rocksdb

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

Vijay Nadimpalli d150e01474 New API to get all merge operands for a Key (#5604 ) Summary: This is a new API added to db.h to allow for fetching all merge operands associated with a Key. The main motivation for this API is to support use cases where doing a full online merge is not necessary as it is performance sensitive. Example use-cases: 1. Update subset of columns and read subset of columns - Imagine a SQL Table, a row is encoded as a K/V pair (as it is done in MyRocks). If there are many columns and users only updated one of them, we can use merge operator to reduce write amplification. While users only read one or two columns in the read query, this feature can avoid a full merging of the whole row, and save some CPU. 2. Updating very few attributes in a value which is a JSON-like document - Updating one attribute can be done efficiently using merge operator, while reading back one attribute can be done more efficiently if we don't need to do a full merge. ---------------------------------------------------------------------------------------------------- API : Status GetMergeOperands( const ReadOptions& options, ColumnFamilyHandle* column_family, const Slice& key, PinnableSlice* merge_operands, GetMergeOperandsOptions* get_merge_operands_options, int* number_of_operands) Example usage : int size = 100; int number_of_operands = 0; std::vector<PinnableSlice> values(size); GetMergeOperandsOptions merge_operands_info; db_->GetMergeOperands(ReadOptions(), db_->DefaultColumnFamily(), "k1", values.data(), merge_operands_info, &number_of_operands); Description : Returns all the merge operands corresponding to the key. If the number of merge operands in DB is greater than merge_operands_options.expected_max_number_of_operands no merge operands are returned and status is Incomplete. Merge operands returned are in the order of insertion. merge_operands-> Points to an array of at-least merge_operands_options.expected_max_number_of_operands and the caller is responsible for allocating it. If the status returned is Incomplete then number_of_operands will contain the total number of merge operands found in DB for key. Pull Request resolved: https://github.com/facebook/rocksdb/pull/5604 Test Plan: Added unit test and perf test in db_bench that can be run using the command: ./db_bench -benchmarks=getmergeoperands --merge_operator=sortlist Differential Revision: D16657366 Pulled By: vjnadimpalli fbshipit-source-id: 0faadd752351745224ee12d4ae9ef3cb529951bf		5 years ago
buckifier	Change buckifier to support parameterized dependencies (#5648 )	5 years ago
build_tools	Upload db directory during cleanup for certain tests (#5554 )	5 years ago
cache	Cleaned up and simplified LRU cache implementation (#5579 )	5 years ago
cmake	cmake: cmake related cleanups (#5662 )	5 years ago
coverage	Fix interpreter lines for files with python2-only syntax.	5 years ago
db	New API to get all merge operands for a Key (#5604 )	5 years ago
docs	Text lint all .gitignore files	5 years ago
env	fix sign compare warnings (#5651 )	5 years ago
examples	simplify include directive involving inttypes (#5402 )	5 years ago
file	New API to get all merge operands for a Key (#5604 )	5 years ago
hdfs	Add copyright headers per FB open-source checkup tool. (#5199 )	5 years ago
include/rocksdb	New API to get all merge operands for a Key (#5604 )	5 years ago
java	Correct the default write buffer size of java doc (#5670 )	5 years ago
logging	Auto Roll Logger to add some extra checking to avoid segfault. (#5623 )	5 years ago
memory	Move some logging related files to logging/ (#5387 )	5 years ago
memtable	simplify include directive involving inttypes (#5402 )	5 years ago
monitoring	WritePrepared: fix Get without snapshot (#5664 )	5 years ago
options	The ObjectRegistry class replaces the Registrar and NewCustomObjects.… (#5293 )	5 years ago
port	fix sign compare warnings (#5651 )	5 years ago
table	New API to get all merge operands for a Key (#5604 )	5 years ago
test_util	Added support for sequential read-ahead file (#5580 )	5 years ago
third-party/gtest-1.7.0/fused-src/gtest	remove bundled but unused fbson library (#5108 )	5 years ago
tools	New API to get all merge operands for a Key (#5604 )	5 years ago
trace_replay	Block cache analyzer: Compute correlation of features and human readable trace file. (#5596 )	5 years ago
util	Avoid user key copying for Get/Put/Write with user-timestamp (#5502 )	5 years ago
utilities	New API to get all merge operands for a Key (#5604 )	5 years ago
.clang-format	A script that automatically reformat affected lines	11 years ago
.gitignore	Block cache simulator: Add pysim to simulate caches using reinforcement learning. (#5610 )	5 years ago
.lgtm.yml	Create lgtm.yml for LGTM.com C/C++ analysis (#4058 )	6 years ago
.travis.yml	Switch Travis to Xenial build (#4789 )	5 years ago
.watchmanconfig	Added .watchmanconfig file to rocksdb repo (#5593 )	5 years ago
AUTHORS	Update RocksDB Authors File	7 years ago
CMakeLists.txt	New API to get all merge operands for a Key (#5604 )	5 years ago
CODE_OF_CONDUCT.md	Add Code of Conduct	7 years ago
CONTRIBUTING.md	Add Code of Conduct	7 years ago
COPYING	Add GPLv2 as an alternative license.	7 years ago
DEFAULT_OPTIONS_HISTORY.md	options.delayed_write_rate use the rate of rate_limiter by default.	7 years ago
DUMP_FORMAT.md	First version of rocksdb_dump and rocksdb_undump.	9 years ago
HISTORY.md	Improve CPU Efficiency of ApproximateSize (part 2) (#5609 )	5 years ago
INSTALL.md	Update the version of the dependencies used by the RocksJava static build (#4761 )	6 years ago
LANGUAGE-BINDINGS.md	LANGUAGE-BINDINGS.md: mention python-rocksdb	5 years ago
LICENSE.Apache	Change RocksDB License	7 years ago
LICENSE.leveldb	Add back the LevelDB license file	7 years ago
Makefile	New API to get all merge operands for a Key (#5604 )	5 years ago
README.md	Add LevelDB repository link in the Readme	5 years ago
ROCKSDB_LITE.md	Fix some typos in comments and docs.	6 years ago
TARGETS	New API to get all merge operands for a Key (#5604 )	5 years ago
USERS.md	Add Alluxio to USERS.md (#5434 )	5 years ago
Vagrantfile	Adding CentOS 7 Vagrantfile & build script	6 years ago
WINDOWS_PORT.md	#5145 , rename port/dirent.h to port/port_dirent.h to avoid compile err when use port dir as header dir output (#5152 )	5 years ago
appveyor.yml	New API to get all merge operands for a Key (#5604 )	5 years ago
defs.bzl	Change buckifier to support parameterized dependencies (#5648 )	5 years ago
issue_template.md	Add a template for issues	7 years ago
src.mk	New API to get all merge operands for a Key (#5604 )	5 years ago
thirdparty.inc	Fix build jemalloc api (#5470 )	5 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/

License

RocksDB is dual-licensed under both the GPLv2 (found in the COPYING file in the root directory) and Apache 2.0 License (found in the LICENSE.Apache file in the root directory). You may select, at your option, one of the above-listed licenses.