Summary: Hello and thanks for RocksDB, Here is a PR to add file deletes, renames and ```Flush()```, ```Sync()```, ```Fsync()``` and ```Close()``` to file ops report. The reason is to help tune RocksDB options when using an env/filesystem with high latencies for file level ("metadata") operations, typically seen during ```DB::Open``` (```db_bench -num 0``` also see https://github.com/facebook/rocksdb/pull/7203 where IOTracing does not trace ```DB::Open```). Before: ``` > db_bench -benchmarks updaterandom -num 0 -report_file_operations true ... Entries: 0 ... Num files opened: 12 Num Read(): 6 Num Append(): 8 Num bytes read: 6216 Num bytes written: 6289 ``` After: ``` > db_bench -benchmarks updaterandom -num 0 -report_file_operations true ... Entries: 0 ... Num files opened: 12 Num files deleted: 3 Num files renamed: 4 Num Flush(): 10 Num Sync(): 5 Num Fsync(): 1 Num Close(): 2 Num Read(): 6 Num Append(): 8 Num bytes read: 6216 Num bytes written: 6289 ``` Before: ``` > db_bench -benchmarks updaterandom -report_file_operations true ... Entries: 1000000 ... Num files opened: 18 Num Read(): 396339 Num Append(): 1000058 Num bytes read: 892030224 Num bytes written: 187569238 ``` After: ``` > db_bench -benchmarks updaterandom -report_file_operations true ... Entries: 1000000 ... Num files opened: 18 Num files deleted: 5 Num files renamed: 4 Num Flush(): 1000068 Num Sync(): 9 Num Fsync(): 1 Num Close(): 6 Num Read(): 396339 Num Append(): 1000058 Num bytes read: 892030224 Num bytes written: 187569238 ``` Another example showing how using ```DB::OpenForReadOnly``` reduces file operations compared to ```((Optimistic)Transaction)DB::Open```: ``` > db_bench -benchmarks updaterandom -num 1 > db_bench -benchmarks updaterandom -num 0 -use_existing_db true -readonly true -report_file_operations true ... Entries: 0 ... Num files opened: 8 Num files deleted: 0 Num files renamed: 0 Num Flush(): 0 Num Sync(): 0 Num Fsync(): 0 Num Close(): 0 Num Read(): 13 Num Append(): 0 Num bytes read: 374 Num bytes written: 0 ``` ``` > db_bench -benchmarks updaterandom -num 1 > db_bench -benchmarks updaterandom -num 0 -use_existing_db true -report_file_operations true ... Entries: 0 ... Num files opened: 14 Num files deleted: 3 Num files renamed: 4 Num Flush(): 14 Num Sync(): 5 Num Fsync(): 1 Num Close(): 3 Num Read(): 11 Num Append(): 10 Num bytes read: 7291 Num bytes written: 7357 ``` Pull Request resolved: https://github.com/facebook/rocksdb/pull/8448 Reviewed By: anand1976 Differential Revision: D29333818 Pulled By: zhichao-cao fbshipit-source-id: a06a8c87f799806462319115195b3e94faf5f542 |
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.circleci | ||
.github/workflows | ||
buckifier | ||
build_tools | ||
cache | ||
cmake | ||
coverage | ||
db | ||
db_stress_tool | ||
docs | ||
env | ||
examples | ||
file | ||
fuzz | ||
hdfs | ||
include/rocksdb | ||
java | ||
logging | ||
memory | ||
memtable | ||
monitoring | ||
options | ||
plugin | ||
port | ||
table | ||
test_util | ||
third-party | ||
tools | ||
trace_replay | ||
util | ||
utilities | ||
.clang-format | ||
.gitignore | ||
.lgtm.yml | ||
.travis.yml | ||
.watchmanconfig | ||
appveyor.yml | ||
AUTHORS | ||
CMakeLists.txt | ||
CODE_OF_CONDUCT.md | ||
CONTRIBUTING.md | ||
COPYING | ||
DEFAULT_OPTIONS_HISTORY.md | ||
defs.bzl | ||
DUMP_FORMAT.md | ||
HISTORY.md | ||
INSTALL.md | ||
issue_template.md | ||
LANGUAGE-BINDINGS.md | ||
LICENSE.Apache | ||
LICENSE.leveldb | ||
Makefile | ||
PLUGINS.md | ||
README.md | ||
ROCKSDB_LITE.md | ||
src.mk | ||
TARGETS | ||
thirdparty.inc | ||
USERS.md | ||
Vagrantfile | ||
WINDOWS_PORT.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 especially 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/ and https://rocksdb.slack.com/
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.