[GitHub] [arrow] mayuropensource commented on a change in pull request #7022: ARROW-8562: [C++] IO: Parameterize I/O Coalescing using S3 metrics

[GitBox <gi...@apache.org>]

mayuropensource commented on a change in pull request #7022:
URL: https://github.com/apache/arrow/pull/7022#discussion_r414031141



##########
File path: cpp/src/arrow/io/caching.h
##########
@@ -27,6 +27,44 @@
 
 namespace arrow {
 namespace io {
+
+struct ARROW_EXPORT CacheOptions {
+  static constexpr double kDefaultIdealBandwidthUtilizationFrac = 0.9;
+  static constexpr int64_t kDefaultMaxIdealRequestSizeMib = 64;
+
+  /// /brief The maximum distance in bytes between two consecutive
+  ///   ranges; beyond this value, ranges are not combined
+  int64_t hole_size_limit;
+  /// /brief The maximum size in bytes of a combined range; if
+  ///   combining two consecutive ranges would produce a range of a
+  ///   size greater than this, they are not combined
+  int64_t range_size_limit;
+
+  bool operator==(const CacheOptions& other) const {
+    return hole_size_limit == other.hole_size_limit &&
+           range_size_limit == other.range_size_limit;
+  }
+
+  /// \brief Construct CacheOptions from S3 storage metrics.
+  ///
+  /// \param[in] time_to_first_byte_millis Seek-time or Time-To-First-Byte (TTFB) in
+  ///   milliseconds, also called call setup latency of a new S3 request.
+  ///   The value is a positive integer.
+  /// \param[in] transfer_bandwidth_mib_per_sec Data transfer Bandwidth (BW) in MiB/sec.
+  ///   The value is a positive integer.
+  /// \param[in] ideal_bandwidth_utilization_frac Transfer bandwidth utilization fraction
+  ///   (per connection) to maximize the net data load.
+  ///   The value is a positive double precision number less than or equal to 1.
+  /// \param[in] max_ideal_request_size_mib The maximum single data request size (in MiB)
+  ///   to maximize the net data load.
+  ///   The value is a positive integer.
+  /// \return A new instance of CacheOptions.
+  static CacheOptions MakeFromS3Metrics(

Review comment:
       good point, I will make the change.




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