Duplicate code is one of the most pungent code smells. A rule that is often used is to re-structure code once it is duplicated in three or more places.
Common duplication problems, and corresponding solutions are:
Complex classes like DatabaseMysqlBase often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes. You can also have a look at the cohesion graph to spot any un-connected, or weakly-connected components.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
While breaking up the class, it is a good idea to analyze how other classes use DatabaseMysqlBase, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
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| 32 | abstract class DatabaseMysqlBase extends DatabaseBase { |
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| 33 | /** @var MysqlMasterPos */ |
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| 34 | protected $lastKnownReplicaPos; |
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| 35 | /** @var string Method to detect replica DB lag */ |
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| 36 | protected $lagDetectionMethod; |
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| 37 | /** @var array Method to detect replica DB lag */ |
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| 38 | protected $lagDetectionOptions = []; |
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| 39 | /** @var bool bool Whether to use GTID methods */ |
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| 40 | protected $useGTIDs = false; |
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| 41 | /** @var string|null */ |
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| 42 | protected $sslKeyPath; |
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| 43 | /** @var string|null */ |
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| 44 | protected $sslCertPath; |
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| 45 | /** @var string|null */ |
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| 46 | protected $sslCAPath; |
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| 47 | /** @var string[]|null */ |
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| 48 | protected $sslCiphers; |
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| 49 | /** @var string sql_mode value to send on connection */ |
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| 50 | protected $sqlMode; |
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| 51 | /** @var bool Use experimental UTF-8 transmission encoding */ |
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| 52 | protected $utf8Mode; |
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| 53 | |||
| 54 | /** @var string|null */ |
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| 55 | private $serverVersion = null; |
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| 56 | |||
| 57 | /** |
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| 58 | * Additional $params include: |
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| 59 | * - lagDetectionMethod : set to one of (Seconds_Behind_Master,pt-heartbeat). |
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| 60 | * pt-heartbeat assumes the table is at heartbeat.heartbeat |
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| 61 | * and uses UTC timestamps in the heartbeat.ts column. |
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| 62 | * (https://www.percona.com/doc/percona-toolkit/2.2/pt-heartbeat.html) |
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| 63 | * - lagDetectionOptions : if using pt-heartbeat, this can be set to an array map to change |
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| 64 | * the default behavior. Normally, the heartbeat row with the server |
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| 65 | * ID of this server's master will be used. Set the "conds" field to |
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| 66 | * override the query conditions, e.g. ['shard' => 's1']. |
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| 67 | * - useGTIDs : use GTID methods like MASTER_GTID_WAIT() when possible. |
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| 68 | * - sslKeyPath : path to key file [default: null] |
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| 69 | * - sslCertPath : path to certificate file [default: null] |
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| 70 | * - sslCAPath : parth to certificate authority PEM files [default: null] |
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| 71 | * - sslCiphers : array list of allowable ciphers [default: null] |
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| 72 | * @param array $params |
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| 73 | */ |
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| 74 | function __construct( array $params ) { |
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| 93 | |||
| 94 | /** |
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| 95 | * @return string |
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| 96 | */ |
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| 97 | function getType() { |
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| 100 | |||
| 101 | /** |
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| 102 | * @param string $server |
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| 103 | * @param string $user |
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| 104 | * @param string $password |
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| 105 | * @param string $dbName |
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| 106 | * @throws Exception|DBConnectionError |
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| 107 | * @return bool |
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| 108 | */ |
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| 109 | function open( $server, $user, $password, $dbName ) { |
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| 204 | |||
| 205 | /** |
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| 206 | * Set the character set information right after connection |
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| 207 | * @return bool |
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| 208 | */ |
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| 209 | protected function connectInitCharset() { |
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| 218 | |||
| 219 | /** |
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| 220 | * Open a connection to a MySQL server |
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| 221 | * |
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| 222 | * @param string $realServer |
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| 223 | * @return mixed Raw connection |
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| 224 | * @throws DBConnectionError |
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| 225 | */ |
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| 226 | abstract protected function mysqlConnect( $realServer ); |
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| 227 | |||
| 228 | /** |
