f5177c761f
Summary: [ This diff is stacked on top of D59577 ] We keep calling timer.ElapsedNanos() on every call to MergeOperator::FullMerge even when statistics are disabled, this is wasteful. I run the readseq benchmark on a DB containing 100K merge operands for 100K keys (1 operand per key) with 1GB block cache I see slight performance improvment Original results ``` $ ./db_bench --benchmarks="readseq,readseq,readseq,readseq,readseq,readseq,readseq,readseq,readseq" --merge_operator="max" --merge_keys=100000 --num=100000 --db="/dev/shm/100K_merge_compacted/" --cache_size=1073741824 --use_existing_db --disable_auto_compactions ------------------------------------------------ DB path: [/dev/shm/100K_merge_compacted/] readseq : 0.498 micros/op 2006597 ops/sec; 222.0 MB/s DB path: [/dev/shm/100K_merge_compacted/] readseq : 0.295 micros/op 3393627 ops/sec; 375.4 MB/s DB path: [/dev/shm/100K_merge_compacted/] readseq : 0.285 micros/op 3511155 ops/sec; 388.4 MB/s DB path: [/dev/shm/100K_merge_compacted/] readseq : 0.286 micros/op 3500470 ops/sec; 387.2 MB/s DB path: [/dev/shm/100K_merge_compacted/] readseq : 0.283 micros/op 3530751 ops/sec; 390.6 MB/s DB path: [/dev/shm/100K_merge_compacted/] readseq : 0.289 micros/op 3464811 ops/sec; 383.3 MB/s DB path: [/dev/shm/100K_merge_compacted/] readseq : 0.277 micros/op 3612814 ops/sec; 399.7 MB/s DB path: [/dev/shm/100K_merge_compacted/] readseq : 0.283 micros/op 3539640 ops/sec; 391.6 MB/s DB path: [/dev/shm/100K_merge_compacted/] readseq : 0.285 micros/op 3503766 ops/sec; 387.6 MB/s ``` After patch ``` $ ./db_bench --benchmarks="readseq,readseq,readseq,readseq,readseq,readseq,readseq,readseq,readseq" --merge_operator="max" --merge_keys=100000 --num=100000 --db="/dev/shm/100K_merge_compacted/" --cache_size=1073741824 --use_existing_db --disable_auto_compactions ------------------------------------------------ DB path: [/dev/shm/100K_merge_compacted/] readseq : 0.476 micros/op 2100119 ops/sec; 232.3 MB/s DB path: [/dev/shm/100K_merge_compacted/] readseq : 0.278 micros/op 3600887 ops/sec; 398.4 MB/s DB path: [/dev/shm/100K_merge_compacted/] readseq : 0.275 micros/op 3636698 ops/sec; 402.3 MB/s DB path: [/dev/shm/100K_merge_compacted/] readseq : 0.271 micros/op 3691661 ops/sec; 408.4 MB/s DB path: [/dev/shm/100K_merge_compacted/] readseq : 0.273 micros/op 3661534 ops/sec; 405.1 MB/s DB path: [/dev/shm/100K_merge_compacted/] readseq : 0.276 micros/op 3627106 ops/sec; 401.3 MB/s DB path: [/dev/shm/100K_merge_compacted/] readseq : 0.272 micros/op 3682635 ops/sec; 407.4 MB/s DB path: [/dev/shm/100K_merge_compacted/] readseq : 0.266 micros/op 3758331 ops/sec; 415.8 MB/s DB path: [/dev/shm/100K_merge_compacted/] readseq : 0.266 micros/op 3761907 ops/sec; 416.2 MB/s ``` Test Plan: make check -j64 Reviewers: yhchiang, sdong Reviewed By: sdong Subscribers: andrewkr, dhruba Differential Revision: https://reviews.facebook.net/D59583
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 specially suitable for storing multiple terabytes of data in a single database.
Start with example usage here: https://github.com/facebook/rocksdb/tree/master/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.
Design discussions are conducted in https://www.facebook.com/groups/rocksdb.dev/