Redirect handling in the resource_prefetch_predictor.

chrome/browser/predictors/resource_prefetch_predictor_tables.cc

 // Copyright 2014 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/predictors/resource_prefetch_predictor_tables.h"
 
 #include <stdint.h>
 
 #include <algorithm>
 #include <memory>
 #include <utility>
 
 #include "base/logging.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/strings/stringprintf.h"
 #include "content/public/browser/browser_thread.h"
 #include "sql/meta_table.h"
 #include "sql/statement.h"
 #include "sql/transaction.h"
 
 using content::BrowserThread;
 using sql::Statement;
 
 namespace {
 
 using ResourceData = predictors::ResourceData;
+using RedirectData = predictors::RedirectData;
 
 const char kMetadataTableName[] = "resource_prefetch_predictor_metadata";
-const char kUrlResourceTableName[] = "resource_prefetch_predictor_url";
+const char kUrlResourceTableName[] = "resource_prefetch_predictor_url_resource";
 const char kUrlMetadataTableName[] = "resource_prefetch_predictor_url_metadata";
-const char kHostResourceTableName[] = "resource_prefetch_predictor_host";
+const char kUrlRedirectTableName[] = "resource_prefetch_predictor_url_redirect";
+const char kHostResourceTableName[] =
+    "resource_prefetch_predictor_host_resource";
 const char kHostMetadataTableName[] =
     "resource_prefetch_predictor_host_metadata";
+const char kHostRedirectTableName[] =
+    "resource_prefetch_predictor_host_redirect";
 
 const char kCreateGlobalMetadataStatementTemplate[] =
     "CREATE TABLE %s ( "
     "key TEXT, value INTEGER, "
     "PRIMARY KEY (key))";
 const char kCreateResourceTableStatementTemplate[] =
     "CREATE TABLE %s ( "
     "main_page_url TEXT, "
     "resource_url TEXT, "
     "proto BLOB, "
     "PRIMARY KEY(main_page_url, resource_url))";
 const char kCreateMetadataTableStatementTemplate[] =
     "CREATE TABLE %s ( "
     "main_page_url TEXT, "
     "last_visit_time INTEGER, "
     "PRIMARY KEY(main_page_url))";
+const char kCreateRedirectTableStatementTemplate[] =
+    "CREATE TABLE %s ( "
+    "main_page_url TEXT, "
+    "proto BLOB, "
+    "PRIMARY KEY(main_page_url))";
 
 const char kInsertResourceTableStatementTemplate[] =
     "INSERT INTO %s (main_page_url, resource_url, proto) VALUES (?,?,?)";
+const char kInsertRedirectTableStatementTemplate[] =
+    "INSERT INTO %s (main_page_url, proto) VALUES (?,?)";
 const char kInsertMetadataTableStatementTemplate[] =
     "INSERT INTO %s (main_page_url, last_visit_time) VALUES (?,?)";
 const char kDeleteStatementTemplate[] = "DELETE FROM %s WHERE main_page_url=?";
 
 void BindResourceDataToStatement(const ResourceData& data,
                                  const std::string& primary_key,
                                  Statement* statement) {
   int size = data.ByteSize();
   DCHECK(size > 0);
   std::vector<char> proto_buffer(size);
   data.SerializeToArray(&proto_buffer[0], size);
 
   statement->BindString(0, primary_key);
   statement->BindString(1, data.resource_url());
   statement->BindBlob(2, &proto_buffer[0], size);
 }
 
+void BindRedirectDataToStatement(const RedirectData& data,
+                                 Statement* statement) {
+  int size = data.ByteSize();
+  DCHECK(size > 0);
+  std::vector<char> proto_buffer(size);
+  data.SerializeToArray(&proto_buffer[0], size);
+
+  statement->BindString(0, data.primary_key());
+  statement->BindBlob(1, &proto_buffer[0], size);
+}
+
 bool StepAndInitializeResourceData(Statement* statement,
                                    ResourceData* data,
                                    std::string* primary_key) {
   if (!statement->Step())
     return false;
 
