mirror of
https://github.com/facebook/rocksdb.git
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12b6cdeed3
Summary: A framework for tracing and replaying RocksDB operations. A binary trace file is created by capturing the DB operations, and it can be replayed back at the same rate using db_bench. - Column-families are supported - Multi-threaded tracing is supported. - TraceReader and TraceWriter are exposed to the user, so that tracing to various destinations can be enabled (say, to other messaging/logging services). By default, a FileTraceReader and FileTraceWriter are implemented to capture to a file and replay from it. - This is not yet ideal to be enabled in production due to large performance overhead, but it can be safely tried out in a shadow setup, say, for analyzing RocksDB operations. Currently supported DB operations: - Writes: -- Put -- Merge -- Delete -- SingleDelete -- DeleteRange -- Write - Reads: -- Get (point lookups) Pull Request resolved: https://github.com/facebook/rocksdb/pull/3837 Differential Revision: D7974837 Pulled By: sagar0 fbshipit-source-id: 8ec65aaf336504bc1f6ed0feae67f6ed5ef97a72
118 lines
3.4 KiB
C++
118 lines
3.4 KiB
C++
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
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// This source code is licensed under both the GPLv2 (found in the
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// COPYING file in the root directory) and Apache 2.0 License
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// (found in the LICENSE.Apache file in the root directory).
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#include "utilities/trace/file_trace_reader_writer.h"
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#include "util/coding.h"
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#include "util/file_reader_writer.h"
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#include "util/trace_replay.h"
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namespace rocksdb {
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const unsigned int FileTraceReader::kBufferSize = 1024; // 1KB
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FileTraceReader::FileTraceReader(
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std::unique_ptr<RandomAccessFileReader>&& reader)
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: file_reader_(std::move(reader)),
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offset_(0),
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buffer_(new char[kBufferSize]) {}
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FileTraceReader::~FileTraceReader() {
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Close();
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delete[] buffer_;
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}
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Status FileTraceReader::Close() {
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file_reader_.reset();
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return Status::OK();
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}
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Status FileTraceReader::Read(std::string* data) {
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assert(file_reader_ != nullptr);
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Status s = file_reader_->Read(offset_, kTraceMetadataSize, &result_, buffer_);
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if (!s.ok()) {
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return s;
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}
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if (result_.size() == 0) {
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// No more data to read
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// Todo: Come up with a better way to indicate end of data. May be this
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// could be avoided once footer is introduced.
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return Status::Incomplete();
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}
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if (result_.size() < kTraceMetadataSize) {
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return Status::Corruption("Corrupted trace file.");
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}
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*data = result_.ToString();
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offset_ += kTraceMetadataSize;
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uint32_t payload_len =
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DecodeFixed32(&buffer_[kTraceTimestampSize + kTraceTypeSize]);
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// Read Payload
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unsigned int bytes_to_read = payload_len;
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unsigned int to_read =
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bytes_to_read > kBufferSize ? kBufferSize : bytes_to_read;
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while (to_read > 0) {
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s = file_reader_->Read(offset_, to_read, &result_, buffer_);
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if (!s.ok()) {
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return s;
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}
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if (result_.size() < to_read) {
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return Status::Corruption("Corrupted trace file.");
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}
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data->append(result_.data(), result_.size());
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offset_ += to_read;
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bytes_to_read -= to_read;
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to_read = bytes_to_read > kBufferSize ? kBufferSize : bytes_to_read;
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}
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return s;
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}
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FileTraceWriter::~FileTraceWriter() { Close(); }
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Status FileTraceWriter::Close() {
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file_writer_.reset();
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return Status::OK();
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}
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Status FileTraceWriter::Write(const Slice& data) {
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return file_writer_->Append(data);
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}
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Status NewFileTraceReader(Env* env, const EnvOptions& env_options,
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const std::string& trace_filename,
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std::unique_ptr<TraceReader>* trace_reader) {
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unique_ptr<RandomAccessFile> trace_file;
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Status s = env->NewRandomAccessFile(trace_filename, &trace_file, env_options);
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if (!s.ok()) {
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return s;
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}
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unique_ptr<RandomAccessFileReader> file_reader;
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file_reader.reset(
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new RandomAccessFileReader(std::move(trace_file), trace_filename));
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trace_reader->reset(new FileTraceReader(std::move(file_reader)));
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return s;
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}
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Status NewFileTraceWriter(Env* env, const EnvOptions& env_options,
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const std::string& trace_filename,
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std::unique_ptr<TraceWriter>* trace_writer) {
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unique_ptr<WritableFile> trace_file;
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Status s = env->NewWritableFile(trace_filename, &trace_file, env_options);
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if (!s.ok()) {
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return s;
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}
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unique_ptr<WritableFileWriter> file_writer;
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file_writer.reset(new WritableFileWriter(std::move(trace_file), env_options));
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trace_writer->reset(new FileTraceWriter(std::move(file_writer)));
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return s;
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}
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} // namespace rocksdb
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