diff options
-rw-r--r-- | src/mongo/db/pipeline/document_source_group.cpp | 11 | ||||
-rw-r--r-- | src/mongo/db/pipeline/document_source_group.h | 6 |
2 files changed, 14 insertions, 3 deletions
diff --git a/src/mongo/db/pipeline/document_source_group.cpp b/src/mongo/db/pipeline/document_source_group.cpp index a82d90b9be3..4a7b48d6cd2 100644 --- a/src/mongo/db/pipeline/document_source_group.cpp +++ b/src/mongo/db/pipeline/document_source_group.cpp @@ -502,11 +502,16 @@ private: } // namespace DocumentSource::GetNextResult DocumentSourceGroup::initialize() { - const size_t numAccumulators = _accumulatedFields.size(); - - // Barring any pausing, this loop exhausts 'pSource' and populates '_groups'. GetNextResult input = pSource->getNext(); + return initializeSelf(input); +} +// This separate NOINLINE function is used here to decrease stack utilization of initialize() and +// prevent stack overflows. +MONGO_COMPILER_NOINLINE DocumentSource::GetNextResult DocumentSourceGroup::initializeSelf( + GetNextResult input) { + const size_t numAccumulators = _accumulatedFields.size(); + // Barring any pausing, this loop exhausts 'pSource' and populates '_groups'. for (; input.isAdvanced(); input = pSource->getNext()) { if (_memoryTracker.shouldSpillWithAttemptToSaveMemory([this]() { return freeMemory(); })) { _sortedFiles.push_back(spill()); diff --git a/src/mongo/db/pipeline/document_source_group.h b/src/mongo/db/pipeline/document_source_group.h index ee8ad1f2f14..16cb45b85b9 100644 --- a/src/mongo/db/pipeline/document_source_group.h +++ b/src/mongo/db/pipeline/document_source_group.h @@ -221,6 +221,12 @@ private: GetNextResult initialize(); /** + * Initializes this $group after any children are potentially initialized see initialize() for + * more details. + */ + GetNextResult initializeSelf(GetNextResult input); + + /** * Spill groups map to disk and returns an iterator to the file. Note: Since a sorted $group * does not exhaust the previous stage before returning, and thus does not maintain as large a * store of documents at any one time, only an unsorted group can spill to disk. |