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| 229 | * Set the character set of the MySQL link |
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| 230 | * |
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| 231 | * @param string $charset |
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| 232 | * @return bool |
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| 233 | */ |
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| 234 | abstract protected function mysqlSetCharset( $charset ); |
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| 235 | |||
| 236 | /** |
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| 237 | * @param ResultWrapper|resource $res |
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| 238 | * @throws DBUnexpectedError |
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| 239 | */ |
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| 240 | View Code Duplication | function freeResult( $res ) { |
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| 251 | |||
| 252 | /** |
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| 253 | * Free result memory |
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| 254 | * |
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| 255 | * @param resource $res Raw result |
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| 256 | * @return bool |
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| 257 | */ |
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| 258 | abstract protected function mysqlFreeResult( $res ); |
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| 259 | |||
| 260 | /** |
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| 261 | * @param ResultWrapper|resource $res |
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| 262 | * @return stdClass|bool |
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| 263 | * @throws DBUnexpectedError |
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| 264 | */ |
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| 265 | View Code Duplication | function fetchObject( $res ) { |
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| 287 | |||
| 288 | /** |
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| 289 | * Fetch a result row as an object |
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| 290 | * |
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| 291 | * @param resource $res Raw result |
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| 292 | * @return stdClass |
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| 293 | */ |
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| 294 | abstract protected function mysqlFetchObject( $res ); |
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| 295 | |||
| 296 | /** |
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| 297 | * @param ResultWrapper|resource $res |
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| 298 | * @return array|bool |
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| 299 | * @throws DBUnexpectedError |
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| 300 | */ |
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| 301 | View Code Duplication | function fetchRow( $res ) { |
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| 323 | |||
| 324 | /** |
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| 325 | * Fetch a result row as an associative and numeric array |
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| 326 | * |
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| 327 | * @param resource $res Raw result |
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| 328 | * @return array |
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| 329 | */ |
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| 330 | abstract protected function mysqlFetchArray( $res ); |
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| 331 | |||
| 332 | /** |
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| 333 | * @throws DBUnexpectedError |
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| 334 | * @param ResultWrapper|resource $res |
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| 335 | * @return int |
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| 336 | */ |
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| 337 | function numRows( $res ) { |
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| 352 | |||
| 353 | /** |
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| 354 | * Get number of rows in result |
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| 355 | * |
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| 356 | * @param resource $res Raw result |
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| 357 | * @return int |
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| 358 | */ |
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| 359 | abstract protected function mysqlNumRows( $res ); |
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| 360 | |||
| 361 | /** |
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| 362 | * @param ResultWrapper|resource $res |
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| 363 | * @return int |
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| 364 | */ |
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| 365 | function numFields( $res ) { |
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| 372 | |||
| 373 | /** |
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| 374 | * Get number of fields in result |
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| 375 | * |
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| 376 | * @param resource $res Raw result |
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| 377 | * @return int |
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| 378 | */ |
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| 379 | abstract protected function mysqlNumFields( $res ); |
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| 380 | |||
| 381 | /** |
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| 382 | * @param ResultWrapper|resource $res |
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| 383 | * @param int $n |
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| 384 | * @return string |
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| 385 | */ |
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| 386 | function fieldName( $res, $n ) { |
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| 393 | |||
| 394 | /** |
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| 395 | * Get the name of the specified field in a result |
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| 396 | * |
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| 397 | * @param ResultWrapper|resource $res |
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| 398 | * @param int $n |
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| 399 | * @return string |
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| 400 | */ |
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| 401 | abstract protected function mysqlFieldName( $res, $n ); |
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| 402 | |||
| 403 | /** |
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| 404 | * mysql_field_type() wrapper |
