a7d4eb2f34
Summary: Currently, when rocksdb tries to run manual compaction to refit data into a level, there's a ReFitLevel() process that requires no bg work is currently running. When RocksDB plans to ReFitLevel(), it will do the following: 1. pause scheduling new bg work. 2. wait until all bg work finished 3. do the ReFitLevel() 4. unpause scheduling new bg work. However, as it pause scheduling new bg work at step one and waiting for all bg work finished in step 2, RocksDB will stop flushing until all bg work is done (which could take a long time.) This patch fix this issue by changing the way ReFitLevel() pause the background work: 1. pause scheduling compaction. 2. wait until all bg work finished. 3. pause scheduling flush 4. do ReFitLevel() 5. unpause both flush and compaction. The major difference is that. We only pause scheduling compaction in step 1 and wait for all bg work finished in step 2. This prevent flush being blocked for a long time. Although there's a very rare case that ReFitLevel() might be in starvation in step 2, but it's less likely the case as flush typically finish very fast. Test Plan: existing test. Reviewers: anthony, IslamAbdelRahman, kradhakrishnan, sdong Reviewed By: sdong Subscribers: dhruba, leveldb Differential Revision: https://reviews.facebook.net/D55029 |
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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 | ||
| AUTHORS | ||
| CMakeLists.txt | ||
| CONTRIBUTING.md | ||
| DUMP_FORMAT.md | ||
| HISTORY.md | ||
| INSTALL.md | ||
| LICENSE | ||
| Makefile | ||
| PATENTS | ||
| README.md | ||
| ROCKSDB_LITE.md | ||
| USERS.md | ||
| Vagrantfile | ||
| WINDOWS_PORT.md | ||
| appveyor.yml | ||
| src.mk | ||
| thirdparty.inc | ||
README.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/