Reverting based on discussions on #chromium with shess and rsleevi

Revert 111386 - Add a field trial for using lower sqlite cache sizes.



There are a few relevant histograms that I annotated with the field trial name, and I added a new AddPage histogram.



TEST=none

BUG=none
Review URL: http://codereview.chromium.org/8379009

TBR=brettw@chromium.org
Review URL: http://codereview.chromium.org/8677025

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@111433 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/autocomplete/history_url_provider.cc

@@ -16,7 +16,6 @@
 #include "chrome/browser/history/history.h"
 #include "chrome/browser/history/history_backend.h"
 #include "chrome/browser/history/history_database.h"
-#include "chrome/browser/history/history_field_trial.h"
 #include "chrome/browser/history/history_types.h"
 #include "chrome/browser/net/url_fixer_upper.h"
 #include "chrome/browser/prefs/pref_service.h"
@@ -352,8 +351,7 @@ void HistoryURLProvider::ExecuteWithDB(history::HistoryBackend* backend,
 
     DoAutocomplete(backend, db, params);
 
-    UMA_HISTOGRAM_TIMES("Autocomplete.HistoryAsyncQueryTime" +
-                            history::HistoryFieldTrial::GetGroupSuffix(),
+    UMA_HISTOGRAM_TIMES("Autocomplete.HistoryAsyncQueryTime",
                         base::TimeTicks::Now() - beginning_time);
   }
 

chrome/browser/history/history_backend.cc

@@ -19,7 +19,6 @@
 #include "base/time.h"
 #include "chrome/browser/autocomplete/history_url_provider.h"
 #include "chrome/browser/bookmarks/bookmark_service.h"
-#include "chrome/browser/history/history_field_trial.h"
 #include "chrome/browser/history/history_notifications.h"
 #include "chrome/browser/history/history_publisher.h"
 #include "chrome/browser/history/in_memory_history_backend.h"
@@ -374,8 +373,6 @@ void HistoryBackend::AddPage(scoped_refptr<HistoryAddPageArgs> request) {
   if (!db_.get())
     return;
 
-  TimeTicks beginning_time = TimeTicks::Now();
-
   // Will be filled with the URL ID and the visit ID of the last addition.
   std::pair<URLID, VisitID> last_ids(0, tracker_.GetLastVisit(
       request->id_scope, request->page_id, request->referrer));
@@ -547,10 +544,6 @@ void HistoryBackend::AddPage(scoped_refptr<HistoryAddPageArgs> request) {
   }
 
   ScheduleCommit();
-
-  UMA_HISTOGRAM_TIMES(
-      "History.AddPage" + HistoryFieldTrial::GetGroupSuffix(),
-      TimeTicks::Now() - beginning_time);
 }
 
 void HistoryBackend::InitImpl(const std::string& languages) {
@@ -560,8 +553,6 @@ void HistoryBackend::InitImpl(const std::string& languages) {
   // we only set db_ to the created database if creation is successful. That
   // way other methods won't do anything as db_ is still NULL.
 
-  HistoryFieldTrial::Activate();
-
   TimeTicks beginning_time = TimeTicks::Now();
 
   // Compute the file names. Note that the index file can be removed when the
@@ -1232,9 +1223,8 @@ void HistoryBackend::QueryHistory(scoped_refptr<QueryHistoryRequest> request,
 
   request->ForwardResult(request->handle(), &request->value);
 
-  UMA_HISTOGRAM_TIMES(
-      "History.QueryHistory" + HistoryFieldTrial::GetGroupSuffix(),
-      TimeTicks::Now() - beginning_time);
+  UMA_HISTOGRAM_TIMES("History.QueryHistory",
+                      TimeTicks::Now() - beginning_time);
 }
 
 // Basic time-based querying of history.

chrome/browser/history/history_database.cc

@@ -14,7 +14,6 @@
 #include "base/rand_util.h"
 #include "base/string_util.h"
 #include "chrome/browser/diagnostics/sqlite_diagnostics.h"
-#include "chrome/browser/history/history_field_trial.h"
 #include "chrome/browser/history/starred_url_database.h"
 #include "sql/transaction.h"
 
@@ -80,15 +79,11 @@ sql::InitStatus HistoryDatabase::Init(const FilePath& history_name,
   // this is a NOP. Must be a power of 2 and a max of 8192.
   db_.set_page_size(4096);
 
-  if (HistoryFieldTrial::IsLowMemFieldTrial()) {
-    db_.set_cache_size(500);
-  } else {
-    // Increase the cache size. The page size, plus a little extra, times this
-    // value, tells us how much memory the cache will use maximum.
-    // 6000 * 4MB = 24MB
-    // TODO(brettw) scale this value to the amount of available memory.
-    db_.set_cache_size(6000);
-  }
+  // Increase the cache size. The page size, plus a little extra, times this
+  // value, tells us how much memory the cache will use maximum.
+  // 6000 * 4MB = 24MB
+  // TODO(brettw) scale this value to the amount of available memory.
+  db_.set_cache_size(6000);
 
