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arangodb/arangod/Aql/AqlItemBlock.cpp

627 lines
20 KiB
C++

////////////////////////////////////////////////////////////////////////////////
/// @brief Aql item block
///
/// @file
///
/// DISCLAIMER
///
/// Copyright 2010-2014 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 triAGENS GmbH, Cologne, Germany
///
/// @author Max Neunhoeffer
/// @author Copyright 2014, triagens GmbH, Cologne, Germany
////////////////////////////////////////////////////////////////////////////////
#include "Aql/AqlItemBlock.h"
#include "Aql/ExecutionNode.h"
using namespace triagens::aql;
using Json = triagens::basics::Json;
using JsonHelper = triagens::basics::JsonHelper;
// -----------------------------------------------------------------------------
// --SECTION-- AqlItemBlock
// -----------------------------------------------------------------------------
// -----------------------------------------------------------------------------
// --SECTION-- constructors / destructors
// -----------------------------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
/// @brief create the block
////////////////////////////////////////////////////////////////////////////////
AqlItemBlock::AqlItemBlock (size_t nrItems,
RegisterId nrRegs)
: _nrItems(nrItems),
_nrRegs(nrRegs) {
TRI_ASSERT(nrItems > 0); // no, empty AqlItemBlocks are not allowed!
if (nrRegs > 0) {
// check that the nrRegs value is somewhat sensible
// this compare value is arbitrary, but having so many registers in a single query seems unlikely
TRI_ASSERT(nrRegs <= ExecutionNode::MaxRegisterId);
_data.resize(nrItems * nrRegs);
_docColls.reserve(nrRegs);
for (size_t i = 0; i < nrRegs; ++i) {
_docColls.emplace_back(nullptr);
}
}
}
////////////////////////////////////////////////////////////////////////////////
/// @brief create the block from Json, note that this can throw
////////////////////////////////////////////////////////////////////////////////
AqlItemBlock::AqlItemBlock (Json const& json) {
bool exhausted = JsonHelper::getBooleanValue(json.json(), "exhausted", false);
if (exhausted) {
THROW_ARANGO_EXCEPTION_MESSAGE(TRI_ERROR_INTERNAL, "exhausted must be false");
}
_nrItems = JsonHelper::getNumericValue<size_t>(json.json(), "nrItems", 0);
if (_nrItems == 0) {
THROW_ARANGO_EXCEPTION_MESSAGE(TRI_ERROR_INTERNAL, "nrItems must be > 0");
}
_nrRegs = JsonHelper::getNumericValue<RegisterId>(json.json(), "nrRegs", 0);
// Initialize the data vector:
if (_nrRegs > 0) {
_data.resize(_nrItems * _nrRegs);
_docColls.reserve(_nrRegs);
for (size_t i = 0; i < _nrRegs; ++i) {
_docColls.emplace_back(nullptr);
}
}
// Now put in the data:
Json data(json.get("data"));
Json raw(json.get("raw"));
std::vector<AqlValue> madeHere;
madeHere.reserve(raw.size());
madeHere.emplace_back(); // an empty AqlValue
madeHere.emplace_back(); // another empty AqlValue, indices start w. 2
try {
size_t posInRaw = 2;
size_t posInData = 0;
int64_t emptyRun = 0;
for (RegisterId column = 0; column < _nrRegs; column++) {
for (size_t i = 0; i < _nrItems; i++) {
if (emptyRun > 0) {
emptyRun--;
}
else {
Json dataEntry(data.at(static_cast<int>(posInData++)));
if (! dataEntry.isNumber()) {
THROW_ARANGO_EXCEPTION_MESSAGE(TRI_ERROR_INTERNAL,
"data must contain only numbers");
}
int64_t n = JsonHelper::getNumericValue<int64_t>(dataEntry.json(), 0);
if (n == 0) {
// empty, do nothing here
}
else if (n == -1) {
// empty run:
Json runLength(data.at(static_cast<int>(posInData++)));
emptyRun = JsonHelper::getNumericValue<int64_t>(runLength.json(), 0);
TRI_ASSERT(emptyRun > 0);
emptyRun--;
}
else if (n == -2) {
// a range
Json lowBound(data.at(static_cast<int>(posInData++)));
Json highBound(data.at(static_cast<int>(posInData++)));
int64_t low = JsonHelper::getNumericValue<int64_t>(lowBound.json(), 0);
int64_t high = JsonHelper::getNumericValue<int64_t>(highBound.json(), 0);
AqlValue a(low, high);
try {
setValue(i, column, a);
}
catch (...) {
a.destroy();
throw;
}
}
else if (n == 1) {
// a JSON value
Json x(raw.at(static_cast<int>(posInRaw++)));
AqlValue a(new Json(TRI_UNKNOWN_MEM_ZONE, x.copy().steal()));
try {
setValue(i, column, a); // if this throws, a is destroyed again
}
catch (...) {
a.destroy();
throw;
}
madeHere.emplace_back(a);
}
else if (n >= 2) {
setValue(i, column, madeHere[static_cast<size_t>(n)]);
// If this throws, all is OK, because it was already put into
// the block elsewhere.
