From 7ca1a1f0d8a3edde5c50292599b98e883bd66247 Mon Sep 17 00:00:00 2001
From: Zhichao Cao <zhichao@fb.com>
Date: Wed, 10 Oct 2018 09:58:15 -0700
Subject: [PATCH] Fix trace_analyzer potential huge memory wasting due to no
 valid query analyzed (#4473)

Summary:
If the query types being analyzed do not appear in the trace, the current trace_analyzer will use 0 as the begin time, which create the time duration from 1970/01/01 to the now time. It will waste huge memory. Fixed by adding the trace_create_time to limit the duration.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4473

Differential Revision: D10246204

Pulled By: zhichao-cao

fbshipit-source-id: 42850b080b2e62f586fe73afd7737c2246d1a8c8
---
 tools/trace_analyzer_tool.cc | 5 +++++
 tools/trace_analyzer_tool.h  | 1 +
 2 files changed, 6 insertions(+)

diff --git a/tools/trace_analyzer_tool.cc b/tools/trace_analyzer_tool.cc
index 7915322f0..e6ec48cd1 100644
--- a/tools/trace_analyzer_tool.cc
+++ b/tools/trace_analyzer_tool.cc
@@ -276,6 +276,7 @@ TraceAnalyzer::TraceAnalyzer(std::string& trace_path, std::string& output_path,
   total_access_keys_ = 0;
   total_gets_ = 0;
   total_writes_ = 0;
+  trace_create_time_ = 0;
   begin_time_ = 0;
   end_time_ = 0;
   time_series_start_ = 0;
@@ -422,6 +423,7 @@ Status TraceAnalyzer::StartProcessing() {
     fprintf(stderr, "Cannot read the header\n");
     return s;
   }
+  trace_create_time_ = header.ts;
   if (FLAGS_output_time_series) {
     time_series_start_ = header.ts;
   }
@@ -740,6 +742,9 @@ Status TraceAnalyzer::MakeStatisticCorrelation(TraceStats& stats,
 
 // Process the statistics of QPS
 Status TraceAnalyzer::MakeStatisticQPS() {
+  if(begin_time_ == 0) {
+    begin_time_ = trace_create_time_;
+  }
   uint32_t duration =
       static_cast<uint32_t>((end_time_ - begin_time_) / 1000000);
   int ret;
diff --git a/tools/trace_analyzer_tool.h b/tools/trace_analyzer_tool.h
index ac9f42f1c..b171ef22c 100644
--- a/tools/trace_analyzer_tool.h
+++ b/tools/trace_analyzer_tool.h
@@ -204,6 +204,7 @@ class TraceAnalyzer {
   uint64_t total_access_keys_;
   uint64_t total_gets_;
   uint64_t total_writes_;
+  uint64_t trace_create_time_;
   uint64_t begin_time_;
   uint64_t end_time_;
   uint64_t time_series_start_;