   *primary_key = statement->ColumnString(0);
-
   int size = statement->ColumnByteLength(2);
   const void* blob = statement->ColumnBlob(2);
   DCHECK(blob);
   data->ParseFromArray(blob, size);
 
   std::string resource_url = statement->ColumnString(1);
   DCHECK(resource_url == data->resource_url());
 
   return true;
 }
 
+bool StepAndInitializeRedirectData(Statement* statement,
+                                   RedirectData* data,
+                                   std::string* primary_key) {
+  if (!statement->Step())
+    return false;
+
+  *primary_key = statement->ColumnString(0);
+
+  int size = statement->ColumnByteLength(1);
+  const void* blob = statement->ColumnBlob(1);
+  DCHECK(blob);
+  data->ParseFromArray(blob, size);
+
+  DCHECK(data->primary_key() == *primary_key);
+
+  return true;
+}
+
 }  // namespace
 
 namespace predictors {
 
 // static
 void ResourcePrefetchPredictorTables::SortResources(
     std::vector<ResourceData>* resources) {
-  // Sort indices instead of ResourceData objects and then apply resulting
-  // permutation to the resources.
   std::sort(resources->begin(), resources->end(),
             [](const ResourceData& x, const ResourceData& y) {
-              return ComputeScore(x) > ComputeScore(y);
+              return ComputeResourceScore(x) > ComputeResourceScore(y);
             });
 }
 
+// static
+void ResourcePrefetchPredictorTables::SortRedirects(
+    std::vector<RedirectStat>* redirects) {
+  std::sort(redirects->begin(), redirects->end(),
+            [](const RedirectStat& x, const RedirectStat& y) {
+              return ComputeRedirectScore(x) > ComputeRedirectScore(y);
+            });
+}
+
 ResourcePrefetchPredictorTables::PrefetchData::PrefetchData(
     PrefetchKeyType i_key_type,
     const std::string& i_primary_key)
     : key_type(i_key_type),
       primary_key(i_primary_key) {
 }
 
 ResourcePrefetchPredictorTables::PrefetchData::PrefetchData(
     const PrefetchData& other)
     : key_type(other.key_type),
       primary_key(other.primary_key),
       last_visit(other.last_visit),
       resources(other.resources) {
 }
 
 ResourcePrefetchPredictorTables::PrefetchData::~PrefetchData() {
 }
 
 void ResourcePrefetchPredictorTables::GetAllData(
     PrefetchDataMap* url_data_map,
-    PrefetchDataMap* host_data_map) {
+    PrefetchDataMap* host_data_map,
+    RedirectDataMap* url_redirect_data_map,
+    RedirectDataMap* host_redirect_data_map) {
   DCHECK_CURRENTLY_ON(BrowserThread::DB);
   if (CantAccessDatabase())
     return;
 
   DCHECK(url_data_map);
   DCHECK(host_data_map);
+  DCHECK(url_redirect_data_map);
+  DCHECK(host_redirect_data_map);
   url_data_map->clear();
   host_data_map->clear();
+  url_redirect_data_map->clear();
+  host_redirect_data_map->clear();
 
   std::vector<std::string> urls_to_delete, hosts_to_delete;
-  GetAllDataHelper(PREFETCH_KEY_TYPE_URL, url_data_map, &urls_to_delete);
-  GetAllDataHelper(PREFETCH_KEY_TYPE_HOST, host_data_map, &hosts_to_delete);
+  GetAllResourceDataHelper(PREFETCH_KEY_TYPE_URL, url_data_map,
+                           &urls_to_delete);
+  GetAllResourceDataHelper(PREFETCH_KEY_TYPE_HOST, host_data_map,
+                           &hosts_to_delete);
+  GetAllRedirectDataHelper(PREFETCH_KEY_TYPE_URL, url_redirect_data_map);
+  GetAllRedirectDataHelper(PREFETCH_KEY_TYPE_HOST, host_redirect_data_map);
 
   if (!urls_to_delete.empty() || !hosts_to_delete.empty())
-    DeleteData(urls_to_delete, hosts_to_delete);
+    DeleteResourceData(urls_to_delete, hosts_to_delete);
 }
 
 void ResourcePrefetchPredictorTables::UpdateData(
     const PrefetchData& url_data,
-    const PrefetchData& host_data) {
+    const PrefetchData& host_data,
+    const RedirectData& url_redirect_data,
+    const RedirectData& host_redirect_data) {
   DCHECK_CURRENTLY_ON(BrowserThread::DB);
   if (CantAccessDatabase())
     return;
 
