9a9d4759b2
Summary: This diff completes the creation of InlineSkipList<Cmp>, which is like SkipList<const char*, Cmp> but it always allocates the key contiguously with the node. This allows us to remove the pointer from the node to the key. As a result the memory usage of the skip list is reduced (by 1 to sizeof(void*) bytes depending on the padding required to align the key storage), cache locality is improved, and we halve the number of calls to the allocator. For skip lists whose keys are freshly-allocated const char*, InlineSkipList is stricly preferrable to SkipList. This diff doesn't replace SkipList, however, because some of the use cases of SkipList in RocksDB are either character sequences that are not allocated at the same time as the skip list node allocation (for example hash_linklist_rep) or have different key types (for example write_batch_with_index). Taking advantage of inline allocation for those cases is left to future work. The perf win is biggest for small values. For single-threaded CPU-bound (32M fillrandom operations with no WAL log) with 16 byte keys and 0 byte values, the db_bench perf goes from ~310k ops/sec to ~410k ops/sec. For large values the improvement is less pronounced, but seems to be between 5% and 10% on the same configuration. Test Plan: make check Reviewers: igor, sdong Reviewed By: sdong Subscribers: dhruba Differential Revision: https://reviews.facebook.net/D51123 |
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| arcanist_util | ||
| build_tools | ||
| coverage | ||
| db | ||
| doc | ||
| examples | ||
| hdfs | ||
| include/rocksdb | ||
| java | ||
| memtable | ||
| port | ||
| table | ||
| third-party | ||
| tools | ||
| util | ||
| utilities | ||
| .arcconfig | ||
| .clang-format | ||
| .gitignore | ||
| .travis.yml | ||
| appveyor.yml | ||
| AUTHORS | ||
| CMakeLists.txt | ||
| CONTRIBUTING.md | ||
| DUMP_FORMAT.md | ||
| HISTORY.md | ||
| INSTALL.md | ||
| LICENSE | ||
| Makefile | ||
| PATENTS | ||
| README.md | ||
| ROCKSDB_LITE.md | ||
| src.mk | ||
| thirdparty.inc | ||
| USERS.md | ||
| Vagrantfile | ||
| WINDOWS_PORT.md | ||
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/