (_options != nullptr) {
_queryOptions.fromVelocyPack(_options->slice());
}
LOG_TOPIC("8b0ff", DEBUG, Logger::QUERIES)
<< TRI_microtime() - _startTime << " "
<< "Query::Query queryStruct: " << queryStruct->slice().toJson()
<< " this: " << (uintptr_t)this;
if (options != nullptr && !options->isEmpty() && !options->slice().isNone()) {
LOG_TOPIC("92c10", DEBUG, Logger::QUERIES)
<< "options: " << options->slice().toJson();
}
// adjust the _isModificationQuery value from the slice we got
auto s = _queryBuilder->slice().get("isModificationQuery");
if (s.isBoolean()) {
_isModificationQuery = s.getBoolean();
}
_resourceMonitor.setMemoryLimit(_queryOptions.memoryLimit);
if (!AqlFeature::lease()) {
THROW_ARANGO_EXCEPTION(TRI_ERROR_SHUTTING_DOWN);
}
}
/// @brief destroys a query
Query::~Query() {
if (_queryOptions.profile >= PROFILE_LEVEL_TRACE_1) {
LOG_TOPIC("36a75", INFO, Logger::QUERIES) << TRI_microtime() - _startTime << " "
<< "Query::~Query queryString: "
<< " this: " << (uintptr_t)this;
}
// this will reset _trx, so _trx is invalid after here
cleanupPlanAndEngineSync(TRI_ERROR_INTERNAL);
exitContext();
_ast.reset();
_graphs.clear();
LOG_TOPIC("f5cee", DEBUG, Logger::QUERIES)
<< TRI_microtime() - _startTime << " "
<< "Query::~Query this: " << (uintptr_t)this;
AqlFeature::unlease();
}
void Query::addDataSource( // track DataSource
std::shared_ptr<arangodb::LogicalDataSource> const& ds // DataSource to track
) {
_queryDataSources.try_emplace(ds->guid(), ds->name());
}
/// @brief clone a query
/// note: as a side-effect, this will also create and start a transaction for
/// the query
Query* Query::clone(QueryPart part, bool withPlan) {
auto clone = std::make_unique<Query>(false, _vocbase, _queryString,
std::shared_ptr<VPackBuilder>(), _options, part);
clone->_resourceMonitor = _resourceMonitor;
clone->_resourceMonitor.clear();
if (_isModificationQuery) {
clone->setIsModificationQuery();
}
if (_plan != nullptr) {
if (withPlan) {
// clone the existing plan
clone->_plan.reset(_plan->clone(*clone));
}
// clone all variables
for (auto& it : _ast->variables()->variables(true)) {
auto var = _ast->variables()->getVariable(it.first);
TRI_ASSERT(var != nullptr);
clone->ast()->variables()->createVariable(var);
}
}
if (clone->_plan == nullptr) {
// initialize an empty plan
clone->_plan.reset(new ExecutionPlan(ast()));
}
TRI_ASSERT(clone->_trx == nullptr);
// A daughter transaction which does not
// actually lock the collections
clone->_trx = _trx; // _trx->clone(_queryOptions.transactionOptions);
TRI_ASSERT(_trx->status() == transaction::Status::RUNNING);
// hack ensure only the first query commits
clone->_isClonedQuery = true;
return clone.release();
}
bool Query::killed() const {
if (_queryOptions.timeout > std::numeric_limits<double>::epsilon()) {
if (TRI_microtime() > (_startTime + _queryOptions.timeout)) {
return true;
}
}
return _killed;
}
/// @brief set the query to killed
void Query::kill() {
_killed = true;
if (_engine != nullptr) {
// killing is best effort...
// intentionally ignoring the result of this call here
_engine->kill();
}
}
void Query::setExecutionTime() {
if (_engine != nullptr) {
_engine->_stats.setPeakMemoryUsage(_resourceMonitor.currentResources.peakMemoryUsage);
_engine->_stats.setExecutionTime(TRI_microtime() - _startTime);
}
}
/// @brief increase number of HTTP requests. this is normally
/// called during the setup of a query
void Query::incHttpRequests(size_t requests) {
if (_engine != nullptr) {
_engine->_stats.requests += requests;
}
}
/// @brief register an error, with an optional parameter inserted into printf
/// this also makes the query abort
void Query::registerError(int code, char const* details) {
TRI_ASSERT(code != TRI_ERROR_NO_ERROR);
if (details == nullptr) {
THROW_ARANGO_EXCEPTION(code);
}
THROW_ARANGO_EXCEPTION_PARAMS(code, details);
}
/// @brief register an error with a custom error message
/// this also makes the query abort
void Query::registerErrorCustom(int code, char const* details) {
TRI_ASSERT(code != TRI_ERROR_NO_ERROR);
if (details == nullptr) {
THROW_ARANGO_EXCEPTION(code);
}
std::string errorMessage(TRI_errno_string(code));
errorMessage.append(": ");
errorMessage.append(details);
THROW_ARANGO_EXCEPTION_MESSAGE(code, errorMessage);
}
void Query::registerWarning(int code, std::string const& details) {
registerWarning(code, details.c_str());
}
/// @brief register a warning
void Query::registerWarning(int code, char const* details) {
TRI_ASSERT(code != TRI_ERROR_NO_ERROR);
if (_queryOptions.failOnWarning) {
// make an error from each warning if requested
if (details == nullptr) {
THROW_ARANGO_EXCEPTION(code);
}
THROW_ARANGO_EXCEPTION_MESSAGE(code, details);
}
if (_warnings.size() >= _queryOptions.maxWarningCount) {
return;
}
if (details == nullptr) {
_warnings.emplace_back(code, TRI_errno_string(code));
} else {
_warnings.emplace_back(code, details);
}
}
void Query::prepare(QueryRegistry* registry, SerializationFormat format) {
TRI_ASSERT(registry != nullptr);
init();
enterState(QueryExecutionState::ValueType::PARSING);
std::unique_ptr<ExecutionPlan> plan;
#if USE_PLAN_CACHE
if (!_queryString.empty() && hashQuery() != DontCache && _part == PART_MAIN) {
// LOG_TOPIC("d79d9", INFO, Logger::FIXME) << "trying to find query in
// execution plan cache: '" << _queryString << "', hash: " << hashQuery();
// store & lookup velocypack plans!!
