SERVER-20582: _id time reflects end of chunk instead of beginning

1 files changed, 12 insertions, 5 deletions

diff --git a/src/mongo/db/ftdc/file_reader.cpp b/src/mongo/db/ftdc/file_reader.cpp
index ca850c374fa..e649a029305 100644
--- a/src/mongo/db/ftdc/file_reader.cpp
+++ b/src/mongo/db/ftdc/file_reader.cpp
@@ -71,6 +71,13 @@ StatusWith<bool> FTDCFileReader::hasNext() {
                 return swType.getStatus();
             }
 
+            auto swId = FTDCBSONUtil::getBSONDocumentId(_parent);
+            if (!swId.isOK()) {
+                return swId.getStatus();
+            }
+
+            _dateId = swId.getValue();
+
             FTDCBSONUtil::FTDCType type = swType.getValue();
 
             if (type == FTDCBSONUtil::FTDCType::kMetadata) {
@@ -120,17 +127,17 @@ StatusWith<bool> FTDCFileReader::hasNext() {
     }
 }
 
-std::tuple<FTDCBSONUtil::FTDCType, const BSONObj&> FTDCFileReader::next() {
+std::tuple<FTDCBSONUtil::FTDCType, const BSONObj&, Date_t> FTDCFileReader::next() {
     dassert(_state == State::kMetricChunk || _state == State::kMetadataDoc);
 
     if (_state == State::kMetadataDoc) {
-        return std::tuple<FTDCBSONUtil::FTDCType, const BSONObj&>(FTDCBSONUtil::FTDCType::kMetadata,
-                                                                  _metadata);
+        return std::tuple<FTDCBSONUtil::FTDCType, const BSONObj&, Date_t>(
+            FTDCBSONUtil::FTDCType::kMetadata, _metadata, _dateId);
     }
 
     if (_state == State::kMetricChunk) {
-        return std::tuple<FTDCBSONUtil::FTDCType, const BSONObj&>(
-            FTDCBSONUtil::FTDCType::kMetricChunk, _docs[_pos]);
+        return std::tuple<FTDCBSONUtil::FTDCType, const BSONObj&, Date_t>(
+            FTDCBSONUtil::FTDCType::kMetricChunk, _docs[_pos], _dateId);
     }
 
     MONGO_UNREACHABLE;