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| 405 | * @param ResultWrapper|resource $res |
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| 406 | * @param int $n |
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| 407 | * @return string |
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| 408 | */ |
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| 409 | public function fieldType( $res, $n ) { |
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| 416 | |||
| 417 | /** |
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| 418 | * Get the type of the specified field in a result |
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| 419 | * |
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| 420 | * @param ResultWrapper|resource $res |
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| 421 | * @param int $n |
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| 422 | * @return string |
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| 423 | */ |
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| 424 | abstract protected function mysqlFieldType( $res, $n ); |
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| 425 | |||
| 426 | /** |
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| 427 | * @param ResultWrapper|resource $res |
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| 428 | * @param int $row |
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| 429 | * @return bool |
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| 430 | */ |
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| 431 | function dataSeek( $res, $row ) { |
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| 438 | |||
| 439 | /** |
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| 440 | * Move internal result pointer |
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| 441 | * |
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| 442 | * @param ResultWrapper|resource $res |
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| 443 | * @param int $row |
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| 444 | * @return bool |
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| 445 | */ |
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| 446 | abstract protected function mysqlDataSeek( $res, $row ); |
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| 447 | |||
| 448 | /** |
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| 449 | * @return string |
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| 450 | */ |
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| 451 | function lastError() { |
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| 469 | |||
| 470 | /** |
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| 471 | * Returns the text of the error message from previous MySQL operation |
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| 472 | * |
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| 473 | * @param resource $conn Raw connection |
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| 474 | * @return string |
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| 475 | */ |
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| 476 | abstract protected function mysqlError( $conn = null ); |
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| 477 | |||
| 478 | /** |
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| 479 | * @param string $table |
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| 480 | * @param array $uniqueIndexes |
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| 481 | * @param array $rows |
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| 482 | * @param string $fname |
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| 483 | * @return ResultWrapper |
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| 484 | */ |
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| 485 | function replace( $table, $uniqueIndexes, $rows, $fname = __METHOD__ ) { |
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| 488 | |||
| 489 | /** |
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| 490 | * Estimate rows in dataset |
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| 491 | * Returns estimated count, based on EXPLAIN output |
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| 492 | * Takes same arguments as Database::select() |
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| 493 | * |
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| 494 | * @param string|array $table |
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| 495 | * @param string|array $vars |
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| 496 | * @param string|array $conds |
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| 497 | * @param string $fname |
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| 498 | * @param string|array $options |
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| 499 | * @return bool|int |
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| 500 | */ |
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| 501 | public function estimateRowCount( $table, $vars = '*', $conds = '', |
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| 520 | |||
| 521 | function tableExists( $table, $fname = __METHOD__ ) { |
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| 526 | |||
| 527 | /** |
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| 528 | * @param string $table |
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| 529 | * @param string $field |
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| 530 | * @return bool|MySQLField |
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| 531 | */ |
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| 532 | function fieldInfo( $table, $field ) { |
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| 548 | |||
| 549 | /** |
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| 550 | * Get column information from a result |
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| 551 | * |
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| 552 | * @param resource $res Raw result |
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| 553 | * @param int $n |
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| 554 | * @return stdClass |
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| 555 | */ |
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| 556 | abstract protected function mysqlFetchField( $res, $n ); |
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| 557 | |||
| 558 | /** |
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| 559 | * Get information about an index into an object |
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| 560 | * Returns false if the index does not exist |
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| 561 | * |
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| 562 | * @param string $table |
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| 563 | * @param string $index |
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| 564 | * @param string $fname |
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| 565 | * @return bool|array|null False or null on failure |
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| 566 | */ |
