Omnibox: Truncate HistoryContents Searches at 10k Characters

chrome/browser/autocomplete/history_contents_provider.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 "chrome/browser/autocomplete/history_contents_provider.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/metrics/histogram.h"
 #include "base/string_util.h"
@@ skipping 13 matching lines @@
 
 using base::TimeTicks;
 using history::HistoryDatabase;
 
 namespace {
 
 // Number of days to search for full text results. The longer this is, the more
 // time it will take.
 const int kDaysToSearch = 30;
 
+// The maximum number of characters used in a search for full text results.
+// This was chosen arbitrarily because omnibox results that come back too
+// late (after tens of seconds) aren't useful to the user so it's not
+// worth spending CPU time on them.  Furthermore, if a URL matches the
+// first 10k of characters the user typed (more likely pasted) into the
+// omnibox, it's likely it matches the rest; there's strongly diminished
+// returns for the ability to add additional search terms.
+const size_t kMaxCharactersToConsider = 10000u;

[Peter Kasting, 2013/04/17 22:34:57]

Even 10K seems like it will take a while.  What about truncating at like... 2K? 
I can't imagine there'd be a noticeable quality difference between the two.

[Mark P, 2013/04/17 22:58:22]

2k is also okay with me.  Done.

+
 }  // namespace
 
 HistoryContentsProvider::MatchReference::MatchReference(
     const history::URLResult* result,
     int relevance)
     : result(result),
       relevance(relevance) {
 }
 
 // static
@@ skipping 88 matching lines @@
     HistoryService* history =
         HistoryServiceFactory::GetForProfile(profile_,
                                              Profile::EXPLICIT_ACCESS);
     if (history) {
       done_ = false;
 
       history::QueryOptions options;
       options.body_only = body_only_;
       options.SetRecentDayRange(kDaysToSearch);
       options.max_count = kMaxMatches;
-      history->QueryHistory(input.text(), options,
+      history->QueryHistory(
+          input.text().substr(0, kMaxCharactersToConsider),
+          options,
           &request_consumer_,
           base::Bind(&HistoryContentsProvider::QueryComplete,
                      base::Unretained(this)));
     }
   }
 }
 
 void HistoryContentsProvider::Stop(bool clear_cached_results) {
   done_ = true;
   request_consumer_.CancelAllRequests();
@@ skipping 112 matching lines @@
 
 int HistoryContentsProvider::CalculateRelevance(
     const history::URLResult& result) {
   const bool in_title = MatchInTitle(result);
   BookmarkModel* bm_model = BookmarkModelFactory::GetForProfile(profile_);
   if (!bm_model || !bm_model->IsBookmarked(result.url()))
     return in_title ? (700 + title_count_++) : (500 + contents_count_++);
   return in_title ?
       (1000 + star_title_count_++) : (550 + star_contents_count_++);
 }