   DCHECK(!url_data.is_host() && host_data.is_host());
-  DCHECK(!url_data.primary_key.empty() || !host_data.primary_key.empty());
+  DCHECK(!url_data.primary_key.empty() || !host_data.primary_key.empty() ||
+         url_redirect_data.has_primary_key() ||
+         host_redirect_data.has_primary_key());
 
   DB()->BeginTransaction();
 
-  bool success = (url_data.primary_key.empty() || UpdateDataHelper(url_data)) &&
-      (host_data.primary_key.empty() || UpdateDataHelper(host_data));
+  bool success =
+      (url_data.primary_key.empty() ||
+       UpdateResourceDataHelper(PREFETCH_KEY_TYPE_URL, url_data)) &&
+      (host_data.primary_key.empty() ||
+       UpdateResourceDataHelper(PREFETCH_KEY_TYPE_HOST, host_data)) &&
+      (!url_redirect_data.has_primary_key() ||
+       UpdateRedirectDataHelper(PREFETCH_KEY_TYPE_URL, url_redirect_data)) &&
+      (!host_redirect_data.has_primary_key() ||
+       UpdateRedirectDataHelper(PREFETCH_KEY_TYPE_HOST, host_redirect_data));
   if (!success)
     DB()->RollbackTransaction();
-
-  DB()->CommitTransaction();
+  else
+    DB()->CommitTransaction();
 }
 
-void ResourcePrefetchPredictorTables::DeleteData(
+void ResourcePrefetchPredictorTables::DeleteResourceData(
     const std::vector<std::string>& urls,
     const std::vector<std::string>& hosts) {
   DCHECK_CURRENTLY_ON(BrowserThread::DB);
+  if (CantAccessDatabase())
+    return;
+
+  DCHECK(!urls.empty() || !hosts.empty());
+
+  if (!urls.empty())
+    DeleteDataHelper(PREFETCH_KEY_TYPE_URL, PREFETCH_DATA_TYPE_RESOURCE, urls);
+  if (!hosts.empty()) {
+    DeleteDataHelper(PREFETCH_KEY_TYPE_HOST, PREFETCH_DATA_TYPE_RESOURCE,
+                     hosts);
+  }
+}
+
+void ResourcePrefetchPredictorTables::DeleteSingleResourceDataPoint(
+    const std::string& key,
+    PrefetchKeyType key_type) {
+  DCHECK_CURRENTLY_ON(BrowserThread::DB);
+  if (CantAccessDatabase())
+    return;
+
+  DeleteDataHelper(key_type, PREFETCH_DATA_TYPE_RESOURCE, {key});
+}
+
+void ResourcePrefetchPredictorTables::DeleteRedirectData(
+    const std::vector<std::string>& urls,
+    const std::vector<std::string>& hosts) {
+  DCHECK_CURRENTLY_ON(BrowserThread::DB);
   if (CantAccessDatabase())
     return;
 
   DCHECK(!urls.empty() || !hosts.empty());
 
   if (!urls.empty())
-    DeleteDataHelper(PREFETCH_KEY_TYPE_URL, urls);
-  if (!hosts.empty())
-    DeleteDataHelper(PREFETCH_KEY_TYPE_HOST, hosts);
+    DeleteDataHelper(PREFETCH_KEY_TYPE_URL, PREFETCH_DATA_TYPE_REDIRECT, urls);
+  if (!hosts.empty()) {
+    DeleteDataHelper(PREFETCH_KEY_TYPE_HOST, PREFETCH_DATA_TYPE_REDIRECT,
+                     hosts);
+  }
 }
 
-void ResourcePrefetchPredictorTables::DeleteSingleDataPoint(
+void ResourcePrefetchPredictorTables::DeleteSingleRedirectDataPoint(
     const std::string& key,
     PrefetchKeyType key_type) {
   DCHECK_CURRENTLY_ON(BrowserThread::DB);
   if (CantAccessDatabase())
     return;
 
