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| 1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. | |
| 2 // Use of this source code is governed by a BSD-style license that can be | |
| 3 // found in the LICENSE file. | |
| 4 | |
| 5 #include "chrome/browser/predictors/resource_prefetch_predictor_tables.h" | |
| 6 | |
| 7 #include <algorithm> | |
| 8 #include <utility> | |
| 9 #include "base/logging.h" | |
| 10 #include "base/metrics/histogram.h" | |
| 11 #include "base/strings/stringprintf.h" | |
| 12 #include "content/public/browser/browser_thread.h" | |
| 13 #include "sql/statement.h" | |
| 14 | |
| 15 using content::BrowserThread; | |
| 16 using sql::Statement; | |
| 17 | |
| 18 namespace { | |
| 19 | |
| 20 const char kUrlResourceTableName[] = "resource_prefetch_predictor_url"; | |
| 21 const char kUrlMetadataTableName[] = "resource_prefetch_predictor_url_metadata"; | |
| 22 const char kHostResourceTableName[] = "resource_prefetch_predictor_host"; | |
| 23 const char kHostMetadataTableName[] = | |
| 24 "resource_prefetch_predictor_host_metadata"; | |
| 25 | |
| 26 void BindResourceRowToStatement( | |
| 27 const predictors::ResourcePrefetchPredictorTables::ResourceRow& row, | |
| 28 const std::string& primary_key, | |
| 29 Statement* statement) { | |
| 30 statement->BindString(0, primary_key); | |
| 31 statement->BindString(1, row.resource_url.spec()); | |
| 32 statement->BindInt(2, static_cast<int>(row.resource_type)); | |
| 33 statement->BindInt(3, row.number_of_hits); | |
| 34 statement->BindInt(4, row.number_of_misses); | |
| 35 statement->BindInt(5, row.consecutive_misses); | |
| 36 statement->BindDouble(6, row.average_position); | |
| 37 } | |
| 38 | |
| 39 bool StepAndInitializeResourceRow( | |
| 40 Statement* statement, | |
| 41 predictors::ResourcePrefetchPredictorTables::ResourceRow* row) { | |
| 42 if (!statement->Step()) | |
| 43 return false; | |
| 44 | |
| 45 row->primary_key = statement->ColumnString(0); | |
| 46 row->resource_url = GURL(statement->ColumnString(1)); | |
| 47 row->resource_type = ResourceType::FromInt(statement->ColumnInt(2)); | |
| 48 row->number_of_hits = statement->ColumnInt(3); | |
| 49 row->number_of_misses = statement->ColumnInt(4); | |
| 50 row->consecutive_misses = statement->ColumnInt(5); | |
| 51 row->average_position = statement->ColumnDouble(6); | |
| 52 return true; | |
| 53 } | |
| 54 | |
| 55 } // namespace | |
| 56 | |
| 57 namespace predictors { | |
| 58 | |
| 59 // static | |
| 60 const size_t ResourcePrefetchPredictorTables::kMaxStringLength = 1024; | |
| 61 | |
| 62 ResourcePrefetchPredictorTables::ResourceRow::ResourceRow() | |
| 63 : resource_type(ResourceType::LAST_TYPE), | |
| 64 number_of_hits(0), | |
| 65 number_of_misses(0), | |
| 66 consecutive_misses(0), | |
| 67 average_position(0.0), | |
| 68 score(0.0) { | |
| 69 } | |
| 70 | |
| 71 ResourcePrefetchPredictorTables::ResourceRow::ResourceRow( | |
| 72 const ResourceRow& other) | |
| 73 : primary_key(other.primary_key), | |
| 74 resource_url(other.resource_url), | |
| 75 resource_type(other.resource_type), | |
| 76 number_of_hits(other.number_of_hits), | |
| 77 number_of_misses(other.number_of_misses), | |
| 78 consecutive_misses(other.consecutive_misses), | |
| 79 average_position(other.average_position), | |
| 80 score(other.score) { | |
| 81 } | |
| 82 | |
| 83 ResourcePrefetchPredictorTables::ResourceRow::ResourceRow( | |
| 84 const std::string& i_primary_key, | |
| 85 const std::string& i_resource_url, | |
