diff --git a/pyproject.toml b/pyproject.toml
index 2bf5ec8096be861930092d5f2f0188c6663e2913..6d1b4c5b6fb56a63069147e3a1de922ce71a45d8 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,3 +1,3 @@
 [build-system]
-requires = ["setuptools", "wheel", "Cython"]
+requires = ["setuptools", "wheel", "cython"]
 build-backend = "setuptools.build_meta"
diff --git a/rocksdb/_rocksdb.pyx b/rocksdb/_rocksdb.pyx
index b37021ad26ff1ab5a7bf51a5b6bc45d966755243..618586e1ba7ec2c464e8e361ba1afa0838fd8b86 100644
--- a/rocksdb/_rocksdb.pyx
+++ b/rocksdb/_rocksdb.pyx
@@ -1738,6 +1738,7 @@ cdef class DB(object):
                     copts.in_use = False
             del self.cf_options[:]
             with nogil:
+                st = self.db.Close()
                 self.db = NULL
             if self.opts is not None:
                 self.opts.in_use = False