Update HISTORY for PR 9187 (#9191)

Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/9191

Reviewed By: riversand963

Differential Revision: D32577939

Pulled By: ltamasi

fbshipit-source-id: 3c52067a0c3e9219c1aafdb711718dfcce5dedf5

HISTORY.md

@@ -8,6 +8,7 @@
 * Added the read count and read bytes related stats to Statistics for tiered storage hot, warm, and cold file reads.
 * Added an option to dynamically charge an updating estimated memory usage of block-based table building to block cache if block cache available. It currently only includes charging memory usage of constructing (new) Bloom Filter and Ribbon Filter to block cache. To enable this feature, set `BlockBasedTableOptions::reserve_table_builder_memory = true`.
 * Add a new API OnIOError in listener.h that notifies listeners when an IO error occurs during FileSystem operation along with filename, status etc.
+* Added compaction readahead support for blob files to the integrated BlobDB implementation, which can improve compaction performance when the database resides on higher-latency storage like HDDs or remote filesystems. Readahead can be configured using the column family option `blob_compaction_readahead_size`.
 
 ### Bug Fixes
 * Prevent a `CompactRange()` with `CompactRangeOptions::change_level == true` from possibly causing corruption to the LSM state (overlapping files within a level) when run in parallel with another manual compaction. Note that setting `force_consistency_checks == true` (the default) would cause the DB to enter read-only mode in this scenario and return `Status::Corruption`, rather than committing any corruption.