| 86 ResourceType::Type i_resource_type, | |
| 87 int i_number_of_hits, | |
| 88 int i_number_of_misses, | |
| 89 int i_consecutive_misses, | |
| 90 double i_average_position) | |
| 91 : primary_key(i_primary_key), | |
| 92 resource_url(i_resource_url), | |
| 93 resource_type(i_resource_type), | |
| 94 number_of_hits(i_number_of_hits), | |
| 95 number_of_misses(i_number_of_misses), | |
| 96 consecutive_misses(i_consecutive_misses), | |
| 97 average_position(i_average_position) { | |
| 98 UpdateScore(); | |
| 99 } | |
| 100 | |
| 101 void ResourcePrefetchPredictorTables::ResourceRow::UpdateScore() { | |
| 102 // The score is calculated so that when the rows are sorted, the stylesheets | |
| 103 // and scripts appear first, sorted by position(ascending) and then the rest | |
| 104 // of the resources sorted by position(ascending). | |
| 105 static const int kMaxResourcesPerType = 100; | |
| 106 switch (resource_type) { | |
| 107 case ResourceType::STYLESHEET: | |
| 108 case ResourceType::SCRIPT: | |
| 109 score = (2 * kMaxResourcesPerType) - average_position; | |
| 110 break; | |
| 111 | |
| 112 case ResourceType::IMAGE: | |
| 113 score = kMaxResourcesPerType - average_position; | |
| 114 break; | |
| 115 | |
| 116 default: | |
| 117 score = kMaxResourcesPerType - average_position; | |
| 118 break; | |
| 119 } | |
| 120 } | |
| 121 | |
| 122 bool ResourcePrefetchPredictorTables::ResourceRow::operator==( | |
| 123 const ResourceRow& rhs) const { | |
| 124 return primary_key == rhs.primary_key && | |
| 125 resource_url == rhs.resource_url && | |
| 126 resource_type == rhs.resource_type && | |
| 127 number_of_hits == rhs.number_of_hits && | |
| 128 number_of_misses == rhs.number_of_misses && | |
| 129 consecutive_misses == rhs.consecutive_misses && | |
| 130 average_position == rhs.average_position && | |
| 131 score == rhs.score; | |
| 132 } | |
| 133 | |
| 134 bool ResourcePrefetchPredictorTables::ResourceRowSorter::operator()( | |
| 135 const ResourceRow& x, const ResourceRow& y) const { | |
| 136 return x.score > y.score; | |
| 137 } | |
| 138 | |
| 139 ResourcePrefetchPredictorTables::PrefetchData::PrefetchData( | |
| 140 PrefetchKeyType i_key_type, | |
| 141 const std::string& i_primary_key) | |
| 142 : key_type(i_key_type), | |
| 143 primary_key(i_primary_key) { | |
| 144 } | |
| 145 | |
| 146 ResourcePrefetchPredictorTables::PrefetchData::PrefetchData( | |
| 147 const PrefetchData& other) | |
| 148 : key_type(other.key_type), | |
| 149 primary_key(other.primary_key), | |
| 150 last_visit(other.last_visit), | |
| 151 resources(other.resources) { | |
| 152 } | |
| 153 | |
| 154 ResourcePrefetchPredictorTables::PrefetchData::~PrefetchData() { | |
| 155 } | |
| 156 | |
| 157 bool ResourcePrefetchPredictorTables::PrefetchData::operator==( | |
| 158 const PrefetchData& rhs) const { | |
| 159 return key_type == rhs.key_type && primary_key == rhs.primary_key && | |
| 160 resources == rhs.resources; | |
| 161 } | |
| 162 | |
| 163 void ResourcePrefetchPredictorTables::GetAllData( | |
| 164 PrefetchDataMap* url_data_map, | |
| 165 PrefetchDataMap* host_data_map) { | |
| 166 CHECK(BrowserThread::CurrentlyOn(BrowserThread::DB)); | |
| 167 if (CantAccessDatabase()) | |
| 168 return; | |
| 169 | |
| 170 DCHECK(url_data_map); | |
| 171 DCHECK(host_data_map); | |
| 172 url_data_map->clear(); | |
| 173 host_data_map->clear(); | |
| 174 | |
| 175 std::vector<std::string> urls_to_delete, hosts_to_delete; | |
| 176 GetAllDataHelper(PREFETCH_KEY_TYPE_URL, url_data_map, &urls_to_delete); | |