-  DeleteDataHelper(key_type, std::vector<std::string>(1, key));
+  DeleteDataHelper(key_type, PREFETCH_DATA_TYPE_REDIRECT, {key});
 }
 
 void ResourcePrefetchPredictorTables::DeleteAllData() {
   if (CantAccessDatabase())
     return;
 
   Statement deleter;
   for (const char* table_name :
-       {kUrlResourceTableName, kUrlMetadataTableName, kHostResourceTableName,
-        kHostMetadataTableName}) {
+       {kUrlResourceTableName, kUrlMetadataTableName, kUrlRedirectTableName,
+        kHostResourceTableName, kHostMetadataTableName,
+        kHostRedirectTableName}) {
     deleter.Assign(DB()->GetUniqueStatement(
         base::StringPrintf("DELETE FROM %s", table_name).c_str()));
     deleter.Run();
   }
 }
 
 ResourcePrefetchPredictorTables::ResourcePrefetchPredictorTables()
     : PredictorTableBase() {
 }
 
 ResourcePrefetchPredictorTables::~ResourcePrefetchPredictorTables() {
 }
 
-void ResourcePrefetchPredictorTables::GetAllDataHelper(
+void ResourcePrefetchPredictorTables::GetAllResourceDataHelper(
     PrefetchKeyType key_type,
     PrefetchDataMap* data_map,
     std::vector<std::string>* to_delete) {
   bool is_host = key_type == PREFETCH_KEY_TYPE_HOST;
 
   // Read the resources table and organize it per primary key.
   const char* resource_table_name = is_host ? kHostResourceTableName :
       kUrlResourceTableName;
   Statement resource_reader(DB()->GetUniqueStatement(
       base::StringPrintf("SELECT * FROM %s", resource_table_name).c_str()));
 
   ResourceData resource;
   std::string primary_key;
   while (StepAndInitializeResourceData(&resource_reader, &resource,
                                        &primary_key)) {
     PrefetchDataMap::iterator it = data_map->find(primary_key);
     if (it == data_map->end()) {
       it = data_map->insert(std::make_pair(
           primary_key, PrefetchData(key_type, primary_key))).first;
     }
     it->second.resources.push_back(resource);
   }
 
   // Sort each of the resource row vectors by score.
   for (auto& kv : *data_map)
     SortResources(&(kv.second.resources));
 
   // Read the metadata and keep track of entries that have metadata, but no
   // resource entries, so they can be deleted.
-  const char* metadata_table_name = is_host ? kHostMetadataTableName :
-      kUrlMetadataTableName;
+  const char* metadata_table_name =
+      is_host ? kHostMetadataTableName : kUrlMetadataTableName;
   Statement metadata_reader(DB()->GetUniqueStatement(
       base::StringPrintf("SELECT * FROM %s", metadata_table_name).c_str()));
 
   while (metadata_reader.Step()) {
     std::string primary_key = metadata_reader.ColumnString(0);
 
     PrefetchDataMap::iterator it = data_map->find(primary_key);
     if (it != data_map->end()) {
       int64_t last_visit = metadata_reader.ColumnInt64(1);
       it->second.last_visit = base::Time::FromInternalValue(last_visit);
     } else {
       to_delete->push_back(primary_key);
     }
   }
 }
 
-bool ResourcePrefetchPredictorTables::UpdateDataHelper(
+void ResourcePrefetchPredictorTables::GetAllRedirectDataHelper(
+    PrefetchKeyType key_type,
+    RedirectDataMap* redirect_map) {
+  bool is_host = key_type == PREFETCH_KEY_TYPE_HOST;
+
+  const char* redirect_table_name =
+      is_host ? kHostRedirectTableName : kUrlRedirectTableName;
+  Statement redirect_reader(DB()->GetUniqueStatement(
+      base::StringPrintf("SELECT * FROM %s", redirect_table_name).c_str()));
+
+  RedirectData data;
+  std::string primary_key;
+  while (StepAndInitializeRedirectData(&redirect_reader, &data, &primary_key)) {
+    auto result = redirect_map->insert(std::make_pair(primary_key, data));
+    DCHECK(result.second);
+  }
+}
+
+bool ResourcePrefetchPredictorTables::UpdateResourceDataHelper(
+    PrefetchKeyType key_type,
     const PrefetchData& data) {
   DCHECK(!data.primary_key.empty());
 
   if (!StringsAreSmallerThanDBLimit(data)) {
     UMA_HISTOGRAM_BOOLEAN("ResourcePrefetchPredictor.DbStringTooLong", true);
     return false;
   }
 
