rocksdb

fork of https://github.com/oxigraph/rocksdb and https://github.com/facebook/rocksdb for nextgraph and oxigraph

Aaron Gao 259a00eaca unbiase readamp bitmap Summary: Consider BlockReadAmpBitmap with bytes_per_bit = 32. Suppose bytes [a, b) were used, while bytes [a-32, a) and [b+1, b+33) weren't used; more formally, the union of ranges passed to BlockReadAmpBitmap::Mark() contains [a, b) and doesn't intersect with [a-32, a) and [b+1, b+33). Then bits [floor(a/32), ceil(b/32)] will be set, and so the number of useful bytes will be estimated as (ceil(b/32) - floor(a/32)) * 32, which is on average equal to b-a+31. An extreme example: if we use 1 byte from each block, it'll be counted as 32 bytes from each block. It's easy to remove this bias by slightly changing the semantics of the bitmap. Currently each bit represents a byte range [i32, (i+1)32). This diff makes each bit represent a single byte: i32 + X, where X is a random number in [0, 31] generated when bitmap is created. So, e.g., if you read a single byte at random, with probability 31/32 it won't be counted at all, and with probability 1/32 it will be counted as 32 bytes; so, on average it's counted as 1 byte. But there is one exception: the last bit will always set with the old way.* (*) - assuming read_amp_bytes_per_bit = 32. Closes https://github.com/facebook/rocksdb/pull/2259 Differential Revision: D5035652 Pulled By: lightmark fbshipit-source-id: bd98b1b9b49fbe61f9e3781d07f624e3cbd92356		8 years ago
arcanist_util	Fix arc setting for Facebook internal tools	8 years ago
buckifier	internal_repo_rocksdb to build Java and RocksDB LITE	8 years ago
build_tools	Set VALGRIND_VER	8 years ago
cache	Add GPLv2 as an alternative license.	8 years ago
cmake/modules	CMake: more MinGW fixes	8 years ago
coverage	Fix coverage script	10 years ago
db	unbiase readamp bitmap	8 years ago
docs	Add documentation license	8 years ago
env	fix memory alignment with logical sector size	8 years ago
examples	CMake: more MinGW fixes	8 years ago
hdfs	Add GPLv2 as an alternative license.	8 years ago
include/rocksdb	Add C API to set max_file_opening_threads option	8 years ago
java	Remove orphaned Java classes	8 years ago
memtable	Add GPLv2 as an alternative license.	8 years ago
monitoring	Add GPLv2 as an alternative license.	8 years ago
options	Print compaction_options_universal.stop_style in LOG file	8 years ago
port	port: updated PhysicalCoreID()	8 years ago
table	unbiase readamp bitmap	8 years ago
third-party	Fix build with MinGW	8 years ago
tools	Allow IntraL0 compaction in FIFO Compaction	8 years ago
util	travis: add Windows cross-compilation	8 years ago
utilities	support PopSavePoint for WriteBatch	8 years ago
.clang-format	A script that automatically reformat affected lines	11 years ago
.deprecated_arcconfig	Update ShipIt to honor TARGETS updates	8 years ago
.gitignore	Add buckifier script to github repo	8 years ago
.travis.yml	travis: add Windows cross-compilation	8 years ago
AUTHORS	Add AUTHORS file. Fix #203	10 years ago
CMakeLists.txt	travis: add Windows cross-compilation	8 years ago
CONTRIBUTING.md	facebook accounts are not required for CLA signers	11 years ago
COPYING	Add GPLv2 as an alternative license.	8 years ago
DEFAULT_OPTIONS_HISTORY.md	Change the default of delayed slowdown value to 16MB/s	8 years ago
DUMP_FORMAT.md	First version of rocksdb_dump and rocksdb_undump.	10 years ago
HISTORY.md	Add bulk create/drop column family API	8 years ago
INSTALL.md	AIX and Solaris Sparc Support	8 years ago
LANGUAGE-BINDINGS.md	Adding Dlang to the list	8 years ago
LICENSE	Updated all copyright headers to the new format.	9 years ago
Makefile	Extract statistics tests into separate file	8 years ago
PATENTS	Update Patent Grant.	10 years ago
README.md	Appveyor badge to show master branch	9 years ago
ROCKSDB_LITE.md	Optimistic Transactions	10 years ago
TARGETS	Extract statistics tests into separate file	8 years ago
USERS.md	Update USERS.md add user Pika	8 years ago
Vagrantfile	Update Vagrant file (test internal phabricator workflow)	8 years ago
WINDOWS_PORT.md	Commit both PR and internal code review changes	10 years ago
appveyor.yml	Rework test running script.	8 years ago
src.mk	Extract statistics tests into separate file	8 years ago
thirdparty.inc	Introduce XPRESS compresssion on Windows. (#1081 )	9 years ago

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/