add configuration for rocksdb direct-io enablement

Signed-off-by: Jason Volk <jason@zemos.net>

conduwuit-example.toml

@@ -384,6 +384,10 @@ allow_profile_lookup_federation_requests = true
 # Defaults to false
 #rocksdb_optimize_for_spinning_disks = false
 
+# Enables direct-io to increase database performance. This is enabled by default. Set this option to false if the
+# database resides on a filesystem which does not support direct-io.
+#rocksdb_direct_io = true
+
 # RocksDB log level. This is not the same as conduwuit's log level. This is the log level for the RocksDB engine/library
 # which show up in your database folder/path as `LOG` files. Defaults to error. conduwuit will typically log RocksDB errors as normal.
 #rocksdb_log_level = "error"

src/config/mod.rs

@@ -218,6 +218,8 @@ pub(crate) struct Config {
 	pub(crate) rocksdb_log_time_to_roll: usize,
 	#[serde(default)]
 	pub(crate) rocksdb_optimize_for_spinning_disks: bool,
+	#[serde(default = "true_fn")]
+	pub(crate) rocksdb_direct_io: bool,
 	#[serde(default = "default_rocksdb_parallelism_threads")]
 	pub(crate) rocksdb_parallelism_threads: usize,
 	#[serde(default = "default_rocksdb_max_log_files")]
@@ -703,6 +705,8 @@ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 				&self.rocksdb_optimize_for_spinning_disks.to_string(),
 			),
 			#[cfg(feature = "rocksdb")]
+			("RocksDB Direct-IO", &self.rocksdb_direct_io.to_string()),
+			#[cfg(feature = "rocksdb")]
 			("RocksDB Parallelism Threads", &self.rocksdb_parallelism_threads.to_string()),
 			#[cfg(feature = "rocksdb")]
 			("RocksDB Compression Algorithm", &self.rocksdb_compression_algo),

src/database/rocksdb/opts.rs

@@ -36,8 +36,10 @@ pub(crate) fn db_options(config: &Config, env: &mut Env, row_cache: &Cache, col_
 
 	// IO
 	opts.set_manual_wal_flush(true);
-	opts.set_use_direct_reads(true);
-	opts.set_use_direct_io_for_flush_and_compaction(true);
+	if config.rocksdb_direct_io {
+		opts.set_use_direct_reads(true);
+		opts.set_use_direct_io_for_flush_and_compaction(true);
+	}
 	if config.rocksdb_optimize_for_spinning_disks {
 		// speeds up opening DB on hard drives
 		opts.set_skip_checking_sst_file_sizes_on_db_open(true);