+  bool is_host = key_type == PREFETCH_KEY_TYPE_HOST;
+
   // Delete the older data from both the tables.
-  std::unique_ptr<Statement> deleter(data.is_host()
-                                         ? GetHostResourceDeleteStatement()
-                                         : GetUrlResourceDeleteStatement());
+  std::unique_ptr<Statement> deleter(is_host ? GetHostResourceDeleteStatement()
+                                             : GetUrlResourceDeleteStatement());
   deleter->BindString(0, data.primary_key);
   if (!deleter->Run())
     return false;
 
-  deleter.reset(data.is_host() ? GetHostMetadataDeleteStatement() :
-      GetUrlMetadataDeleteStatement());
+  deleter.reset(data.is_host() ? GetHostMetadataDeleteStatement()
+                               : GetUrlMetadataDeleteStatement());
   deleter->BindString(0, data.primary_key);
   if (!deleter->Run())
     return false;
 
   // Add the new data to the tables.
   for (const ResourceData& resource : data.resources) {
     std::unique_ptr<Statement> resource_inserter(
-        data.is_host() ? GetHostResourceUpdateStatement()
-                       : GetUrlResourceUpdateStatement());
+        is_host ? GetHostResourceUpdateStatement()
+                : GetUrlResourceUpdateStatement());
     BindResourceDataToStatement(resource, data.primary_key,
                                 resource_inserter.get());
     if (!resource_inserter->Run())
       return false;
   }
 
   std::unique_ptr<Statement> metadata_inserter(
-      data.is_host() ? GetHostMetadataUpdateStatement()
-                     : GetUrlMetadataUpdateStatement());
+      is_host ? GetHostMetadataUpdateStatement()
+              : GetUrlMetadataUpdateStatement());
   metadata_inserter->BindString(0, data.primary_key);
   metadata_inserter->BindInt64(1, data.last_visit.ToInternalValue());
   if (!metadata_inserter->Run())
     return false;
 
   return true;
 }
 
+bool ResourcePrefetchPredictorTables::UpdateRedirectDataHelper(
+    PrefetchKeyType key_type,
+    const RedirectData& data) {
+  DCHECK(data.has_primary_key());
+
+  if (!StringsAreSmallerThanDBLimit(data)) {
+    UMA_HISTOGRAM_BOOLEAN("ResourcePrefetchPredictor.DbStringTooLong", true);
+    return false;
+  }
+
+  bool is_host = key_type == PREFETCH_KEY_TYPE_HOST;
+
+  // Delete the older data from the table.
+  std::unique_ptr<Statement> deleter(is_host ? GetHostRedirectDeleteStatement()
+                                             : GetUrlRedirectDeleteStatement());
+  deleter->BindString(0, data.primary_key());
+  if (!deleter->Run())
+    return false;
+
+  // Add the new data to the table.
+  std::unique_ptr<Statement> inserter(is_host
+                                          ? GetHostRedirectUpdateStatement()

[Benoit L, 2016/09/26 12:51:14]

tiny nit: is this the result of git cl format?

If not, please re-run it on the updated CL.

[pasko, 2016/09/26 14:18:23]

lol: I was actually checking it with git cl format, while there is certainly
reasonable logic behind it, the end result indeed looks weird to humans.

I am wondering if this could be one function:
GetTableUpdateStatement(URL/HOST, RESOURCE/REDIRECT, UPDATE/DELETE).

[alexilin, 2016/09/26 15:38:28]

There is the problem with SQL cached statements and SQL_FROM_HERE macro. 
I could write this common get statement function but we should still save
different DB()->GetCachedStatement calls for all tables and operations.

[pasko, 2016/09/26 16:44:06]

hah, you are right, the way sql::StatementID is created by SQL_FROM_HERE would
not work for us.

How about:

sql::StatementID(__FILE__, is_host | (is_redirect << 1) | (is_update << 2)) ?

