Summary:
Pull Request resolved: https://github.com/facebook/rocksdb/pull/14557
RocksDB's PerfContext tracks block_decompress_time but has no counter for the
number of block decompressions. The global Statistics ticker
NUMBER_BLOCK_DECOMPRESSED exists but is not accessible through PerfContext,
which is the thread-local, per-operation metric system used by benchmarks.
Add block_decompress_count as a new PerfContext counter (gated at
kEnableCount level) incremented in DecompressBlockData alongside the existing
NUMBER_BLOCK_DECOMPRESSED ticker. This enables benchmarks and applications to
observe how many blocks required decompression per operation, complementing
the existing block_read_count.
Reviewed By: anand1976
Differential Revision: D99233514
fbshipit-source-id: 40a68c1d9321f560cebdb7c30a544a0c62ae64f0
405e1a4ac6