| 177 GetAllDataHelper(PREFETCH_KEY_TYPE_HOST, host_data_map, &hosts_to_delete); | |
| 178 | |
| 179 if (!urls_to_delete.empty() || !hosts_to_delete.empty()) | |
| 180 DeleteData(urls_to_delete, hosts_to_delete); | |
| 181 } | |
| 182 | |
| 183 void ResourcePrefetchPredictorTables::UpdateData( | |
| 184 const PrefetchData& url_data, | |
| 185 const PrefetchData& host_data) { | |
| 186 CHECK(BrowserThread::CurrentlyOn(BrowserThread::DB)); | |
| 187 if (CantAccessDatabase()) | |
| 188 return; | |
| 189 | |
| 190 DCHECK(!url_data.is_host() && host_data.is_host()); | |
| 191 DCHECK(!url_data.primary_key.empty() || !host_data.primary_key.empty()); | |
| 192 | |
| 193 DB()->BeginTransaction(); | |
| 194 | |
| 195 bool success = (url_data.primary_key.empty() || UpdateDataHelper(url_data)) && | |
| 196 (host_data.primary_key.empty() || UpdateDataHelper(host_data)); | |
| 197 if (!success) | |
| 198 DB()->RollbackTransaction(); | |
| 199 | |
| 200 DB()->CommitTransaction(); | |
| 201 } | |
| 202 | |
| 203 void ResourcePrefetchPredictorTables::DeleteData( | |
| 204 const std::vector<std::string>& urls, | |
| 205 const std::vector<std::string>& hosts) { | |
| 206 CHECK(BrowserThread::CurrentlyOn(BrowserThread::DB)); | |
| 207 if (CantAccessDatabase()) | |
| 208 return; | |
| 209 | |
| 210 DCHECK(!urls.empty() || !hosts.empty()); | |
| 211 | |
| 212 if (!urls.empty()) | |
| 213 DeleteDataHelper(PREFETCH_KEY_TYPE_URL, urls); | |
| 214 if (!hosts.empty()) | |
| 215 DeleteDataHelper(PREFETCH_KEY_TYPE_HOST, hosts); | |
| 216 } | |
| 217 | |
| 218 void ResourcePrefetchPredictorTables::DeleteSingleDataPoint( | |
| 219 const std::string& key, | |
| 220 PrefetchKeyType key_type) { | |
| 221 CHECK(BrowserThread::CurrentlyOn(BrowserThread::DB)); | |
| 222 if (CantAccessDatabase()) | |
| 223 return; | |
| 224 | |
| 225 DeleteDataHelper(key_type, std::vector<std::string>(1, key)); | |
| 226 } | |
| 227 | |
| 228 void ResourcePrefetchPredictorTables::DeleteAllData() { | |
| 229 if (CantAccessDatabase()) | |
| 230 return; | |
| 231 | |
| 232 Statement deleter(DB()->GetUniqueStatement( | |
| 233 base::StringPrintf("DELETE FROM %s", kUrlResourceTableName).c_str())); | |
| 234 deleter.Run(); | |
| 235 deleter.Assign(DB()->GetUniqueStatement( | |
| 236 base::StringPrintf("DELETE FROM %s", kUrlMetadataTableName).c_str())); | |
| 237 deleter.Run(); | |
| 238 deleter.Assign(DB()->GetUniqueStatement( | |
| 239 base::StringPrintf("DELETE FROM %s", kHostResourceTableName).c_str())); | |
| 240 deleter.Run(); | |
| 241 deleter.Assign(DB()->GetUniqueStatement( | |
| 242 base::StringPrintf("DELETE FROM %s", kHostMetadataTableName).c_str())); | |
| 243 deleter.Run(); | |
| 244 } | |
| 245 | |
| 246 ResourcePrefetchPredictorTables::ResourcePrefetchPredictorTables() | |
| 247 : PredictorTableBase() { | |
| 248 } | |
| 249 | |
| 250 ResourcePrefetchPredictorTables::~ResourcePrefetchPredictorTables() { | |
| 251 } | |
| 252 | |
| 253 void ResourcePrefetchPredictorTables::GetAllDataHelper( | |
| 254 PrefetchKeyType key_type, | |
| 255 PrefetchDataMap* data_map, | |
| 256 std::vector<std::string>* to_delete) { | |
| 257 bool is_host = key_type == PREFETCH_KEY_TYPE_HOST; | |
| 258 | |
| 259 // Read the resources table and organize it per primary key. | |
| 260 const char* resource_table_name = is_host ? kHostResourceTableName : | |
| 261 kUrlResourceTableName; | |
| 262 Statement resource_reader(DB()->GetUniqueStatement( | |
| 263 base::StringPrintf("SELECT * FROM %s", resource_table_name).c_str())); | |
