Update upstream source from tag 'upstream/6.0.10'debian/6.0.10-1

Update to upstream version '6.0.10'
with Debian dir 2d176fa254eee97b139f712fec5709641335a8c3

1 files changed, 279 insertions, 0 deletions

diff --git a/src/mongo/db/pipeline/document_source_streaming_group.cpp b/src/mongo/db/pipeline/document_source_streaming_group.cpp
new file mode 100644
index 00000000000..44702ab550d
--- /dev/null
+++ b/src/mongo/db/pipeline/document_source_streaming_group.cpp
@@ -0,0 +1,279 @@
+/**
+ *    Copyright (C) 2022-present MongoDB, Inc.
+ *
+ *    This program is free software: you can redistribute it and/or modify
+ *    it under the terms of the Server Side Public License, version 1,
+ *    as published by MongoDB, Inc.
+ *
+ *    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
+ *    Server Side Public License for more details.
+ *
+ *    You should have received a copy of the Server Side Public License
+ *    along with this program. If not, see
+ *    <http://www.mongodb.com/licensing/server-side-public-license>.
+ *
+ *    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 Server Side 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.
+ */
+
+#include "mongo/platform/basic.h"
+
+#include <memory>
+
+#include "mongo/db/exec/document_value/document.h"
+#include "mongo/db/exec/document_value/value.h"
+#include "mongo/db/exec/document_value/value_comparator.h"
+#include "mongo/db/pipeline/accumulation_statement.h"
+#include "mongo/db/pipeline/accumulator.h"
+#include "mongo/db/pipeline/document_source_group.h"
+#include "mongo/db/pipeline/document_source_streaming_group.h"
+#include "mongo/db/pipeline/expression.h"
+#include "mongo/db/pipeline/expression_context.h"
+#include "mongo/db/pipeline/lite_parsed_document_source.h"
+#include "mongo/db/stats/resource_consumption_metrics.h"
+#include "mongo/util/destructor_guard.h"
+
+namespace mongo {
+
+/*
+ * $_internalStreamingGroup is an internal stage that is only used in certain cases by the
+ * pipeline optimizer. For now it should not be used anywhere outside the MongoDB server.
+ */
+REGISTER_DOCUMENT_SOURCE(_internalStreamingGroup,
+                         LiteParsedDocumentSourceDefault::parse,
+                         DocumentSourceStreamingGroup::createFromBson,
+                         AllowedWithApiStrict::kAlways);
+
+constexpr StringData DocumentSourceStreamingGroup::kStageName;
+
+const char* DocumentSourceStreamingGroup::getSourceName() const {
+    return kStageName.rawData();
+}
+
+DocumentSource::GetNextResult DocumentSourceStreamingGroup::doGetNext() {
+    auto getReadyResult = getNextReadyGroup();
+    if (!getReadyResult.isEOF()) {
+        return getReadyResult;
+    } else if (_sourceDepleted) {
+        dispose();
+        return getReadyResult;
+    }
+
+    auto prepareResult = readyNextBatch();
+    if (prepareResult.isPaused()) {
+        return prepareResult;
+    }
+    return getNextReadyGroup();
+}
+
+DocumentSourceStreamingGroup::DocumentSourceStreamingGroup(
+    const boost::intrusive_ptr<ExpressionContext>& expCtx,
+    boost::optional<size_t> maxMemoryUsageBytes)
+    : DocumentSourceGroupBase(kStageName, expCtx, maxMemoryUsageBytes), _sourceDepleted(false) {}
+
+boost::intrusive_ptr<DocumentSourceStreamingGroup> DocumentSourceStreamingGroup::create(
+    const boost::intrusive_ptr<ExpressionContext>& expCtx,
+    const boost::intrusive_ptr<Expression>& groupByExpression,
+    std::vector<size_t> monotonicExpressionIndexes,
+    std::vector<AccumulationStatement> accumulationStatements,
+    boost::optional<size_t> maxMemoryUsageBytes) {
+    boost::intrusive_ptr<DocumentSourceStreamingGroup> groupStage =
+        new DocumentSourceStreamingGroup(expCtx, maxMemoryUsageBytes);
+    groupStage->setIdExpression(groupByExpression);
+    for (auto&& statement : accumulationStatements) {
+        groupStage->addAccumulator(statement);
+    }
+    uassert(7026709,
+            "streaming group must have at least one monotonic id expression",
+            !monotonicExpressionIndexes.empty());
+    uassert(7026710,
