From 28e5a9a9fbde73b69f143dffc058e111d4410209 Mon Sep 17 00:00:00 2001
From: Maysam Yabandeh <myabandeh@fb.com>
Date: Mon, 6 Jan 2020 10:15:00 -0800
Subject: [PATCH] Increase max_log_size in FlushJob to 1024 bytes (#6258)

Summary:
When measure_io_stats_ is enabled, the volume of logging is beyond the default limit of 512 size. The patch allows the EventLoggerStream to change the limit, and also sets it to 1024 for FlushJob.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6258

Differential Revision: D19279269

Pulled By: maysamyabandeh

fbshipit-source-id: 3fb5d468dad488f289ac99d713378177eb7504d6
---
 db/flush_job.cc         |  3 ++-
 logging/event_logger.cc | 24 ++++++++++++++++--------
 logging/event_logger.h  | 13 ++++++++++---
 logging/log_buffer.cc   |  3 +--
 logging/log_buffer.h    |  1 +
 5 files changed, 30 insertions(+), 14 deletions(-)

diff --git a/db/flush_job.cc b/db/flush_job.cc
index 2190c45c2..23ca044c0 100644
--- a/db/flush_job.cc
+++ b/db/flush_job.cc
@@ -249,7 +249,8 @@ Status FlushJob::Run(LogsWithPrepTracker* prep_tracker,
   }
   RecordFlushIOStats();
 
-  auto stream = event_logger_->LogToBuffer(log_buffer_);
+  // When measure_io_stats_ is true, the default 512 bytes is not enough.
+  auto stream = event_logger_->LogToBuffer(log_buffer_, 1024);
   stream << "job" << job_context_->job_id << "event"
          << "flush_finished";
   stream << "output_compression"
diff --git a/logging/event_logger.cc b/logging/event_logger.cc
index 4ae9d2d66..5e07fd96f 100644
--- a/logging/event_logger.cc
+++ b/logging/event_logger.cc
@@ -15,12 +15,18 @@
 
 namespace rocksdb {
 
-
 EventLoggerStream::EventLoggerStream(Logger* logger)
-    : logger_(logger), log_buffer_(nullptr), json_writer_(nullptr) {}
+    : logger_(logger),
+      log_buffer_(nullptr),
+      max_log_size_(0),
+      json_writer_(nullptr) {}
 
-EventLoggerStream::EventLoggerStream(LogBuffer* log_buffer)
-    : logger_(nullptr), log_buffer_(log_buffer), json_writer_(nullptr) {}
+EventLoggerStream::EventLoggerStream(LogBuffer* log_buffer,
+                                     const size_t max_log_size)
+    : logger_(nullptr),
+      log_buffer_(log_buffer),
+      max_log_size_(max_log_size),
+      json_writer_(nullptr) {}
 
 EventLoggerStream::~EventLoggerStream() {
   if (json_writer_) {
@@ -31,7 +37,8 @@ EventLoggerStream::~EventLoggerStream() {
     if (logger_) {
       EventLogger::Log(logger_, *json_writer_);
     } else if (log_buffer_) {
-      EventLogger::LogToBuffer(log_buffer_, *json_writer_);
+      assert(max_log_size_);
+      EventLogger::LogToBuffer(log_buffer_, *json_writer_, max_log_size_);
     }
 #endif
     delete json_writer_;
@@ -50,13 +57,14 @@ void EventLogger::Log(Logger* logger, const JSONWriter& jwriter) {
 #endif
 }
 
-void EventLogger::LogToBuffer(
-    LogBuffer* log_buffer, const JSONWriter& jwriter) {
+void EventLogger::LogToBuffer(LogBuffer* log_buffer, const JSONWriter& jwriter,
+                              const size_t max_log_size) {
 #ifdef ROCKSDB_PRINT_EVENTS_TO_STDOUT
   printf("%s\n", jwriter.Get().c_str());
 #else
   assert(log_buffer);
-  rocksdb::LogToBuffer(log_buffer, "%s %s", Prefix(), jwriter.Get().c_str());
+  rocksdb::LogToBuffer(log_buffer, max_log_size, "%s %s", Prefix(),
+                       jwriter.Get().c_str());
 #endif
 }
 
diff --git a/logging/event_logger.h b/logging/event_logger.h
index c3a7c30c6..6206993c8 100644
--- a/logging/event_logger.h
+++ b/logging/event_logger.h
@@ -162,10 +162,11 @@ class EventLoggerStream {
   }
   friend class EventLogger;
   explicit EventLoggerStream(Logger* logger);
-  explicit EventLoggerStream(LogBuffer* log_buffer);
+  explicit EventLoggerStream(LogBuffer* log_buffer, const size_t max_log_size);
   // exactly one is non-nullptr
   Logger* const logger_;
   LogBuffer* const log_buffer_;
+  const size_t max_log_size_;  // used only for log_buffer_
   // ownership
   JSONWriter* json_writer_;
 };
@@ -183,11 +184,17 @@ class EventLogger {
   explicit EventLogger(Logger* logger) : logger_(logger) {}
   EventLoggerStream Log() { return EventLoggerStream(logger_); }
   EventLoggerStream LogToBuffer(LogBuffer* log_buffer) {
-    return EventLoggerStream(log_buffer);
+    return EventLoggerStream(log_buffer, LogBuffer::kDefaultMaxLogSize);
+  }
+  EventLoggerStream LogToBuffer(LogBuffer* log_buffer,
+                                const size_t max_log_size) {
+    return EventLoggerStream(log_buffer, max_log_size);
   }
   void Log(const JSONWriter& jwriter);
   static void Log(Logger* logger, const JSONWriter& jwriter);
-  static void LogToBuffer(LogBuffer* log_buffer, const JSONWriter& jwriter);
+  static void LogToBuffer(
+      LogBuffer* log_buffer, const JSONWriter& jwriter,
+      const size_t max_log_size = LogBuffer::kDefaultMaxLogSize);
 
  private:
   Logger* logger_;
diff --git a/logging/log_buffer.cc b/logging/log_buffer.cc
index 74db11c66..5327c1814 100644
--- a/logging/log_buffer.cc
+++ b/logging/log_buffer.cc
@@ -81,11 +81,10 @@ void LogToBuffer(LogBuffer* log_buffer, size_t max_log_size, const char* format,
 }
 
 void LogToBuffer(LogBuffer* log_buffer, const char* format, ...) {
-  const size_t kDefaultMaxLogSize = 512;
   if (log_buffer != nullptr) {
     va_list ap;
     va_start(ap, format);
-    log_buffer->AddLogToBuffer(kDefaultMaxLogSize, format, ap);
+    log_buffer->AddLogToBuffer(LogBuffer::kDefaultMaxLogSize, format, ap);
     va_end(ap);
   }
 }
diff --git a/logging/log_buffer.h b/logging/log_buffer.h
index 16fb24311..b54bf4d49 100644
--- a/logging/log_buffer.h
+++ b/logging/log_buffer.h
@@ -30,6 +30,7 @@ class LogBuffer {
 
   // Flush all buffered log to the info log.
   void FlushBufferToLog();
+  static const size_t kDefaultMaxLogSize = 512;
 
  private:
   // One log entry with its timestamp