| 264 | |
| 265 ResourceRow row; | |
| 266 while (StepAndInitializeResourceRow(&resource_reader, &row)) { | |
| 267 row.UpdateScore(); | |
| 268 std::string primary_key = row.primary_key; | |
| 269 // Don't need to store primary key since the data is grouped by primary key. | |
| 270 row.primary_key.clear(); | |
| 271 | |
| 272 PrefetchDataMap::iterator it = data_map->find(primary_key); | |
| 273 if (it == data_map->end()) { | |
| 274 it = data_map->insert(std::make_pair( | |
| 275 primary_key, PrefetchData(key_type, primary_key))).first; | |
| 276 } | |
| 277 it->second.resources.push_back(row); | |
| 278 } | |
| 279 | |
| 280 // Sort each of the resource row vectors by score. | |
| 281 for (PrefetchDataMap::iterator it = data_map->begin(); it != data_map->end(); | |
| 282 ++it) { | |
| 283 std::sort(it->second.resources.begin(), | |
| 284 it->second.resources.end(), | |
| 285 ResourceRowSorter()); | |
| 286 } | |
| 287 | |
| 288 // Read the metadata and keep track of entries that have metadata, but no | |
| 289 // resource entries, so they can be deleted. | |
| 290 const char* metadata_table_name = is_host ? kHostMetadataTableName : | |
| 291 kUrlMetadataTableName; | |
| 292 Statement metadata_reader(DB()->GetUniqueStatement( | |
| 293 base::StringPrintf("SELECT * FROM %s", metadata_table_name).c_str())); | |
| 294 | |
| 295 while (metadata_reader.Step()) { | |
| 296 std::string primary_key = metadata_reader.ColumnString(0); | |
| 297 | |
| 298 PrefetchDataMap::iterator it = data_map->find(primary_key); | |
| 299 if (it != data_map->end()) { | |
| 300 int64 last_visit = metadata_reader.ColumnInt64(1); | |
| 301 it->second.last_visit = base::Time::FromInternalValue(last_visit); | |
| 302 } else { | |
| 303 to_delete->push_back(primary_key); | |
| 304 } | |
| 305 } | |
| 306 } | |
| 307 | |
| 308 bool ResourcePrefetchPredictorTables::UpdateDataHelper( | |
| 309 const PrefetchData& data) { | |
| 310 DCHECK(!data.primary_key.empty()); | |
| 311 | |
| 312 if (!StringsAreSmallerThanDBLimit(data)) { | |
| 313 UMA_HISTOGRAM_BOOLEAN("ResourcePrefetchPredictor.DbStringTooLong", true); | |
| 314 return false; | |
| 315 } | |
| 316 | |
| 317 // Delete the older data from both the tables. | |
| 318 scoped_ptr<Statement> deleter(data.is_host() ? | |
| 319 GetHostResourceDeleteStatement() : GetUrlResourceDeleteStatement()); | |
| 320 deleter->BindString(0, data.primary_key); | |
| 321 if (!deleter->Run()) | |
| 322 return false; | |
| 323 | |
| 324 deleter.reset(data.is_host() ? GetHostMetadataDeleteStatement() : | |
| 325 GetUrlMetadataDeleteStatement()); | |
| 326 deleter->BindString(0, data.primary_key); | |
| 327 if (!deleter->Run()) | |
| 328 return false; | |
| 329 | |
| 330 // Add the new data to the tables. | |
| 331 const ResourceRows& resources = data.resources; | |
| 332 for (ResourceRows::const_iterator it = resources.begin(); | |
| 333 it != resources.end(); ++it) { | |
| 334 scoped_ptr<Statement> resource_inserter(data.is_host() ? | |
| 335 GetHostResourceUpdateStatement() : GetUrlResourceUpdateStatement()); | |
| 336 BindResourceRowToStatement(*it, data.primary_key, resource_inserter.get()); | |
| 337 if (!resource_inserter->Run()) | |
| 338 return false; | |
| 339 } | |
| 340 | |
| 341 scoped_ptr<Statement> metadata_inserter(data.is_host() ? | |
| 342 GetHostMetadataUpdateStatement() : GetUrlMetadataUpdateStatement()); | |
| 343 metadata_inserter->BindString(0, data.primary_key); | |