+            "streaming group monotonic expression indexes must correspond to id expressions",
+            std::all_of(monotonicExpressionIndexes.begin(),
+                        monotonicExpressionIndexes.end(),
+                        [&](size_t i) { return i < groupStage->_idExpressions.size(); }));
+    groupStage->_monotonicExpressionIndexes = std::move(monotonicExpressionIndexes);
+    return groupStage;
+}
+
+boost::intrusive_ptr<DocumentSource> DocumentSourceStreamingGroup::createFromBson(
+    BSONElement elem, const boost::intrusive_ptr<ExpressionContext>& expCtx) {
+    return createFromBsonWithMaxMemoryUsage(std::move(elem), expCtx, boost::none);
+}
+
+boost::intrusive_ptr<DocumentSource> DocumentSourceStreamingGroup::createFromBsonWithMaxMemoryUsage(
+    BSONElement elem,
+    const boost::intrusive_ptr<ExpressionContext>& expCtx,
+    boost::optional<size_t> maxMemoryUsageBytes) {
+    boost::intrusive_ptr<DocumentSourceStreamingGroup> groupStage =
+        new DocumentSourceStreamingGroup(expCtx, maxMemoryUsageBytes);
+    groupStage->initializeFromBson(elem);
+
+    const auto& monotonicIdFieldsElem = elem.Obj().getField(kMonotonicIdFieldsSpecField);
+    uassert(7026702,
+            "streaming group must specify an array of monotonic id fields " +
+                kMonotonicIdFieldsSpecField,
+            monotonicIdFieldsElem.type() == Array);
+    const auto& monotonicIdFields = monotonicIdFieldsElem.Array();
+    if (groupStage->_idFieldNames.empty()) {
+        uassert(7026703,
+                "if there is no explicit id fields, " + kMonotonicIdFieldsSpecField +
+                    " must contain a single \"_id\" string",
+                monotonicIdFields.size() == 1 &&
+                    monotonicIdFields[0].valueStringDataSafe() == "_id"_sd);
+        groupStage->_monotonicExpressionIndexes.push_back(0);
+    } else {
+        groupStage->_monotonicExpressionIndexes.reserve(monotonicIdFields.size());
+        for (const auto& fieldNameElem : monotonicIdFields) {
+            uassert(7026704,
+                    kMonotonicIdFieldsSpecField + " elements must be strings",
+                    fieldNameElem.type() == String);
+            StringData fieldName = fieldNameElem.valueStringData();
+            auto it = std::find(
+                groupStage->_idFieldNames.begin(), groupStage->_idFieldNames.end(), fieldName);
+            uassert(7026705, "id field not found", it != groupStage->_idFieldNames.end());
+            groupStage->_monotonicExpressionIndexes.push_back(
+                std::distance(groupStage->_idFieldNames.begin(), it));
+        }
+        std::sort(groupStage->_monotonicExpressionIndexes.begin(),
+                  groupStage->_monotonicExpressionIndexes.end());
+    }
+
+    return groupStage;
+}
+
+void DocumentSourceStreamingGroup::serializeAdditionalFields(
+    MutableDocument& out, boost::optional<ExplainOptions::Verbosity> explain) const {
+    std::vector<Value> monotonicIdFields;
+    if (_idFieldNames.empty()) {
+        monotonicIdFields.emplace_back("_id"_sd);
+    } else {
+        for (size_t i : _monotonicExpressionIndexes) {
+            monotonicIdFields.emplace_back(_idFieldNames[i]);
+        }
+    }
+    out[kMonotonicIdFieldsSpecField] = Value(std::move(monotonicIdFields));
+}
+
+bool DocumentSourceStreamingGroup::isSpecFieldReserved(StringData fieldName) {
+    return fieldName == kMonotonicIdFieldsSpecField;
+}
+
+DocumentSource::GetNextResult DocumentSourceStreamingGroup::getNextDocument() {
+    if (_firstDocumentOfNextBatch) {
+        GetNextResult result = std::move(_firstDocumentOfNextBatch.value());
+        _firstDocumentOfNextBatch.reset();
+        return result;
+    }
+    return pSource->getNext();
+}
+
+DocumentSource::GetNextResult DocumentSourceStreamingGroup::readyNextBatch() {
+    resetReadyGroups();
+    GetNextResult input = getNextDocument();
+    return readyNextBatchInner(input);
+}
+
+// This separate NOINLINE function is used here to decrease stack utilization of readyNextBatch()
+// and prevent stack overflows.
+MONGO_COMPILER_NOINLINE DocumentSource::GetNextResult
+DocumentSourceStreamingGroup::readyNextBatchInner(GetNextResult input) {
+    setExecutionStarted();
+    // Calculate groups until we either exaust pSource or encounter change in monotonic id
+    // expression, which means all current groups are finalized.
+    for (; input.isAdvanced(); input = pSource->getNext()) {
+        if (shouldSpillWithAttemptToSaveMemory()) {
+            spill();
+        }
+        auto root = input.releaseDocument();
+        Value id = computeId(root);
+
+        if (isBatchFinished(id)) {
+            _firstDocumentOfNextBatch = std::move(root);
+            readyGroups();
+            return input;
+        }
+
+        processDocument(id, root);
+    }
+
+    switch (input.getStatus()) {
+        case DocumentSource::GetNextResult::ReturnStatus::kAdvanced: {
+            MONGO_UNREACHABLE;  // We consumed all advances above.
+        }
+        case DocumentSource::GetNextResult::ReturnStatus::kPauseExecution: {
+            return input;  // Propagate pause.
+        }
+        case DocumentSource::GetNextResult::ReturnStatus::kEOF: {
+            readyGroups();
+            _sourceDepleted = true;
+            return input;
+        }
+    }
+    MONGO_UNREACHABLE;
+}
+
+bool DocumentSourceStreamingGroup::isBatchFinished(const Value& id) {
+    if (_idExpressions.size() == 1) {
+        tassert(7026706,
+                "if there are no explicit id fields, it is only one monotonic expression with id 0",
+                _monotonicExpressionIndexes.size() == 1 && _monotonicExpressionIndexes[0] == 0);
+        return checkForBatchEndAndUpdateLastIdValues([&](size_t) { return id; });
+    } else {
+        tassert(7026707,
+                "if there are explicit id fields, internal representation of id is an array",
+                id.isArray());
+        const std::vector<Value>& idValues = id.getArray();
+        return checkForBatchEndAndUpdateLastIdValues([&](size_t i) { return idValues[i]; });
+    }
+}
+
+template <typename IdValueGetter>
+bool DocumentSourceStreamingGroup::checkForBatchEndAndUpdateLastIdValues(
+    const IdValueGetter& idValueGetter) {
+    auto assertStreamable = [&](Value value) {
+        // Nullish and array values will mess us up because they sort differently than they group.
+        // A null and a missing value will compare equal in sorting, but could result in different
+        // groups, e.g. {_id: {x: null, y: null}} vs {_id: {}}. An array value will sort by the min
+        // or max element, with no tie breaking, but group by the whole array. This means that two
+        // of the exact same array could appear in the input sequence, but with a different array in
+        // the middle of them, and that would still be considered sorted. That would break our
+        // batching group logic.
+        uassert(7026708,
+                "Monotonic value should not be missing, null or an array",
+                !value.nullish() && !value.isArray());
+        return value;
+    };
+
+    // If _lastMonotonicIdFieldValues is empty, it is the first document, so the only thing we need
+    // to do is initialize it.
+    if (_lastMonotonicIdFieldValues.empty()) {
+        for (size_t i : _monotonicExpressionIndexes) {
+            _lastMonotonicIdFieldValues.push_back(assertStreamable(idValueGetter(i)));
+        }
+        return false;
+    } else {
+        bool batchFinished = false;
+        for (size_t index = 0; index < _monotonicExpressionIndexes.size(); ++index) {
+            Value& oldId = _lastMonotonicIdFieldValues[index];
+            const Value& id = assertStreamable(idValueGetter(_monotonicExpressionIndexes[index]));
+            if (pExpCtx->getValueComparator().compare(oldId, id) != 0) {
+                oldId = id;
+                batchFinished = true;
+            }
+        }
+        return batchFinished;
+    }
+}
+
+}  // namespace mongo