Peter Dillinger ffe1e4b820 Make some FilterPolicy deprecations more clear (#9403)
Summary:
The old block-based filter has been deprecated for years, but
this makes that more clear by marking the functions specific to it and
logging a warning when the feature is used.

It is deprecated because of performance. In that old design, you have to
binary search through the full SST index before a bloom filter query, which
is much more expensive than a bloom query itself.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9403

Test Plan:
Used db_bench with and without -use_block_based_filter,
running at the same time

    TEST_TMPDIR=/dev/shm/rocksdb ./db_bench -benchmarks=fillrandom,readrandom -num=10000000 -duration=20 -disable_wal=1 -write_buffer_size=10000000 -bloom_bits=16 -compaction_style=2 -fifo_compaction_max_table_files_size_mb=10000 -fifo_compaction_allow_compaction=0

No significant difference in construction time but 3x slower readrandom
with -use_block_based_filter:
readrandom   :     100.517 micros/op 9948 ops/sec;    1.1 MB/s
vs.
readrandom   :      33.368 micros/op 29968 ops/sec;    3.3 MB/s

Also saw deprecation message (just once) in LOG only with
-use_block_based_filter

Reviewed By: ajkr

Differential Revision: D33673202

Pulled By: pdillinger

fbshipit-source-id: 99f6f0eff619408d9e5f7ef546954ed0be6c7a5b
2022-01-19 18:12:10 -08:00
..