| 344 metadata_inserter->BindInt64(1, data.last_visit.ToInternalValue()); | |
| 345 if (!metadata_inserter->Run()) | |
| 346 return false; | |
| 347 | |
| 348 return true; | |
| 349 } | |
| 350 | |
| 351 void ResourcePrefetchPredictorTables::DeleteDataHelper( | |
| 352 PrefetchKeyType key_type, | |
| 353 const std::vector<std::string>& keys) { | |
| 354 bool is_host = key_type == PREFETCH_KEY_TYPE_HOST; | |
| 355 | |
| 356 for (std::vector<std::string>::const_iterator it = keys.begin(); | |
| 357 it != keys.end(); ++it) { | |
| 358 scoped_ptr<Statement> deleter(is_host ? GetHostResourceDeleteStatement() : | |
| 359 GetUrlResourceDeleteStatement()); | |
| 360 deleter->BindString(0, *it); | |
| 361 deleter->Run(); | |
| 362 | |
| 363 deleter.reset(is_host ? GetHostMetadataDeleteStatement() : | |
| 364 GetUrlMetadataDeleteStatement()); | |
| 365 deleter->BindString(0, *it); | |
| 366 deleter->Run(); | |
| 367 } | |
| 368 } | |
| 369 | |
| 370 bool ResourcePrefetchPredictorTables::StringsAreSmallerThanDBLimit( | |
| 371 const PrefetchData& data) const { | |
| 372 if (data.primary_key.length() > kMaxStringLength) | |
| 373 return false; | |
| 374 | |
| 375 for (ResourceRows::const_iterator it = data.resources.begin(); | |
| 376 it != data.resources.end(); ++it) { | |
| 377 if (it->resource_url.spec().length() > kMaxStringLength) | |
| 378 return false; | |
| 379 } | |
| 380 return true; | |
| 381 } | |
| 382 | |
| 383 void ResourcePrefetchPredictorTables::CreateTableIfNonExistent() { | |
| 384 CHECK(BrowserThread::CurrentlyOn(BrowserThread::DB)); | |
| 385 if (CantAccessDatabase()) | |
| 386 return; | |
| 387 | |
| 388 const char* resource_table_creator = | |
| 389 "CREATE TABLE %s ( " | |
| 390 "main_page_url TEXT, " | |
| 391 "resource_url TEXT, " | |
| 392 "resource_type INTEGER, " | |
| 393 "number_of_hits INTEGER, " | |
| 394 "number_of_misses INTEGER, " | |
| 395 "consecutive_misses INTEGER, " | |
| 396 "average_position DOUBLE, " | |
| 397 "PRIMARY KEY(main_page_url, resource_url))"; | |
| 398 const char* metadata_table_creator = | |
| 399 "CREATE TABLE %s ( " | |
| 400 "main_page_url TEXT, " | |
| 401 "last_visit_time INTEGER, " | |
| 402 "PRIMARY KEY(main_page_url))"; | |
| 403 | |
| 404 sql::Connection* db = DB(); | |
| 405 bool success = | |
| 406 (db->DoesTableExist(kUrlResourceTableName) || | |
| 407 db->Execute(base::StringPrintf(resource_table_creator, | |
| 408 kUrlResourceTableName).c_str())) && | |
| 409 (db->DoesTableExist(kUrlMetadataTableName) || | |
| 410 db->Execute(base::StringPrintf(metadata_table_creator, | |
| 411 kUrlMetadataTableName).c_str())) && | |
| 412 (db->DoesTableExist(kHostResourceTableName) || | |
| 413 db->Execute(base::StringPrintf(resource_table_creator, | |
| 414 kHostResourceTableName).c_str())) && | |
| 415 (db->DoesTableExist(kHostMetadataTableName) || | |
| 416 db->Execute(base::StringPrintf(metadata_table_creator, | |
| 417 kHostMetadataTableName).c_str())); | |
| 418 | |
| 419 if (!success) | |
| 420 ResetDB(); | |
| 421 } | |
| 422 | |
| 423 void ResourcePrefetchPredictorTables::LogDatabaseStats() { | |
| 424 CHECK(BrowserThread::CurrentlyOn(BrowserThread::DB)); | |
| 425 if (CantAccessDatabase()) | |
| 426 return; | |
| 427 | |
| 428 Statement statement(DB()->GetUniqueStatement( | |
| 429 base::StringPrintf("SELECT count(*) FROM %s", | |
| 430 kUrlResourceTableName).c_str())); | |
| 431 if (statement.Step()) | |
| 432 UMA_HISTOGRAM_COUNTS("ResourcePrefetchPredictor.UrlTableRowCount", | |
| 433 statement.ColumnInt(0)); | |
| 434 | |
