Method sync

nodedb-wal/src/writer.rs:346–366

Flush the write buffer to disk (group commit). This issues a single write + fsync for all records accumulated since the last flush. The DWB is also fsynced (one fsync for all deferred DWB writes in this batch).

(&mut self)

    /// since the last flush. The DWB is also fsynced (one fsync for all
    /// deferred DWB writes in this batch).
    pub fn sync(&mut self) -> Result<()> {
        if self.buffer.is_empty() {
            return Ok(());
        }
        // Flush DWB first — records must be durable in DWB before WAL.
        // If DWB flush fails, torn-write protection is lost for this batch.
        // We log a warning and detach the DWB rather than silently continuing
        // as if torn-write protection is active.
        if let Some(dwb) = &mut self.double_write
            && let Err(e) = dwb.flush()
        {
            tracing::warn!(
                error = %e,
                "DWB flush failed — torn-write protection lost for this batch, detaching DWB"
            );
            self.double_write = None;
        }
        self.flush_buffer()?;
        self.file.sync_all()?;
        Ok(())
    }

    /// Seal the WAL — no more writes will be accepted.
    ///