From 867f52afbb79bc00e35c70f8e0681b7d602f97b2 Mon Sep 17 00:00:00 2001 From: "Mickey. J Winters" Date: Fri, 24 Sep 2021 22:15:03 +0000 Subject: SERVER-60218 add initialize helper function for document_source_group --- src/mongo/db/pipeline/document_source_group.cpp | 11 ++++++++--- 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 2ab40378383..73f3a76d81d 100644 --- a/src/mongo/db/pipeline/document_source_group.cpp +++ b/src/mongo/db/pipeline/document_source_group.cpp @@ -549,11 +549,16 @@ 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 (shouldSpillWithAttemptToSaveMemory()) { _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 1e2e1c1d3d4..c9f635af90e 100644 --- a/src/mongo/db/pipeline/document_source_group.h +++ b/src/mongo/db/pipeline/document_source_group.h @@ -222,6 +222,12 @@ 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 -- cgit v1.2.1