| 435 statement.Assign(DB()->GetUniqueStatement( | |
| 436 base::StringPrintf("SELECT count(*) FROM %s", | |
| 437 kHostResourceTableName).c_str())); | |
| 438 if (statement.Step()) | |
| 439 UMA_HISTOGRAM_COUNTS("ResourcePrefetchPredictor.HostTableRowCount", | |
| 440 statement.ColumnInt(0)); | |
| 441 } | |
| 442 | |
| 443 Statement* | |
| 444 ResourcePrefetchPredictorTables::GetUrlResourceDeleteStatement() { | |
| 445 return new Statement(DB()->GetCachedStatement( | |
| 446 SQL_FROM_HERE, | |
| 447 base::StringPrintf("DELETE FROM %s WHERE main_page_url=?", | |
| 448 kUrlResourceTableName).c_str())); | |
| 449 } | |
| 450 | |
| 451 Statement* | |
| 452 ResourcePrefetchPredictorTables::GetUrlResourceUpdateStatement() { | |
| 453 return new Statement(DB()->GetCachedStatement( | |
| 454 SQL_FROM_HERE, | |
| 455 base::StringPrintf( | |
| 456 "INSERT INTO %s " | |
| 457 "(main_page_url, resource_url, resource_type, number_of_hits, " | |
| 458 "number_of_misses, consecutive_misses, average_position) " | |
| 459 "VALUES (?,?,?,?,?,?,?)", kUrlResourceTableName).c_str())); | |
| 460 } | |
| 461 | |
| 462 Statement* | |
| 463 ResourcePrefetchPredictorTables::GetUrlMetadataDeleteStatement() { | |
| 464 return new Statement(DB()->GetCachedStatement( | |
| 465 SQL_FROM_HERE, | |
| 466 base::StringPrintf("DELETE FROM %s WHERE main_page_url=?", | |
| 467 kUrlMetadataTableName).c_str())); | |
| 468 } | |
| 469 | |
| 470 Statement* | |
| 471 ResourcePrefetchPredictorTables::GetUrlMetadataUpdateStatement() { | |
| 472 return new Statement(DB()->GetCachedStatement( | |
| 473 SQL_FROM_HERE, | |
| 474 base::StringPrintf( | |
| 475 "INSERT INTO %s (main_page_url, last_visit_time) VALUES (?,?)", | |
| 476 kUrlMetadataTableName).c_str())); | |
| 477 } | |
| 478 | |
| 479 Statement* | |
| 480 ResourcePrefetchPredictorTables::GetHostResourceDeleteStatement() { | |
| 481 return new Statement(DB()->GetCachedStatement( | |
| 482 SQL_FROM_HERE, | |
| 483 base::StringPrintf("DELETE FROM %s WHERE main_page_url=?", | |
| 484 kHostResourceTableName).c_str())); | |
| 485 } | |
| 486 | |
| 487 Statement* | |
| 488 ResourcePrefetchPredictorTables::GetHostResourceUpdateStatement() { | |
| 489 return new Statement(DB()->GetCachedStatement( | |
| 490 SQL_FROM_HERE, | |
| 491 base::StringPrintf( | |
| 492 "INSERT INTO %s " | |
| 493 "(main_page_url, resource_url, resource_type, number_of_hits, " | |
| 494 "number_of_misses, consecutive_misses, average_position) " | |
| 495 "VALUES (?,?,?,?,?,?,?)", kHostResourceTableName).c_str())); | |
| 496 } | |
| 497 | |
| 498 Statement* | |
| 499 ResourcePrefetchPredictorTables::GetHostMetadataDeleteStatement() { | |
| 500 return new Statement(DB()->GetCachedStatement( | |
| 501 SQL_FROM_HERE, | |
| 502 base::StringPrintf("DELETE FROM %s WHERE main_page_url=?", | |
| 503 kHostMetadataTableName).c_str())); | |
| 504 } | |
| 505 | |
| 506 Statement* ResourcePrefetchPredictorTables::GetHostMetadataUpdateStatement() { | |
| 507 return new Statement(DB()->GetCachedStatement( | |
| 508 SQL_FROM_HERE, | |
| 509 base::StringPrintf( | |
| 510 "INSERT INTO %s (main_page_url, last_visit_time) VALUES (?,?)", | |
| 511 kHostMetadataTableName).c_str())); | |
| 512 } | |
| 513 | |
| 514 } // namespace predictors | |
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Chromium Code Reviews
Issue 117933003:
Remove the speculative resource prefetching code. This was experimental code added 1.5 years ago an… (Closed)
Base URL: svn://chrome-svn/chrome/trunk/src/