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Summary: **Context/Summary:** During prefix scan, prefetched data blocks containing keys not in the same prefix as the `Seek()`'s key will be wasted when `ReadOptions::prefix_same_as_start = true` since they won't be returned to the user. This PR is to exclude those data blocks from being prefetched in a similar manner like trimming according to `ReadOptions::iterate_upper_bound`. Bonus: refactoring to some existing prefetch test so they are easier to extend and read Pull Request resolved: https://github.com/facebook/rocksdb/pull/13040 Test Plan: - New UT, integration to existing UTs - Benchmark to ensure no regression from CPU due to more trimming logic ``` // Build DB with one sorted run under the same prefix ./db_bench --benchmarks=fillrandom --prefix_size=3 --keys_per_prefix=5000000 --num=5000000 --db=/dev/shm/db_bench --disable_auto_compactions=1 ``` ``` // Augment the existing db bench to call `Seek()` instead of `SeekToFirst()` in `void ReadSequential(){..}` to trigger the logic in this PR +++ b/tools/db_bench_tool.cc @@ -5900,7 +5900,12 @@ class Benchmark { Iterator* iter = db->NewIterator(options); int64_t i = 0; int64_t bytes = 0; - for (iter->SeekToFirst(); i < reads_ && iter->Valid(); iter->Next()) { + + iter->SeekToFirst(); + assert(iter->status().ok() && iter->Valid()); + auto prefix = prefix_extractor_->Transform(iter->key()); + + for (iter->Seek(prefix); i < reads_ && iter->Valid(); iter->Next()) { bytes += iter->key().size() + iter->value().size(); thread->stats.FinishedOps(nullptr, db, 1, kRead); ++i; : ``` ``` // Compare prefix scan performance ./db_bench --benchmarks=readseq[-X20] --prefix_size=3 --prefix_same_as_start=1 --auto_readahead_size=1 --cache_size=1 --use_existing_db=1 --db=/dev/shm/db_bench --disable_auto_compactions=1 // Before PR readseq [AVG 20 runs] : 2449011 (± 50238) ops/sec; 270.9 (± 5.6) MB/sec readseq [MEDIAN 20 runs] : 2499167 ops/sec; 276.5 MB/sec // After PR (regress 0.4 %) readseq [AVG 20 runs] : 2439098 (± 42931) ops/sec; 269.8 (± 4.7) MB/sec readseq [MEDIAN 20 runs] : 2460859 ops/sec; 272.2 MB/sec ``` - Stress test: randomly set `prefix_same_as_start` in `TestPrefixScan()`. Run below for a while ``` python3 tools/db_crashtest.py --simple blackbox --prefix_size=5 --prefixpercent=65 --WAL_size_limit_MB=1 --WAL_ttl_seconds=0 --acquire_snapshot_one_in=10000 --adm_policy=1 --advise_random_on_open=1 --allow_data_in_errors=True --allow_fallocate=0 --async_io=0 --avoid_flush_during_recovery=1 --avoid_flush_during_shutdown=1 --avoid_unnecessary_blocking_io=0 --backup_max_size=104857600 --backup_one_in=1000 --batch_protection_bytes_per_key=8 --bgerror_resume_retry_interval=100 --block_align=1 --block_protection_bytes_per_key=4 --block_size=16384 --bloom_before_level=-1 --bloom_bits=3 --bottommost_compression_type=none --bottommost_file_compaction_delay=3600 --bytes_per_sync=262144 --cache_index_and_filter_blocks=0 --cache_index_and_filter_blocks_with_high_priority=0 --cache_size=33554432 --cache_type=lru_cache --charge_compression_dictionary_building_buffer=1 --charge_file_metadata=0 --charge_filter_construction=0 --charge_table_reader=0 --check_multiget_consistency=0 --check_multiget_entity_consistency=0 --checkpoint_one_in=10000 --checksum_type=kxxHash --clear_column_family_one_in=0 --compact_files_one_in=1000 --compact_range_one_in=1000 --compaction_pri=4 --compaction_readahead_size=0 --compaction_style=2 --compaction_ttl=0 --compress_format_version=2 --compressed_secondary_cache_size=16777216 --compression_checksum=0 --compression_max_dict_buffer_bytes=0 --compression_max_dict_bytes=0 --compression_parallel_threads=1 --compression_type=none --compression_use_zstd_dict_trainer=1 --compression_zstd_max_train_bytes=0 --continuous_verification_interval=0 --daily_offpeak_time_utc= --data_block_index_type=0 --db_write_buffer_size=8388608 --decouple_partitioned_filters=1 --default_temperature=kCold --default_write_temperature=kWarm --delete_obsolete_files_period_micros=21600000000 --delpercent=4 --delrangepercent=1 --destroy_db_initially=1 --detect_filter_construct_corruption=0 --disable_file_deletions_one_in=10000 --disable_manual_compaction_one_in=1000000 --disable_wal=0 --dump_malloc_stats=1 --enable_checksum_handoff=0 --enable_compaction_filter=0 --enable_custom_split_merge=1 --enable_do_not_compress_roles=1 --enable_index_compression=1 --enable_memtable_insert_with_hint_prefix_extractor=0 --enable_pipelined_write=1 --enable_sst_partitioner_factory=0 --enable_thread_tracking=1 --enable_write_thread_adaptive_yield=0 --error_recovery_with_no_fault_injection=0 --exclude_wal_from_write_fault_injection=1 --fail_if_options_file_error=0 --fifo_allow_compaction=1 --file_checksum_impl=big --fill_cache=0 --flush_one_in=1000000 --format_version=6 --get_all_column_family_metadata_one_in=10000 --get_current_wal_file_one_in=0 --get_live_files_apis_one_in=10000 --get_properties_of_all_tables_one_in=1000000 --get_property_one_in=1000000 --get_sorted_wal_files_one_in=0 --hard_pending_compaction_bytes_limit=274877906944 --high_pri_pool_ratio=0 --index_block_restart_interval=15 --index_shortening=2 --index_type=2 --ingest_external_file_one_in=0 --inplace_update_support=0 --iterpercent=10 --key_len_percent_dist=1,30,69 --key_may_exist_one_in=100000 --last_level_temperature=kUnknown --level_compaction_dynamic_level_bytes=0 --lock_wal_one_in=1000000 --log2_keys_per_lock=10 --log_file_time_to_roll=0 --log_readahead_size=0 --long_running_snapshots=0 --low_pri_pool_ratio=0.5 --lowest_used_cache_tier=2 --manifest_preallocation_size=5120 --manual_wal_flush_one_in=1000 --mark_for_compaction_one_file_in=10 --max_background_compactions=20 --max_bytes_for_level_base=10485760 --max_key=1000 --max_key_len=3 --max_log_file_size=1048576 --max_manifest_file_size=1073741824 --max_sequential_skip_in_iterations=8 --max_total_wal_size=0 --max_write_batch_group_size_bytes=16777216 --max_write_buffer_number=10 --max_write_buffer_size_to_maintain=4194304 --memtable_insert_hint_per_batch=1 --memtable_max_range_deletions=0 --memtable_prefix_bloom_size_ratio=0.01 --memtable_protection_bytes_per_key=2 --memtable_whole_key_filtering=1 --memtablerep=skip_list --metadata_charge_policy=1 --metadata_read_fault_one_in=32 --metadata_write_fault_one_in=0 --min_write_buffer_number_to_merge=2 --mmap_read=0 --mock_direct_io=True --nooverwritepercent=1 --open_files=-1 --open_metadata_read_fault_one_in=0 --open_metadata_write_fault_one_in=8 --open_read_fault_one_in=0 --open_write_fault_one_in=0 --ops_per_thread=40000 --optimize_filters_for_hits=0 --optimize_filters_for_memory=1 --optimize_multiget_for_io=1 --paranoid_file_checks=1 --paranoid_memory_checks=0 --partition_filters=0 --partition_pinning=3 --pause_background_one_in=10000 --periodic_compaction_seconds=0 --prepopulate_block_cache=1 --preserve_internal_time_seconds=0 --progress_reports=0 --promote_l0_one_in=0 --read_amp_bytes_per_bit=0 --read_fault_one_in=32 --readpercent=10 --recycle_log_file_num=0 --reopen=0 --report_bg_io_stats=0 --reset_stats_one_in=1000000 --sample_for_compression=5 --secondary_cache_fault_one_in=0 --secondary_cache_uri= --skip_stats_update_on_db_open=0 --snapshot_hold_ops=100000 --soft_pending_compaction_bytes_limit=1048576 --sqfc_name=foo --sqfc_version=2 --sst_file_manager_bytes_per_sec=104857600 --sst_file_manager_bytes_per_truncate=1048576 --stats_dump_period_sec=10 --stats_history_buffer_size=1048576 --strict_bytes_per_sync=1 --subcompactions=4 --sync=0 --sync_fault_injection=1 --table_cache_numshardbits=-1 --target_file_size_base=524288 --target_file_size_multiplier=2 --test_batches_snapshots=0 --top_level_index_pinning=0 --uncache_aggressiveness=1 --universal_max_read_amp=10 --unpartitioned_pinning=0 --use_adaptive_mutex=1 --use_adaptive_mutex_lru=1 --use_attribute_group=0 --use_delta_encoding=0 --use_direct_io_for_flush_and_compaction=0 --use_direct_reads=1 --use_full_merge_v1=1 --use_get_entity=0 --use_merge=1 --use_multi_cf_iterator=1 --use_multi_get_entity=0 --use_multiget=1 --use_put_entity_one_in=0 --use_sqfc_for_range_queries=1 --use_timed_put_one_in=0 --use_write_buffer_manager=1 --user_timestamp_size=0 --value_size_mult=32 --verification_only=0 --verify_checksum=1 --verify_checksum_one_in=1000 --verify_compression=0 --verify_db_one_in=100000 --verify_file_checksums_one_in=1000 --verify_iterator_with_expected_state_one_in=5 --verify_sst_unique_id_in_manifest=1 --wal_bytes_per_sync=0 --wal_compression=none --write_buffer_size=1048576 --write_dbid_to_manifest=1 --write_fault_one_in=1000 --writepercent=10 ``` Reviewed By: anand1976 Differential Revision: D64367065 Pulled By: hx235 fbshipit-source-id: 5750c05ccc835c3e9dc81c961b76deaf30bd23c2 |
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| crash_test.mk | ||
| DEFAULT_OPTIONS_HISTORY.md | ||
| DUMP_FORMAT.md | ||
| HISTORY.md | ||
| INSTALL.md | ||
| issue_template.md | ||
| LANGUAGE-BINDINGS.md | ||
| LICENSE.Apache | ||
| LICENSE.leveldb | ||
| Makefile | ||
| PLUGINS.md | ||
| README.md | ||
| rocksdb.pc.in | ||
| src.mk | ||
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RocksDB: A Persistent Key-Value Store for Flash and RAM Storage
RocksDB is developed and maintained by Facebook Database Engineering Team. It is built on earlier work on LevelDB by Sanjay Ghemawat (sanjay@google.com) and Jeff Dean (jeff@google.com)
This code is a library that forms the core building block for a fast key-value server, especially suited for storing data on flash drives. It has a Log-Structured-Merge-Database (LSM) design with flexible tradeoffs between Write-Amplification-Factor (WAF), Read-Amplification-Factor (RAF) and Space-Amplification-Factor (SAF). It has multi-threaded compactions, making it especially suitable for storing multiple terabytes of data in a single database.
Start with example usage here: https://github.com/facebook/rocksdb/tree/main/examples
See the github wiki for more explanation.
The public interface is in include/. Callers should not include or
rely on the details of any other header files in this package. Those
internal APIs may be changed without warning.
Questions and discussions are welcome on the RocksDB Developers Public Facebook group and email list on Google Groups.
License
RocksDB is dual-licensed under both the GPLv2 (found in the COPYING file in the root directory) and Apache 2.0 License (found in the LICENSE.Apache file in the root directory). You may select, at your option, one of the above-listed licenses.