diff --git a/src/column_family.rs b/src/column_family.rs
index 1cde254..f39e895 100644
--- a/src/column_family.rs
+++ b/src/column_family.rs
@@ -141,4 +141,6 @@ impl<'a> AsColumnFamilyRef for Arc<BoundColumnFamily<'a>> {
 }
 
 unsafe impl Send for ColumnFamily {}
+unsafe impl Send for UnboundColumnFamily {}
+unsafe impl Sync for UnboundColumnFamily {}
 unsafe impl<'a> Send for BoundColumnFamily<'a> {}
diff --git a/src/db.rs b/src/db.rs
index 9b673ec..e8e0338 100644
--- a/src/db.rs
+++ b/src/db.rs
@@ -245,7 +245,7 @@ pub type DB = DBWithThreadMode<MultiThreaded>;
 // Safety note: auto-implementing Send on most db-related types is prevented by the inner FFI
 // pointer. In most cases, however, this pointer is Send-safe because it is never aliased and
 // rocksdb internally does not rely on thread-local information for its user-exposed types.
-unsafe impl<T: ThreadMode> Send for DBWithThreadMode<T> {}
+unsafe impl<T: ThreadMode + Send> Send for DBWithThreadMode<T> {}
 
 // Sync is similarly safe for many types because they do not expose interior mutability, and their
 // use within the rocksdb library is generally behind a const reference
diff --git a/src/db_options.rs b/src/db_options.rs
index 2a66d8e..768a463 100644
--- a/src/db_options.rs
+++ b/src/db_options.rs
@@ -92,7 +92,7 @@ impl Cache {
 #[derive(Clone)]
 pub struct Env(Arc<EnvWrapper>);
 
-struct EnvWrapper {
+pub(crate) struct EnvWrapper {
     inner: *mut ffi::rocksdb_env_t,
 }
 
@@ -381,8 +381,8 @@ unsafe impl Send for BlockBasedOptions {}
 unsafe impl Send for CuckooTableOptions {}
 unsafe impl Send for ReadOptions {}
 unsafe impl Send for IngestExternalFileOptions {}
-unsafe impl Send for Cache {}
-unsafe impl Send for Env {}
+unsafe impl Send for CacheWrapper {}
+unsafe impl Send for EnvWrapper {}
 
 // Sync is similarly safe for many types because they do not expose interior mutability, and their
 // use within the rocksdb library is generally behind a const reference
@@ -392,8 +392,8 @@ unsafe impl Sync for BlockBasedOptions {}
 unsafe impl Sync for CuckooTableOptions {}
 unsafe impl Sync for ReadOptions {}
 unsafe impl Sync for IngestExternalFileOptions {}
-unsafe impl Sync for Cache {}
-unsafe impl Sync for Env {}
+unsafe impl Sync for CacheWrapper {}
+unsafe impl Sync for EnvWrapper {}
 
 impl Drop for Options {
     fn drop(&mut self) {
diff --git a/src/ffi_util.rs b/src/ffi_util.rs
index dc2aa39..6421f46 100644
--- a/src/ffi_util.rs
+++ b/src/ffi_util.rs
@@ -28,9 +28,9 @@ pub(crate) unsafe fn raw_data(ptr: *const c_char, size: usize) -> Option<Vec<u8>
     if ptr.is_null() {
         None
     } else {
-        let mut dst = Vec::with_capacity(size);
+        let mut dst = vec![0; size];
         ptr::copy_nonoverlapping(ptr as *const u8, dst.as_mut_ptr(), size);
-        dst.set_len(size);
+
         Some(dst)
     }
 }
diff --git a/src/lib.rs b/src/lib.rs
index c84f834..f132115 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -168,6 +168,8 @@ impl fmt::Display for Error {
 #[cfg(test)]
 mod test {
     use super::{
+        column_family::UnboundColumnFamily,
+        db_options::{CacheWrapper, EnvWrapper},
         BlockBasedOptions, BoundColumnFamily, Cache, ColumnFamily, ColumnFamilyDescriptor,
         DBIterator, DBRawIterator, Env, IngestExternalFileOptions, Options,
         PlainTableFactoryOptions, ReadOptions, Snapshot, SstFileWriter, WriteBatch, WriteOptions,
@@ -196,10 +198,13 @@ mod test {
         is_send::<ColumnFamilyDescriptor>();
         is_send::<ColumnFamily>();
         is_send::<BoundColumnFamily<'_>>();
+        is_send::<UnboundColumnFamily>();
         is_send::<SstFileWriter>();
         is_send::<WriteBatch>();
         is_send::<Cache>();
+        is_send::<CacheWrapper>();
         is_send::<Env>();
+        is_send::<EnvWrapper>();
     }
 
