Merge "objectcache: optimize MemcachedPeclBagOStuff::*Multi() write methods"
[lhc/web/wiklou.git] / includes / libs / rdbms / database / IDatabase.php
1 <?php
2 /**
3 * This program is free software; you can redistribute it and/or modify
4 * it under the terms of the GNU General Public License as published by
5 * the Free Software Foundation; either version 2 of the License, or
6 * (at your option) any later version.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public License along
14 * with this program; if not, write to the Free Software Foundation, Inc.,
15 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
16 * http://www.gnu.org/copyleft/gpl.html
17 *
18 * @file
19 */
20 namespace Wikimedia\Rdbms;
21
22 use InvalidArgumentException;
23 use Wikimedia\ScopedCallback;
24 use RuntimeException;
25 use stdClass;
26
27 /**
28 * @defgroup Database Database
29 * This group deals with database interface functions
30 * and query specifics/optimisations.
31 */
32 /**
33 * Basic database interface for live and lazy-loaded relation database handles
34 *
35 * @note IDatabase and DBConnRef should be updated to reflect any changes
36 * @ingroup Database
37 */
38 interface IDatabase {
39 /** @var int Callback triggered immediately due to no active transaction */
40 const TRIGGER_IDLE = 1;
41 /** @var int Callback triggered by COMMIT */
42 const TRIGGER_COMMIT = 2;
43 /** @var int Callback triggered by ROLLBACK */
44 const TRIGGER_ROLLBACK = 3;
45 /** @var int Callback triggered by atomic section cancel (ROLLBACK TO SAVEPOINT) */
46 const TRIGGER_CANCEL = 4;
47
48 /** @var string Transaction is requested by regular caller outside of the DB layer */
49 const TRANSACTION_EXPLICIT = '';
50 /** @var string Transaction is requested internally via DBO_TRX/startAtomic() */
51 const TRANSACTION_INTERNAL = 'implicit';
52
53 /** @var string Atomic section is not cancelable */
54 const ATOMIC_NOT_CANCELABLE = '';
55 /** @var string Atomic section is cancelable */
56 const ATOMIC_CANCELABLE = 'cancelable';
57
58 /** @var string Commit/rollback is from outside the IDatabase handle and connection manager */
59 const FLUSHING_ONE = '';
60 /** @var string Commit/rollback is from the connection manager for the IDatabase handle */
61 const FLUSHING_ALL_PEERS = 'flush';
62 /** @var string Commit/rollback is from the IDatabase handle internally */
63 const FLUSHING_INTERNAL = 'flush-internal';
64
65 /** @var string Do not remember the prior flags */
66 const REMEMBER_NOTHING = '';
67 /** @var string Remember the prior flags */
68 const REMEMBER_PRIOR = 'remember';
69 /** @var string Restore to the prior flag state */
70 const RESTORE_PRIOR = 'prior';
71 /** @var string Restore to the initial flag state */
72 const RESTORE_INITIAL = 'initial';
73
74 /** @var string Estimate total time (RTT, scanning, waiting on locks, applying) */
75 const ESTIMATE_TOTAL = 'total';
76 /** @var string Estimate time to apply (scanning, applying) */
77 const ESTIMATE_DB_APPLY = 'apply';
78
79 /** @var int Combine list with comma delimeters */
80 const LIST_COMMA = 0;
81 /** @var int Combine list with AND clauses */
82 const LIST_AND = 1;
83 /** @var int Convert map into a SET clause */
84 const LIST_SET = 2;
85 /** @var int Treat as field name and do not apply value escaping */
86 const LIST_NAMES = 3;
87 /** @var int Combine list with OR clauses */
88 const LIST_OR = 4;
89
90 /** @var int Enable debug logging */
91 const DBO_DEBUG = 1;
92 /** @var int Disable query buffering (only one result set can be iterated at a time) */
93 const DBO_NOBUFFER = 2;
94 /** @var int Ignore query errors (internal use only!) */
95 const DBO_IGNORE = 4;
96 /** @var int Automatically start a transaction before running a query if none is active */
97 const DBO_TRX = 8;
98 /** @var int Use DBO_TRX in non-CLI mode */
99 const DBO_DEFAULT = 16;
100 /** @var int Use DB persistent connections if possible */
101 const DBO_PERSISTENT = 32;
102 /** @var int DBA session mode; mostly for Oracle */
103 const DBO_SYSDBA = 64;
104 /** @var int Schema file mode; mostly for Oracle */
105 const DBO_DDLMODE = 128;
106 /** @var int Enable SSL/TLS in connection protocol */
107 const DBO_SSL = 256;
108 /** @var int Enable compression in connection protocol */
109 const DBO_COMPRESS = 512;
110
111 /** @var int Idiom for "no special flags" */
112 const QUERY_NORMAL = 0;
113 /** @var int Ignore query errors and return false when they happen */
114 const QUERY_SILENCE_ERRORS = 1; // b/c for 1.32 query() argument; note that (int)true = 1
115 /**
116 * @var int Treat the TEMPORARY table from the given CREATE query as if it is
117 * permanent as far as write tracking is concerned. This is useful for testing.
118 */
119 const QUERY_PSEUDO_PERMANENT = 2;
120 /** @var int Enforce that a query does not make effective writes */
121 const QUERY_REPLICA_ROLE = 4;
122 /** @var int Ignore the current presence of any DBO_TRX flag */
123 const QUERY_IGNORE_DBO_TRX = 8;
124 /** @var int Do not try to retry the query if the connection was lost */
125 const QUERY_NO_RETRY = 16;
126
127 /** @var bool Parameter to unionQueries() for UNION ALL */
128 const UNION_ALL = true;
129 /** @var bool Parameter to unionQueries() for UNION DISTINCT */
130 const UNION_DISTINCT = false;
131
132 /**
133 * A string describing the current software version, and possibly
134 * other details in a user-friendly way. Will be listed on Special:Version, etc.
135 * Use getServerVersion() to get machine-friendly information.
136 *
137 * @return string Version information from the database server
138 */
139 public function getServerInfo();
140
141 /**
142 * Turns buffering of SQL result sets on (true) or off (false). Default is "on".
143 *
144 * Unbuffered queries are very troublesome in MySQL:
145 *
146 * - If another query is executed while the first query is being read
147 * out, the first query is killed. This means you can't call normal
148 * Database functions while you are reading an unbuffered query result
149 * from a normal Database connection.
150 *
151 * - Unbuffered queries cause the MySQL server to use large amounts of
152 * memory and to hold broad locks which block other queries.
153 *
154 * If you want to limit client-side memory, it's almost always better to
155 * split up queries into batches using a LIMIT clause than to switch off
156 * buffering.
157 *
158 * @param null|bool $buffer
159 * @return null|bool The previous value of the flag
160 */
161 public function bufferResults( $buffer = null );
162
163 /**
164 * Gets the current transaction level.
165 *
166 * Historically, transactions were allowed to be "nested". This is no
167 * longer supported, so this function really only returns a boolean.
168 *
169 * @return int The previous value
170 */
171 public function trxLevel();
172
173 /**
174 * Get the UNIX timestamp of the time that the transaction was established
175 *
176 * This can be used to reason about the staleness of SELECT data in REPEATABLE-READ
177 * transaction isolation level. Callers can assume that if a view-snapshot isolation
178 * is used, then the data read by SQL queries is *at least* up to date to that point
179 * (possibly more up-to-date since the first SELECT defines the snapshot).
180 *
181 * @return float|null Returns null if there is not active transaction
182 * @since 1.25
183 */
184 public function trxTimestamp();
185
186 /**
187 * @return bool Whether an explicit transaction or atomic sections are still open
188 * @since 1.28
189 */
190 public function explicitTrxActive();
191
192 /**
193 * Assert that all explicit transactions or atomic sections have been closed.
194 * @throws DBTransactionError
195 * @since 1.32
196 */
197 public function assertNoOpenTransactions();
198
199 /**
200 * Get/set the table prefix.
201 * @param string|null $prefix The table prefix to set, or omitted to leave it unchanged.
202 * @return string The previous table prefix
203 * @throws DBUnexpectedError
204 */
205 public function tablePrefix( $prefix = null );
206
207 /**
208 * Get/set the db schema.
209 * @param string|null $schema The database schema to set, or omitted to leave it unchanged.
210 * @return string The previous db schema
211 */
212 public function dbSchema( $schema = null );
213
214 /**
215 * Get properties passed down from the server info array of the load
216 * balancer.
217 *
218 * @param string|null $name The entry of the info array to get, or null to get the
219 * whole array
220 *
221 * @return array|mixed|null
222 */
223 public function getLBInfo( $name = null );
224
225 /**
226 * Set the entire array or a particular key of the managing load balancer info array
227 *
228 * @param array|string $nameOrArray The new array or the name of a key to set
229 * @param array|null $value If $nameOrArray is a string, the new key value (null to unset)
230 */
231 public function setLBInfo( $nameOrArray, $value = null );
232
233 /**
234 * Set a lazy-connecting DB handle to the master DB (for replication status purposes)
235 *
236 * @param IDatabase $conn
237 * @since 1.27
238 */
239 public function setLazyMasterHandle( IDatabase $conn );
240
241 /**
242 * Returns true if this database does an implicit sort when doing GROUP BY
243 *
244 * @return bool
245 * @deprecated Since 1.30; only use grouped or aggregated fields in the SELECT
246 */
247 public function implicitGroupby();
248
249 /**
250 * Returns true if this database does an implicit order by when the column has an index
251 * For example: SELECT page_title FROM page LIMIT 1
252 *
253 * @return bool
254 */
255 public function implicitOrderby();
256
257 /**
258 * Return the last query that sent on account of IDatabase::query()
259 * @return string SQL text or empty string if there was no such query
260 */
261 public function lastQuery();
262
263 /**
264 * Returns true if the connection may have been used for write queries.
265 * Should return true if unsure.
266 *
267 * @return bool
268 * @deprecated Since 1.31; use lastDoneWrites()
269 */
270 public function doneWrites();
271
272 /**
273 * Returns the last time the connection may have been used for write queries.
274 * Should return a timestamp if unsure.
275 *
276 * @return int|float UNIX timestamp or false
277 * @since 1.24
278 */
279 public function lastDoneWrites();
280
281 /**
282 * @return bool Whether there is a transaction open with possible write queries
283 * @since 1.27
284 */
285 public function writesPending();
286
287 /**
288 * @return bool Whether there is a transaction open with pre-commit callbacks pending
289 * @since 1.32
290 */
291 public function preCommitCallbacksPending();
292
293 /**
294 * Whether there is a transaction open with either possible write queries
295 * or unresolved pre-commit/commit/resolution callbacks pending
296 *
297 * This does *not* count recurring callbacks, e.g. from setTransactionListener().
