3 commits

Author	SHA1	Message	Date
sdong	f6b7e1ed1a	Allow user to specify DB path of output file of manual compaction ... Summary: Add a parameter path_id to DB::CompactRange(), to indicate where the output file should be placed to. Test Plan: add a unit test Reviewers: yhchiang, ljin Reviewed By: ljin Subscribers: xjin, igor, dhruba, MarkCallaghan, leveldb Differential Revision: https://reviews.facebook.net/D20085	2014-07-21 19:06:00 -07:00
Feng Zhu	c11d604ab3	store file_indexer info in sequential memory ... Summary: use arena to allocate space for next_level_index_ and level_rb_ Thus increasing data locality and make Version::Get faster. Benchmark detail Base version: commit d2a727c182 command used: ./db_bench --db=/mnt/db/rocksdb --num_levels=6 --key_size=20 --prefix_size=20 --keys_per_prefix=0 --value_size=100 --block_size=4096 --cache_size=17179869184 --cache_numshardbits=6 --compression_type=none --compression_ratio=1 --min_level_to_compress=-1 --disable_seek_compaction=1 --hard_rate_limit=2 --write_buffer_size=134217728 --max_write_buffer_number=2 --level0_file_num_compaction_trigger=8 --target_file_size_base=2097152 --max_bytes_for_level_base=1073741824 --disable_wal=0 --sync=0 --disable_data_sync=1 --verify_checksum=1 --delete_obsolete_files_period_micros=314572800 --max_grandparent_overlap_factor=10 --max_background_compactions=4 --max_background_flushes=0 --level0_slowdown_writes_trigger=16 --level0_stop_writes_trigger=24 --statistics=0 --stats_per_interval=0 --stats_interval=1048576 --histogram=0 --use_plain_table=1 --open_files=-1 --mmap_read=1 --mmap_write=0 --memtablerep=prefix_hash --bloom_bits=10 --bloom_locality=1 --perf_level=0 --benchmarks=fillseq, readrandom,readrandom,readrandom --use_existing_db=0 --num=52428800 --threads=1 Result: cpu running percentage: Version::Get, improved from 7.98% to 7.42% FileIndexer::GetNextLevelIndex, improved from 1.18% to 0.68%. Test Plan: make all check Reviewers: ljin, haobo, yhchiang, sdong Reviewed By: sdong Subscribers: dhruba, igor Differential Revision: https://reviews.facebook.net/D19845	2014-07-16 11:21:30 -07:00
Lei Jin	0f2d768191	hints for narrowing down FindFile range and avoiding checking unrelevant L0 files ... Summary: The file tree structure in Version is prebuilt and the range of each file is known. On the Get() code path, we do binary search in FindFile() by comparing target key with each file's largest key and also check the range for each L0 file. With some pre-calculated knowledge, each key comparision that has been done can serve as a hint to narrow down further searches: (1) If a key falls within a L0 file's range, we can safely skip the next file if its range does not overlap with the current one. (2) If a key falls within a file's range in level L0 - Ln-1, we should only need to binary search in the next level for files that overlap with the current one. (1) will be able to skip some files depending one the key distribution. (2) can greatly reduce the range of binary search, especially for bottom levels, given that one file most likely only overlaps with N files from the level below (where N is max_bytes_for_level_multiplier). So on level L, we will only look at ~N files instead of N^L files. Some inital results: measured with 500M key DB, when write is light (10k/s = 1.2M/s), this improves QPS ~7% on top of blocked bloom. When write is heavier (80k/s = 9.6M/s), it gives us ~13% improvement. Test Plan: make all check Reviewers: haobo, igor, dhruba, sdong, yhchiang Reviewed By: haobo CC: leveldb Differential Revision: https://reviews.facebook.net/D17205	2014-04-21 09:10:12 -07:00