}
else {
THROW_ARANGO_EXCEPTION_MESSAGE(TRI_ERROR_INTERNAL,
"found undefined data value");
}
}
}
}
}
catch (...) {
destroy();
}
}
////////////////////////////////////////////////////////////////////////////////
/// @brief destroy the block, used in the destructor and elsewhere
////////////////////////////////////////////////////////////////////////////////
void AqlItemBlock::destroy () {
if (_valueCount.empty()) {
return;
}
for (auto& it : _data) {
if (it.requiresDestruction()) {
try { // can find() really throw???
auto it2 = _valueCount.find(it);
if (it2 != _valueCount.end()) { // if we know it, we are still responsible
TRI_ASSERT_EXPENSIVE(it2->second > 0);
if (--(it2->second) == 0) {
it.destroy();
try {
_valueCount.erase(it2);
}
catch (...) {
}
}
}
}
catch (...) {
}
// Note that if we do not know it the thing it has been stolen from us!
}
else {
it.erase();
}
}
_valueCount.clear();
}
// -----------------------------------------------------------------------------
// --SECTION-- public methods
// -----------------------------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
/// @brief shrink the block to the specified number of rows
////////////////////////////////////////////////////////////////////////////////
void AqlItemBlock::shrink (size_t nrItems) {
TRI_ASSERT(nrItems > 0);
if (nrItems == _nrItems) {
// nothing to do
return;
}
if (nrItems > _nrItems) {
// cannot use shrink() to increase the size of the block
THROW_ARANGO_EXCEPTION(TRI_ERROR_INTERNAL);
}
// erase all stored values in the region that we freed
for (size_t i = nrItems; i < _nrItems; ++i) {
for (RegisterId j = 0; j < _nrRegs; ++j) {
AqlValue& a(_data[_nrRegs * i + j]);
if (a.requiresDestruction()) {
auto it = _valueCount.find(a);
if (it != _valueCount.end()) {
TRI_ASSERT_EXPENSIVE(it->second > 0);
if (--it->second == 0) {
a.destroy();
try {
_valueCount.erase(it);
}
catch (...) {
}
}
}
}
a.erase();
}
}
// adjust the size of the block
_nrItems = nrItems;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief clears out some columns (registers), this deletes the values if
/// necessary, using the reference count.
////////////////////////////////////////////////////////////////////////////////
void AqlItemBlock::clearRegisters (std::unordered_set<RegisterId> const& toClear) {
for (auto const& reg : toClear) {
for (size_t i = 0; i < _nrItems; i++) {
AqlValue& a(_data[_nrRegs * i + reg]);
if (a.requiresDestruction()) {
auto it = _valueCount.find(a);
if (it != _valueCount.end()) {
TRI_ASSERT_EXPENSIVE(it->second > 0);
if (--it->second == 0) {
a.destroy();
try {
_valueCount.erase(it);
continue; // no need for an extra a.erase() here
}
catch (...) {
}
}
}
}
a.erase();
}
}
}
////////////////////////////////////////////////////////////////////////////////
/// @brief slice/clone, this does a deep copy of all entries
////////////////////////////////////////////////////////////////////////////////
AqlItemBlock* AqlItemBlock::slice (size_t from,
size_t to) const {
TRI_ASSERT(from < to && to <= _nrItems);
std::unordered_map<AqlValue, AqlValue> cache;
cache.reserve((to - from) * _nrRegs / 4 + 1);
std::unique_ptr<AqlItemBlock> res(new AqlItemBlock(to - from, _nrRegs));
for (RegisterId col = 0; col < _nrRegs; col++) {
res->_docColls[col] = _docColls[col];
}
for (size_t row = from; row < to; row++) {
for (RegisterId col = 0; col < _nrRegs; col++) {
AqlValue const& a(_data[row * _nrRegs + col]);
if (! a.isEmpty()) {
auto it = cache.find(a);
if (it == cache.end()) {
AqlValue b = a.clone();
try {
res->setValue(row - from, col, b);
