Bump rocksdb to 0.21

Fixes #315

Build of sonic-server is failing on NixOS
for a few weeks now, see https://hydra.nixos.org/build/239524816

This failing build has been caused by a clang 16 upgrade,
because rocksdb depends on a old rust-bindgen version which
is not compatible with this version of clang.

See rust-lang/rust-bindgen#2312

A resolution is to upgrade rocksdb to its latest version.

Cargo.toml

@@ -26,7 +26,7 @@ serde_derive = "1.0"
 rand = "0.8"
 unicode-segmentation = "1.6"
 radix = "0.6"
-rocksdb = { version = "0.17", features = ["zstd"] }
+rocksdb = { version = "0.21", features = ["zstd"] }
 fst = "0.3"
 fst-levenshtein = "0.3"
 fst-regex = "0.3"

src/store/kv.rs

@@ -12,8 +12,8 @@ use rocksdb::backup::{
     RestoreOptions as DBRestoreOptions,
 };
 use rocksdb::{
-    DBCompactionStyle, DBCompressionType, Error as DBError, FlushOptions, Options as DBOptions,
-    WriteBatch, WriteOptions, DB,
+    DBCompactionStyle, DBCompressionType, Env as DBEnv, Error as DBError, FlushOptions, Options as DBOptions,
+    WriteBatch, WriteOptions, DB, DBPath,
 };
 use std::fmt;
 use std::fs;
@@ -298,8 +298,9 @@ impl StoreKVPool {
                     .map_err(|_| io_error!("database open failure"))?;
 
                 // Initialize KV database backup engine
+                let backup_opts = DBBackupEngineOptions::new(&DBPath::new(&kv_backup_path)).unwrap();
                 let mut kv_backup_engine =
-                    DBBackupEngine::open(&DBBackupEngineOptions::default(), &kv_backup_path)
+                    DBBackupEngine::open(&backup_opts, &DBEnv::new().unwrap())
                         .map_err(|_| io_error!("backup engine failure"))?;
 
                 // Proceed actual KV database backup
@@ -350,8 +351,9 @@ impl StoreKVPool {
                 fs::create_dir_all(&kv_path)?;
 
                 // Initialize KV database backup engine
+                let backup_opts = DBBackupEngineOptions::new(&DBPath::new(&origin_path)).unwrap();
                 let mut kv_backup_engine =
-                    DBBackupEngine::open(&DBBackupEngineOptions::default(), &origin_path)
+                    DBBackupEngine::open(&backup_opts, &DBEnv::new().unwrap())
                         .map_err(|_| io_error!("backup engine failure"))?;
 
                 kv_backup_engine