add RocksDB rocksdb_compression_level and rocksdb_bottommost_compression

Signed-off-by: strawberry <strawberry@puppygock.gay>

src/config/mod.rs

@@ -121,6 +121,10 @@ pub struct Config {
 	pub rocksdb_max_log_files: usize,
 	#[serde(default = "default_rocksdb_compression_algo")]
 	pub rocksdb_compression_algo: String,
+	#[serde(default = "default_rocksdb_compression_level")]
+	pub rocksdb_compression_level: i32,
+	#[serde(default)]
+	pub rocksdb_bottommost_compression: bool,
 
 	pub emergency_password: Option<String>,
 
@@ -342,19 +346,33 @@ impl fmt::Display for Config {
 			}),
 			#[cfg(feature = "compression-zstd")]
 			("zstd Response Body Compression", &self.zstd_compression.to_string()),
+			#[cfg(feature = "rocksdb")]
 			("RocksDB database log level", &self.rocksdb_log_level),
+			#[cfg(feature = "rocksdb")]
 			("RocksDB database log time-to-roll", &self.rocksdb_log_time_to_roll.to_string()),
+			#[cfg(feature = "rocksdb")]
 			("RocksDB Max LOG Files", &self.rocksdb_max_log_files.to_string()),
+			#[cfg(feature = "rocksdb")]
 			(
 				"RocksDB database max log file size",
 				&self.rocksdb_max_log_file_size.to_string(),
 			),
+			#[cfg(feature = "rocksdb")]
 			(
 				"RocksDB database optimize for spinning disks",
 				&self.rocksdb_optimize_for_spinning_disks.to_string(),
 			),
+			#[cfg(feature = "rocksdb")]
 			("RocksDB Parallelism Threads", &self.rocksdb_parallelism_threads.to_string()),
+			#[cfg(feature = "rocksdb")]
 			("RocksDB Compression Algorithm", &self.rocksdb_compression_algo),
+			#[cfg(feature = "rocksdb")]
+			("RocksDB Compression Level", &self.rocksdb_compression_level.to_string()),
+			#[cfg(feature = "rocksdb")]
+			(
+				"RocksDB Bottommost Level Compression",
+				&self.rocksdb_bottommost_compression.to_string(),
+			),
 			("Prevent Media Downloads From", {
 				let mut lst = vec![];
 				for domain in &self.prevent_media_downloads_from {
@@ -456,6 +474,11 @@ fn default_rocksdb_parallelism_threads() -> usize { num_cpus::get_physical() / 2
 
 fn default_rocksdb_compression_algo() -> String { "zstd".to_owned() }
 
+/// Default RocksDB compression level is 32767, which is internally read by
+/// RocksDB as the default magic number and translated to the library's default
+/// compression level as they all differ. See their `kDefaultCompressionLevel`.
+fn default_rocksdb_compression_level() -> i32 { 32767 }
+
 // I know, it's a great name
 pub(crate) fn default_default_room_version() -> RoomVersionId { RoomVersionId::V10 }
 

src/database/abstraction/rocksdb.rs

@@ -84,6 +84,17 @@ fn db_options(rocksdb_cache: &rust_rocksdb::Cache, config: &Config) -> rust_rock
 		db_opts.set_use_direct_io_for_flush_and_compaction(true);
 	}
 
+	if config.rocksdb_bottommost_compression {
+		db_opts.set_bottommost_compression_type(rocksdb_compression_algo);
+		db_opts.set_bottommost_zstd_max_train_bytes(0, true);
+
+		// -14 w_bits is only read by zlib.
+		db_opts.set_bottommost_compression_options(-14, config.rocksdb_compression_level, 0, 0, true);
+	}
+
+	// -14 w_bits is only read by zlib.
+	db_opts.set_compression_options(-14, config.rocksdb_compression_level, 0, 0);
+
 	db_opts.set_block_based_table_factory(&block_based_options);
 	db_opts.create_if_missing(true);
 	db_opts.increase_parallelism(

src/service/globals/mod.rs

@@ -371,6 +371,8 @@ impl Service<'_> {
 
 	pub fn rocksdb_compression_algo(&self) -> &String { &self.config.rocksdb_compression_algo }
 
+	pub fn rocksdb_compression_level(&self) -> i32 { self.config.rocksdb_compression_level }
+
 	pub fn prevent_media_downloads_from(&self) -> &[OwnedServerName] { &self.config.prevent_media_downloads_from }
 
 	pub fn ip_range_denylist(&self) -> &[String] { &self.config.ip_range_denylist }