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| 567 | function indexInfo( $table, $index, $fname = __METHOD__ ) { |
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| 591 | |||
| 592 | /** |
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| 593 | * @param string $s |
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| 594 | * @return string |
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| 595 | */ |
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| 596 | function strencode( $s ) { |
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| 599 | |||
| 600 | /** |
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| 601 | * @param string $s |
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| 602 | * @return mixed |
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| 603 | */ |
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| 604 | abstract protected function mysqlRealEscapeString( $s ); |
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| 605 | |||
| 606 | /** |
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| 607 | * MySQL uses `backticks` for identifier quoting instead of the sql standard "double quotes". |
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| 608 | * |
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| 609 | * @param string $s |
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| 610 | * @return string |
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| 611 | */ |
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| 612 | public function addIdentifierQuotes( $s ) { |
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| 617 | |||
| 618 | /** |
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| 619 | * @param string $name |
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| 620 | * @return bool |
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| 621 | */ |
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| 622 | public function isQuotedIdentifier( $name ) { |
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| 625 | |||
| 626 | function getLag() { |
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| 633 | |||
| 634 | /** |
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| 635 | * @return string |
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| 636 | */ |
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| 637 | protected function getLagDetectionMethod() { |
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| 640 | |||
| 641 | /** |
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| 642 | * @return bool|int |
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| 643 | */ |
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| 644 | protected function getLagFromSlaveStatus() { |
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| 653 | |||
| 654 | /** |
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| 655 | * @return bool|float |
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| 656 | */ |
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| 657 | protected function getLagFromPtHeartbeat() { |
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| 699 | |||
| 700 | protected function getMasterServerInfo() { |
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| 737 | |||
| 738 | /** |
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| 739 | * @param array $conds WHERE clause conditions to find a row |
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| 740 | * @return array (heartbeat `ts` column value or null, UNIX timestamp) for the newest beat |
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| 741 | * @see https://www.percona.com/doc/percona-toolkit/2.1/pt-heartbeat.html |
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| 742 | */ |
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| 743 | protected function getHeartbeatData( array $conds ) { |
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| 755 | |||
| 756 | public function getApproximateLagStatus() { |
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| 773 | |||
| 774 | function masterPosWait( DBMasterPos $pos, $timeout ) { |
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| 821 | |||
| 822 | /** |
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| 823 | * Get the position of the master from SHOW SLAVE STATUS |
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| 824 | * |
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| 825 | * @return MySQLMasterPos|bool |
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| 826 | */ |
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| 827 | function getSlavePos() { |
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| 849 | |||
| 850 | /** |
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| 851 | * Get the position of the master from SHOW MASTER STATUS |
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| 852 | * |
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| 853 | * @return MySQLMasterPos|bool |
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| 854 | */ |
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| 855 | function getMasterPos() { |
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| 874 | |||
| 875 | public function serverIsReadOnly() { |
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| 881 | |||
| 882 | /** |
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| 883 | * @param string $index |
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| 884 | * @return string |
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| 885 | */ |
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| 886 | function useIndexClause( $index ) { |
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| 889 | |||
| 890 | /** |
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| 891 | * @param string $index |
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| 892 | * @return string |
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| 893 | */ |
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| 894 | function ignoreIndexClause( $index ) { |
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| 897 | |||
| 898 | /** |
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| 899 | * @return string |
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| 900 | */ |
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| 901 | function lowPriorityOption() { |
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| 904 | |||
| 905 | /** |
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| 906 | * @return string |
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| 907 | */ |
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| 908 | public function getSoftwareLink() { |
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| 922 | |||
| 923 | /** |
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| 924 | * @return string |
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| 925 | */ |
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| 926 | public function getServerVersion() { |
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| 935 | |||
| 936 | /** |
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| 937 | * @param array $options |
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| 938 | */ |
