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#include "sync_page_cache_file.h"
#include "record.h"
#include <util/generic/buffer.h>
#include <util/generic/yexception.h>
#include <util/system/align.h>
#include <util/system/event.h>
#include <util/system/file.h>
#include <util/system/info.h>
#include <util/system/mutex.h>
#include <util/system/thread.h>
class TSyncPageCacheFileLogBackend::TImpl: public TNonCopyable {
public:
TImpl(
const TString& path,
size_t maxBufferSize,
size_t maxPendingCacheSize,
TMaybe<TDuration> bufferFlushPeriod
)
: File_{OpenFile(path)}
, MaxBufferSize_{maxBufferSize}
, MaxPendingCacheSize_{maxPendingCacheSize}
, Buffer_{maxBufferSize}
, BufferFlushPeriod_{bufferFlushPeriod}
{
ResetPtrs();
if (BufferFlushPeriod_) {
BufferFlushThreadPtr_ = MakeHolder<TThread>([this] {RunBufferFlushThread();});
BufferFlushThreadPtr_->Start();
}
}
~TImpl() noexcept {
try {
if (BufferFlushThreadPtr_) {
BufferFlushThreadExitWaiter_.Signal();
}
Write();
FlushSync(GuaranteedWrittenPtr_, WrittenPtr_);
} catch (...) {
}
}
void WriteData(const TLogRecord& rec) {
TGuard guard{Lock_};
Buffer_.Append(rec.Data, rec.Len);
if (Buffer_.size() >= MaxBufferSize_) {
WriteAndFlush();
}
}
void ReopenLog() {
TGuard guard{Lock_};
Write();
FlushSync(GuaranteedWrittenPtr_, WrittenPtr_);
File_.LinkTo(OpenFile(File_.GetName()));
ResetPtrs();
}
private:
void ResetPtrs() {
WrittenPtr_ = File_.GetLength();
PageAlignedWrittenPtr_ = AlignDown(WrittenPtr_, GetPageSize());
GuaranteedWrittenPtr_ = WrittenPtr_;
}
static TFile OpenFile(const TString& path) {
return TFile{path, OpenAlways | WrOnly | ForAppend | Seq | NoReuse};
}
static i64 GetPageSize() {
static const i64 pageSize = NSystemInfo::GetPageSize();
Y_ASSUME(IsPowerOf2(pageSize));
return pageSize;
}
void Write() {
try {
File_.Write(Buffer_.Data(), Buffer_.Size());
WrittenPtr_ += Buffer_.Size();
PageAlignedWrittenPtr_ = AlignDown(WrittenPtr_, GetPageSize());
Buffer_.Clear();
} catch (TFileError&) {
Buffer_.Clear();
throw;
}
}
void FlushAsync(const i64 from, const i64 to) {
File_.FlushCache(from, to - from, /* wait = */ false);
}
void FlushSync(const i64 from, const i64 to) {
const i64 begin = AlignDown(from, GetPageSize());
const i64 end = AlignUp(to, GetPageSize());
const i64 length = end - begin;
File_.FlushCache(begin, length, /* wait = */ true);
File_.EvictCache(begin, length);
GuaranteedWrittenPtr_ = to;
}
void WriteAndFlush() {
const i64 prevAlignedEndPtr = PageAlignedWrittenPtr_;
Write();
if (prevAlignedEndPtr < PageAlignedWrittenPtr_) {
FlushAsync(prevAlignedEndPtr, PageAlignedWrittenPtr_);
}
const i64 minPendingCacheOffset = PageAlignedWrittenPtr_ - MaxPendingCacheSize_;
if (minPendingCacheOffset > GuaranteedWrittenPtr_) {
FlushSync(GuaranteedWrittenPtr_, minPendingCacheOffset);
}
}
void RunBufferFlushThread() {
Y_ENSURE(BufferFlushPeriod_);
TInstant deadline;
do {
deadline = TInstant::Now() + *BufferFlushPeriod_;
try {
TGuard guard{Lock_};
if (!Buffer_.Empty()) {
WriteAndFlush();
}
} catch (...) {
Cerr << "Failed to flush eventlog buffer: " << CurrentExceptionMessage() << Endl;
}
} while (!BufferFlushThreadExitWaiter_.WaitD(deadline));
}
private:
TMutex Lock_;
TFile File_;
const size_t MaxBufferSize_ = 0;
const size_t MaxPendingCacheSize_ = 0;
TBuffer Buffer_;
i64 WrittenPtr_ = 0;
i64 PageAlignedWrittenPtr_ = 0;
i64 GuaranteedWrittenPtr_ = 0;
const TMaybe<TDuration> BufferFlushPeriod_;
TManualEvent BufferFlushThreadExitWaiter_;
// thread should be declared last to be destroyed before other props
THolder<TThread> BufferFlushThreadPtr_;
};
TSyncPageCacheFileLogBackend::TSyncPageCacheFileLogBackend(
const TString& path,
size_t maxBufferSize,
size_t maxPengingCacheSize,
TMaybe<TDuration> bufferFlushPeriod
)
: Impl_(MakeHolder<TImpl>(
path,
maxBufferSize,
maxPengingCacheSize,
bufferFlushPeriod
))
{}
TSyncPageCacheFileLogBackend::~TSyncPageCacheFileLogBackend() {
}
void TSyncPageCacheFileLogBackend::WriteData(const TLogRecord& rec) {
Impl_->WriteData(rec);
}
void TSyncPageCacheFileLogBackend::ReopenLog() {
Impl_->ReopenLog();
}
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