std::shared_ptr<PlanCacheEntry> planCacheEntry =
PlanCache::instance()->lookup(_vocbase, hashQuery(), queryString);
if (planCacheEntry != nullptr) {
// LOG_TOPIC("8aa30", INFO, Logger::FIXME) << "query found in execution plan cache:
// '" << _queryString << "'";
TRI_ASSERT(_trx == nullptr);
TRI_ASSERT(_collections.empty());
// create the transaction object, but do not start it yet
_trx = AqlTransaction::create(createTransactionContext(), _collections.collections(),
_queryOptions.transactionOptions, _part == PART_MAIN);
_trx->addHint(transaction::Hints::Hint::FROM_TOPLEVEL_AQL); // only used on toplevel
VPackBuilder* builder = planCacheEntry->builder.get();
VPackSlice slice = builder->slice();
ExecutionPlan::getCollectionsFromVelocyPack(_ast.get(), slice);
_ast->variables()->fromVelocyPack(slice);
enterState(QueryExecutionState::ValueType::LOADING_COLLECTIONS);
Result res = trx->addCollections(*_collections.collections());
if (res.ok()) {
res = _trx->begin();
}
if (res.fail()) {
if (!_queryString.empty() && _queryOptions.verboseErrors) {
std::string msg = res.errorMessage();
msg.append("\nwhile executing:\n");
_queryString.append(msg);
msg.push_back('\n');
}
THROW_ARANGO_EXCEPTION(res);
}
enterState(QueryExecutionState::ValueType::PLAN_INSTANTIATION);
plan.reset(ExecutionPlan::instantiateFromVelocyPack(_ast.get(), slice));
TRI_ASSERT(plan != nullptr);
}
}
#endif
if (plan == nullptr) {
plan = preparePlan();
TRI_ASSERT(plan != nullptr);
#if USE_PLAN_CACHE
if (!_queryString.empty() && hashQuery() != DontCache &&
_part == PART_MAIN && _warnings.empty() && _ast->root()->isCacheable()) {
// LOG_TOPIC("6de32", INFO, Logger::FIXME) << "storing query in execution
// plan cache '" << _queryString << "', hash: " << hashQuery();
PlanCache::instance()->store(_vocbase, hashQuery(), _queryString, plan.get());
}
#endif
}
TRI_ASSERT(plan != nullptr);
plan->findVarUsage();
TRI_ASSERT(_engine == nullptr);
TRI_ASSERT(_trx != nullptr);
// note that the engine returned here may already be present in our
// own _engine attribute (the instanciation procedure may modify us
// by calling our engine(ExecutionEngine*) function
// this is confusing and should be fixed!
std::unique_ptr<ExecutionEngine> engine(
ExecutionEngine::instantiateFromPlan(*registry, *this, *plan,
!_queryString.empty(), format));
if (_engine == nullptr) {
_engine = std::move(engine);
} else {
engine.release();
}
_plan = std::move(plan);
enterState(QueryExecutionState::ValueType::EXECUTION);
}
/// @brief prepare an AQL query, this is a preparation for execute, but
/// execute calls it internally. The purpose of this separate method is
/// to be able to only prepare a query from VelocyPack and then store it in the
/// QueryRegistry.
