1 files changed, 33 insertions, 1 deletions
diff --git a/src/mongo/db/catalog/drop_collection.cpp b/src/mongo/db/catalog/drop_collection.cpp
index b5f30ae2a3e..18ab3311ca0 100644
--- a/src/mongo/db/catalog/drop_collection.cpp
+++ b/src/mongo/db/catalog/drop_collection.cpp
@@ -34,6 +34,7 @@
 #include "mongo/db/catalog/drop_collection.h"
 
 #include "mongo/db/background.h"
+#include "mongo/db/catalog/database_holder.h"
 #include "mongo/db/catalog/index_catalog.h"
 #include "mongo/db/client.h"
 #include "mongo/db/concurrency/write_conflict_exception.h"
@@ -147,6 +148,29 @@ Status _dropCollection(OperationContext* opCtx,
     return Status::OK();
 }
 
+void closeDatabaseIfEmpty(OperationContext* opCtx, StringData ns) {
+    invariant(opCtx->lockState()->isDbLockedForMode(ns, MODE_NONE));
+
+    bool empty = CollectionCatalog::get(opCtx).empty(ns);
+    if (!empty) {
+        return;
+    }
+
+    AutoGetDb autoDb(opCtx, ns, MODE_X);
+    if (!autoDb.getDb()) {
+        return;
+    }
+
+    // Double check that we're still empty. A new collection could've been created before we got the
+    // exclusive lock.
+    empty = CollectionCatalog::get(opCtx).empty(ns);
+    if (!empty) {
+        return;
+    }
+
+    DatabaseHolder::get(opCtx)->close(opCtx, ns);
+}
+
 Status dropCollection(OperationContext* opCtx,
                       const NamespaceString& collectionName,
                       BSONObjBuilder& result,
@@ -160,7 +184,7 @@ Status dropCollection(OperationContext* opCtx,
         log() << "Hanging drop collection before lock acquisition while fail point is set";
         MONGO_FAIL_POINT_PAUSE_WHILE_SET(hangDropCollectionBeforeLockAcquisition);
     }
-    return writeConflictRetry(opCtx, "drop", collectionName.ns(), [&] {
+    Status status = writeConflictRetry(opCtx, "drop", collectionName.ns(), [&] {
         AutoGetDb autoDb(opCtx, collectionName.db(), MODE_IX);
         Database* db = autoDb.getDb();
         if (!db) {
@@ -175,6 +199,14 @@ Status dropCollection(OperationContext* opCtx,
                 opCtx, db, collectionName, dropOpTime, systemCollectionMode, result);
         }
     });
+
+    if (!status.isOK()) {
+        return status;
+    }
+
+    // If this dropped the last collection in the database, we should close the database.
+    closeDatabaseIfEmpty(opCtx, collectionName.db());
+    return Status::OK();
 }
 
 }  // namespace mongo