298 *
299 * @return bool
300 */
301 public function writesOrCallbacksPending();
302
303 /**
304 * Get the time spend running write queries for this transaction
305 *
306 * High times could be due to scanning, updates, locking, and such
307 *
308 * @param string $type IDatabase::ESTIMATE_* constant [default: ESTIMATE_ALL]
309 * @return float|bool Returns false if not transaction is active
310 * @since 1.26
311 */
312 public function pendingWriteQueryDuration( $type = self::ESTIMATE_TOTAL );
313
314 /**
315 * Get the list of method names that did write queries for this transaction
316 *
317 * @return array
318 * @since 1.27
319 */
320 public function pendingWriteCallers();
321
322 /**
323 * Get the number of affected rows from pending write queries
324 *
325 * @return int
326 * @since 1.30
327 */
328 public function pendingWriteRowsAffected();
329
330 /**
331 * Is a connection to the database open?
332 * @return bool
333 */
334 public function isOpen();
335
336 /**
337 * Set a flag for this connection
338 *
339 * @param int $flag DBO_* constants from Defines.php:
340 * - DBO_DEBUG: output some debug info (same as debug())
341 * - DBO_NOBUFFER: don't buffer results (inverse of bufferResults())
342 * - DBO_TRX: automatically start transactions
343 * - DBO_DEFAULT: automatically sets DBO_TRX if not in command line mode
344 * and removes it in command line mode
345 * - DBO_PERSISTENT: use persistant database connection
346 * @param string $remember IDatabase::REMEMBER_* constant [default: REMEMBER_NOTHING]
347 */
348 public function setFlag( $flag, $remember = self::REMEMBER_NOTHING );
349
350 /**
351 * Clear a flag for this connection
352 *
353 * @param int $flag DBO_* constants from Defines.php:
354 * - DBO_DEBUG: output some debug info (same as debug())
355 * - DBO_NOBUFFER: don't buffer results (inverse of bufferResults())
356 * - DBO_TRX: automatically start transactions
357 * - DBO_DEFAULT: automatically sets DBO_TRX if not in command line mode
358 * and removes it in command line mode
359 * - DBO_PERSISTENT: use persistant database connection
360 * @param string $remember IDatabase::REMEMBER_* constant [default: REMEMBER_NOTHING]
361 */
362 public function clearFlag( $flag, $remember = self::REMEMBER_NOTHING );
363
364 /**
365 * Restore the flags to their prior state before the last setFlag/clearFlag call
366 *
367 * @param string $state IDatabase::RESTORE_* constant. [default: RESTORE_PRIOR]
368 * @since 1.28
369 */
370 public function restoreFlags( $state = self::RESTORE_PRIOR );
371
372 /**
373 * Returns a boolean whether the flag $flag is set for this connection
374 *
375 * @param int $flag DBO_* constants from Defines.php:
376 * - DBO_DEBUG: output some debug info (same as debug())
377 * - DBO_NOBUFFER: don't buffer results (inverse of bufferResults())
378 * - DBO_TRX: automatically start transactions
379 * - DBO_PERSISTENT: use persistant database connection
380 * @return bool
381 */
382 public function getFlag( $flag );
383
384 /**
385 * Return the currently selected domain ID
386 *
387 * Null components (database/schema) might change once a connection is established
388 *
389 * @return string
390 */
391 public function getDomainID();
392
393 /**
394 * Alias for getDomainID()
395 *
396 * @return string
397 * @deprecated 1.30
398 */
399 public function getWikiID();
400
401 /**
402 * Get the type of the DBMS, as it appears in $wgDBtype.
403 *
404 * @return string
405 */
406 public function getType();
407
408 /**
409 * Fetch the next row from the given result object, in object form.
410 * Fields can be retrieved with $row->fieldname, with fields acting like
411 * member variables.
412 * If no more rows are available, false is returned.
413 *
414 * @param IResultWrapper|stdClass $res Object as returned from IDatabase::query(), etc.
415 * @return stdClass|bool
416 * @throws DBUnexpectedError Thrown if the database returns an error
417 */
418 public function fetchObject( $res );
419
420 /**
421 * Fetch the next row from the given result object, in associative array
422 * form. Fields are retrieved with $row['fieldname'].
423 * If no more rows are available, false is returned.
424 *
425 * @param IResultWrapper $res Result object as returned from IDatabase::query(), etc.
426 * @return array|bool
427 * @throws DBUnexpectedError Thrown if the database returns an error
428 */
429 public function fetchRow( $res );
430
431 /**
432 * Get the number of rows in a query result. If the query did not return
433 * any rows (for example, if it was a write query), this returns zero.
434 *
435 * @param mixed $res A SQL result
436 * @return int
437 */
438 public function numRows( $res );
439
440 /**
441 * Get the number of fields in a result object
442 * @see https://www.php.net/mysql_num_fields
443 *
444 * @param mixed $res A SQL result
445 * @return int
446 */
447 public function numFields( $res );
448
449 /**
450 * Get a field name in a result object
451 * @see https://www.php.net/mysql_field_name
452 *
453 * @param mixed $res A SQL result
454 * @param int $n
455 * @return string
456 */
457 public function fieldName( $res, $n );
458
459 /**
460 * Get the inserted value of an auto-increment row
461 *
462 * This should only be called after an insert that used an auto-incremented
463 * value. If no such insert was previously done in the current database
464 * session, the return value is undefined.
465 *
466 * @return int
467 */
468 public function insertId();
469
470 /**
471 * Change the position of the cursor in a result object
472 * @see https://www.php.net/mysql_data_seek
473 *
474 * @param mixed $res A SQL result
475 * @param int $row
476 */
477 public function dataSeek( $res, $row );
478
479 /**
480 * Get the last error number
481 * @see https://www.php.net/mysql_errno
482 *
483 * @return int
484 */
485 public function lastErrno();
486
487 /**
488 * Get a description of the last error
489 * @see https://www.php.net/mysql_error
490 *
491 * @return string
492 */
493 public function lastError();
494
495 /**
496 * Get the number of rows affected by the last write query
497 * @see https://www.php.net/mysql_affected_rows
498 *
499 * @return int
500 */
501 public function affectedRows();
502
503 /**
504 * Returns a wikitext link to the DB's website, e.g.,
505 * return "[https://www.mysql.com/ MySQL]";
506 * Should at least contain plain text, if for some reason
507 * your database has no website.
508 *
509 * @return string Wikitext of a link to the server software's web site
510 */
511 public function getSoftwareLink();
512
513 /**
514 * A string describing the current software version, like from
515 * mysql_get_server_info().
516 *
517 * @return string Version information from the database server.
518 */
519 public function getServerVersion();
520
521 /**
522 * Close the database connection
523 *
524 * This should only be called after any transactions have been resolved,
525 * aside from read-only automatic transactions (assuming no callbacks are registered).
526 * If a transaction is still open anyway, it will be rolled back.
527 *
528 * @throws DBError
529 * @return bool Operation success. true if already closed.
530 */
531 public function close();
532
533 /**
534 * Run an SQL query and return the result. Normally throws a DBQueryError
535 * on failure. If errors are ignored, returns false instead.
536 *
537 * If a connection loss is detected, then an attempt to reconnect will be made.
538 * For queries that involve no larger transactions or locks, they will be re-issued
539 * for convenience, provided the connection was re-established.
540 *
541 * In new code, the query wrappers select(), insert(), update(), delete(),
542 * etc. should be used where possible, since they give much better DBMS
543 * independence and automatically quote or validate user input in a variety
544 * of contexts. This function is generally only useful for queries which are
545 * explicitly DBMS-dependent and are unsupported by the query wrappers, such
546 * as CREATE TABLE.
547 *
548 * However, the query wrappers themselves should call this function.
549 *
550 * @param string $sql SQL query
551 * @param string $fname Name of the calling function, for profiling/SHOW PROCESSLIST
552 * comment (you can use __METHOD__ or add some extra info)
553 * @param int $flags Bitfield of IDatabase::QUERY_* constants. Note that suppression
554 * of errors is best handled by try/catch rather than using one of these flags.
555 * @return bool|IResultWrapper True for a successful write query, IResultWrapper object
556 * for a successful read query, or false on failure if QUERY_SILENCE_ERRORS is set.
557 * @throws DBError
558 */
559 public function query( $sql, $fname = __METHOD__, $flags = 0 );
560
561 /**
562 * Free a result object returned by query() or select(). It's usually not
563 * necessary to call this, just use unset() or let the variable holding
564 * the result object go out of scope.
565 *
566 * @param mixed $res A SQL result
567 */
568 public function freeResult( $res );
569
570 /**
571 * A SELECT wrapper which returns a single field from a single result row.
572 *
573 * Usually throws a DBQueryError on failure. If errors are explicitly
574 * ignored, returns false on failure.
575 *
576 * If no result rows are returned from the query, false is returned.
577 *
578 * @param string|array $table Table name. See IDatabase::select() for details.
579 * @param string $var The field name to select. This must be a valid SQL
580 * fragment: do not use unvalidated user input.
581 * @param string|array $cond The condition array. See IDatabase::select() for details.
582 * @param string $fname The function name of the caller.
583 * @param string|array $options The query options. See IDatabase::select() for details.
584 * @param string|array $join_conds The query join conditions. See IDatabase::select() for details.
585 *
586 * @return mixed The value from the field
587 * @throws DBError
588 */
589 public function selectField(
590 $table, $var, $cond = '', $fname = __METHOD__, $options = [], $join_conds = []
591 );
592
593 /**
594 * A SELECT wrapper which returns a list of single field values from result rows.
595 *
596 * Usually throws a DBQueryError on failure. If errors are explicitly
597 * ignored, returns false on failure.
598 *
599 * If no result rows are returned from the query, false is returned.
600 *
601 * @param string|array $table Table name. See IDatabase::select() for details.
602 * @param string $var The field name to select. This must be a valid SQL
603 * fragment: do not use unvalidated user input.
604 * @param string|array $cond The condition array. See IDatabase::select() for details.
605 * @param string $fname The function name of the caller.
606 * @param string|array $options The query options. See IDatabase::select() for details.