[alexilin, 2016/09/27 14:52:46]

Done.

+                                          : GetUrlRedirectUpdateStatement());
+  BindRedirectDataToStatement(data, inserter.get());
+  if (!inserter->Run())

[Benoit L, 2016/09/26 12:51:14]

nit: What about:

return inserter->Run();

?

(here and above)

[alexilin, 2016/09/26 15:38:28]

Done.

+    return false;
+
+  return true;
+}
+
 void ResourcePrefetchPredictorTables::DeleteDataHelper(
     PrefetchKeyType key_type,
+    PrefetchDataType data_type,
     const std::vector<std::string>& keys) {
   bool is_host = key_type == PREFETCH_KEY_TYPE_HOST;
+  bool is_resource = data_type == PREFETCH_DATA_TYPE_RESOURCE;
 
   for (const std::string& key : keys) {
-    std::unique_ptr<Statement> deleter(is_host
-                                           ? GetHostResourceDeleteStatement()
-                                           : GetUrlResourceDeleteStatement());
+    std::unique_ptr<Statement> deleter(
+        is_host ? (is_resource ? GetHostResourceDeleteStatement()
+                               : GetHostRedirectDeleteStatement())
+                : (is_resource ? GetUrlResourceDeleteStatement()
+                               : GetUrlRedirectDeleteStatement()));
+
     deleter->BindString(0, key);
     deleter->Run();
 
-    deleter.reset(is_host ? GetHostMetadataDeleteStatement() :
-        GetUrlMetadataDeleteStatement());
-    deleter->BindString(0, key);
-    deleter->Run();
+    if (data_type == PREFETCH_DATA_TYPE_RESOURCE) {
+      // Delete corresponding resource metadata as well.
+      deleter.reset(is_host ? GetHostMetadataDeleteStatement()
+                            : GetUrlMetadataDeleteStatement());
+      deleter->BindString(0, key);
+      deleter->Run();
+    }
   }
 }
 
 // static
 bool ResourcePrefetchPredictorTables::StringsAreSmallerThanDBLimit(
     const PrefetchData& data) {
   if (data.primary_key.length() > kMaxStringLength)
     return false;
 
   for (const ResourceData& resource : data.resources) {
     if (resource.resource_url().length() > kMaxStringLength)
       return false;
   }
   return true;
 }
 
+bool ResourcePrefetchPredictorTables::StringsAreSmallerThanDBLimit(
+    const RedirectData& data) {
+  if (data.primary_key().length() > kMaxStringLength)
+    return false;
+
+  for (const RedirectStat& redirect : data.redirects()) {
+    if (redirect.url().length() > kMaxStringLength)
+      return false;
+  }
+  return true;
+}
+
 // static
-float ResourcePrefetchPredictorTables::ComputeScore(const ResourceData& data) {
+float ResourcePrefetchPredictorTables::ComputeResourceScore(
+    const ResourceData& data) {
   // The score is calculated so that when the rows are sorted, stylesheets,
   // scripts and fonts appear first, sorted by position(ascending) and then the
   // rest of the resources sorted by position (ascending).
   static const int kMaxResourcesPerType = 100;
   switch (data.resource_type()) {
     case ResourceData::RESOURCE_TYPE_STYLESHEET:
     case ResourceData::RESOURCE_TYPE_SCRIPT:
     case ResourceData::RESOURCE_TYPE_FONT_RESOURCE:
       return (2 * kMaxResourcesPerType) - data.average_position();
 
     case ResourceData::RESOURCE_TYPE_IMAGE:
     default:
       return kMaxResourcesPerType - data.average_position();
   }
   // TODO(lizeb): Take priority into account.
 }
 
