Add the DB::key_may_exist_cf_opt method

CHANGELOG.md

@@ -2,6 +2,9 @@
 
 ## [Unreleased]
 
+* Add `DB::key_may_exist_cf_opt` method (stanislav-tkach)
+* Add `Options::set_zstd_max_train_bytes` method (stanislav-tkach)
+
 ## 0.16.0 (2021-04-18)
 
 * Add `DB::cancel_all_background_work` method (stanislav-tkach)
@@ -15,13 +18,13 @@
 * Bump `librocksdb-sys` up to 6.17.3 (ordian)
 * Remove the need for `&mut self` in `create_cf` and `drop_cf` (v2) (ryoqun)
 * Keep Cache and Env alive with Rc (acrrd)
-* Add DB::open_cf_with_ttl method (fdeantoni)
+* Add `DB::open_cf_with_ttl` method (fdeantoni)
 
 ## 0.15.0 (2020-08-25)
 
 * Fix building rocksdb library on windows host (aleksuss)
 * Add github actions CI for windows build (aleksuss)
-* Update doc for Options::set_compression_type (wqfish)
+* Update doc for `Options::set_compression_type` (wqfish)
 * Add clippy linter in CI (aleksuss)
 * Use DBPath for backup_restore test (wqfish)
 * Allow to build RocksDB with a different stdlib (calavera)

src/db_options.rs

@@ -977,6 +977,19 @@ impl Options {
         }
     }
 
+    /// Sets maximum size of training data passed to zstd's dictionary trainer. Using zstd's
+    /// dictionary trainer can achieve even better compression ratio improvements than using
+    /// `max_dict_bytes` alone.
+    ///
+    /// The training data will be used to generate a dictionary of max_dict_bytes.
+    ///
+    /// Default: 0.
+    pub fn set_zstd_max_train_bytes(&mut self, value: c_int) {
+        unsafe {
+            ffi::rocksdb_options_set_compression_options_zstd_max_train_bytes(self.inner, value);
+        }
+    }
+
     /// If non-zero, we perform bigger reads when doing compaction. If you're
     /// running RocksDB on spinning disks, you should set this to at least 2MB.
     /// That way RocksDB's compaction is doing sequential instead of random reads.

tests/test_db.rs

@@ -968,7 +968,7 @@ fn multi_get_cf() {
 
 #[test]
 fn key_may_exist() {
-    let path = DBPath::new("_rust_rocksdb_multi_get");
+    let path = DBPath::new("_rust_key_may_exist");
 
     {
         let db = DB::open_default(&path).unwrap();
@@ -982,7 +982,7 @@ fn key_may_exist() {
 
 #[test]
 fn key_may_exist_cf() {
-    let path = DBPath::new("_rust_rocksdb_multi_get_cf");
+    let path = DBPath::new("_rust_key_may_exist_cf");
 
     {
         let mut opts = Options::default();

tests/test_rocksdb_options.rs

@@ -134,3 +134,14 @@ fn test_set_data_block_index_type() {
         assert!(settings.contains("data_block_hash_table_util_ratio: 0.350000"));
     }
 }
+
+#[test]
+fn set_compression_options_zstd_max_train_bytes() {
+    let path = DBPath::new("_rust_set_compression_options_zstd_max_train_bytes");
+    {
+        let mut opts = Options::default();
+        opts.create_if_missing(true);
+        opts.set_zstd_max_train_bytes(100);
+        let _db = DB::open(&opts, &path).unwrap();
+    }
+}