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| 939 | public function setSessionOptions( array $options ) { |
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| 946 | |||
| 947 | /** |
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| 948 | * @param string $sql |
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| 949 | * @param string $newLine |
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| 950 | * @return bool |
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| 951 | */ |
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| 952 | public function streamStatementEnd( &$sql, &$newLine ) { |
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| 961 | |||
| 962 | /** |
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| 963 | * Check to see if a named lock is available. This is non-blocking. |
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| 964 | * |
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| 965 | * @param string $lockName Name of lock to poll |
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| 966 | * @param string $method Name of method calling us |
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| 967 | * @return bool |
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| 968 | * @since 1.20 |
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| 969 | */ |
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| 970 | View Code Duplication | public function lockIsFree( $lockName, $method ) { |
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| 977 | |||
| 978 | /** |
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| 979 | * @param string $lockName |
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| 980 | * @param string $method |
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| 981 | * @param int $timeout |
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| 982 | * @return bool |
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| 983 | */ |
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| 984 | View Code Duplication | public function lock( $lockName, $method, $timeout = 5 ) { |
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| 998 | |||
| 999 | /** |
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| 1000 | * FROM MYSQL DOCS: |
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| 1001 | * http://dev.mysql.com/doc/refman/5.0/en/miscellaneous-functions.html#function_release-lock |
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| 1002 | * @param string $lockName |
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| 1003 | * @param string $method |
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| 1004 | * @return bool |
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| 1005 | */ |
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| 1006 | View Code Duplication | public function unlock( $lockName, $method ) { |
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| 1020 | |||
| 1021 | private function makeLockName( $lockName ) { |
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| 1026 | |||
| 1027 | public function namedLocksEnqueue() { |
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| 1030 | |||
| 1031 | /** |
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| 1032 | * @param array $read |
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| 1033 | * @param array $write |
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| 1034 | * @param string $method |
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| 1035 | * @param bool $lowPriority |
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| 1036 | * @return bool |
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| 1037 | */ |
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| 1038 | public function lockTables( $read, $write, $method, $lowPriority = true ) { |
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| 1055 | |||
| 1056 | /** |
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| 1057 | * @param string $method |
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| 1058 | * @return bool |
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| 1059 | */ |
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| 1060 | public function unlockTables( $method ) { |
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| 1065 | |||
| 1066 | /** |
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| 1067 | * @param bool $value |
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| 1068 | */ |
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| 1069 | public function setBigSelects( $value = true ) { |
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| 1084 | |||
| 1085 | /** |
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| 1086 | * DELETE where the condition is a join. MySql uses multi-table deletes. |
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| 1087 | * @param string $delTable |
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| 1088 | * @param string $joinTable |
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| 1089 | * @param string $delVar |
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| 1090 | * @param string $joinVar |
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| 1091 | * @param array|string $conds |
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| 1092 | * @param bool|string $fname |
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| 1093 | * @throws DBUnexpectedError |
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| 1094 | * @return bool|ResultWrapper |
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| 1095 | */ |
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| 1096 | View Code Duplication | function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds, $fname = __METHOD__ ) { |
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| 1111 | |||
| 1112 | /** |
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| 1113 | * @param string $table |
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| 1114 | * @param array $rows |
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| 1115 | * @param array $uniqueIndexes |
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| 1116 | * @param array $set |
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| 1117 | * @param string $fname |
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| 1118 | * @return bool |
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| 1119 | */ |
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| 1120 | public function upsert( $table, array $rows, array $uniqueIndexes, |
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| 1144 | |||
| 1145 | /** |
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| 1146 | * Determines how long the server has been up |
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| 1147 | * |
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| 1148 | * @return int |
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| 1149 | */ |
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| 1150 | function getServerUptime() { |
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| 1155 | |||
| 1156 | /** |
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| 1157 | * Determines if the last failure was due to a deadlock |