 // static
+float ResourcePrefetchPredictorTables::ComputeRedirectScore(
+    const RedirectStat& data) {
+  // TODO(alexilin): Invent some scoring.
+  return 0.0;
+}
+
+// static
 bool ResourcePrefetchPredictorTables::DropTablesIfOutdated(
     sql::Connection* db) {
   int version = GetDatabaseVersion(db);
   bool success = true;
   // Too new is also a problem.
   bool incompatible_version = version != kDatabaseVersion;
 
   if (incompatible_version) {
     for (const char* table_name :
          {kMetadataTableName, kUrlResourceTableName, kHostResourceTableName,
-          kUrlMetadataTableName, kHostMetadataTableName}) {
+          kUrlRedirectTableName, kHostRedirectTableName, kUrlMetadataTableName,
+          kHostMetadataTableName}) {
       success =
           success &&
           db->Execute(base::StringPrintf("DROP TABLE IF EXISTS %s", table_name)
                           .c_str());
     }
   }
 
   if (incompatible_version) {
     success =
         success &&
@@ skipping 46 matching lines @@
   success =
       success &&
       (db->DoesTableExist(kUrlResourceTableName) ||
        db->Execute(base::StringPrintf(kCreateResourceTableStatementTemplate,
                                       kUrlResourceTableName)
                        .c_str())) &&
       (db->DoesTableExist(kUrlMetadataTableName) ||
        db->Execute(base::StringPrintf(kCreateMetadataTableStatementTemplate,
                                       kUrlMetadataTableName)
                        .c_str())) &&
+      (db->DoesTableExist(kUrlRedirectTableName) ||
+       db->Execute(base::StringPrintf(kCreateRedirectTableStatementTemplate,
+                                      kUrlRedirectTableName)
+                       .c_str())) &&
       (db->DoesTableExist(kHostResourceTableName) ||
        db->Execute(base::StringPrintf(kCreateResourceTableStatementTemplate,
                                       kHostResourceTableName)
                        .c_str())) &&
       (db->DoesTableExist(kHostMetadataTableName) ||
        db->Execute(base::StringPrintf(kCreateMetadataTableStatementTemplate,
                                       kHostMetadataTableName)
+                       .c_str())) &&
+      (db->DoesTableExist(kHostRedirectTableName) ||
+       db->Execute(base::StringPrintf(kCreateRedirectTableStatementTemplate,
+                                      kHostRedirectTableName)
                        .c_str()));
 
   if (success)
     success = transaction.Commit();
   else
     transaction.Rollback();
 
   if (!success)
     ResetDB();
 }
 
 void ResourcePrefetchPredictorTables::LogDatabaseStats()  {
   DCHECK_CURRENTLY_ON(BrowserThread::DB);
   if (CantAccessDatabase())
     return;
 
   Statement statement(DB()->GetUniqueStatement(
       base::StringPrintf("SELECT count(*) FROM %s",
                          kUrlResourceTableName).c_str()));
   if (statement.Step())
     UMA_HISTOGRAM_COUNTS("ResourcePrefetchPredictor.UrlTableRowCount",
                          statement.ColumnInt(0));
 
   statement.Assign(DB()->GetUniqueStatement(
       base::StringPrintf("SELECT count(*) FROM %s",
                          kHostResourceTableName).c_str()));
   if (statement.Step())
     UMA_HISTOGRAM_COUNTS("ResourcePrefetchPredictor.HostTableRowCount",
                          statement.ColumnInt(0));
+
+  statement.Assign(DB()->GetUniqueStatement(

[Benoit L, 2016/09/26 12:51:14]

I'm not sure these histograms are really useful now.

Let's discuss, but I would lean towards not introducing them now.

[pasko, 2016/09/26 14:18:23]

I probably lean towards the same opinion because:
* more histograms now make reviews slower
* we will rethink the histograms after the implementation is done, and these
ones in the new light could appear to be better as part of something other

[alexilin, 2016/09/27 14:52:46]

Done.

+      base::StringPrintf("SELECT count(*) FROM %s", kUrlRedirectTableName)
+          .c_str()));
+  if (statement.Step())
+    UMA_HISTOGRAM_COUNTS("ResourcePrefetchPredictor.UrlRedirectTableRowCount",
+                         statement.ColumnInt(0));
+
+  statement.Assign(DB()->GetUniqueStatement(
+      base::StringPrintf("SELECT count(*) FROM %s", kHostRedirectTableName)
+          .c_str()));
+  if (statement.Step())
+    UMA_HISTOGRAM_COUNTS("ResourcePrefetchPredictor.HostRedirectTableRowCount",
+                         statement.ColumnInt(0));
 }
 
