A library that provides an embeddable, persistent key-value store for fast storage.
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Mark Callaghan 993543d1be Add rate_delay_limit_milliseconds
Summary:
This adds the rate_delay_limit_milliseconds option to make the delay
configurable in MakeRoomForWrite when the max compaction score is too high.
This delay is called the Ln slowdown. This change also counts the Ln slowdown
per level to make it possible to see where the stalls occur.

From IO-bound performance testing, the Level N stalls occur:
* with compression -> at the largest uncompressed level. This makes sense
                      because compaction for compressed levels is much
                      slower. When Lx is uncompressed and Lx+1 is compressed
                      then files pile up at Lx because the (Lx,Lx+1)->Lx+1
                      compaction process is the first to be slowed by
                      compression.
* without compression -> at level 1

Task ID: #1832108

Blame Rev:

Test Plan:
run with real data, added test

Revert Plan:

Database Impact:

Memcache Impact:

Other Notes:

EImportant:

- begin *PUBLIC* platform impact section -
Bugzilla: #
- end platform impact -

Reviewers: dhruba

Reviewed By: dhruba

Differential Revision: https://reviews.facebook.net/D9045
2013-03-04 07:41:15 -08:00
db Add rate_delay_limit_milliseconds 2013-03-04 07:41:15 -08:00
doc merge 1.5 2012-08-28 11:43:33 -07:00
hdfs Fix a number of object lifetime/ownership issues 2013-01-23 16:54:11 -08:00
helpers/memenv Fix a number of object lifetime/ownership issues 2013-01-23 16:54:11 -08:00
include/leveldb Add rate_delay_limit_milliseconds 2013-03-04 07:41:15 -08:00
java Pom changes to make relase 1.5.7 for java. 2013-01-10 10:43:43 -08:00
linters/src fixing linters. 2012-12-14 14:05:27 -08:00
port Make compression options configurable. These include window-bits, level and strategy for ZlibCompression 2012-11-02 11:26:39 -07:00
scribe fix db_test error with scribe logger turned on 2012-08-28 11:22:58 -07:00
snappy Build with gcc-4.7.1-glibc-2.14.1. 2012-09-17 10:56:26 -07:00
table Codemod NULL to nullptr 2013-02-28 18:04:58 -08:00
thrift Implement RowLocks for assoc schema 2012-10-03 23:19:01 -07:00
tools Refactor statistics. Remove individual functions like incNumFileOpens 2013-02-25 13:58:34 -08:00
util Add rate_delay_limit_milliseconds 2013-03-04 07:41:15 -08:00
VALGRIND_LOGS Automating valgrind to run with jenkins 2013-03-01 11:44:40 -08:00
.arcconfig Enable linting in arc. 2013-02-01 11:34:25 -08:00
.gitignore Various build cleanups/improvements 2013-01-14 18:40:22 -08:00
build_detect_platform Add optional clang compile mode 2013-01-15 18:48:37 -08:00
build_detect_version Stop continually re-creating build_version.c 2013-01-24 17:51:39 -08:00
build_java.sh Release 1.5.6 for Java code + Script to automate it. 2012-12-17 12:11:11 -08:00
fbcode.clang31.sh Cleanup TODO/NEWS/AUTHORS files 2013-01-25 09:11:26 -08:00
fbcode.gcc471.sh Add zlib to our builds and tweak histogram output 2013-02-07 15:31:53 -08:00
LICENSE reverting disastrous MOE commit, returning to r21 2011-04-19 23:11:15 +00:00
Makefile Automating valgrind to run with jenkins 2013-03-01 11:44:40 -08:00
README cleanup README. 2013-02-18 19:42:29 -08:00
README.fb Cleanup README.fb 2013-02-19 09:54:54 -08:00
regression_build_test.sh Minor improvements to the regression testing 2013-01-16 14:47:20 -08:00
valgrind_test.sh Automating valgrind to run with jenkins 2013-03-01 11:44:40 -08:00

rocksdb: A persistent key-value store for flash storage
Authors: The Facebook Database Engineering Team

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 an Log-Stuctured-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.

The core of this code has been derived from open-source leveldb.

The code under this directory implements a system for maintaining a
persistent key/value store.

See doc/index.html for more explanation.
See doc/impl.html for a brief overview of the implementation.

The public interface is in include/*.h.  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.

Guide to header files:

include/db.h
    Main interface to the DB: Start here

include/options.h
    Control over the behavior of an entire database, and also
    control over the behavior of individual reads and writes.

include/comparator.h
    Abstraction for user-specified comparison function.  If you want
    just bytewise comparison of keys, you can use the default comparator,
    but clients can write their own comparator implementations if they
    want custom ordering (e.g. to handle different character
    encodings, etc.)

include/iterator.h
    Interface for iterating over data. You can get an iterator
    from a DB object.

include/write_batch.h
    Interface for atomically applying multiple updates to a database.

include/slice.h
    A simple module for maintaining a pointer and a length into some
    other byte array.

include/status.h
    Status is returned from many of the public interfaces and is used
    to report success and various kinds of errors.

include/env.h
    Abstraction of the OS environment.  A posix implementation of
    this interface is in util/env_posix.cc

include/table.h
include/table_builder.h
    Lower-level modules that most clients probably won't use directly