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| 1158 | * |
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| 1159 | * @return bool |
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| 1160 | */ |
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| 1161 | function wasDeadlock() { |
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| 1164 | |||
| 1165 | /** |
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| 1166 | * Determines if the last failure was due to a lock timeout |
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| 1167 | * |
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| 1168 | * @return bool |
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| 1169 | */ |
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| 1170 | function wasLockTimeout() { |
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| 1173 | |||
| 1174 | function wasErrorReissuable() { |
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| 1177 | |||
| 1178 | /** |
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| 1179 | * Determines if the last failure was due to the database being read-only. |
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| 1180 | * |
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| 1181 | * @return bool |
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| 1182 | */ |
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| 1183 | function wasReadOnlyError() { |
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| 1187 | |||
| 1188 | function wasConnectionError( $errno ) { |
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| 1191 | |||
| 1192 | /** |
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| 1193 | * Get the underlying binding handle, mConn |
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| 1194 | * |
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| 1195 | * Makes sure that mConn is set (disconnects and ping() failure can unset it). |
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| 1196 | * This catches broken callers than catch and ignore disconnection exceptions. |
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| 1197 | * Unlike checking isOpen(), this is safe to call inside of open(). |
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| 1198 | * |
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| 1199 | * @return resource|object |
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| 1200 | * @throws DBUnexpectedError |
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| 1201 | * @since 1.26 |
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| 1202 | */ |
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| 1203 | protected function getBindingHandle() { |
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| 1213 | |||
| 1214 | /** |
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| 1215 | * @param string $oldName |
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| 1216 | * @param string $newName |
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| 1217 | * @param bool $temporary |
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| 1218 | * @param string $fname |
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| 1219 | * @return bool |
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| 1220 | */ |
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| 1221 | function duplicateTableStructure( $oldName, $newName, $temporary = false, $fname = __METHOD__ ) { |
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| 1229 | |||
| 1230 | /** |
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| 1231 | * List all tables on the database |
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| 1232 | * |
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| 1233 | * @param string $prefix Only show tables with this prefix, e.g. mw_ |
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| 1234 | * @param string $fname Calling function name |
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| 1235 | * @return array |
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| 1236 | */ |
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| 1237 | function listTables( $prefix = null, $fname = __METHOD__ ) { |
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| 1253 | |||
| 1254 | /** |
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| 1255 | * @param string $tableName |
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| 1256 | * @param string $fName |
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| 1257 | * @return bool|ResultWrapper |
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| 1258 | */ |
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| 1259 | View Code Duplication | public function dropTable( $tableName, $fName = __METHOD__ ) { |
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| 1266 | |||
| 1267 | /** |
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| 1268 | * @return array |
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| 1269 | */ |
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| 1270 | protected function getDefaultSchemaVars() { |
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| 1281 | |||
| 1282 | /** |
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| 1283 | * Get status information from SHOW STATUS in an associative array |
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| 1284 | * |
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| 1285 | * @param string $which |
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| 1286 | * @return array |
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| 1287 | */ |
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| 1288 | function getMysqlStatus( $which = "%" ) { |
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| 1298 | |||
| 1299 | /** |
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| 1300 | * Lists VIEWs in the database |
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| 1301 | * |
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| 1302 | * @param string $prefix Only show VIEWs with this prefix, eg. |
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| 1303 | * unit_test_, or $wgDBprefix. Default: null, would return all views. |
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| 1304 | * @param string $fname Name of calling function |
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| 1305 | * @return array |
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| 1306 | * @since 1.22 |
||
| 1307 | */ |
||
| 1308 | public function listViews( $prefix = null, $fname = __METHOD__ ) { |
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| 1337 | |||
| 1338 | /** |
||
| 1339 | * Differentiates between a TABLE and a VIEW. |
||
| 1340 | * |
||
| 1341 | * @param string $name Name of the TABLE/VIEW to test |
||
| 1342 | * @param string $prefix |
||
| 1343 | * @return bool |
||
| 1344 | * @since 1.22 |
||
| 1345 | */ |
||
| 1346 | public function isView( $name, $prefix = null ) { |
||
| 1349 | } |
||
| 1350 | |||
| 1351 |
In PHP, under loose comparison (like
==, or!=, orswitchconditions), values of different types might be equal.For
stringvalues, the empty string''is a special case, in particular the following results might be unexpected: