[tracing] Add sqlite memory statistics to tracing.

sql/connection.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "sql/connection.h"
 
 #include <string.h>
 
 #include "base/bind.h"
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
 #include "base/metrics/histogram.h"
 #include "base/metrics/sparse_histogram.h"
 #include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/synchronization/lock.h"
+#include "base/trace_event/memory_dump_manager.h"
+#include "base/trace_event/process_memory_dump.h"
 #include "sql/statement.h"
 #include "third_party/sqlite/sqlite3.h"
 
 #if defined(OS_IOS) && defined(USE_SYSTEM_SQLITE)
 #include "third_party/sqlite/src/ext/icu/sqliteicu.h"
 #endif
 
 namespace {
 
 // Spin for up to a second waiting for the lock to clear when setting
@@ skipping 178 matching lines @@
 // static
 Connection::ErrorIgnorerCallback* Connection::current_ignorer_cb_ = NULL;
 
 // static
 bool Connection::ShouldIgnoreSqliteError(int error) {
   if (!current_ignorer_cb_)
     return false;
   return current_ignorer_cb_->Run(error);
 }
 
+bool Connection::OnMemoryDump(const base::trace_event::MemoryDumpArgs& args,

[michaeln, 2015/10/15 23:03:28]

what prevents this method from being called after ~Connection has happened?

[Scott Hess - ex-Googler, 2015/10/15 23:50:29]

~Connection unregisters, and the !db_ test below should handle cases where the
db closed but the instance is still live.  [I should have suggested is_open()
there, but they mean the same thing at this time.]

[Primiano Tucci (use gerrit), 2015/10/16 08:37:44]

As long as the dtor happens on the same thread of the ctor, the OnMemoryDump is
guaranteed to not be called adter the UnregisterDumpProvider call (which happens
on the dtor)

+                              base::trace_event::ProcessMemoryDump* pmd) {
+  if (args.level_of_detail ==
+          base::trace_event::MemoryDumpLevelOfDetail::LIGHT ||
+      !db_) {
+    return true;
+  }
+
+  // The high water mark is not tracked for the following usages.
+  int cache_size, dummy_int;
+  sqlite3_db_status(db_, SQLITE_DBSTATUS_CACHE_USED, &cache_size, &dummy_int,
+                    0 /* resetFlag */);
+  int schema_size;
+  sqlite3_db_status(db_, SQLITE_DBSTATUS_SCHEMA_USED, &schema_size, &dummy_int,
+                    0 /* resetFlag */);
+  int statement_size;
+  sqlite3_db_status(db_, SQLITE_DBSTATUS_STMT_USED, &statement_size, &dummy_int,
+                    0 /* resetFlag */);
+
+  std::string name = base::StringPrintf(
+      "sqlite/%s_connection/%p",
+      histogram_tag_.empty() ? "Unknown" : histogram_tag_.c_str(), this);
+  base::trace_event::MemoryAllocatorDump* dump = pmd->CreateAllocatorDump(name);
+  dump->AddScalar(base::trace_event::MemoryAllocatorDump::kNameSize,
+                  base::trace_event::MemoryAllocatorDump::kUnitsBytes,
+                  cache_size + schema_size + statement_size);
+  dump->AddScalar("cache_size",
+                  base::trace_event::MemoryAllocatorDump::kUnitsBytes,
+                  cache_size);
+  dump->AddScalar("schema_size",
+                  base::trace_event::MemoryAllocatorDump::kUnitsBytes,
+                  schema_size);
+  dump->AddScalar("statement_size",
+                  base::trace_event::MemoryAllocatorDump::kUnitsBytes,
+                  statement_size);
+  return true;
+}
+
 // static
 void Connection::SetErrorIgnorer(Connection::ErrorIgnorerCallback* cb) {
   CHECK(current_ignorer_cb_ == NULL);
   current_ignorer_cb_ = cb;
 }
 
 // static
 void Connection::ResetErrorIgnorer() {
   CHECK(current_ignorer_cb_);
   current_ignorer_cb_ = NULL;
@@ skipping 54 matching lines @@
       poisoned_(false),
       mmap_disabled_(false),
       mmap_enabled_(false),
       total_changes_at_last_release_(0),
       stats_histogram_(NULL),
       commit_time_histogram_(NULL),
       autocommit_time_histogram_(NULL),
       update_time_histogram_(NULL),
       query_time_histogram_(NULL),
       clock_(new TimeSource()) {
+  base::trace_event::MemoryDumpManager::GetInstance()->RegisterDumpProvider(
+      this);
 }
 
 Connection::~Connection() {
+  base::trace_event::MemoryDumpManager::GetInstance()->UnregisterDumpProvider(
+      this);
   Close();
 }
 
 void Connection::RecordEvent(Events event, size_t count) {
   for (size_t i = 0; i < count; ++i) {
     UMA_HISTOGRAM_ENUMERATION("Sqlite.Stats", event, EVENT_MAX_VALUE);
   }
 
   if (stats_histogram_) {
     for (size_t i = 0; i < count; ++i) {
@@ skipping 1176 matching lines @@
   ignore_result(Execute(kNoWritableSchema));
 
   return ret;
 }
 
 base::TimeTicks TimeSource::Now() {
   return base::TimeTicks::Now();
 }
 
 }  // namespace sql