A library that provides an embeddable, persistent key-value store for fast storage.
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Haobo Xu d9dd2a1926 [RocksDB] Expose thread local perf counter for low overhead, per call level performance statistics.
Summary:
As title. No locking/atomic is needed due to thread local. There is also no need to modify the existing client interface, in order to expose related counters.

perf_context_test shows a simple example of retrieving the number of user key comparison done for each put and get call. More counters could be added later.

Sample output
./perf_context_test 1000000
==== Test PerfContextTest.KeyComparisonCount
Inserting 1000000 key/value pairs
...
total user key comparison get: 43446523
total user key comparison put: 8017877
max user key comparison get: 88939
avg user key comparison get:43

Basically, the current skiplist does well on average, but could perform poorly in extreme cases.

Test Plan: run perf_context_test <total number of entries to put/get>

Reviewers: dhruba

Differential Revision: https://reviews.facebook.net/D12225
2013-08-14 15:24:06 -07:00
coverage Add automatic coverage report scripts 2013-08-12 23:53:37 -07:00
db [RocksDB] Expose thread local perf counter for low overhead, per call level performance statistics. 2013-08-14 15:24:06 -07:00
doc merge 1.5 2012-08-28 11:43:33 -07:00
hdfs Ability to configure bufferedio-reads, filesystem-readaheads and mmap-read-write per database. 2013-03-20 23:14:03 -07:00
helpers/memenv [RocksDB] cleanup EnvOptions 2013-06-12 11:17:19 -07:00
include [RocksDB] Expose thread local perf counter for low overhead, per call level performance statistics. 2013-08-14 15:24:06 -07:00
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 Fix Zlib_Compress and Zlib_Uncompress 2013-06-18 16:57:42 -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 Prefix filters for scans (v4) 2013-08-13 14:04:56 -07:00
thrift Implement RowLocks for assoc schema 2012-10-03 23:19:01 -07:00
tools Merge remote-tracking branch 'origin' into performance 2013-08-12 09:58:50 -07:00
util Add options to dump. 2013-08-14 09:06:10 -07:00
utilities Counter for merge failure 2013-08-13 14:25:42 -07:00
VALGRIND_LOGS Use version 3.8.1 for valgrind in third_party and do away with log files 2013-03-06 17:47:31 -08:00
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.gitignore Add automatic coverage report scripts 2013-08-12 23:53:37 -07:00
build_detect_platform Modify build_detect_platform to run fbcode.*.* irrespective of $PATH 2013-05-14 22:09:01 -07:00
build_detect_version Make the build-time show up in the leveldb library. 2013-03-11 10:33:15 -07:00
build_java.sh Release 1.5.6 for Java code + Script to automate it. 2012-12-17 12:11:11 -08:00
e Enhance db_bench 2013-03-14 16:00:23 -07:00
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fbcode.gcc471.sh Updating fbcode.gcc471.sh to use jemalloc 3.3.1 2013-03-13 15:34:50 -07:00
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Makefile [RocksDB] Expose thread local perf counter for low overhead, per call level performance statistics. 2013-08-14 15:24:06 -07:00
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README.fb Updating readme to 2.1 2013-08-06 14:43:16 -07:00
regression_build_test.sh Add automatic coverage report scripts 2013-08-12 23:53:37 -07:00
valgrind_test.sh make clean in valgrind_test.sh first 2013-04-23 14:25:19 -07:00

rocksdb: A persistent key-value store for flash storage
Authors: * The Facebook Database Engineering Team
         * Build 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 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_builder.h
    Lower-level modules that most clients probably won't use directly

include/cache.h
    An API for the block cache.

include/compaction_filter.h
    An API for a application filter invoked on every compaction.

include/filter_policy.h
    An API for configuring a bloom filter.

include/memtablerep.h
    An API for implementing a memtable.

include/statistics.h
    An API to retrieve various database statistics.

include/transaction_log_iterator.h
    An API to retrieve transaction logs from a database.