607 * @param string|array $join_conds The query join conditions. See IDatabase::select() for details.
608 *
609 * @return array The values from the field in the order they were returned from the DB
610 * @throws DBError
611 * @since 1.25
612 */
613 public function selectFieldValues(
614 $table, $var, $cond = '', $fname = __METHOD__, $options = [], $join_conds = []
615 );
616
617 /**
618 * Execute a SELECT query constructed using the various parameters provided.
619 * See below for full details of the parameters.
620 *
621 * @param string|array $table Table name(s)
622 *
623 * May be either an array of table names, or a single string holding a table
624 * name. If an array is given, table aliases can be specified, for example:
625 *
626 * [ 'a' => 'user' ]
627 *
628 * This includes the user table in the query, with the alias "a" available
629 * for use in field names (e.g. a.user_name).
630 *
631 * A derived table, defined by the result of selectSQLText(), requires an alias
632 * key and a Subquery instance value which wraps the SQL query, for example:
633 *
634 * [ 'c' => new Subquery( 'SELECT ...' ) ]
635 *
636 * Joins using parentheses for grouping (since MediaWiki 1.31) may be
637 * constructed using nested arrays. For example,
638 *
639 * [ 'tableA', 'nestedB' => [ 'tableB', 'b2' => 'tableB2' ] ]
640 *
641 * along with `$join_conds` like
642 *
643 * [ 'b2' => [ 'JOIN', 'b_id = b2_id' ], 'nestedB' => [ 'LEFT JOIN', 'b_a = a_id' ] ]
644 *
645 * will produce SQL something like
646 *
647 * FROM tableA LEFT JOIN (tableB JOIN tableB2 AS b2 ON (b_id = b2_id)) ON (b_a = a_id)
648 *
649 * All of the table names given here are automatically run through
650 * Database::tableName(), which causes the table prefix (if any) to be
651 * added, and various other table name mappings to be performed.
652 *
653 * Do not use untrusted user input as a table name. Alias names should
654 * not have characters outside of the Basic multilingual plane.
655 *
656 * @param string|array $vars Field name(s)
657 *
658 * May be either a field name or an array of field names. The field names
659 * can be complete fragments of SQL, for direct inclusion into the SELECT
660 * query. If an array is given, field aliases can be specified, for example:
661 *
662 * [ 'maxrev' => 'MAX(rev_id)' ]
663 *
664 * This includes an expression with the alias "maxrev" in the query.
665 *
666 * If an expression is given, care must be taken to ensure that it is
667 * DBMS-independent.
668 *
669 * Untrusted user input must not be passed to this parameter.
670 *
671 * @param string|array $conds
672 *
673 * May be either a string containing a single condition, or an array of
674 * conditions. If an array is given, the conditions constructed from each
675 * element are combined with AND.
676 *
677 * Array elements may take one of two forms:
678 *
679 * - Elements with a numeric key are interpreted as raw SQL fragments.
680 * - Elements with a string key are interpreted as equality conditions,
681 * where the key is the field name.
682 * - If the value of such an array element is a scalar (such as a
683 * string), it will be treated as data and thus quoted appropriately.
684 * If it is null, an IS NULL clause will be added.
685 * - If the value is an array, an IN (...) clause will be constructed
686 * from its non-null elements, and an IS NULL clause will be added
687 * if null is present, such that the field may match any of the
688 * elements in the array. The non-null elements will be quoted.
689 *
690 * Note that expressions are often DBMS-dependent in their syntax.
691 * DBMS-independent wrappers are provided for constructing several types of
692 * expression commonly used in condition queries. See:
693 * - IDatabase::buildLike()
694 * - IDatabase::conditional()
695 *
696 * Untrusted user input is safe in the values of string keys, however untrusted
697 * input must not be used in the array key names or in the values of numeric keys.
698 * Escaping of untrusted input used in values of numeric keys should be done via
699 * IDatabase::addQuotes()
700 *
701 * Use an empty array, string, or '*' to update all rows.
702 *
703 * @param string $fname Caller function name
704 *
705 * @param string|array $options Query options
706 *
707 * Optional: Array of query options. Boolean options are specified by
708 * including them in the array as a string value with a numeric key, for
709 * example:
710 *
711 * [ 'FOR UPDATE' ]
712 *
713 * The supported options are:
714 *
715 * - OFFSET: Skip this many rows at the start of the result set. OFFSET
716 * with LIMIT can theoretically be used for paging through a result set,
717 * but this is discouraged for performance reasons.
718 *
719 * - LIMIT: Integer: return at most this many rows. The rows are sorted
720 * and then the first rows are taken until the limit is reached. LIMIT
721 * is applied to a result set after OFFSET.
722 *
723 * - FOR UPDATE: Boolean: lock the returned rows so that they can't be
724 * changed until the next COMMIT. Cannot be used with aggregate functions
725 * (COUNT, MAX, etc., but also DISTINCT).
726 *
727 * - DISTINCT: Boolean: return only unique result rows.
728 *
729 * - GROUP BY: May be either an SQL fragment string naming a field or
730 * expression to group by, or an array of such SQL fragments.
731 *
732 * - HAVING: May be either an string containing a HAVING clause or an array of
733 * conditions building the HAVING clause. If an array is given, the conditions
734 * constructed from each element are combined with AND.
735 *
736 * - ORDER BY: May be either an SQL fragment giving a field name or
737 * expression to order by, or an array of such SQL fragments.
738 *
739 * - USE INDEX: This may be either a string giving the index name to use
740 * for the query, or an array. If it is an associative array, each key
741 * gives the table name (or alias), each value gives the index name to
742 * use for that table. All strings are SQL fragments and so should be
743 * validated by the caller.
744 *
745 * - EXPLAIN: In MySQL, this causes an EXPLAIN SELECT query to be run,
746 * instead of SELECT.
747 *
748 * And also the following boolean MySQL extensions, see the MySQL manual
749 * for documentation:
750 *
751 * - LOCK IN SHARE MODE
752 * - STRAIGHT_JOIN
753 * - HIGH_PRIORITY
754 * - SQL_BIG_RESULT
755 * - SQL_BUFFER_RESULT
756 * - SQL_SMALL_RESULT
757 * - SQL_CALC_FOUND_ROWS
758 * - SQL_CACHE
759 * - SQL_NO_CACHE
760 *
761 *
762 * @param string|array $join_conds Join conditions
763 *
764 * Optional associative array of table-specific join conditions. In the
765 * most common case, this is unnecessary, since the join condition can be
766 * in $conds. However, it is useful for doing a LEFT JOIN.
767 *
768 * The key of the array contains the table name or alias. The value is an
769 * array with two elements, numbered 0 and 1. The first gives the type of
770 * join, the second is the same as the $conds parameter. Thus it can be
771 * an SQL fragment, or an array where the string keys are equality and the
772 * numeric keys are SQL fragments all AND'd together. For example:
773 *
774 * [ 'page' => [ 'LEFT JOIN', 'page_latest=rev_id' ] ]
775 *
776 * @return IResultWrapper Resulting rows
777 * @throws DBError
778 */
779 public function select(
780 $table, $vars, $conds = '', $fname = __METHOD__,
781 $options = [], $join_conds = []
782 );
783
784 /**
785 * The equivalent of IDatabase::select() except that the constructed SQL
786 * is returned, instead of being immediately executed. This can be useful for
787 * doing UNION queries, where the SQL text of each query is needed. In general,
788 * however, callers outside of Database classes should just use select().
789 *
790 * @see IDatabase::select()
791 *
792 * @param string|array $table Table name
793 * @param string|array $vars Field names
794 * @param string|array $conds Conditions
795 * @param string $fname Caller function name
796 * @param string|array $options Query options
797 * @param string|array $join_conds Join conditions
798 * @return string SQL query string
799 */
800 public function selectSQLText(
801 $table, $vars, $conds = '', $fname = __METHOD__,
802 $options = [], $join_conds = []
803 );
804
805 /**
806 * Single row SELECT wrapper. Equivalent to IDatabase::select(), except
807 * that a single row object is returned. If the query returns no rows,
808 * false is returned.
809 *
810 * @param string|array $table Table name
811 * @param string|array $vars Field names
812 * @param string|array $conds Conditions
813 * @param string $fname Caller function name
814 * @param string|array $options Query options
815 * @param array|string $join_conds Join conditions
816 *
817 * @return stdClass|bool
818 * @throws DBError
819 */
820 public function selectRow( $table, $vars, $conds, $fname = __METHOD__,
821 $options = [], $join_conds = []
822 );
823
824 /**
825 * Estimate the number of rows in dataset
826 *
827 * MySQL allows you to estimate the number of rows that would be returned
828 * by a SELECT query, using EXPLAIN SELECT. The estimate is provided using
829 * index cardinality statistics, and is notoriously inaccurate, especially
830 * when large numbers of rows have recently been added or deleted.
831 *
832 * For DBMSs that don't support fast result size estimation, this function
833 * will actually perform the SELECT COUNT(*).
834 *
835 * Takes the same arguments as IDatabase::select().
836 *
837 * @param string $table Table name
838 * @param string $var Column for which NULL values are not counted [default "*"]
839 * @param array|string $conds Filters on the table
840 * @param string $fname Function name for profiling
841 * @param array $options Options for select
842 * @param array|string $join_conds Join conditions
843 * @return int Row count
844 * @throws DBError
845 */
846 public function estimateRowCount(
847 $table, $var = '*', $conds = '', $fname = __METHOD__, $options = [], $join_conds = []
848 );
849
850 /**
851 * Get the number of rows in dataset
852 *
853 * This is useful when trying to do COUNT(*) but with a LIMIT for performance.
854 *
855 * Takes the same arguments as IDatabase::select().
856 *
857 * @since 1.27 Added $join_conds parameter
858 *
859 * @param array|string $tables Table names
860 * @param string $var Column for which NULL values are not counted [default "*"]
861 * @param array|string $conds Filters on the table
862 * @param string $fname Function name for profiling
863 * @param array $options Options for select
864 * @param array $join_conds Join conditions (since 1.27)
865 * @return int Row count
866 * @throws DBError
867 */
868 public function selectRowCount(
869 $tables, $var = '*', $conds = '', $fname = __METHOD__, $options = [], $join_conds = []
870 );
871
872 /**
873 * Lock all rows meeting the given conditions/options FOR UPDATE
874 *
875 * @param array|string $table Table names
876 * @param array|string $conds Filters on the table
877 * @param string $fname Function name for profiling
878 * @param array $options Options for select ("FOR UPDATE" is added automatically)
879 * @param array $join_conds Join conditions
880 * @return int Number of matching rows found (and locked)
881 * @since 1.32
882 */
883 public function lockForUpdate(
884 $table, $conds = '', $fname = __METHOD__, $options = [], $join_conds = []
885 );
886
887 /**
888 * Determines whether a field exists in a table
889 *
890 * @param string $table Table name
891 * @param string $field Filed to check on that table
892 * @param string $fname Calling function name (optional)
893 * @return bool Whether $table has filed $field
894 * @throws DBError
895 */
896 public function fieldExists( $table, $field, $fname = __METHOD__ );
897
898 /**
899 * Determines whether an index exists
900 * Usually throws a DBQueryError on failure
901 * If errors are explicitly ignored, returns NULL on failure
902 *
903 * @param string $table
904 * @param string $index
905 * @param string $fname
906 * @return bool|null
907 * @throws DBError
908 */
909 public function indexExists( $table, $index, $fname = __METHOD__ );
910
911 /**
912 * Query whether a given table exists
913 *
914 * @param string $table
915 * @param string $fname
916 * @return bool
917 * @throws DBError
918 */
919 public function tableExists( $table, $fname = __METHOD__ );
920
921 /**
922 * INSERT wrapper, inserts an array into a table.
923 *
924 * $a may be either:
925 *
926 * - A single associative array. The array keys are the field names, and
927 * the values are the values to insert. The values are treated as data
928 * and will be quoted appropriately. If NULL is inserted, this will be
929 * converted to a database NULL.
930 * - An array with numeric keys, holding a list of associative arrays.
931 * This causes a multi-row INSERT on DBMSs that support it. The keys in
932 * each subarray must be identical to each other, and in the same order.
933 *
934 * Usually throws a DBQueryError on failure. If errors are explicitly ignored,
935 * returns success.
936 *
937 * $options is an array of options, with boolean options encoded as values
938 * with numeric keys, in the same style as $options in
939 * IDatabase::select(). Supported options are:
940 *
941 * - IGNORE: Boolean: if present, duplicate key errors are ignored, and
942 * any rows which cause duplicate key errors are not inserted. It's
943 * possible to determine how many rows were successfully inserted using
944 * IDatabase::affectedRows().
945 *
946 * @param string $table Table name. This will be passed through
947 * Database::tableName().
948 * @param array $a Array of rows to insert
949 * @param string $fname Calling function name (use __METHOD__) for logs/profiling
950 * @param array $options Array of options
951 * @return bool Return true if no exception was thrown (deprecated since 1.33)
952 * @throws DBError
953 */
954 public function insert( $table, $a, $fname = __METHOD__, $options = [] );
955
956 /**
957 * UPDATE wrapper. Takes a condition array and a SET array.
958 *
959 * @param string $table Name of the table to UPDATE. This will be passed through
960 * Database::tableName().
961 * @param array $values An array of values to SET. For each array element,
962 * the key gives the field name, and the value gives the data to set
963 * that field to. The data will be quoted by IDatabase::addQuotes().
964 * Values with integer keys form unquoted SET statements, which can be used for
965 * things like "field = field + 1" or similar computed values.
966 * @param array $conds An array of conditions (WHERE). See
967 * IDatabase::select() for the details of the format of condition
968 * arrays. Use '*' to update all rows.
969 * @param string $fname The function name of the caller (from __METHOD__),
970 * for logging and profiling.
971 * @param array $options An array of UPDATE options, can be:
972 * - IGNORE: Ignore unique key conflicts
973 * - LOW_PRIORITY: MySQL-specific, see MySQL manual.
974 * @return bool Return true if no exception was thrown (deprecated since 1.33)
975 * @throws DBError
976 */
977 public function update( $table, $values, $conds, $fname = __METHOD__, $options = [] );
978
979 /**
980 * Makes an encoded list of strings from an array
981 *
982 * These can be used to make conjunctions or disjunctions on SQL condition strings
983 * derived from an array (see IDatabase::select() $conds documentation).
984 *
985 * Example usage:
986 * @code
987 * $sql = $db->makeList( [
988 * 'rev_page' => $id,
989 * $db->makeList( [ 'rev_minor' => 1, 'rev_len' < 500 ], $db::LIST_OR ] )
990 * ], $db::LIST_AND );
991 * @endcode
992 * This would set $sql to "rev_page = '$id' AND (rev_minor = '1' OR rev_len < '500')"
993 *
994 * @param array $a Containing the data
995 * @param int $mode IDatabase class constant:
996 * - IDatabase::LIST_COMMA: Comma separated, no field names
997 * - IDatabase::LIST_AND: ANDed WHERE clause (without the WHERE).
998 * - IDatabase::LIST_OR: ORed WHERE clause (without the WHERE)
999 * - IDatabase::LIST_SET: Comma separated with field names, like a SET clause
1000 * - IDatabase::LIST_NAMES: Comma separated field names
1001 * @throws DBError
1002 * @return string
1003 */
1004 public function makeList( $a, $mode = self::LIST_COMMA );
1005
1006 /**
1007 * Build a partial where clause from a 2-d array such as used for LinkBatch.
1008 * The keys on each level may be either integers or strings.
1009 *
1010 * @param array $data Organized as 2-d
1011 * [ baseKeyVal => [ subKeyVal => [ignored], ... ], ... ]
1012 * @param string $baseKey Field name to match the base-level keys to (eg 'pl_namespace')
1013 * @param string $subKey Field name to match the sub-level keys to (eg 'pl_title')
1014 * @return string|bool SQL fragment, or false if no items in array
1015 */
1016 public function makeWhereFrom2d( $data, $baseKey, $subKey );
1017
1018 /**
1019 * Return aggregated value alias
1020 *
1021 * @param array $valuedata
1022 * @param string $valuename
1023 *
1024 * @return string
1025 * @deprecated Since 1.33
1026 */
1027 public function aggregateValue( $valuedata, $valuename = 'value' );
1028
1029 /**
1030 * @param string $field
1031 * @return string
1032 */
1033 public function bitNot( $field );
1034
1035 /**
1036 * @param string $fieldLeft
1037 * @param string $fieldRight
1038 * @return string
1039 */
1040 public function bitAnd( $fieldLeft, $fieldRight );
1041
1042 /**
1043 * @param string $fieldLeft
1044 * @param string $fieldRight
1045 * @return string
1046 */
1047 public function bitOr( $fieldLeft, $fieldRight );
1048
1049 /**
1050 * Build a concatenation list to feed into a SQL query
1051 * @param array $stringList List of raw SQL expressions; caller is
1052 * responsible for any quoting
1053 * @return string
1054 */
1055 public function buildConcat( $stringList );
1056
1057 /**
1058 * Build a GROUP_CONCAT or equivalent statement for a query.
1059 *
1060 * This is useful for combining a field for several rows into a single string.
1061 * NULL values will not appear in the output, duplicated values will appear,
1062 * and the resulting delimiter-separated values have no defined sort order.
1063 * Code using the results may need to use the PHP unique() or sort() methods.
1064 *
1065 * @param string $delim Glue to bind the results together
1066 * @param string|array $table Table name
1067 * @param string $field Field name
1068 * @param string|array $conds Conditions
1069 * @param string|array $join_conds Join conditions
1070 * @return string SQL text
1071 * @since 1.23
1072 */
1073 public function buildGroupConcatField(
1074 $delim, $table, $field, $conds = '', $join_conds = []
1075 );
1076
1077 /**
1078 * Build a SUBSTRING function.
1079 *
1080 * Behavior for non-ASCII values is undefined.
1081 *
1082 * @param string $input Field name
1083 * @param int $startPosition Positive integer
1084 * @param int|null $length Non-negative integer length or null for no limit
1085 * @throws InvalidArgumentException
1086 * @return string SQL text
1087 * @since 1.31
1088 */
1089 public function buildSubString( $input, $startPosition, $length = null );
1090
1091 /**
1092 * @param string $field Field or column to cast
1093 * @return string
1094 * @since 1.28
1095 */
1096 public function buildStringCast( $field );
1097
1098 /**
1099 * @param string $field Field or column to cast
1100 * @return string
1101 * @since 1.31
1102 */
1103 public function buildIntegerCast( $field );
1104
1105 /**
1106 * Equivalent to IDatabase::selectSQLText() except wraps the result in Subqyery
1107 *
1108 * @see IDatabase::selectSQLText()
1109 *
1110 * @param string|array $table Table name
1111 * @param string|array $vars Field names
1112 * @param string|array $conds Conditions
1113 * @param string $fname Caller function name
1114 * @param string|array $options Query options
1115 * @param string|array $join_conds Join conditions
1116 * @return Subquery
1117 * @since 1.31
1118 */
1119 public function buildSelectSubquery(
1120 $table, $vars, $conds = '', $fname = __METHOD__,
1121 $options = [], $join_conds = []
1122 );
1123
1124 /**
1125 * Construct a LIMIT query with optional offset. This is used for query
1126 * pages. The SQL should be adjusted so that only the first $limit rows
1127 * are returned. If $offset is provided as well, then the first $offset
1128 * rows should be discarded, and the next $limit rows should be returned.
1129 * If the result of the query is not ordered, then the rows to be returned
1130 * are theoretically arbitrary.
1131 *
1132 * $sql is expected to be a SELECT, if that makes a difference.
1133 *
1134 * @param string $sql SQL query we will append the limit too
1135 * @param int $limit The SQL limit
1136 * @param int|bool $offset The SQL offset (default false)
1137 * @throws DBUnexpectedError
1138 * @return string
1139 * @since 1.34
1140 */
1141 public function limitResult( $sql, $limit, $offset = false );
1142
1143 /**
1144 * Returns true if DBs are assumed to be on potentially different servers
1145 *
1146 * In systems like mysql/mariadb, different databases can easily be referenced on a single
1147 * connection merely by name, even in a single query via JOIN. On the other hand, Postgres
1148 * treats databases as fully separate, only allowing mechanisms like postgres_fdw to
1149 * effectively "mount" foreign DBs. This is true even among DBs on the same server.