std::unique_ptr<ExecutionPlan> Query::preparePlan() {
LOG_TOPIC("9625e", DEBUG, Logger::QUERIES) << TRI_microtime() - _startTime << " "
<< "Query::prepare"
<< " this: " << (uintptr_t)this;
auto ctx = createTransactionContext();
std::unique_ptr<ExecutionPlan> plan;
if (!ctx) {
THROW_ARANGO_EXCEPTION_MESSAGE(
TRI_ERROR_INTERNAL, "failed to create query transaction context");
}
if (!_queryString.empty()) {
Parser parser(this);
parser.parse();
// put in bind parameters
parser.ast()->injectBindParameters(_bindParameters, ctx->resolver());
}
TRI_ASSERT(_trx == nullptr);
// TODO: Remove once we have cluster wide transactions
std::unordered_set<std::string> inaccessibleCollections;
#ifdef USE_ENTERPRISE
if (_queryOptions.transactionOptions.skipInaccessibleCollections) {
inaccessibleCollections = _queryOptions.inaccessibleCollections;
}
#endif
auto trx = AqlTransaction::create(ctx, _collections.collections(),
_queryOptions.transactionOptions, _part == PART_MAIN,
std::move(inaccessibleCollections));
// create the transaction object, but do not start it yet
_trx = trx;
_trx->addHint(transaction::Hints::Hint::FROM_TOPLEVEL_AQL); // only used on toplevel
// As soon as we start to instantiate the plan we have to clean it
// up before killing the unique_ptr
if (!_queryString.empty()) {
// we have an AST
// optimize the ast
enterState(QueryExecutionState::ValueType::AST_OPTIMIZATION);
_ast->validateAndOptimize();
enterState(QueryExecutionState::ValueType::LOADING_COLLECTIONS);
Result res = _trx->begin();
if (!res.ok()) {
THROW_ARANGO_EXCEPTION(res);
}
enterState(QueryExecutionState::ValueType::PLAN_INSTANTIATION);
plan = ExecutionPlan::instantiateFromAst(_ast.get());
if (plan == nullptr) {
// oops
THROW_ARANGO_EXCEPTION_MESSAGE(TRI_ERROR_INTERNAL,
"failed to create query execution engine");
}
// Run the query optimizer:
enterState(QueryExecutionState::ValueType::PLAN_OPTIMIZATION);
arangodb::aql::Optimizer opt(_queryOptions.maxNumberOfPlans);
// get enabled/disabled rules
opt.createPlans(std::move(plan), _queryOptions, false);
// Now plan and all derived plans belong to the optimizer
plan = opt.stealBest(); // Now we own the best one again
} else { // no queryString, we are instantiating from _queryBuilder
VPackSlice const querySlice = _queryBuilder->slice();
ExecutionPlan::getCollectionsFromVelocyPack(_ast.get(), querySlice);
_ast->variables()->fromVelocyPack(querySlice);
// creating the plan may have produced some collections
// we need to add them to the transaction now (otherwise the query will
// fail)
enterState(QueryExecutionState::ValueType::LOADING_COLLECTIONS);
Result res = trx->addCollections(*_collections.collections());
if (res.ok()) {
res = _trx->begin();
}
if (!res.ok()) {
THROW_ARANGO_EXCEPTION(res);
}
enterState(QueryExecutionState::ValueType::PLAN_INSTANTIATION);
// we have an execution plan in VelocyPack format
plan.reset(ExecutionPlan::instantiateFromVelocyPack(_ast.get(),
_queryBuilder->slice()));
if (plan == nullptr) {
// oops
THROW_ARANGO_EXCEPTION_MESSAGE(TRI_ERROR_INTERNAL,
"could not create plan from vpack");
}
plan->findVarUsage();
}
TRI_ASSERT(plan != nullptr);
// return the V8 context if we are in one
exitContext();
return plan;
}
/// @brief execute an AQL query
ExecutionState Query::execute(QueryRegistry* registry, QueryResult& queryResult) {
LOG_TOPIC("e8ed7", DEBUG, Logger::QUERIES) << TRI_microtime() - _startTime << " "
<< "Query::execute"
<< " this: " << (uintptr_t)this;
TRI_ASSERT(registry != nullptr);
try {
if (_killed) {
THROW_ARANGO_EXCEPTION(TRI_ERROR_QUERY_KILLED);
}
bool useQueryCache = canUseQueryCache();
switch (_executionPhase) {
case ExecutionPhase::INITIALIZE: {
if (useQueryCache) {
// check the query cache for an existing result
auto cacheEntry =
arangodb::aql::QueryCache::instance()->lookup(&_vocbase, hash(), _queryString,
bindParameters());
if (cacheEntry != nullptr) {
bool hasPermissions = true;
ExecContext const& exec = ExecContext::current();
// got a result from the query cache
if (!exec.isSuperuser()) {
for (auto& dataSource : cacheEntry->_dataSources) {
auto const& dataSourceName = dataSource.second;
if (!exec.canUseCollection(dataSourceName, auth::Level::RO)) {
// cannot use query cache result because of permissions
hasPermissions = false;
break;
}
}
}
if (hasPermissions) {
// we don't have yet a transaction when we're here, so let's
// create a mimimal context to build the result
queryResult.context = transaction::StandaloneContext::Create(_vocbase);
TRI_ASSERT(cacheEntry->_queryResult != nullptr);
queryResult.data = cacheEntry->_queryResult;
queryResult.extra = cacheEntry->_stats;
queryResult.cached = true;
return ExecutionState::DONE;
}
// if no permissions, fall through to regular querying
}
}
// will throw if it fails
prepare(registry, SerializationFormat::SHADOWROWS);
log();
_resultBuilderOptions = std::make_shared<VPackOptions>(VPackOptions::Defaults);
_resultBuilderOptions->buildUnindexedArrays = true;
_resultBuilderOptions->buildUnindexedObjects = true;
// NOTE: If the options have a shorter lifetime than the builder, it
// gets invalid (at least set() and close() are broken).
_resultBuilder = std::make_shared<VPackBuilder>(_resultBuilderOptions.get());
// reserve some space in Builder to avoid frequent reallocs
_resultBuilder->reserve(16 * 1024);
_resultBuilder->openArray();
_executionPhase = ExecutionPhase::EXECUTE;
}
[[fallthrough]];
case ExecutionPhase::EXECUTE: {
TRI_ASSERT(_resultBuilder != nullptr);
TRI_ASSERT(_resultBuilder->isOpenArray());
TRI_ASSERT(_trx != nullptr);
if (useQueryCache && (_isModificationQuery || !_warnings.empty() ||
!_ast->root()->isCacheable())) {
useQueryCache = false;
}
TRI_ASSERT(_engine != nullptr);
// this is the RegisterId our results can be found in
RegisterId const resultRegister = _engine->resultRegister();
// We loop as long as we are having ExecState::DONE returned
// In case of WAITING we return, this function is repeatable!
