remove unnecessary fsync

pingcap · Jun 8, 2023 · 2b0339d · 2b0339d
1 parent b1d8e8e
commit 2b0339d
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Showing 4 changed files with 14 additions and 10 deletions.
diff --git a/dbms/src/Common/CurrentMetrics.cpp b/dbms/src/Common/CurrentMetrics.cpp
@@ -28,6 +28,7 @@
     M(PSMVCCSnapshotsList)                      \
     M(PSMVCCNumDelta)                           \
     M(PSMVCCNumBase)                            \
+    M(PSWriterQueueSize)                        \
     M(RWLockWaitingReaders)                     \
     M(RWLockWaitingWriters)                     \
     M(RWLockActiveReaders)                      \

diff --git a/dbms/src/Storages/Page/V3/LogFile/LogWriter.cpp b/dbms/src/Storages/Page/V3/LogFile/LogWriter.cpp
@@ -15,6 +15,8 @@
 #include <Common/Checksum.h>
 #include <Common/Exception.h>
 #include <Common/Logger.h>
+#include <Common/Stopwatch.h>
+#include <Common/TiFlashMetrics.h>
 #include <IO/ReadBuffer.h>
 #include <IO/WriteBufferFromFile.h>
 #include <IO/WriteHelpers.h>
@@ -69,7 +71,7 @@ size_t LogWriter::writtenBytes() const
     return written_bytes;
 }
 
-void LogWriter::flush(const WriteLimiterPtr & write_limiter, bool background)
+void LogWriter::flush(const WriteLimiterPtr & write_limiter, bool background, bool sync)
 {
     if (write_buffer.offset() == 0)
     {
@@ -84,7 +86,10 @@ void LogWriter::flush(const WriteLimiterPtr & write_limiter, bool background)
                         /*background=*/background,
                         /*truncate_if_failed=*/false,
                         /*enable_failpoint=*/false);
-    log_file->fsync();
+    if (sync)
+    {
+        log_file->fsync();
+    }
     written_bytes += write_buffer.offset();
 
     // reset the write_buffer
@@ -115,7 +120,7 @@ void LogWriter::addRecord(ReadBuffer & payload, const size_t payload_size, const
         static constexpr char MAX_ZERO_HEADER[Format::RECYCLABLE_HEADER_SIZE]{'\x00'};
         if (unlikely(buffer_size - write_buffer.offset() < leftover))
         {
-            flush(write_limiter, background);
+            flush(write_limiter, background, false);
         }
         writeString(MAX_ZERO_HEADER, leftover, write_buffer);
         block_offset = 0;
@@ -141,7 +146,7 @@ void LogWriter::addRecord(ReadBuffer & payload, const size_t payload_size, const
         // Check available space in write_buffer before writing
         if (buffer_size - write_buffer.offset() < fragment_length + header_size)
         {
-            flush(write_limiter, background);
+            flush(write_limiter, background, false);
         }
         try
         {
@@ -158,10 +163,7 @@ void LogWriter::addRecord(ReadBuffer & payload, const size_t payload_size, const
         begin = false;
     } while (payload.hasPendingData());
 
-    if (!manual_flush)
-    {
-        flush(write_limiter, background);
-    }
+    flush(write_limiter, background, !manual_flush);
 }
 
 void LogWriter::emitPhysicalRecord(Format::RecordType type, ReadBuffer & payload, size_t length)

diff --git a/dbms/src/Storages/Page/V3/LogFile/LogWriter.h b/dbms/src/Storages/Page/V3/LogFile/LogWriter.h
@@ -87,7 +87,7 @@ class LogWriter final : private Allocator<false>
 
     void addRecord(ReadBuffer & payload, size_t payload_size, const WriteLimiterPtr & write_limiter = nullptr, bool background = false);
 
-    void flush(const WriteLimiterPtr & write_limiter = nullptr, bool background = false);
+    void flush(const WriteLimiterPtr & write_limiter = nullptr, bool background = false, bool sync = true);
 
     void close();
 

diff --git a/dbms/src/Storages/Page/V3/PageDirectory.cpp b/dbms/src/Storages/Page/V3/PageDirectory.cpp
@@ -50,6 +50,7 @@
 namespace CurrentMetrics
 {
 extern const Metric PSMVCCSnapshotsList;
+extern const Metric PSWriterQueueSize;
 } // namespace CurrentMetrics
 
 namespace DB
@@ -1484,6 +1485,7 @@ std::unordered_set<String> PageDirectory<Trait>::apply(PageEntriesEdit && edit,
     watch.restart();
 
     writers.push_back(&w);
+    CurrentMetrics::set(CurrentMetrics::PSWriterQueueSize, writers.size());
     w.cv.wait(apply_lock, [&] { return w.done || &w == writers.front(); });
     GET_METRIC(tiflash_storage_page_write_duration_seconds, type_wait_in_group).Observe(watch.elapsedSeconds());
     watch.restart();
@@ -1504,7 +1506,6 @@ std::unordered_set<String> PageDirectory<Trait>::apply(PageEntriesEdit && edit,
         // group owner, others just return an empty set.
         return {};
     }
-
     auto * last_writer = buildWriteGroup(&w, apply_lock);
     apply_lock.unlock();