1150 *
1151 * @return bool
1152 * @since 1.29
1153 */
1154 public function databasesAreIndependent();
1155
1156 /**
1157 * Change the current database
1158 *
1159 * This should only be called by a load balancer or if the handle is not attached to one
1160 *
1161 * @param string $db
1162 * @return bool True unless an exception was thrown
1163 * @throws DBConnectionError If databasesAreIndependent() is true and an error occurs
1164 * @throws DBError
1165 * @deprecated Since 1.32 Use selectDomain() instead
1166 */
1167 public function selectDB( $db );
1168
1169 /**
1170 * Set the current domain (database, schema, and table prefix)
1171 *
1172 * This will throw an error for some database types if the database is unspecified
1173 *
1174 * This should only be called by a load balancer or if the handle is not attached to one
1175 *
1176 * @param string|DatabaseDomain $domain
1177 * @since 1.32
1178 * @throws DBConnectionError
1179 */
1180 public function selectDomain( $domain );
1181
1182 /**
1183 * Get the current DB name
1184 * @return string|null
1185 */
1186 public function getDBname();
1187
1188 /**
1189 * Get the server hostname or IP address
1190 * @return string
1191 */
1192 public function getServer();
1193
1194 /**
1195 * Adds quotes and backslashes.
1196 *
1197 * @param string|int|null|bool|Blob $s
1198 * @return string|int
1199 */
1200 public function addQuotes( $s );
1201
1202 /**
1203 * Quotes an identifier, in order to make user controlled input safe
1204 *
1205 * Depending on the database this will either be `backticks` or "double quotes"
1206 *
1207 * @param string $s
1208 * @return string
1209 * @since 1.33
1210 */
1211 public function addIdentifierQuotes( $s );
1212
1213 /**
1214 * LIKE statement wrapper, receives a variable-length argument list with
1215 * parts of pattern to match containing either string literals that will be
1216 * escaped or tokens returned by anyChar() or anyString(). Alternatively,
1217 * the function could be provided with an array of aforementioned
1218 * parameters.
1219 *
1220 * Example: $dbr->buildLike( 'My_page_title/', $dbr->anyString() ) returns
1221 * a LIKE clause that searches for subpages of 'My page title'.
1222 * Alternatively:
1223 * $pattern = [ 'My_page_title/', $dbr->anyString() ];
1224 * $query .= $dbr->buildLike( $pattern );
1225 *
1226 * @since 1.16
1227 * @param array[]|string|LikeMatch $param
1228 * @return string Fully built LIKE statement
1229 * @phan-suppress-next-line PhanMismatchVariadicComment
1230 * @phan-param array|string|LikeMatch ...$param T226223
1231 */
1232 public function buildLike( $param );
1233
1234 /**
1235 * Returns a token for buildLike() that denotes a '_' to be used in a LIKE query
1236 *
1237 * @return LikeMatch
1238 */
1239 public function anyChar();
1240
1241 /**
1242 * Returns a token for buildLike() that denotes a '%' to be used in a LIKE query
1243 *
1244 * @return LikeMatch
1245 */
1246 public function anyString();
1247
1248 /**
1249 * Deprecated method, calls should be removed.
1250 *
1251 * This was formerly used for PostgreSQL and Oracle to handle
1252 * self::insertId() auto-incrementing fields. It is no longer necessary
1253 * since DatabasePostgres::insertId() has been reimplemented using
1254 * `lastval()` and Oracle has been reimplemented using triggers.
1255 *
1256 * Implementations should return null if inserting `NULL` into an
1257 * auto-incrementing field works, otherwise it should return an instance of
1258 * NextSequenceValue and filter it on calls to relevant methods.
1259 *
1260 * @deprecated since 1.30, no longer needed
1261 * @param string $seqName
1262 * @return null|NextSequenceValue
1263 */
1264 public function nextSequenceValue( $seqName );
1265
1266 /**
1267 * REPLACE query wrapper.
1268 *
1269 * REPLACE is a very handy MySQL extension, which functions like an INSERT
1270 * except that when there is a duplicate key error, the old row is deleted
1271 * and the new row is inserted in its place.
1272 *
1273 * We simulate this with standard SQL with a DELETE followed by INSERT. To
1274 * perform the delete, we need to know what the unique indexes are so that
1275 * we know how to find the conflicting rows.
1276 *
1277 * It may be more efficient to leave off unique indexes which are unlikely
1278 * to collide. However if you do this, you run the risk of encountering
1279 * errors which wouldn't have occurred in MySQL.
1280 *
1281 * @param string $table The table to replace the row(s) in.
1282 * @param array[]|string[]|string $uniqueIndexes All unique indexes. One of the following:
1283 * a) the one unique field in the table (when no composite unique key exist)
1284 * b) a list of all unique fields in the table (when no composite unique key exist)
1285 * c) a list of all unique indexes in the table (each as a list of the indexed fields)
1286 * @param array $rows Can be either a single row to insert, or multiple rows,
1287 * in the same format as for IDatabase::insert()
1288 * @param string $fname Calling function name (use __METHOD__) for logs/profiling
1289 * @throws DBError
1290 */
1291 public function replace( $table, $uniqueIndexes, $rows, $fname = __METHOD__ );
1292
1293 /**
1294 * INSERT ON DUPLICATE KEY UPDATE wrapper, upserts an array into a table.
1295 *
1296 * This updates any conflicting rows (according to the unique indexes) using
1297 * the provided SET clause and inserts any remaining (non-conflicted) rows.
1298 *
1299 * $rows may be either:
1300 * - A single associative array. The array keys are the field names, and
1301 * the values are the values to insert. The values are treated as data
1302 * and will be quoted appropriately. If NULL is inserted, this will be
1303 * converted to a database NULL.
1304 * - An array with numeric keys, holding a list of associative arrays.
1305 * This causes a multi-row INSERT on DBMSs that support it. The keys in
1306 * each subarray must be identical to each other, and in the same order.
1307 *
1308 * It may be more efficient to leave off unique indexes which are unlikely
1309 * to collide. However if you do this, you run the risk of encountering
1310 * errors which wouldn't have occurred in MySQL.
1311 *
1312 * Usually throws a DBQueryError on failure. If errors are explicitly ignored,
1313 * returns success.
1314 *
1315 * @since 1.22
1316 *
1317 * @param string $table Table name. This will be passed through Database::tableName().
1318 * @param array $rows A single row or list of rows to insert
1319 * @param array[]|string[]|string $uniqueIndexes All unique indexes. One of the following:
1320 * a) the one unique field in the table (when no composite unique key exist)
1321 * b) a list of all unique fields in the table (when no composite unique key exist)
1322 * c) a list of all unique indexes in the table (each as a list of the indexed fields)
1323 * @param array $set An array of values to SET. For each array element, the
1324 * key gives the field name, and the value gives the data to set that
1325 * field to. The data will be quoted by IDatabase::addQuotes().
1326 * Values with integer keys form unquoted SET statements, which can be used for
1327 * things like "field = field + 1" or similar computed values.
1328 * @param string $fname Calling function name (use __METHOD__) for logs/profiling
1329 * @throws DBError
1330 * @return bool Return true if no exception was thrown (deprecated since 1.33)
1331 */
1332 public function upsert(
1333 $table, array $rows, $uniqueIndexes, array $set, $fname = __METHOD__
1334 );
1335
1336 /**
1337 * DELETE where the condition is a join.
1338 *
1339 * MySQL overrides this to use a multi-table DELETE syntax, in other databases
1340 * we use sub-selects
1341 *
1342 * For safety, an empty $conds will not delete everything. If you want to
1343 * delete all rows where the join condition matches, set $conds='*'.
1344 *
1345 * DO NOT put the join condition in $conds.
1346 *
1347 * @param string $delTable The table to delete from.
1348 * @param string $joinTable The other table.
1349 * @param string $delVar The variable to join on, in the first table.
1350 * @param string $joinVar The variable to join on, in the second table.
1351 * @param array $conds Condition array of field names mapped to variables,
1352 * ANDed together in the WHERE clause
1353 * @param string $fname Calling function name (use __METHOD__) for logs/profiling
1354 * @throws DBError
1355 */
1356 public function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds,
1357 $fname = __METHOD__
1358 );
1359
1360 /**
1361 * DELETE query wrapper.
1362 *
1363 * @param string $table Table name
1364 * @param string|array $conds Array of conditions. See $conds in IDatabase::select()
1365 * for the format. Use $conds == "*" to delete all rows
1366 * @param string $fname Name of the calling function
1367 * @throws DBUnexpectedError
1368 * @return bool Return true if no exception was thrown (deprecated since 1.33)
1369 * @throws DBError
1370 */
1371 public function delete( $table, $conds, $fname = __METHOD__ );
1372
1373 /**
1374 * INSERT SELECT wrapper. Takes data from a SELECT query and inserts it
1375 * into another table.
1376 *
1377 * @warning If the insert will use an auto-increment or sequence to
1378 * determine the value of a column, this may break replication on
1379 * databases using statement-based replication if the SELECT is not
1380 * deterministically ordered.
1381 *
1382 * @param string $destTable The table name to insert into
1383 * @param string|array $srcTable May be either a table name, or an array of table names
1384 * to include in a join.
1385 *
1386 * @param array $varMap Must be an associative array of the form
1387 * [ 'dest1' => 'source1', ... ]. Source items may be literals
1388 * rather than field names, but strings should be quoted with
1389 * IDatabase::addQuotes()
1390 *
1391 * @param array $conds Condition array. See $conds in IDatabase::select() for
1392 * the details of the format of condition arrays. May be "*" to copy the
1393 * whole table.
1394 *
1395 * @param string $fname The function name of the caller, from __METHOD__
1396 *
1397 * @param array $insertOptions Options for the INSERT part of the query, see
1398 * IDatabase::insert() for details. Also, one additional option is
1399 * available: pass 'NO_AUTO_COLUMNS' to hint that the query does not use
1400 * an auto-increment or sequence to determine any column values.
1401 * @param array $selectOptions Options for the SELECT part of the query, see
1402 * IDatabase::select() for details.
1403 * @param array $selectJoinConds Join conditions for the SELECT part of the query, see
1404 * IDatabase::select() for details.
1405 *
1406 * @return bool Return true if no exception was thrown (deprecated since 1.33)
1407 * @throws DBError
1408 */
1409 public function insertSelect( $destTable, $srcTable, $varMap, $conds,
1410 $fname = __METHOD__,
1411 $insertOptions = [], $selectOptions = [], $selectJoinConds = []
1412 );
1413
1414 /**
1415 * Returns true if current database backend supports ORDER BY or LIMIT for separate subqueries
1416 * within the UNION construct.
1417 * @return bool
1418 */
1419 public function unionSupportsOrderAndLimit();
1420
1421 /**
1422 * Construct a UNION query
1423 * This is used for providing overload point for other DB abstractions
1424 * not compatible with the MySQL syntax.
1425 * @param array $sqls SQL statements to combine
1426 * @param bool $all Either IDatabase::UNION_ALL or IDatabase::UNION_DISTINCT
1427 * @return string SQL fragment
1428 */
1429 public function unionQueries( $sqls, $all );
1430
1431 /**
1432 * Construct a UNION query for permutations of conditions
1433 *
1434 * Databases sometimes have trouble with queries that have multiple values
1435 * for multiple condition parameters combined with limits and ordering.
1436 * This method constructs queries for the Cartesian product of the
1437 * conditions and unions them all together.
1438 *
1439 * @see IDatabase::select()
1440 * @since 1.30
1441 * @param string|array $table Table name
1442 * @param string|array $vars Field names
1443 * @param array $permute_conds Conditions for the Cartesian product. Keys
1444 * are field names, values are arrays of the possible values for that
1445 * field.
1446 * @param string|array $extra_conds Additional conditions to include in the
1447 * query.
1448 * @param string $fname Caller function name
1449 * @param string|array $options Query options. In addition to the options
1450 * recognized by IDatabase::select(), the following may be used:
1451 * - NOTALL: Set to use UNION instead of UNION ALL.
1452 * - INNER ORDER BY: If specified and supported, subqueries will use this
1453 * instead of ORDER BY.
1454 * @param string|array $join_conds Join conditions
1455 * @return string SQL query string.
1456 */
1457 public function unionConditionPermutations(
1458 $table, $vars, array $permute_conds, $extra_conds = '', $fname = __METHOD__,
1459 $options = [], $join_conds = []
1460 );
1461
1462 /**
1463 * Returns an SQL expression for a simple conditional. This doesn't need
1464 * to be overridden unless CASE isn't supported in your DBMS.
1465 *
1466 * @param string|array $cond SQL expression which will result in a boolean value
1467 * @param string $trueVal SQL expression to return if true
1468 * @param string $falseVal SQL expression to return if false
1469 * @return string SQL fragment
1470 */
1471 public function conditional( $cond, $trueVal, $falseVal );
1472
1473 /**
1474 * Returns a command for str_replace function in SQL query.
1475 * Uses REPLACE() in MySQL
1476 *
1477 * @param string $orig Column to modify
1478 * @param string $old Column to seek
1479 * @param string $new Column to replace with
1480 *
1481 * @return string
1482 */
1483 public function strreplace( $orig, $old, $new );
1484
1485 /**
1486 * Determines how long the server has been up
1487 *
1488 * @return int
1489 * @throws DBError
1490 */
1491 public function getServerUptime();
1492
1493 /**
1494 * Determines if the last failure was due to a deadlock
1495 *
1496 * Note that during a deadlock, the prior transaction will have been lost
1497 *
1498 * @return bool
1499 */
1500 public function wasDeadlock();
1501
1502 /**
1503 * Determines if the last failure was due to a lock timeout
1504 *
1505 * Note that during a lock wait timeout, the prior transaction will have been lost
1506 *
1507 * @return bool
1508 */
1509 public function wasLockTimeout();
1510
1511 /**
1512 * Determines if the last query error was due to a dropped connection
1513 *
1514 * Note that during a connection loss, the prior transaction will have been lost
1515 *
1516 * @return bool
1517 * @since 1.31
1518 */
1519 public function wasConnectionLoss();
1520
1521 /**
1522 * Determines if the last failure was due to the database being read-only.
1523 *
1524 * @return bool
1525 */
1526 public function wasReadOnlyError();
1527
1528 /**
1529 * Determines if the last query error was due to something outside of the query itself
1530 *
1531 * Note that the transaction may have been lost, discarding prior writes and results
1532 *
1533 * @return bool
1534 */
1535 public function wasErrorReissuable();
1536
1537 /**
1538 * Wait for the replica DB to catch up to a given master position
1539 *
1540 * Note that this does not start any new transactions. If any existing transaction
1541 * is flushed, and this is called, then queries will reflect the point the DB was synced
1542 * up to (on success) without interference from REPEATABLE-READ snapshots.
1543 *
1544 * @param DBMasterPos $pos
1545 * @param int $timeout The maximum number of seconds to wait for synchronisation
1546 * @return int|null Zero if the replica DB was past that position already,
1547 * greater than zero if we waited for some period of time, less than
1548 * zero if it timed out, and null on error
1549 * @throws DBError
1550 */
1551 public function masterPosWait( DBMasterPos $pos, $timeout );
1552
1553 /**
1554 * Get the replication position of this replica DB
1555 *
1556 * @return DBMasterPos|bool False if this is not a replica DB
1557 * @throws DBError
1558 */
1559 public function getReplicaPos();
1560
1561 /**
1562 * Get the position of this master
1563 *
1564 * @return DBMasterPos|bool False if this is not a master
1565 * @throws DBError
1566 */
1567 public function getMasterPos();
1568
1569 /**
1570 * @return bool Whether the DB is marked as read-only server-side
1571 * @since 1.28
1572 */
1573 public function serverIsReadOnly();
1574
1575 /**
1576 * Run a callback as soon as the current transaction commits or rolls back.
1577 * An error is thrown if no transaction is pending. Queries in the function will run in
1578 * AUTOCOMMIT mode unless there are begin() calls. Callbacks must commit any transactions
1579 * that they begin.
1580 *
1581 * This is useful for combining cooperative locks and DB transactions.
1582 *
1583 * Note this is called when the whole transaction is resolved. To take action immediately
1584 * when an atomic section is cancelled, use onAtomicSectionCancel().
1585 *
1586 * @note do not assume that *other* IDatabase instances will be AUTOCOMMIT mode
1587 *
1588 * The callback takes the following arguments:
1589 * - How the transaction ended (IDatabase::TRIGGER_COMMIT or IDatabase::TRIGGER_ROLLBACK)
1590 * - This IDatabase instance (since 1.32)
1591 *
1592 * @param callable $callback
1593 * @param string $fname Caller name
1594 * @since 1.28
1595 */
1596 public function onTransactionResolution( callable $callback, $fname = __METHOD__ );
1597
1598 /**
1599 * Run a callback as soon as there is no transaction pending.
1600 * If there is a transaction and it is rolled back, then the callback is cancelled.
1601 *
1602 * When transaction round mode (DBO_TRX) is set, the callback will run at the end
1603 * of the round, just after all peer transactions COMMIT. If the transaction round
1604 * is rolled back, then the callback is cancelled.
1605 *
1606 * Queries in the function will run in AUTOCOMMIT mode unless there are begin() calls.
1607 * Callbacks must commit any transactions that they begin.
1608 *
1609 * This is useful for updates to different systems or when separate transactions are needed.
1610 * For example, one might want to enqueue jobs into a system outside the database, but only
1611 * after the database is updated so that the jobs will see the data when they actually run.
1612 * It can also be used for updates that easily suffer from lock timeouts and deadlocks,
1613 * but where atomicity is not essential.
1614 *
1615 * Avoid using IDatabase instances aside from this one in the callback, unless such instances
1616 * never have IDatabase::DBO_TRX set. This keeps callbacks from interfering with one another.
1617 *
1618 * Updates will execute in the order they were enqueued.
1619 *
1620 * @note do not assume that *other* IDatabase instances will be AUTOCOMMIT mode
1621 *
1622 * The callback takes the following arguments:
1623 * - How the transaction ended (IDatabase::TRIGGER_COMMIT or IDatabase::TRIGGER_IDLE)
1624 * - This IDatabase instance (since 1.32)
1625 *
1626 * @param callable $callback
1627 * @param string $fname Caller name
1628 * @since 1.32
1629 */
1630 public function onTransactionCommitOrIdle( callable $callback, $fname = __METHOD__ );
1631
1632 /**
1633 * Alias for onTransactionCommitOrIdle() for backwards-compatibility
1634 *
1635 * @param callable $callback
1636 * @param string $fname
1637 * @since 1.20
1638 * @deprecated Since 1.32
1639 */
1640 public function onTransactionIdle( callable $callback, $fname = __METHOD__ );
1641
1642 /**
1643 * Run a callback before the current transaction commits or now if there is none.
1644 * If there is a transaction and it is rolled back, then the callback is cancelled.
1645 *
1646 * When transaction round mode (DBO_TRX) is set, the callback will run at the end
1647 * of the round, just before all peer transactions COMMIT. If the transaction round
1648 * is rolled back, then the callback is cancelled.
1649 *
1650 * Callbacks must not start nor commit any transactions. If no transaction is active,
1651 * then a transaction will wrap the callback.
1652 *
1653 * This is useful for updates that easily suffer from lock timeouts and deadlocks,
1654 * but where atomicity is strongly desired for these updates and some related updates.
1655 *
1656 * Updates will execute in the order they were enqueued.
1657 *
1658 * The callback takes the one argument:
1659 * - This IDatabase instance (since 1.32)
1660 *
1661 * @param callable $callback
1662 * @param string $fname Caller name
1663 * @since 1.22
1664 */
1665 public function onTransactionPreCommitOrIdle( callable $callback, $fname = __METHOD__ );
1666
1667 /**
1668 * Run a callback when the atomic section is cancelled.
1669 *
1670 * The callback is run just after the current atomic section, any outer
1671 * atomic section, or the whole transaction is rolled back.
1672 *
1673 * An error is thrown if no atomic section is pending. The atomic section
1674 * need not have been created with the ATOMIC_CANCELABLE flag.
1675 *
1676 * Queries in the function may be running in the context of an outer
1677 * transaction or may be running in AUTOCOMMIT mode. The callback should
1678 * use atomic sections if necessary.
1679 *
1680 * @note do not assume that *other* IDatabase instances will be AUTOCOMMIT mode
1681 *
1682 * The callback takes the following arguments:
1683 * - IDatabase::TRIGGER_CANCEL or IDatabase::TRIGGER_ROLLBACK
1684 * - This IDatabase instance
1685 *
1686 * @param callable $callback
1687 * @param string $fname Caller name
1688 * @since 1.34
1689 */
1690 public function onAtomicSectionCancel( callable $callback, $fname = __METHOD__ );
1691
1692 /**
1693 * Run a callback after each time any transaction commits or rolls back
1694 *
1695 * The callback takes two arguments:
1696 * - IDatabase::TRIGGER_COMMIT or IDatabase::TRIGGER_ROLLBACK
1697 * - This IDatabase object
1698 * Callbacks must commit any transactions that they begin.
