A library that provides an embeddable, persistent key-value store for fast storage.
f8d8cf53fe
Hello and thanks for RocksDB, When log_write_bench is run with the -bytes_per_sync option, the option does not influence any *sync* behaviour. > strace -e trace=write,sync_file_range ./log_write_bench -record_interval 0 -record_size 1048576 -num_records 11 -bytes_per_sync 2097152 2>&1 | egrep '^(sync|write.*XXXX)' write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 1048576) = 1048576 write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 1048576) = 1048576 write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 1048576) = 1048576 write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 1048576) = 1048576 write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 1048576) = 1048576 write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 1048576) = 1048576 write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 1048576) = 1048576 write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 1048576) = 1048576 write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 1048576) = 1048576 write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 1048576) = 1048576 write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 1048576) = 1048576 I suspect that this is because the bytes_per_sync option now needs to be using a `WritableFileWriter` and not a `WritableFile`. With the diff below applied, it changes to: > strace -e trace=write,sync_file_range ./log_write_bench -record_interval 0 -record_size 1048576 -num_records 11 -bytes_per_sync 2097152 2>&1 | egrep '^(sync|write.*XXXX)' write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 1048576) = 1048576 write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 1048576) = 1048576 write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 1048576) = 1048576 sync_file_range(0x3, 0, 0x200000, 0x2) = 0 write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 1048576) = 1048576 write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 1048576) = 1048576 sync_file_range(0x3, 0x200000, 0x200000, 0x2) = 0 write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 1048576) = 1048576 write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 1048576) = 1048576 sync_file_range(0x3, 0x400000, 0x200000, 0x2) = 0 write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 1048576) = 1048576 write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 1048576) = 1048576 sync_file_range(0x3, 0x600000, 0x200000, 0x2) = 0 write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 1048576) = 1048576 write(3, "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"..., 1048576) = 1048576 sync_file_range(0x3, 0x800000, 0x200000, 0x2) = 0 ( Note that the first 1MB is not synced as mentioned in util/file_reader_writer.cc::WritableFileWriter::Flush() ) This diff also includes the fix from https://github.com/facebook/rocksdb/pull/1373 > diff -du util/log_write_bench.cc.orig util/log_write_bench.cc --- util/log_write_bench.cc.orig 2016-10-04 12:06:29.115122580 -0400 +++ util/log_write_bench.cc 2016-10-05 07:24:09.677037576 -0400 @@ -14,6 +14,7 @@ #include <gflags/gflags.h> #include "rocksdb/env.h" +#include "util/file_reader_writer.h" #include "util/histogram.h" #include "util/testharness.h" #include "util/testutil.h" @@ -38,19 +39,21 @@ env_options.bytes_per_sync = FLAGS_bytes_per_sync; unique_ptr<WritableFile> file; env->NewWritableFile(file_name, &file, env_options); + unique_ptr<WritableFileWriter> writer; + writer.reset(new WritableFileWriter(std::move(file), env_options)); std::string record; - record.assign('X', FLAGS_record_size); + record.assign(FLAGS_record_size, 'X'); HistogramImpl hist; uint64_t start_time = env->NowMicros(); for (int i = 0; i < FLAGS_num_records; i++) { uint64_t start_nanos = env->NowNanos(); - file->Append(record); - file->Flush(); + writer->Append(record); + writer->Flush(); if (FLAGS_enable_sync) { - file->Sync(); + writer->Sync(false); } hist.Add(env->NowNanos() - start_nanos); |
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| arcanist_util | ||
| build_tools | ||
| cmake/modules | ||
| coverage | ||
| db | ||
| docs | ||
| examples | ||
| hdfs | ||
| include/rocksdb | ||
| java | ||
| memtable | ||
| port | ||
| table | ||
| third-party | ||
| tools | ||
| util | ||
| utilities | ||
| .arcconfig | ||
| .clang-format | ||
| .gitignore | ||
| .travis.yml | ||
| appveyor.yml | ||
| AUTHORS | ||
| CMakeLists.txt | ||
| CONTRIBUTING.md | ||
| DEFAULT_OPTIONS_HISTORY.md | ||
| DUMP_FORMAT.md | ||
| HISTORY.md | ||
| INSTALL.md | ||
| LANGUAGE-BINDINGS.md | ||
| LICENSE | ||
| Makefile | ||
| PATENTS | ||
| README.md | ||
| ROCKSDB_LITE.md | ||
| src.mk | ||
| 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 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/