   // Note that we don't set exclusive locking here. That's done by
   // BeginExclusiveMode below which is called later (we have to be in shared

chrome/browser/history/history_field_trial.cc

-// Copyright (c) 2011 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 "chrome/browser/history/history_field_trial.h"
-
-#include "base/metrics/field_trial.h"
-
-namespace history {
-
-namespace {
-
-int g_low_mem_trial_group = 0;
-bool g_low_mem_trial = false;
-
-static const char kHistoryFieldTrialName[] = "History";
-
-}  // namespace
-
-// static
-void HistoryFieldTrial::Activate() {
-  if (g_low_mem_trial_group)
-    return;  // Already initialized.
-
-  scoped_refptr<base::FieldTrial> trial(new base::FieldTrial(
-      kHistoryFieldTrialName, 1000, "Inactive", 2012, 2, 1));
-
-  g_low_mem_trial_group = trial->AppendGroup("LowMem", 50);  // 5%
-  if (trial->group() == g_low_mem_trial_group)
-    g_low_mem_trial = true;
-}
-
-// static
-bool HistoryFieldTrial::IsLowMemFieldTrial() {
-  return g_low_mem_trial;
-}
-
-// static
-std::string HistoryFieldTrial::GetGroupSuffix() {
-  return g_low_mem_trial ? std::string("_LowMem") : std::string();
-}
-
-}  // namespace history

chrome/browser/history/history_field_trial.h

-// Copyright (c) 2011 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.
-
-#ifndef CHROME_BROWSER_HISTORY_HISTORY_FIELD_TRIAL_H_
-#define CHROME_BROWSER_HISTORY_HISTORY_FIELD_TRIAL_H_
-#pragma once
-
-#include <string>
-
-namespace history {
-
-class HistoryFieldTrial {
- public:
-  static void Activate();
-
-  // Returns true if history should try to use less memory.
-  static bool IsLowMemFieldTrial();
-
-  // Returns the group name as a suffix to append to histogram names for the
-  // current field trial, or the empty string if none.
-  static std::string GetGroupSuffix();
-};
-
-}  // namespace history
-
-#endif  // CHROME_BROWSER_HISTORY_HISTORY_FIELD_TRIAL_H_

chrome/browser/history/in_memory_database.cc

@@ -10,7 +10,6 @@
 #include "base/time.h"
 #include "base/utf_string_conversions.h"
 #include "build/build_config.h"
-#include "chrome/browser/history/history_field_trial.h"
 
 namespace history {
 
@@ -92,9 +91,8 @@ bool InMemoryDatabase::InitFromDisk(const FilePath& history_name) {
     // just not exist yet.
   }
   base::TimeTicks end_load = base::TimeTicks::Now();
-  UMA_HISTOGRAM_MEDIUM_TIMES(
-      "History.InMemoryDBPopulate" + HistoryFieldTrial::GetGroupSuffix(),
-      end_load - begin_load);
+  UMA_HISTOGRAM_MEDIUM_TIMES("History.InMemoryDBPopulate",
+                             end_load - begin_load);
   UMA_HISTOGRAM_COUNTS("History.InMemoryDBItemCount", db_.GetLastChangeCount());
 
   {

chrome/browser/history/text_database.cc

@@ -15,7 +15,6 @@
 #include "base/stringprintf.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/diagnostics/sqlite_diagnostics.h"
-#include "chrome/browser/history/history_field_trial.h"
 #include "sql/statement.h"
 #include "sql/transaction.h"
 
@@ -139,13 +138,7 @@ bool TextDatabase::Init() {
   // have 2-3 of these objects, each with their own 8MB, this adds up very fast.
   // We therefore reduce the size so when there are multiple objects, we're not
   // too big.
-  if (HistoryFieldTrial::IsLowMemFieldTrial()) {
-    // FTS does merges of 16 pages at a time, so we need a working set size
-    // somewhat greater than that to prevent too much thrashing.
-    db_.set_cache_size(128);
-  } else {
-    db_.set_cache_size(512);
-  }
+  db_.set_cache_size(512);
 
   // Run the database in exclusive mode. Nobody else should be accessing the
   // database while we're running, and this will give somewhat improved perf.

chrome/chrome_browser.gypi

@@ -1323,8 +1323,6 @@
         'browser/history/history_database.h',
         'browser/history/history_extension_api.cc',
         'browser/history/history_extension_api.h',
-        'browser/history/history_field_trial.cc',
-        'browser/history/history_field_trial.h',
         'browser/history/history_marshaling.h',
         'browser/history/history_notifications.cc',
         'browser/history/history_notifications.h',