Expose config of write buffer size

Author: kim

crates/commitlog/src/lib.rs

@@ -89,6 +89,12 @@ pub struct Options {
     /// Has no effect if the `fallocate` feature is not enabled.
     #[cfg_attr(feature = "serde", serde(default = "Options::default_preallocate_segments"))]
     pub preallocate_segments: bool,
+    /// Size in bytes of the memory buffer holding commit data before flushing
+    /// to storage.
+    ///
+    /// Default: 4KiB
+    #[cfg_attr(feature = "serde", serde(default = "Options::default_write_buffer_size"))]
+    pub write_buffer_size: usize,
 }
 
 impl Default for Options {
@@ -102,13 +108,15 @@ impl Options {
     pub const DEFAULT_OFFSET_INDEX_INTERVAL_BYTES: NonZeroU64 = NonZeroU64::new(4096).expect("4096 > 0, qed");
     pub const DEFAULT_OFFSET_INDEX_REQUIRE_SEGMENT_FSYNC: bool = false;
     pub const DEFAULT_PREALLOCATE_SEGMENTS: bool = false;
+    pub const DEFAULT_WRITE_BUFFER_SIZE: usize = 4 * 1024;
 
     pub const DEFAULT: Self = Self {
         log_format_version: DEFAULT_LOG_FORMAT_VERSION,
         max_segment_size: Self::default_max_segment_size(),
         offset_index_interval_bytes: Self::default_offset_index_interval_bytes(),
         offset_index_require_segment_fsync: Self::default_offset_index_require_segment_fsync(),
         preallocate_segments: Self::default_preallocate_segments(),
+        write_buffer_size: Self::default_write_buffer_size(),
     };
 
     pub const fn default_log_format_version() -> u8 {
@@ -131,6 +139,10 @@ impl Options {
         Self::DEFAULT_PREALLOCATE_SEGMENTS
     }
 
+    pub const fn default_write_buffer_size() -> usize {
+        Self::DEFAULT_WRITE_BUFFER_SIZE
+    }
+
     /// Compute the length in bytes of an offset index based on the settings in
     /// `self`.
     pub fn offset_index_len(&self) -> u64 {

crates/commitlog/src/repo/mod.rs

@@ -214,7 +214,7 @@ pub fn create_segment_writer<R: Repo>(
             records: Vec::new(),
             epoch,
         },
-        inner: io::BufWriter::new(storage),
+        inner: io::BufWriter::with_capacity(opts.write_buffer_size, storage),
 
         min_tx_offset: offset,
         bytes_written: Header::LEN as u64,