// In case of HASMORE we loop
while (true) {
auto res = _engine->getSome(ExecutionBlock::DefaultBatchSize());
if (res.first == ExecutionState::WAITING) {
return res.first;
}
// res.second == nullptr => state == DONE
TRI_ASSERT(res.second != nullptr || res.first == ExecutionState::DONE);
if (res.second == nullptr) {
TRI_ASSERT(res.first == ExecutionState::DONE);
break;
}
// cache low-level pointer to avoid repeated shared-ptr-derefs
TRI_ASSERT(_resultBuilder != nullptr);
auto& resultBuilder = *_resultBuilder;
size_t const n = res.second->size();
for (size_t i = 0; i < n; ++i) {
AqlValue const& val = res.second->getValueReference(i, resultRegister);
if (!val.isEmpty()) {
val.toVelocyPack(_trx.get(), resultBuilder, useQueryCache);
}
}
if (res.first == ExecutionState::DONE) {
break;
}
}
// must close result array here because it must be passed as a closed
// array to the query cache
_resultBuilder->close();
if (useQueryCache && _warnings.empty()) {
auto dataSources = _queryDataSources;
_trx->state()->allCollections( // collect transaction DataSources
[&dataSources](TransactionCollection& trxCollection) -> bool {
auto const& c = trxCollection.collection();
dataSources.try_emplace(c->guid(), c->name());
return true; // continue traversal
});
// create a query cache entry for later storage
_cacheEntry =
std::make_unique<QueryCacheResultEntry>(hash(), _queryString, _resultBuilder,
bindParameters(),
std::move(dataSources) // query DataSources
);
}
queryResult.data = std::move(_resultBuilder);
queryResult.context = _trx->transactionContext();
_executionPhase = ExecutionPhase::FINALIZE;
}
[[fallthrough]];
case ExecutionPhase::FINALIZE: {
// will set warnings, stats, profile and cleanup plan and engine
return finalize(queryResult);
}
}
// We should not be able to get here
TRI_ASSERT(false);
return ExecutionState::DONE;
} catch (arangodb::basics::Exception const& ex) {
setExecutionTime();
cleanupPlanAndEngineSync(ex.code());
queryResult.reset(Result(ex.code(), "AQL: " + ex.message() +
QueryExecutionState::toStringWithPrefix(_state)));
return ExecutionState::DONE;
} catch (std::bad_alloc const&) {
setExecutionTime();
cleanupPlanAndEngineSync(TRI_ERROR_OUT_OF_MEMORY);
queryResult.reset(Result(TRI_ERROR_OUT_OF_MEMORY,
TRI_errno_string(TRI_ERROR_OUT_OF_MEMORY) +
QueryExecutionState::toStringWithPrefix(_state)));
return ExecutionState::DONE;
} catch (std::exception const& ex) {
setExecutionTime();
cleanupPlanAndEngineSync(TRI_ERROR_INTERNAL);
queryResult.reset(Result(TRI_ERROR_INTERNAL,
ex.what() + QueryExecutionState::toStringWithPrefix(_state)));
return ExecutionState::DONE;
} catch (...) {
setExecutionTime();
cleanupPlanAndEngineSync(TRI_ERROR_INTERNAL);
queryResult.reset(Result(TRI_ERROR_INTERNAL,
TRI_errno_string(TRI_ERROR_INTERNAL) +
QueryExecutionState::toStringWithPrefix(_state)));
return ExecutionState::DONE;
}
}
/**
* @brief Execute the query in a synchronous way, so if
* the query needs to wait (e.g. IO) this thread
* will be blocked.
*
* @param registry The query registry.
*
* @return The result of this query. The result is always complete
*/
QueryResult Query::executeSync(QueryRegistry* registry) {
std::shared_ptr<SharedQueryState> ss = sharedState();
ss->resetWakeupHandler();
QueryResult queryResult;
while (true) {
auto state = execute(registry, queryResult);
if (state != aql::ExecutionState::WAITING) {
TRI_ASSERT(state == aql::ExecutionState::DONE);
return queryResult;
}
ss->waitForAsyncWakeup();
}
}
// execute an AQL query: may only be called with an active V8 handle scope
QueryResultV8 Query::executeV8(v8::Isolate* isolate, QueryRegistry* registry) {
LOG_TOPIC("6cac7", DEBUG, Logger::QUERIES) << TRI_microtime() - _startTime << " "
<< "Query::executeV8"
<< " this: " << (uintptr_t)this;
TRI_ASSERT(registry != nullptr);
std::shared_ptr<SharedQueryState> ss = sharedState();
aql::QueryResultV8 queryResult;
try {
bool useQueryCache = canUseQueryCache();
if (useQueryCache) {
// check the query cache for an existing result
auto cacheEntry =
arangodb::aql::QueryCache::instance()->lookup(&_vocbase, hash(), _queryString,
bindParameters());
if (cacheEntry != nullptr) {
bool hasPermissions = true;
auto ctx = transaction::StandaloneContext::Create(_vocbase);
ExecContext const& exec = ExecContext::current();
// got a result from the query cache
if (!exec.isSuperuser()) {
for (auto const& dataSource : cacheEntry->_dataSources) {
auto const& dataSourceName = dataSource.second;
if (!exec.canUseCollection(dataSourceName, auth::Level::RO)) {
// cannot use query cache result because of permissions