1699 *
1700 * Registering a callback here will not affect writesOrCallbacks() pending.
1701 *
1702 * Since callbacks from this or onTransactionCommitOrIdle() can start and end transactions,
1703 * a single call to IDatabase::commit might trigger multiple runs of the listener callbacks.
1704 *
1705 * @param string $name Callback name
1706 * @param callable|null $callback Use null to unset a listener
1707 * @since 1.28
1708 */
1709 public function setTransactionListener( $name, callable $callback = null );
1710
1711 /**
1712 * Begin an atomic section of SQL statements
1713 *
1714 * Start an implicit transaction if no transaction is already active, set a savepoint
1715 * (if $cancelable is ATOMIC_CANCELABLE), and track the given section name to enforce
1716 * that the transaction is not committed prematurely. The end of the section must be
1717 * signified exactly once, either by endAtomic() or cancelAtomic(). Sections can have
1718 * have layers of inner sections (sub-sections), but all sections must be ended in order
1719 * of innermost to outermost. Transactions cannot be started or committed until all
1720 * atomic sections are closed.
1721 *
1722 * ATOMIC_CANCELABLE is useful when the caller needs to handle specific failure cases
1723 * by discarding the section's writes. This should not be used for failures when:
1724 * - upsert() could easily be used instead
1725 * - insert() with IGNORE could easily be used instead
1726 * - select() with FOR UPDATE could be checked before issuing writes instead
1727 * - The failure is from code that runs after the first write but doesn't need to
1728 * - The failures are from contention solvable via onTransactionPreCommitOrIdle()
1729 * - The failures are deadlocks; the RDBMs usually discard the whole transaction
1730 *
1731 * @note callers must use additional measures for situations involving two or more
1732 * (peer) transactions (e.g. updating two database servers at once). The transaction
1733 * and savepoint logic of this method only applies to this specific IDatabase instance.
1734 *
1735 * Example usage:
1736 * @code
1737 * // Start a transaction if there isn't one already
1738 * $dbw->startAtomic( __METHOD__ );
1739 * // Serialize these thread table updates
1740 * $dbw->select( 'thread', '1', [ 'td_id' => $tid ], __METHOD__, 'FOR UPDATE' );
1741 * // Add a new comment for the thread
1742 * $dbw->insert( 'comment', $row, __METHOD__ );
1743 * $cid = $db->insertId();
1744 * // Update thread reference to last comment
1745 * $dbw->update( 'thread', [ 'td_latest' => $cid ], [ 'td_id' => $tid ], __METHOD__ );
1746 * // Demark the end of this conceptual unit of updates
1747 * $dbw->endAtomic( __METHOD__ );
1748 * @endcode
1749 *
1750 * Example usage (atomic changes that might have to be discarded):
1751 * @code
1752 * // Start a transaction if there isn't one already
1753 * $sectionId = $dbw->startAtomic( __METHOD__, $dbw::ATOMIC_CANCELABLE );
1754 * // Create new record metadata row
1755 * $dbw->insert( 'records', $row, __METHOD__ );
1756 * // Figure out where to store the data based on the new row's ID
1757 * $path = $recordDirectory . '/' . $dbw->insertId();
1758 * // Write the record data to the storage system
1759 * $status = $fileBackend->create( [ 'dst' => $path, 'content' => $data ] );
1760 * if ( $status->isOK() ) {
1761 * // Try to cleanup files orphaned by transaction rollback
1762 * $dbw->onTransactionResolution(
1763 * function ( $type ) use ( $fileBackend, $path ) {
1764 * if ( $type === IDatabase::TRIGGER_ROLLBACK ) {
1765 * $fileBackend->delete( [ 'src' => $path ] );
1766 * }
1767 * },
1768 * __METHOD__
1769 * );
1770 * // Demark the end of this conceptual unit of updates
1771 * $dbw->endAtomic( __METHOD__ );
1772 * } else {
1773 * // Discard these writes from the transaction (preserving prior writes)
1774 * $dbw->cancelAtomic( __METHOD__, $sectionId );
1775 * }
1776 * @endcode
1777 *
1778 * @since 1.23
1779 * @param string $fname
1780 * @param string $cancelable Pass self::ATOMIC_CANCELABLE to use a
1781 * savepoint and enable self::cancelAtomic() for this section.
1782 * @return AtomicSectionIdentifier section ID token
1783 * @throws DBError
1784 */
1785 public function startAtomic( $fname = __METHOD__, $cancelable = self::ATOMIC_NOT_CANCELABLE );
1786
1787 /**
1788 * Ends an atomic section of SQL statements
1789 *
1790 * Ends the next section of atomic SQL statements and commits the transaction
1791 * if necessary.
1792 *
1793 * @since 1.23
1794 * @see IDatabase::startAtomic
1795 * @param string $fname
1796 * @throws DBError
1797 */
1798 public function endAtomic( $fname = __METHOD__ );
1799
1800 /**
1801 * Cancel an atomic section of SQL statements
1802 *
1803 * This will roll back only the statements executed since the start of the
1804 * most recent atomic section, and close that section. If a transaction was
1805 * open before the corresponding startAtomic() call, any statements before
1806 * that call are *not* rolled back and the transaction remains open. If the
1807 * corresponding startAtomic() implicitly started a transaction, that
1808 * transaction is rolled back.
1809 *
1810 * @note callers must use additional measures for situations involving two or more
1811 * (peer) transactions (e.g. updating two database servers at once). The transaction
1812 * and savepoint logic of startAtomic() are bound to specific IDatabase instances.
1813 *
1814 * Note that a call to IDatabase::rollback() will also roll back any open atomic sections.
1815 *
1816 * @note As a micro-optimization to save a few DB calls, this method may only
1817 * be called when startAtomic() was called with the ATOMIC_CANCELABLE flag.
1818 * @since 1.31
1819 * @see IDatabase::startAtomic
1820 * @param string $fname
1821 * @param AtomicSectionIdentifier|null $sectionId Section ID from startAtomic();
1822 * passing this enables cancellation of unclosed nested sections [optional]
1823 * @throws DBError
1824 */
1825 public function cancelAtomic( $fname = __METHOD__, AtomicSectionIdentifier $sectionId = null );
1826
1827 /**
1828 * Perform an atomic section of reversable SQL statements from a callback
1829 *
1830 * The $callback takes the following arguments:
1831 * - This database object
1832 * - The value of $fname
1833 *
1834 * This will execute the callback inside a pair of startAtomic()/endAtomic() calls.
1835 * If any exception occurs during execution of the callback, it will be handled as follows:
1836 * - If $cancelable is ATOMIC_CANCELABLE, cancelAtomic() will be called to back out any
1837 * (and only) statements executed during the atomic section. If that succeeds, then the
1838 * exception will be re-thrown; if it fails, then a different exception will be thrown
1839 * and any further query attempts will fail until rollback() is called.
1840 * - If $cancelable is ATOMIC_NOT_CANCELABLE, cancelAtomic() will be called to mark the
1841 * end of the section and the error will be re-thrown. Any further query attempts will
1842 * fail until rollback() is called.
1843 *
1844 * This method is convenient for letting calls to the caller of this method be wrapped
1845 * in a try/catch blocks for exception types that imply that the caller failed but was
1846 * able to properly discard the changes it made in the transaction. This method can be
1847 * an alternative to explicit calls to startAtomic()/endAtomic()/cancelAtomic().
1848 *
1849 * Example usage, "RecordStore::save" method:
1850 * @code
1851 * $dbw->doAtomicSection( __METHOD__, function ( $dbw ) use ( $record ) {
1852 * // Create new record metadata row
1853 * $dbw->insert( 'records', $record->toArray(), __METHOD__ );
1854 * // Figure out where to store the data based on the new row's ID
1855 * $path = $this->recordDirectory . '/' . $dbw->insertId();
1856 * // Write the record data to the storage system;
1857 * // blob store throughs StoreFailureException on failure
1858 * $this->blobStore->create( $path, $record->getJSON() );
1859 * // Try to cleanup files orphaned by transaction rollback
1860 * $dbw->onTransactionResolution(
1861 * function ( $type ) use ( $path ) {
1862 * if ( $type === IDatabase::TRIGGER_ROLLBACK ) {
1863 * $this->blobStore->delete( $path );
1864 * }
1865 * },
1866 * __METHOD__
1867 * );
1868 * }, $dbw::ATOMIC_CANCELABLE );
1869 * @endcode
1870 *
1871 * Example usage, caller of the "RecordStore::save" method:
1872 * @code
1873 * $dbw->startAtomic( __METHOD__ );
1874 * // ...various SQL writes happen...
1875 * try {
1876 * $recordStore->save( $record );
1877 * } catch ( StoreFailureException $e ) {
1878 * // ...various SQL writes happen...
1879 * }
1880 * // ...various SQL writes happen...
1881 * $dbw->endAtomic( __METHOD__ );
1882 * @endcode
1883 *
1884 * @see Database::startAtomic
1885 * @see Database::endAtomic
1886 * @see Database::cancelAtomic
1887 *
1888 * @param string $fname Caller name (usually __METHOD__)
1889 * @param callable $callback Callback that issues DB updates
1890 * @param string $cancelable Pass self::ATOMIC_CANCELABLE to use a
1891 * savepoint and enable self::cancelAtomic() for this section.
1892 * @return mixed $res Result of the callback (since 1.28)
1893 * @throws DBError
1894 * @throws RuntimeException
1895 * @since 1.27; prior to 1.31 this did a rollback() instead of
1896 * cancelAtomic(), and assumed no callers up the stack would ever try to
1897 * catch the exception.
1898 */
1899 public function doAtomicSection(
1900 $fname, callable $callback, $cancelable = self::ATOMIC_NOT_CANCELABLE
1901 );
1902
1903 /**
1904 * Begin a transaction. If a transaction is already in progress,
1905 * that transaction will be committed before the new transaction is started.
1906 *
1907 * Only call this from code with outer transcation scope.
1908 * See https://www.mediawiki.org/wiki/Database_transactions for details.
1909 * Nesting of transactions is not supported.
1910 *
1911 * Note that when the DBO_TRX flag is set (which is usually the case for web
1912 * requests, but not for maintenance scripts), any previous database query
1913 * will have started a transaction automatically.
