SERVER-48414 Extend Sorter and BulkBuilder interfaces to return data for resuming index builds

2 files changed, 28 insertions, 0 deletions

diff --git a/src/mongo/db/index/index_access_method.cpp b/src/mongo/db/index/index_access_method.cpp
index 00980d9905f..a365dc163f8 100644
--- a/src/mongo/db/index/index_access_method.cpp
+++ b/src/mongo/db/index/index_access_method.cpp
@@ -471,6 +471,8 @@ public:
 
     int64_t getKeysInserted() const final;
 
+    State getState() const final;
+
 private:
     std::unique_ptr<Sorter> _sorter;
     IndexCatalogEntry* _indexCatalogEntry;
@@ -487,6 +489,10 @@ private:
     // These are inserted into the sorter after all normal data keys have been added, just
     // before the bulk build is committed.
     KeyStringSet _multikeyMetadataKeys;
+
+    // The RecordId corresponding to the object most recently inserted using this BulkBuilder, or
+    // boost::none if nothing has been inserted into the sorter or done() has already been called.
+    boost::optional<RecordId> _lastRecordIdInserted;
 };
 
 std::unique_ptr<IndexAccessMethod::BulkBuilder> AbstractIndexAccessMethod::initiateBulk(
@@ -567,6 +573,7 @@ Status AbstractIndexAccessMethod::BulkBuilderImpl::insert(OperationContext* opCt
     _isMultiKey = _isMultiKey ||
         _indexCatalogEntry->accessMethod()->shouldMarkIndexAsMultikey(
             keys->size(), _multikeyMetadataKeys, *multikeyPaths);
+    _lastRecordIdInserted = loc;
 
     return Status::OK();
 }
@@ -585,6 +592,7 @@ AbstractIndexAccessMethod::BulkBuilderImpl::done() {
         _sorter->add(keyString, mongo::NullValue());
         ++_keysInserted;
     }
+    _lastRecordIdInserted = boost::none;
     return _sorter->done();
 }
 
@@ -592,6 +600,14 @@ int64_t AbstractIndexAccessMethod::BulkBuilderImpl::getKeysInserted() const {
     return _keysInserted;
 }
 
+AbstractIndexAccessMethod::BulkBuilder::State AbstractIndexAccessMethod::BulkBuilderImpl::getState()
+    const {
+    return {_lastRecordIdInserted,
+            _sorter->getTempDir(),
+            _sorter->getFileName(),
+            _sorter->getRangeInfos()};
+}
+
 Status AbstractIndexAccessMethod::commitBulk(OperationContext* opCtx,
                                              BulkBuilder* bulk,
                                              bool dupsAllowed,
diff --git a/src/mongo/db/index/index_access_method.h b/src/mongo/db/index/index_access_method.h
index bf41334ce1f..deb586ddeb6 100644
--- a/src/mongo/db/index/index_access_method.h
+++ b/src/mongo/db/index/index_access_method.h
@@ -205,6 +205,13 @@ public:
     public:
         using Sorter = mongo::Sorter<KeyString::Value, mongo::NullValue>;
 
+        struct State {
+            boost::optional<RecordId> lastRecordIdInserted;
+            std::string tempDir;
+            std::string fileName;
+            std::vector<SorterRangeInfo> ranges;
+        };
+
         virtual ~BulkBuilder() = default;
 
         /**
@@ -229,6 +236,11 @@ public:
          * Returns number of keys inserted using this BulkBuilder.
          */
         virtual int64_t getKeysInserted() const = 0;
+
+        /**
+         * Returns the current state of this BulkBuilder and its underlying Sorter.
+         */
+        virtual State getState() const = 0;
     };
 
     /**