}
catch (...) {
b.destroy();
throw;
}
cache.emplace(a, b);
}
else {
res->setValue(row - from, col, it->second);
}
}
}
}
return res.release();
}
////////////////////////////////////////////////////////////////////////////////
/// @brief slice/clone, this does a deep copy of all entries
////////////////////////////////////////////////////////////////////////////////
AqlItemBlock* AqlItemBlock::slice (size_t row,
std::unordered_set<RegisterId> const& registers) const {
std::unordered_map<AqlValue, AqlValue> cache;
std::unique_ptr<AqlItemBlock> res(new AqlItemBlock(1, _nrRegs));
for (RegisterId col = 0; col < _nrRegs; col++) {
if (registers.find(col) == registers.end()) {
continue;
}
res->_docColls[col] = _docColls[col];
AqlValue const& a(_data[row * _nrRegs + col]);
if (! a.isEmpty()) {
auto it = cache.find(a);
if (it == cache.end()) {
AqlValue b = a.clone();
try {
res->setValue(0, col, b);
}
catch (...) {
b.destroy();
throw;
}
cache.emplace(a, b);
}
else {
res->setValue(0, col, it->second);
}
}
}
return res.release();
}
////////////////////////////////////////////////////////////////////////////////
/// @brief slice/clone chosen rows for a subset, this does a deep copy
/// of all entries
////////////////////////////////////////////////////////////////////////////////
AqlItemBlock* AqlItemBlock::slice (std::vector<size_t>& chosen,
size_t from,
size_t to) const {
TRI_ASSERT(from < to && to <= chosen.size());
std::unordered_map<AqlValue, AqlValue> cache;
cache.reserve((to - from) * _nrRegs / 4 + 1);
std::unique_ptr<AqlItemBlock> res(new AqlItemBlock(to - from, _nrRegs));
for (RegisterId col = 0; col < _nrRegs; col++) {
res->_docColls[col] = _docColls[col];
}
for (size_t row = from; row < to; row++) {
for (RegisterId col = 0; col < _nrRegs; col++) {
AqlValue const& a(_data[chosen[row] * _nrRegs + col]);
if (! a.isEmpty()) {
auto it = cache.find(a);
if (it == cache.end()) {
AqlValue b = a.clone();
try {
res->setValue(row - from, col, b);
}
catch (...) {
b.destroy();
}
cache.emplace(a, b);
}
else {
res->setValue(row - from, col, it->second);
}
}
}
}
return res.release();
}
////////////////////////////////////////////////////////////////////////////////
/// @brief steal for a subset, this does not copy the entries, rather,
/// it remembers which it has taken. This is stored in the
/// this by removing the value counts in _valueCount.
/// It is highly recommended to delete this object right after this
/// operation, because it is unclear, when the values to which our
/// AqlValues point will vanish! In particular, do not use setValue
/// any more.
////////////////////////////////////////////////////////////////////////////////
AqlItemBlock* AqlItemBlock::steal (std::vector<size_t>& chosen,
size_t from,
size_t to) {
TRI_ASSERT(from < to && to <= chosen.size());
std::unique_ptr<AqlItemBlock> res(new AqlItemBlock(to - from, _nrRegs));
for (RegisterId col = 0; col < _nrRegs; col++) {
res->_docColls[col] = _docColls[col];
}
for (size_t row = from; row < to; row++) {
for (RegisterId col = 0; col < _nrRegs; col++) {
AqlValue& a(_data[chosen[row] * _nrRegs + col]);
if (! a.isEmpty()) {
steal(a);
try {
res->setValue(row - from, col, a);
}
catch (...) {
a.destroy();
}
eraseValue(chosen[row], col);
}
}
}
return res.release();
}
////////////////////////////////////////////////////////////////////////////////
/// @brief concatenate multiple blocks, note that the new block now owns all
/// AqlValue pointers in the old blocks, therefore, the latter are all
/// set to nullptr, just to be sure.