 Statement*
     ResourcePrefetchPredictorTables::GetUrlResourceDeleteStatement() {
   return new Statement(DB()->GetCachedStatement(
       SQL_FROM_HERE,
       base::StringPrintf(kDeleteStatementTemplate, kUrlResourceTableName)
           .c_str()));
 }
 
 Statement*
     ResourcePrefetchPredictorTables::GetUrlResourceUpdateStatement() {
   return new Statement(DB()->GetCachedStatement(
       SQL_FROM_HERE, base::StringPrintf(kInsertResourceTableStatementTemplate,
                                         kUrlResourceTableName)
                          .c_str()));
 }
 
-Statement*
-    ResourcePrefetchPredictorTables::GetUrlMetadataDeleteStatement() {
+Statement* ResourcePrefetchPredictorTables::GetUrlMetadataDeleteStatement() {
   return new Statement(DB()->GetCachedStatement(
       SQL_FROM_HERE,
       base::StringPrintf(kDeleteStatementTemplate, kUrlMetadataTableName)
           .c_str()));
 }
 
-Statement*
-    ResourcePrefetchPredictorTables::GetUrlMetadataUpdateStatement() {
+Statement* ResourcePrefetchPredictorTables::GetUrlMetadataUpdateStatement() {
   return new Statement(DB()->GetCachedStatement(
       SQL_FROM_HERE, base::StringPrintf(kInsertMetadataTableStatementTemplate,
                                         kUrlMetadataTableName)
                          .c_str()));
 }
 
+Statement* ResourcePrefetchPredictorTables::GetUrlRedirectDeleteStatement() {
+  return new Statement(DB()->GetCachedStatement(
+      SQL_FROM_HERE,
+      base::StringPrintf(kDeleteStatementTemplate, kUrlRedirectTableName)
+          .c_str()));
+}
+
+Statement* ResourcePrefetchPredictorTables::GetUrlRedirectUpdateStatement() {
+  return new Statement(DB()->GetCachedStatement(
+      SQL_FROM_HERE, base::StringPrintf(kInsertRedirectTableStatementTemplate,
+                                        kUrlRedirectTableName)
+                         .c_str()));
+}
+
 Statement*
     ResourcePrefetchPredictorTables::GetHostResourceDeleteStatement() {
   return new Statement(DB()->GetCachedStatement(
       SQL_FROM_HERE,
       base::StringPrintf(kDeleteStatementTemplate, kHostResourceTableName)
           .c_str()));
 }
 
 Statement*
     ResourcePrefetchPredictorTables::GetHostResourceUpdateStatement() {
   return new Statement(DB()->GetCachedStatement(
       SQL_FROM_HERE, base::StringPrintf(kInsertResourceTableStatementTemplate,
                                         kHostResourceTableName)
                          .c_str()));
 }
 
-Statement*
-    ResourcePrefetchPredictorTables::GetHostMetadataDeleteStatement() {
+Statement* ResourcePrefetchPredictorTables::GetHostMetadataDeleteStatement() {
   return new Statement(DB()->GetCachedStatement(
       SQL_FROM_HERE,
       base::StringPrintf(kDeleteStatementTemplate, kHostMetadataTableName)
           .c_str()));
 }
 
 Statement* ResourcePrefetchPredictorTables::GetHostMetadataUpdateStatement() {
   return new Statement(DB()->GetCachedStatement(
       SQL_FROM_HERE, base::StringPrintf(kInsertMetadataTableStatementTemplate,
                                         kHostMetadataTableName)
                          .c_str()));
 }
 
+Statement* ResourcePrefetchPredictorTables::GetHostRedirectDeleteStatement() {
+  return new Statement(DB()->GetCachedStatement(
+      SQL_FROM_HERE,
+      base::StringPrintf(kDeleteStatementTemplate, kHostRedirectTableName)
+          .c_str()));
+}
+
+Statement* ResourcePrefetchPredictorTables::GetHostRedirectUpdateStatement() {
+  return new Statement(DB()->GetCachedStatement(
+      SQL_FROM_HERE, base::StringPrintf(kInsertRedirectTableStatementTemplate,
+                                        kHostRedirectTableName)
+                         .c_str()));
+}
+
 }  // namespace predictors