Improved O_DIRECT Performance with min_bytes_to_use_direct_io Option

Why it matters

This feature enhances the efficiency of direct I/O operations by optimizing how ClickHouse reads data from disk when O_DIRECT is used. It reduces overhead and latency for workloads that benefit from bypassing the OS cache, providing faster and more predictable read performance.

How to use it

Enable the feature by setting the min_bytes_to_use_direct_io option in the configuration to specify the minimum number of bytes for which direct I/O should be used. When this threshold is met, ClickHouse will perform reads using O_DIRECT with optimized performance.