A library that provides an embeddable, persistent key-value store for fast storage.
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Andrew Kryczka 9b18cc2363 single-file bottom-level compaction when snapshot released
Summary:
When snapshots are held for a long time, files may reach the bottom level containing overwritten/deleted keys. We previously had no mechanism to trigger compaction on such files. This particularly impacted DBs that write to different parts of the keyspace over time, as such files would never be naturally compacted due to second-last level files moving down. This PR introduces a mechanism for bottommost files to be recompacted upon releasing all snapshots that prevent them from dropping their deleted/overwritten keys.

- Changed `CompactionPicker` to compact files in `BottommostFilesMarkedForCompaction()`. These are the last choice when picking. Each file will be compacted alone and output to the same level in which it originated. The goal of this type of compaction is to rewrite the data excluding deleted/overwritten keys.
- Changed `ReleaseSnapshot()` to recompute the bottom files marked for compaction when the oldest existing snapshot changes, and schedule a compaction if needed. We cache the value that oldest existing snapshot needs to exceed in order for another file to be marked in `bottommost_files_mark_threshold_`, which allows us to avoid recomputing marked files for most snapshot releases.
- Changed `VersionStorageInfo` to track the list of bottommost files, which is recomputed every time the version changes by `UpdateBottommostFiles()`. The list of marked bottommost files is first computed in `ComputeBottommostFilesMarkedForCompaction()` when the version changes, but may also be recomputed when `ReleaseSnapshot()` is called.
- Extracted core logic of `Compaction::IsBottommostLevel()` into `VersionStorageInfo::RangeMightExistAfterSortedRun()` since logic to check whether a file is bottommost is now necessary outside of compaction.
Closes https://github.com/facebook/rocksdb/pull/3009

Differential Revision: D6062044

Pulled By: ajkr

fbshipit-source-id: 123d201cf140715a7d5928e8b3cb4f9cd9f7ad21
2017-10-25 16:30:37 -07:00
buckifier rocksdb: make buildable on aarch64 2017-08-13 17:13:54 -07:00
build_tools fix lite build 2017-10-17 08:57:09 -07:00
cache Fix unstable floating point exception 2017-10-20 10:12:49 -07:00
cmake CMake: Add support for CMake packages 2017-08-28 17:14:37 -07:00
coverage Fix /bin/bash shebangs 2017-08-03 15:56:46 -07:00
db single-file bottom-level compaction when snapshot released 2017-10-25 16:30:37 -07:00
docs Blog post for 5.8 release 2017-09-28 10:14:09 -07:00
env Fix build on OpenBSD 2017-10-24 13:27:38 -07:00
examples Pinnableslice examples and blog post 2017-08-24 12:26:07 -07:00
hdfs Revert "comment out unused parameters" 2017-07-21 18:26:26 -07:00
include/rocksdb single-file bottom-level compaction when snapshot released 2017-10-25 16:30:37 -07:00
java added missing subcodes and improved error message for missing enum values 2017-10-23 16:42:07 -07:00
memtable Enable MSVC W4 with a few exceptions. Fix warnings and bugs 2017-10-19 10:57:12 -07:00
monitoring Fix unused var warnings in Release mode 2017-10-23 14:27:04 -07:00
options Make FIFO compaction options dynamically configurable 2017-10-19 15:26:36 -07:00
port Fix unused var warnings in Release mode 2017-10-23 14:27:04 -07:00
table Add DB::Properties::kEstimateOldestKeyTime 2017-10-23 15:27:27 -07:00
third-party Enable MSVC W4 with a few exceptions. Fix warnings and bugs 2017-10-19 10:57:12 -07:00
tools db_stress support long-held snapshots 2017-10-20 15:26:59 -07:00
util Make FIFO compaction options dynamically configurable 2017-10-19 15:26:36 -07:00
utilities Return write error on reaching blob dir size limit 2017-10-25 16:30:37 -07:00
.clang-format A script that automatically reformat affected lines 2014-01-14 12:21:24 -08:00
.gitignore Remove leftover references to phutil_module_cache 2017-08-23 12:12:21 -07:00
.travis.yml fix lite build 2017-10-17 08:57:09 -07:00
appveyor.yml Add -DPORTABLE=1 to MSVC CI build 2017-08-31 16:42:48 -07:00
AUTHORS Update RocksDB Authors File 2017-10-18 14:42:10 -07:00
CMakeLists.txt Enable MSVC W4 with a few exceptions. Fix warnings and bugs 2017-10-19 10:57:12 -07:00
CONTRIBUTING.md Remove the licensing description in CONTRIBUTING.md 2017-07-16 15:57:18 -07:00
COPYING Add GPLv2 as an alternative license. 2017-04-27 18:06:12 -07:00
DEFAULT_OPTIONS_HISTORY.md options.delayed_write_rate use the rate of rate_limiter by default. 2017-05-24 09:58:24 -07:00
DUMP_FORMAT.md First version of rocksdb_dump and rocksdb_undump. 2015-06-19 16:24:36 -07:00
HISTORY.md single-file bottom-level compaction when snapshot released 2017-10-25 16:30:37 -07:00
INSTALL.md Default one to rocksdb:x64-windows 2017-09-28 16:12:24 -07:00
issue_template.md Add a template for issues 2017-09-29 11:41:28 -07:00
LANGUAGE-BINDINGS.md add Erlang to the list of language bindings 2017-08-28 16:43:16 -07:00
LICENSE.Apache Change RocksDB License 2017-07-15 16:11:23 -07:00
LICENSE.leveldb Add back the LevelDB license file 2017-07-16 18:42:18 -07:00
Makefile PinnableSlice move assignment 2017-10-12 18:28:24 -07:00
README.md Appveyor badge to show master branch 2016-07-26 13:54:08 -07:00
ROCKSDB_LITE.md Optimistic Transactions 2015-05-29 14:36:35 -07:00
src.mk PinnableSlice move assignment 2017-10-12 18:28:24 -07:00
TARGETS PinnableSlice move assignment 2017-10-12 18:28:24 -07:00
thirdparty.inc Introduce XPRESS compresssion on Windows. (#1081) 2016-04-19 22:54:24 -07:00
USERS.md Add LogDevice to USERS.md 2017-09-25 15:56:40 -07:00
Vagrantfile Update Vagrant file (test internal phabricator workflow) 2016-10-28 15:39:19 -07:00
WINDOWS_PORT.md Commit both PR and internal code review changes 2015-07-07 16:58:20 -07:00

RocksDB: A Persistent Key-Value Store for Flash and RAM Storage

Build Status Build status

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/