hasPermissions = false;
break;
}
}
}
if (hasPermissions) {
// we don't have yet a transaction when we're here, so let's create
// a mimimal context to build the result
queryResult.context = ctx;
v8::Handle<v8::Value> values =
TRI_VPackToV8(isolate, cacheEntry->_queryResult->slice(),
queryResult.context->getVPackOptions());
TRI_ASSERT(values->IsArray());
queryResult.v8Data = v8::Handle<v8::Array>::Cast(values);
queryResult.extra = cacheEntry->_stats;
queryResult.cached = true;
return queryResult;
}
// if no permissions, fall through to regular querying
}
}
// will throw if it fails
prepare(registry, SerializationFormat::SHADOWROWS);
log();
if (useQueryCache && (_isModificationQuery || !_warnings.empty() ||
!_ast->root()->isCacheable())) {
useQueryCache = false;
}
v8::Handle<v8::Array> resArray = v8::Array::New(isolate);
TRI_ASSERT(_engine != nullptr);
// this is the RegisterId our results can be found in
auto const resultRegister = _engine->resultRegister();
// following options and builder only required for query cache
VPackOptions options = VPackOptions::Defaults;
options.buildUnindexedArrays = true;
options.buildUnindexedObjects = true;
auto builder = std::make_shared<VPackBuilder>(&options);
try {
ss->resetWakeupHandler();
// iterate over result, return it and optionally store it in query cache
builder->openArray();
// iterate over result and return it
uint32_t j = 0;
ExecutionState state = ExecutionState::HASMORE;
while (state != ExecutionState::DONE) {
auto res = _engine->getSome(ExecutionBlock::DefaultBatchSize());
state = res.first;
while (state == ExecutionState::WAITING) {
ss->waitForAsyncWakeup();
res = _engine->getSome(ExecutionBlock::DefaultBatchSize());
state = res.first;
}
SharedAqlItemBlockPtr value = std::move(res.second);
// value == nullptr => state == DONE
TRI_ASSERT(value != nullptr || state == ExecutionState::DONE);
if (value == nullptr) {
continue;
}
if (!_queryOptions.silent) {
size_t const n = value->size();
for (size_t i = 0; i < n; ++i) {
AqlValue const& val = value->getValueReference(i, resultRegister);
if (!val.isEmpty()) {
resArray->Set(j++, val.toV8(isolate, _trx.get()));
if (useQueryCache) {
val.toVelocyPack(_trx.get(), *builder, true);
}
}
if (V8PlatformFeature::isOutOfMemory(isolate)) {
THROW_ARANGO_EXCEPTION(TRI_ERROR_OUT_OF_MEMORY);
}
}
}
if (_killed) {
THROW_ARANGO_EXCEPTION(TRI_ERROR_QUERY_KILLED);
}
}
builder->close();
} catch (...) {
LOG_TOPIC("8a6bf", DEBUG, Logger::QUERIES)
<< TRI_microtime() - _startTime << " "
<< "got an exception executing "
<< " this: " << (uintptr_t)this;
throw;
}
queryResult.v8Data = resArray;
queryResult.context = _trx->transactionContext();
if (useQueryCache && _warnings.empty()) {
auto dataSources = _queryDataSources;
_trx->state()->allCollections( // collect transaction DataSources
[&dataSources](TransactionCollection& trxCollection) -> bool {
auto const& c = trxCollection.collection();
dataSources.try_emplace(c->guid(), c->name());
return true; // continue traversal
});
// create a cache entry for later usage
_cacheEntry = std::make_unique<QueryCacheResultEntry>(hash(), _queryString,
builder, bindParameters(),
std::move(dataSources) // query DataSources
);
}
ss->resetWakeupHandler();
// will set warnings, stats, profile and cleanup plan and engine
ExecutionState state = finalize(queryResult);
while (state == ExecutionState::WAITING) {
ss->waitForAsyncWakeup();
state = finalize(queryResult);
}
} catch (arangodb::basics::Exception const& ex) {
setExecutionTime();
cleanupPlanAndEngineSync(ex.code());
queryResult.reset(Result(ex.code(), "AQL: " + ex.message() +
QueryExecutionState::toStringWithPrefix(_state)));
} catch (std::bad_alloc const&) {
setExecutionTime();
cleanupPlanAndEngineSync(TRI_ERROR_OUT_OF_MEMORY);
queryResult.reset(Result(TRI_ERROR_OUT_OF_MEMORY,
TRI_errno_string(TRI_ERROR_OUT_OF_MEMORY) +
QueryExecutionState::toStringWithPrefix(_state)));
} catch (std::exception const& ex) {
setExecutionTime();
cleanupPlanAndEngineSync(TRI_ERROR_INTERNAL);
queryResult.reset(Result(TRI_ERROR_INTERNAL,
ex.what() + QueryExecutionState::toStringWithPrefix(_state)));
} catch (...) {
setExecutionTime();
cleanupPlanAndEngineSync(TRI_ERROR_INTERNAL);
queryResult.reset(Result(TRI_ERROR_INTERNAL,
TRI_errno_string(TRI_ERROR_INTERNAL) +
QueryExecutionState::toStringWithPrefix(_state)));
}
return queryResult;
}
ExecutionState Query::finalize(QueryResult& result) {
if (result.extra == nullptr || !result.extra->isOpenObject()) {
// The above condition is not true if we have already waited.
LOG_TOPIC("fc22c", DEBUG, Logger::QUERIES)
<< TRI_microtime() - _startTime << " "
<< "Query::finalize: before _trx->commit"
<< " this: " << (uintptr_t)this;
if (!_isClonedQuery) {
Result commitResult = _trx->commit();
if (commitResult.fail()) {
THROW_ARANGO_EXCEPTION(commitResult);
}
}
LOG_TOPIC("7ef18", DEBUG, Logger::QUERIES)
<< TRI_microtime() - _startTime << " "
<< "Query::finalize: before cleanupPlanAndEngine"
<< " this: " << (uintptr_t)this;
setExecutionTime();
enterState(QueryExecutionState::ValueType::FINALIZATION);
result.extra = std::make_shared<VPackBuilder>();
result.extra->openObject(true);
if (_queryOptions.profile >= PROFILE_LEVEL_BLOCKS) {
result.extra->add(VPackValue("plan"));
_plan->toVelocyPack(*result.extra, _ast.get(), false);
// needed to happen before plan cleanup
}
}
auto state = cleanupPlanAndEngine(TRI_ERROR_NO_ERROR, result.extra.get());
if (state == ExecutionState::WAITING) {
return state;
}
addWarningsToVelocyPack(*result.extra);
double now = TRI_microtime();
if (_profile != nullptr && _queryOptions.profile >= PROFILE_LEVEL_BASIC) {
_profile->setStateEnd(QueryExecutionState::ValueType::FINALIZATION, now);
_profile->toVelocyPack(*(result.extra));
}
result.extra->close();
if (_cacheEntry != nullptr) {
_cacheEntry->_stats = result.extra;
QueryCache::instance()->store(&_vocbase, std::move(_cacheEntry));
}
// patch executionTime stats value in place
// we do this because "executionTime" should include the whole span of the
// execution and we have to set it at the very end
double const rt = now - _startTime;
basics::VelocyPackHelper::patchDouble(result.extra->slice().get("stats").get("executionTime"),
rt);
LOG_TOPIC("95996", DEBUG, Logger::QUERIES) << rt << " "
<< "Query::finalize:returning"
<< " this: " << (uintptr_t)this;
return ExecutionState::DONE;
}
/// @brief parse an AQL query
QueryResult Query::parse() {
try {
init();
Parser parser(this);
return parser.parseWithDetails();
} catch (arangodb::basics::Exception const& ex) {
return QueryResult(Result(ex.code(), ex.message()));
} catch (std::bad_alloc const&) {
cleanupPlanAndEngineSync(TRI_ERROR_OUT_OF_MEMORY);
return QueryResult(Result(TRI_ERROR_OUT_OF_MEMORY,
TRI_errno_string(TRI_ERROR_OUT_OF_MEMORY)));
} catch (std::exception const& ex) {
cleanupPlanAndEngineSync(TRI_ERROR_INTERNAL);
return QueryResult(Result(TRI_ERROR_INTERNAL, ex.what()));
} catch (...) {
return QueryResult(
Result(TRI_ERROR_INTERNAL,
"an unknown error occurred while parsing the query"));
}
}
/// @brief explain an AQL query
QueryResult Query::explain() {
try {
init();
enterState(QueryExecutionState::ValueType::PARSING);
auto ctx = createTransactionContext();
Parser parser(this);
parser.parse();
// put in bind parameters
parser.ast()->injectBindParameters(_bindParameters, ctx->resolver());
// optimize and validate the ast
enterState(QueryExecutionState::ValueType::AST_OPTIMIZATION);
// create the transaction object, but do not start it yet
_trx = AqlTransaction::create(std::move(ctx), _collections.collections(),
_queryOptions.transactionOptions, true);
// we have an AST
Result res = _trx->begin();
if (!res.ok()) {
THROW_ARANGO_EXCEPTION(res);
}
enterState(QueryExecutionState::ValueType::LOADING_COLLECTIONS);
parser.ast()->validateAndOptimize();
enterState(QueryExecutionState::ValueType::PLAN_INSTANTIATION);
std::unique_ptr<ExecutionPlan> plan =
ExecutionPlan::instantiateFromAst(parser.ast());
if (plan == nullptr) {
// oops
return QueryResult(
Result(TRI_ERROR_INTERNAL, "unable to create plan from AST"));
}
// Run the query optimizer:
enterState(QueryExecutionState::ValueType::PLAN_OPTIMIZATION);
arangodb::aql::Optimizer opt(_queryOptions.maxNumberOfPlans);
// get enabled/disabled rules
opt.createPlans(std::move(plan), _queryOptions, true);
enterState(QueryExecutionState::ValueType::FINALIZATION);
QueryResult result;
if (_queryOptions.allPlans) {
result.data = std::make_shared<VPackBuilder>();
{
VPackArrayBuilder guard(result.data.get());
auto const& plans = opt.getPlans();
for (auto& it : plans) {
auto& plan = it.first;
TRI_ASSERT(plan != nullptr);
plan->findVarUsage();
plan->planRegisters();
plan->toVelocyPack(*result.data.get(), parser.ast(), _queryOptions.verbosePlans);
}
}
// cacheability not available here
result.cached = false;
} else {
// Now plan and all derived plans belong to the optimizer
std::unique_ptr<ExecutionPlan> bestPlan = opt.stealBest(); // Now we own the best one again
TRI_ASSERT(bestPlan != nullptr);
bestPlan->findVarUsage();
bestPlan->planRegisters();
result.data = bestPlan->toVelocyPack(parser.ast(), _queryOptions.verbosePlans);
// cacheability
result.cached = (!_queryString.empty() && !_isModificationQuery &&
_warnings.empty() && _ast->root()->isCacheable());
}
// technically no need to commit, as we are only explaining here
auto commitResult = _trx->commit();
if (commitResult.fail()) {
THROW_ARANGO_EXCEPTION(commitResult);
}
result.extra = std::make_shared<VPackBuilder>();
{
VPackObjectBuilder guard(result.extra.get(), true);
addWarningsToVelocyPack(*result.extra);
result.extra->add(VPackValue("stats"));
opt._stats.toVelocyPack(*result.extra);
}
return result;
} catch (arangodb::basics::Exception const& ex) {
return QueryResult(
Result(ex.code(), ex.message() + QueryExecutionState::toStringWithPrefix(_state)));
} catch (std::bad_alloc const&) {
return QueryResult(Result(TRI_ERROR_OUT_OF_MEMORY,
TRI_errno_string(TRI_ERROR_OUT_OF_MEMORY) +
QueryExecutionState::toStringWithPrefix(_state)));
} catch (std::exception const& ex) {
return QueryResult(Result(TRI_ERROR_INTERNAL,
ex.what() + QueryExecutionState::toStringWithPrefix(_state)));
} catch (...) {
return QueryResult(Result(TRI_ERROR_INTERNAL,
TRI_errno_string(TRI_ERROR_INTERNAL) +
QueryExecutionState::toStringWithPrefix(_state)));
}
}
void Query::setEngine(ExecutionEngine* engine) {
TRI_ASSERT(engine != nullptr);
_engine.reset(engine);
}
/// @brief prepare a V8 context for execution for this expression
/// this needs to be called once before executing any V8 function in this
/// expression
void Query::prepareV8Context() {
if (_preparedV8Context) {
// already done
return;
}
TRI_ASSERT(_trx != nullptr);
ISOLATE;
TRI_ASSERT(isolate != nullptr);
std::string body(
"if (_AQL === undefined) { _AQL = require(\"@arangodb/aql\"); }");
{
v8::HandleScope scope(isolate);
v8::ScriptOrigin scriptOrigin(TRI_V8_ASCII_STRING(isolate, "--script--"));
v8::Handle<v8::Script> compiled =
v8::Script::Compile(TRI_IGETC, TRI_V8_STD_STRING(isolate, body), &scriptOrigin)
.FromMaybe(v8::Local<v8::Script>());
if (!compiled.IsEmpty()) {
compiled->Run(TRI_IGETC).FromMaybe(v8::Local<v8::Value>()); // TODO: Result?
_preparedV8Context = true;
}
}
}
/// @brief enter a V8 context
void Query::enterContext() {
if (!_contextOwnedByExterior) {
if (_context == nullptr) {
if (V8DealerFeature::DEALER == nullptr) {
THROW_ARANGO_EXCEPTION_MESSAGE(TRI_ERROR_INTERNAL,
"V8 engine is disabled");
}
TRI_ASSERT(V8DealerFeature::DEALER != nullptr);
JavaScriptSecurityContext securityContext =
JavaScriptSecurityContext::createQueryContext();
_context = V8DealerFeature::DEALER->enterContext(&_vocbase, securityContext);
if (_context == nullptr) {
THROW_ARANGO_EXCEPTION_MESSAGE(
TRI_ERROR_RESOURCE_LIMIT,
"unable to enter V8 context for query execution");
}
// register transaction and resolver in context
TRI_ASSERT(_trx != nullptr);
ISOLATE;
TRI_GET_GLOBALS();
_preparedV8Context = false;
auto ctx = static_cast<arangodb::transaction::V8Context*>(v8g->_transactionContext);
if (ctx != nullptr) {
ctx->registerTransaction(_trx->state());
}
}
_preparedV8Context = false;
TRI_ASSERT(_context != nullptr);
}
}
/// @brief return a V8 context
void Query::exitContext() {
if (!_contextOwnedByExterior) {
if (_context != nullptr) {
// unregister transaction and resolver in context
ISOLATE;
TRI_GET_GLOBALS();
auto ctx = static_cast<arangodb::transaction::V8Context*>(v8g->_transactionContext);
if (ctx != nullptr) {
ctx->unregisterTransaction();
}
TRI_ASSERT(V8DealerFeature::DEALER != nullptr);
V8DealerFeature::DEALER->exitContext(_context);
_context = nullptr;
}
_preparedV8Context = false;
}
}
/// @brief returns statistics for current query.
void Query::getStats(VPackBuilder& builder) {
if (_engine != nullptr) {
setExecutionTime();
_engine->_stats.toVelocyPack(builder, _queryOptions.fullCount);
} else {
ExecutionStats::toVelocyPackStatic(builder);
}
}
/// @brief convert the list of warnings to VelocyPack.
/// Will add a new entry { ..., warnings: <warnings>, } if there are
/// warnings. If there are none it will not modify the builder
void Query::addWarningsToVelocyPack(VPackBuilder& builder) const {
TRI_ASSERT(builder.isOpenObject());
size_t const n = _warnings.size();
builder.add(VPackValue("warnings"));
{
VPackArrayBuilder guard(&builder);
for (size_t i = 0; i < n; ++i) {
VPackObjectBuilder objGuard(&builder);
builder.add("code", VPackValue(_warnings[i].first));
builder.add("message", VPackValue(_warnings[i].second));
}
}
}
/// @brief initializes the query
void Query::init() {
TRI_ASSERT(!_profile && !_ast);
if (_profile || _ast) {
// already called
return;
}
TRI_ASSERT(_profile == nullptr);
// adds query to QueryList which is needed for /_api/query/current
_profile = std::make_unique<QueryProfile>(this);
enterState(QueryExecutionState::ValueType::INITIALIZATION);
TRI_ASSERT(_ast == nullptr);
_ast = std::make_unique<Ast>(this);
}
/// @brief calculate a hash for the query, once
uint64_t Query::hash() const {
if (!_queryHashCalculated) {
_queryHash = calculateHash();
_queryHashCalculated = true;
}
return _queryHash;
}
/// @brief log a query
void Query::log() {
if (!_queryString.empty()) {
LOG_TOPIC("8a86a", TRACE, Logger::QUERIES)
<< "executing query " << _id << ": '" << _queryString.extract(1024) << "'";
}
}
/// @brief calculate a hash value for the query and bind parameters
uint64_t Query::calculateHash() const {
if (_queryString.empty()) {
return DontCache;
}
// hash the query string first
uint64_t hashval = _queryString.hash();
// handle "fullCount" option. if this option is set, the query result will
// be different to when it is not set!
if (_queryOptions.fullCount) {
hashval = fasthash64(TRI_CHAR_LENGTH_PAIR("fullcount:true"), hashval);
} else {
hashval = fasthash64(TRI_CHAR_LENGTH_PAIR("fullcount:false"), hashval);
}
// handle "count" option
if (_queryOptions.count) {
hashval = fasthash64(TRI_CHAR_LENGTH_PAIR("count:true"), hashval);
} else {
hashval = fasthash64(TRI_CHAR_LENGTH_PAIR("count:false"), hashval);
}
// also hash "optimizer" options
VPackSlice options = arangodb::velocypack::Slice::emptyObjectSlice();
if (_options != nullptr && _options->slice().isObject()) {
options = _options->slice().get("optimizer");
}
hashval ^= options.hash();
// blend query hash with bind parameters
return hashval ^ _bindParameters.hash();
}
/// @brief whether or not the query cache can be used for the query
bool Query::canUseQueryCache() const {
if (_queryString.size() < 8) {
return false;
}
if (_isModificationQuery) {
return false;
}
auto queryCacheMode = QueryCache::instance()->mode();
if (_queryOptions.cache &&
(queryCacheMode == CACHE_ALWAYS_ON || queryCacheMode == CACHE_ON_DEMAND)) {
// cache mode is set to always on or on-demand...
// query will only be cached if `cache` attribute is not set to false
// cannot use query cache on a coordinator at the moment
return !arangodb::ServerState::instance()->isRunningInCluster();
}
return false;
}
/// @brief enter a new state
void Query::enterState(QueryExecutionState::ValueType state) {
LOG_TOPIC("d8767", DEBUG, Logger::QUERIES)
<< TRI_microtime() - _startTime << " "
<< "Query::enterState: " << state << " this: " << (uintptr_t)this;
if (_profile != nullptr) {
// record timing for previous state
_profile->setStateDone(_state);
}
// and adjust the state
_state = state;
}
void Query::cleanupPlanAndEngineSync(int errorCode, VPackBuilder* statsBuilder) noexcept {
try {
std::shared_ptr<SharedQueryState> ss = sharedState();
ss->resetWakeupHandler();
ExecutionState state = cleanupPlanAndEngine(errorCode, statsBuilder);
while (state == ExecutionState::WAITING) {
ss->waitForAsyncWakeup();
state = cleanupPlanAndEngine(errorCode, statsBuilder);
}
ss->invalidate();
} catch (...) {
// this is called from the destructor... we must not leak exceptions from
// here
}
}
/// @brief cleanup plan and engine for current query
ExecutionState Query::cleanupPlanAndEngine(int errorCode, VPackBuilder* statsBuilder) {
if (_engine != nullptr) {
try {
ExecutionState state;
std::tie(state, std::ignore) = _engine->shutdown(errorCode);
if (state == ExecutionState::WAITING) {
return state;
}
if (statsBuilder != nullptr) {
TRI_ASSERT(statsBuilder->isOpenObject());
statsBuilder->add(VPackValue("stats"));
_engine->_stats.toVelocyPack(*statsBuilder, _queryOptions.fullCount);
}
} catch (...) {
// shutdown may fail but we must not throw here
// (we're also called from the destructor)
}
_sharedState->invalidate();
_engine.reset();
}
// the following call removes the query from the list of currently
// running queries. so whoever fetches that list will not see a Query that
// is about to shut down/be destroyed
if (_profile != nullptr) {
_profile->unregisterFromQueryList();
}
// If the transaction was not committed, it is automatically aborted
_trx = nullptr;
_plan.reset();
return ExecutionState::DONE;
}
/// @brief create a transaction::Context
std::shared_ptr<transaction::Context> Query::createTransactionContext() {
if (!_transactionContext) {
if (_contextOwnedByExterior) {
// we must use v8
_transactionContext = transaction::V8Context::Create(_vocbase, true);
} else {
_transactionContext = transaction::StandaloneContext::Create(_vocbase);
}
}
TRI_ASSERT(_transactionContext != nullptr);
return _transactionContext;
}
/// @brief pass-thru a resolver object from the transaction context
CollectionNameResolver const& Query::resolver() {
return createTransactionContext()->resolver();
}
/// @brief look up a graph either from our cache list or from the _graphs
/// collection
graph::Graph const* Query::lookupGraphByName(std::string const& name) {
auto it = _graphs.find(name);
if (it != _graphs.end()) {
return it->second.get();
}
graph::GraphManager graphManager{_vocbase, _contextOwnedByExterior};
auto g = graphManager.lookupGraphByName(name);
if (g.fail()) {
return nullptr;
}
auto graph = g.get().get();
_graphs.emplace(name, std::move(g.get()));
return graph;
}
/// @brief returns the next query id
TRI_voc_tick_t Query::nextId() {
return ::nextQueryId.fetch_add(1, std::memory_order_seq_cst) + 1;
}
Reference in New Issue View Git Blame Copy Permalink