add rocksdb_bottommost_compression_level config option

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

conduwuit-example.toml

@@ -325,6 +325,16 @@ url_preview_check_root_domain = false
 #
 #rocksdb_compression_level = 32767
 
+# Level of compression the specified compression algorithm for the bottommost level/data for RocksDB to use.
+# Default 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`.
+#
+# Since this is the bottommost level (generally old and least used data), it may be desirable to have a very
+# high compression level here as it's lesss likely for this data to be used. Research your chosen compression algorithm.
+#
+#rocksdb_bottommost_compression_level = 32767
+
 # Whether to enable RocksDB "bottommost_compression".
 # At the expense of more CPU usage, this will further compress the database to reduce more storage.
 # It is recommended to use ZSTD compression with this for best compression results.

src/config/mod.rs

@@ -123,6 +123,8 @@ pub struct Config {
 	pub rocksdb_compression_algo: String,
 	#[serde(default = "default_rocksdb_compression_level")]
 	pub rocksdb_compression_level: i32,
+	#[serde(default = "default_rocksdb_bottommost_compression_level")]
+	pub rocksdb_bottommost_compression_level: i32,
 	#[serde(default)]
 	pub rocksdb_bottommost_compression: bool,
 
@@ -368,6 +370,10 @@ impl fmt::Display for Config {
 			("RocksDB Compression Algorithm", &self.rocksdb_compression_algo),
 			#[cfg(feature = "rocksdb")]
 			("RocksDB Compression Level", &self.rocksdb_compression_level.to_string()),
+			(
+				"RocksDB Bottommost Compression Level",
+				&self.rocksdb_bottommost_compression_level.to_string(),
+			),
 			#[cfg(feature = "rocksdb")]
 			(
 				"RocksDB Bottommost Level Compression",
@@ -479,6 +485,11 @@ fn default_rocksdb_compression_algo() -> String { "zstd".to_owned() }
 /// compression level as they all differ. See their `kDefaultCompressionLevel`.
 fn default_rocksdb_compression_level() -> i32 { 32767 }
 
+/// 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_bottommost_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

@@ -89,7 +89,7 @@ fn db_options(rocksdb_cache: &rust_rocksdb::Cache, config: &Config) -> rust_rock
 		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);
+		db_opts.set_bottommost_compression_options(-14, config.rocksdb_bottommost_compression_level, 0, 0, true);
 	}
 
 	// -14 w_bits is only read by zlib.

src/service/globals/mod.rs

@@ -373,6 +373,8 @@ impl Service<'_> {
 
 	pub fn rocksdb_compression_level(&self) -> i32 { self.config.rocksdb_compression_level }
 
+	pub fn rocksdb_bottommost_compression_level(&self) -> i32 { self.config.rocksdb_bottommost_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 }