////////////////////////////////////////////////////////////////////////////////
AqlItemBlock* AqlItemBlock::concatenate (std::vector<AqlItemBlock*> const& blocks) {
TRI_ASSERT(! blocks.empty());
auto it = blocks.begin();
TRI_ASSERT(it != blocks.end());
size_t totalSize = (*it)->size();
RegisterId nrRegs = (*it)->getNrRegs();
while (true) {
if (++it == blocks.end()) {
break;
}
totalSize += (*it)->size();
TRI_ASSERT((*it)->getNrRegs() == nrRegs);
}
TRI_ASSERT(totalSize > 0);
TRI_ASSERT(nrRegs > 0);
std::unique_ptr<AqlItemBlock> res(new AqlItemBlock(totalSize, nrRegs));
size_t pos = 0;
for (it = blocks.begin(); it != blocks.end(); ++it) {
// handle collections
if (it == blocks.begin()) {
// copy collection info over
for (RegisterId col = 0; col < nrRegs; ++col) {
res->setDocumentCollection(col, (*it)->getDocumentCollection(col));
}
}
else {
for (RegisterId col = 0; col < nrRegs; ++col) {
TRI_ASSERT(res->getDocumentCollection(col) ==
(*it)->getDocumentCollection(col));
}
}
TRI_ASSERT((*it) != res.get());
size_t const n = (*it)->size();
for (size_t row = 0; row < n; ++row) {
for (RegisterId col = 0; col < nrRegs; ++col) {
// copy over value
if (! (*it)->getValueReference(row, col).isEmpty()) {
res->setValue(pos + row, col, (*it)->getValue(row, col));
}
}
}
(*it)->eraseAll();
pos += (*it)->size();
}
return res.release();
}
////////////////////////////////////////////////////////////////////////////////
/// @brief toJson, transfer a whole AqlItemBlock to Json, the result can
/// be used to recreate the AqlItemBlock via the Json constructor
/// Here is a description of the data format: The resulting Json has
/// the following attributes:
/// "nrItems": the number of rows of the AqlItemBlock
/// "nrRegs": the number of registers of the AqlItemBlock
/// "error": always set to false
/// "data": this contains the actual data in the form of a list of
/// numbers. The AqlItemBlock is stored columnwise, starting
/// from the first column (top to bottom) and going right.
/// Each entry found is encoded in the following way:
/// 0.0 means a single empty entry
/// -1.0 followed by a positive integer N (encoded as number)
/// means a run of that many empty entries
/// -2.0 followed by two numbers LOW and HIGH means a range
/// and LOW and HIGH are the boundaries (inclusive)
/// 1.0 means a JSON entry at the "next" position in "raw"
/// the "next" position starts with 2 and is increased
/// by one for every 1.0 found in data
/// integer values >= 2.0 mean a JSON entry, in this
/// case the "raw" list contains an entry in the
/// corresponding position
/// "raw": List of actual values, positions 0 and 1 are always null
/// such that actual indices start at 2
////////////////////////////////////////////////////////////////////////////////
Json AqlItemBlock::toJson (triagens::arango::AqlTransaction* trx) const {
Json json(Json::Object, 6);
json("nrItems", Json(static_cast<double>(_nrItems)))
("nrRegs", Json(static_cast<double>(_nrRegs)));
Json data(Json::Array, _data.size());
Json raw(Json::Array, _data.size() + 2);
raw(Json(Json::Null))
(Json(Json::Null)); // Two nulls in the beginning such that
// indices start with 2
std::unordered_map<AqlValue, size_t> table; // remember duplicates
size_t emptyCount = 0; // here we count runs of empty AqlValues
auto commitEmpties = [&] () { // this commits an empty run to the data
if (emptyCount > 0) {
if (emptyCount == 1) {
data(Json(0.0));
}
else {
data(Json(-1.0))
(Json(static_cast<double>(emptyCount)));
}
emptyCount = 0;
}
};
size_t pos = 2; // write position in raw
for (RegisterId column = 0; column < _nrRegs; column++) {
for (size_t i = 0; i < _nrItems; i++) {
AqlValue const& a(_data[i * _nrRegs + column]);
if (a.isEmpty()) {
emptyCount++;
}
else {
commitEmpties();
if (a._type == AqlValue::RANGE) {
data(Json(-2.0))
(Json(static_cast<double>(a._range->_low)))
(Json(static_cast<double>(a._range->_high)));
}
else {
auto it = table.find(a);
if (it == table.end()) {
raw(a.toJson(trx, _docColls[column], true));
data(Json(1.0));
table.emplace(std::make_pair(a, pos++));
}
else {
data(Json(static_cast<double>(it->second)));
}
}
}
}
}
commitEmpties();
json("data", data)
("raw", raw)
("error", Json(false))
("exhausted", Json(false));
return json;
}
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