     #[test]
@@ -218,9 +223,12 @@ mod test {
         is_sync::<IngestExternalFileOptions>();
         is_sync::<BlockBasedOptions>();
         is_sync::<PlainTableFactoryOptions>();
+        is_sync::<UnboundColumnFamily>();
         is_sync::<ColumnFamilyDescriptor>();
         is_sync::<SstFileWriter>();
         is_sync::<Cache>();
+        is_sync::<CacheWrapper>();
         is_sync::<Env>();
+        is_sync::<EnvWrapper>();
     }
 }
diff --git a/tests/test_column_family.rs b/tests/test_column_family.rs
index 9b4fde8..fc71bed 100644
--- a/tests/test_column_family.rs
+++ b/tests/test_column_family.rs
@@ -47,6 +47,9 @@ fn test_column_family() {
         let mut opts = Options::default();
         opts.create_if_missing(true);
         opts.set_merge_operator_associative("test operator", test_provided_merge);
+        #[cfg(feature = "multi-threaded-cf")]
+        let db = DB::open(&opts, &n).unwrap();
+        #[cfg(not(feature = "multi-threaded-cf"))]
         let mut db = DB::open(&opts, &n).unwrap();
         let opts = Options::default();
         match db.create_cf("cf1", &opts) {
@@ -97,7 +100,11 @@ fn test_column_family() {
     {}
     // should b able to drop a cf
     {
+        #[cfg(feature = "multi-threaded-cf")]
+        let db = DB::open_cf(&Options::default(), &n, &["cf1"]).unwrap();
+        #[cfg(not(feature = "multi-threaded-cf"))]
         let mut db = DB::open_cf(&Options::default(), &n, &["cf1"]).unwrap();
+
         match db.drop_cf("cf1") {
             Ok(_) => println!("cf1 successfully dropped."),
             Err(e) => panic!("failed to drop column family: {}", e),
@@ -114,6 +121,9 @@ fn test_can_open_db_with_results_of_list_cf() {
     {
         let mut opts = Options::default();
         opts.create_if_missing(true);
+        #[cfg(feature = "multi-threaded-cf")]
+        let db = DB::open(&opts, &n).unwrap();
+        #[cfg(not(feature = "multi-threaded-cf"))]
         let mut db = DB::open(&opts, &n).unwrap();
         let opts = Options::default();
 
@@ -261,10 +271,10 @@ fn test_create_duplicate_column_family() {
         opts.create_if_missing(true);
         opts.create_missing_column_families(true);
 
-        let mut db = match DB::open_cf(&opts, &n, &["cf1"]) {
-            Ok(d) => d,
-            Err(e) => panic!("failed to create new column family: {}", e),
-        };
+        #[cfg(feature = "multi-threaded-cf")]
+        let db = DB::open_cf(&opts, &n, &["cf1"]).unwrap();
+        #[cfg(not(feature = "multi-threaded-cf"))]
+        let mut db = DB::open_cf(&opts, &n, &["cf1"]).unwrap();
 
         assert!(db.create_cf("cf1", &opts).is_err());
     }
@@ -282,6 +292,9 @@ fn test_no_leaked_column_family() {
         write_options.set_sync(false);
         write_options.disable_wal(true);
 
+        #[cfg(feature = "multi-threaded-cf")]
+        let db = DB::open(&opts, &n).unwrap();
+        #[cfg(not(feature = "multi-threaded-cf"))]
         let mut db = DB::open(&opts, &n).unwrap();
         let large_blob = [0x20; 1024 * 1024];
 
diff --git a/tests/test_property.rs b/tests/test_property.rs
index 5571441..13217f7 100644
--- a/tests/test_property.rs
+++ b/tests/test_property.rs
@@ -35,6 +35,9 @@ fn property_cf_test() {
     let n = DBPath::new("_rust_rocksdb_property_cf_test");
     {
         let opts = Options::default();
+        #[cfg(feature = "multi-threaded-cf")]
+        let db = DB::open_default(&n).unwrap();
+        #[cfg(not(feature = "multi-threaded-cf"))]
         let mut db = DB::open_default(&n).unwrap();
         db.create_cf("cf1", &opts).unwrap();
         let cf = db.cf_handle("cf1").unwrap();
@@ -62,6 +65,9 @@ fn property_int_cf_test() {
     let n = DBPath::new("_rust_rocksdb_property_int_cf_test");
     {
         let opts = Options::default();
+        #[cfg(feature = "multi-threaded-cf")]
+        let db = DB::open_default(&n).unwrap();
+        #[cfg(not(feature = "multi-threaded-cf"))]
         let mut db = DB::open_default(&n).unwrap();
         db.create_cf("cf1", &opts).unwrap();
         let cf = db.cf_handle("cf1").unwrap();