1914 *
1915 * Nesting of transactions is not supported. Attempts to nest transactions
1916 * will cause a warning, unless the current transaction was started
1917 * automatically because of the DBO_TRX flag.
1918 *
1919 * @param string $fname Calling function name
1920 * @param string $mode A situationally valid IDatabase::TRANSACTION_* constant [optional]
1921 * @throws DBError
1922 */
1923 public function begin( $fname = __METHOD__, $mode = self::TRANSACTION_EXPLICIT );
1924
1925 /**
1926 * Commits a transaction previously started using begin().
1927 * If no transaction is in progress, a warning is issued.
1928 *
1929 * Only call this from code with outer transcation scope.
1930 * See https://www.mediawiki.org/wiki/Database_transactions for details.
1931 * Nesting of transactions is not supported.
1932 *
1933 * @param string $fname
1934 * @param string $flush Flush flag, set to situationally valid IDatabase::FLUSHING_*
1935 * constant to disable warnings about explicitly committing implicit transactions,
1936 * or calling commit when no transaction is in progress.
1937 *
1938 * This will trigger an exception if there is an ongoing explicit transaction.
1939 *
1940 * Only set the flush flag if you are sure that these warnings are not applicable,
1941 * and no explicit transactions are open.
1942 *
1943 * @throws DBError
1944 */
1945 public function commit( $fname = __METHOD__, $flush = self::FLUSHING_ONE );
1946
1947 /**
1948 * Rollback a transaction previously started using begin().
1949 * If no transaction is in progress, a warning is issued.
1950 *
1951 * Only call this from code with outer transcation scope.
1952 * See https://www.mediawiki.org/wiki/Database_transactions for details.
1953 * Nesting of transactions is not supported. If a serious unexpected error occurs,
1954 * throwing an Exception is preferrable, using a pre-installed error handler to trigger
1955 * rollback (in any case, failure to issue COMMIT will cause rollback server-side).
1956 *
1957 * Query, connection, and onTransaction* callback errors will be suppressed and logged.
1958 *
1959 * @param string $fname Calling function name
1960 * @param string $flush Flush flag, set to a situationally valid IDatabase::FLUSHING_*
1961 * constant to disable warnings about calling rollback when no transaction is in
1962 * progress. This will silently break any ongoing explicit transaction. Only set the
1963 * flush flag if you are sure that it is safe to ignore these warnings in your context.
1964 * @throws DBError
1965 * @since 1.23 Added $flush parameter
1966 */
1967 public function rollback( $fname = __METHOD__, $flush = self::FLUSHING_ONE );
1968
1969 /**
1970 * Commit any transaction but error out if writes or callbacks are pending
1971 *
1972 * This is intended for clearing out REPEATABLE-READ snapshots so that callers can
1973 * see a new point-in-time of the database. This is useful when one of many transaction
1974 * rounds finished and significant time will pass in the script's lifetime. It is also
1975 * useful to call on a replica DB after waiting on replication to catch up to the master.
1976 *
1977 * @param string $fname Calling function name
1978 * @param string $flush Flush flag, set to situationally valid IDatabase::FLUSHING_*
1979 * constant to disable warnings about explicitly committing implicit transactions,
1980 * or calling commit when no transaction is in progress.
1981 *
1982 * This will trigger an exception if there is an ongoing explicit transaction.
1983 *
1984 * Only set the flush flag if you are sure that these warnings are not applicable,
1985 * and no explicit transactions are open.
1986 *
1987 * @throws DBError
1988 * @since 1.28
1989 * @since 1.34 Added $flush parameter
1990 */
1991 public function flushSnapshot( $fname = __METHOD__, $flush = self::FLUSHING_ONE );
1992
1993 /**
1994 * Convert a timestamp in one of the formats accepted by wfTimestamp()
1995 * to the format used for inserting into timestamp fields in this DBMS.
1996 *
1997 * The result is unquoted, and needs to be passed through addQuotes()
1998 * before it can be included in raw SQL.
1999 *
2000 * @param string|int $ts
2001 *
2002 * @return string
2003 */
2004 public function timestamp( $ts = 0 );
2005
2006 /**
2007 * Convert a timestamp in one of the formats accepted by wfTimestamp()
2008 * to the format used for inserting into timestamp fields in this DBMS. If
2009 * NULL is input, it is passed through, allowing NULL values to be inserted
2010 * into timestamp fields.
2011 *
2012 * The result is unquoted, and needs to be passed through addQuotes()
2013 * before it can be included in raw SQL.
2014 *
2015 * @param string|int|null $ts
2016 *
2017 * @return string
2018 */
2019 public function timestampOrNull( $ts = null );
2020
2021 /**
2022 * Ping the server and try to reconnect if it there is no connection
2023 *
2024 * @param float|null &$rtt Value to store the estimated RTT [optional]
2025 * @return bool Success or failure
2026 */
2027 public function ping( &$rtt = null );
2028
2029 /**
2030 * Get the amount of replication lag for this database server
2031 *
2032 * Callers should avoid using this method while a transaction is active
2033 *
2034 * @return int|bool Database replication lag in seconds or false on error
2035 * @throws DBError
2036 */
2037 public function getLag();
2038
2039 /**
2040 * Get the replica DB lag when the current transaction started
2041 * or a general lag estimate if not transaction is active
2042 *
2043 * This is useful when transactions might use snapshot isolation
2044 * (e.g. REPEATABLE-READ in innodb), so the "real" lag of that data
2045 * is this lag plus transaction duration. If they don't, it is still
2046 * safe to be pessimistic. In AUTOCOMMIT mode, this still gives an
2047 * indication of the staleness of subsequent reads.
2048 *
2049 * @return array ('lag': seconds or false on error, 'since': UNIX timestamp of BEGIN)
2050 * @throws DBError
2051 * @since 1.27
2052 */
2053 public function getSessionLagStatus();
2054
2055 /**
2056 * Return the maximum number of items allowed in a list, or 0 for unlimited.
2057 *
2058 * @return int
2059 */
2060 public function maxListLen();
2061
2062 /**
2063 * Some DBMSs have a special format for inserting into blob fields, they
2064 * don't allow simple quoted strings to be inserted. To insert into such
2065 * a field, pass the data through this function before passing it to
2066 * IDatabase::insert().
2067 *
2068 * @param string $b
2069 * @return string|Blob
2070 */
2071 public function encodeBlob( $b );
2072
2073 /**
2074 * Some DBMSs return a special placeholder object representing blob fields
2075 * in result objects. Pass the object through this function to return the
2076 * original string.
2077 *
2078 * @param string|Blob $b
2079 * @return string
2080 */
2081 public function decodeBlob( $b );
2082
2083 /**
2084 * Override database's default behavior. $options include:
2085 * 'connTimeout' : Set the connection timeout value in seconds.
2086 * May be useful for very long batch queries such as
2087 * full-wiki dumps, where a single query reads out over
2088 * hours or days.
2089 *
2090 * @param array $options
2091 * @return void
2092 * @throws DBError
2093 */
2094 public function setSessionOptions( array $options );
2095
2096 /**
2097 * Set variables to be used in sourceFile/sourceStream, in preference to the
2098 * ones in $GLOBALS. If an array is set here, $GLOBALS will not be used at
2099 * all. If it's set to false, $GLOBALS will be used.
2100 *
2101 * @param bool|array $vars Mapping variable name to value.
2102 */
2103 public function setSchemaVars( $vars );
2104
2105 /**
2106 * Check to see if a named lock is not locked by any thread (non-blocking)
2107 *
2108 * @param string $lockName Name of lock to poll
2109 * @param string $method Name of method calling us
2110 * @return bool
2111 * @throws DBError
2112 * @since 1.20
2113 */
2114 public function lockIsFree( $lockName, $method );
2115
2116 /**
2117 * Acquire a named lock
2118 *
2119 * Named locks are not related to transactions
2120 *
2121 * @param string $lockName Name of lock to aquire
2122 * @param string $method Name of the calling method
2123 * @param int $timeout Acquisition timeout in seconds (0 means non-blocking)
2124 * @return bool
2125 * @throws DBError
2126 */
2127 public function lock( $lockName, $method, $timeout = 5 );
2128
2129 /**
2130 * Release a lock
2131 *
2132 * Named locks are not related to transactions
2133 *
2134 * @param string $lockName Name of lock to release
2135 * @param string $method Name of the calling method
2136 *
2137 * @return int Returns 1 if the lock was released, 0 if the lock was not established
2138 * by this thread (in which case the lock is not released), and NULL if the named lock
2139 * did not exist
2140 *
2141 * @throws DBError
2142 */
2143 public function unlock( $lockName, $method );
2144
2145 /**
2146 * Acquire a named lock, flush any transaction, and return an RAII style unlocker object
2147 *
2148 * Only call this from outer transcation scope and when only one DB will be affected.
2149 * See https://www.mediawiki.org/wiki/Database_transactions for details.
2150 *
2151 * This is suitiable for transactions that need to be serialized using cooperative locks,
2152 * where each transaction can see each others' changes. Any transaction is flushed to clear
2153 * out stale REPEATABLE-READ snapshot data. Once the returned object falls out of PHP scope,
2154 * the lock will be released unless a transaction is active. If one is active, then the lock
2155 * will be released when it either commits or rolls back.
2156 *
2157 * If the lock acquisition failed, then no transaction flush happens, and null is returned.
2158 *
2159 * @param string $lockKey Name of lock to release
2160 * @param string $fname Name of the calling method
2161 * @param int $timeout Acquisition timeout in seconds
2162 * @return ScopedCallback|null
2163 * @throws DBError
2164 * @since 1.27
2165 */
2166 public function getScopedLockAndFlush( $lockKey, $fname, $timeout );
2167
2168 /**
2169 * Check to see if a named lock used by lock() use blocking queues
2170 *
2171 * @return bool
2172 * @since 1.26
2173 */
2174 public function namedLocksEnqueue();
2175
2176 /**
2177 * Find out when 'infinity' is. Most DBMSes support this. This is a special
2178 * keyword for timestamps in PostgreSQL, and works with CHAR(14) as well
2179 * because "i" sorts after all numbers.
2180 *
2181 * @return string
2182 */
2183 public function getInfinity();
2184
2185 /**
2186 * Encode an expiry time into the DBMS dependent format
2187 *
2188 * @param string $expiry Timestamp for expiry, or the 'infinity' string
2189 * @return string
2190 */
2191 public function encodeExpiry( $expiry );
2192
2193 /**
2194 * Decode an expiry time into a DBMS independent format
2195 *
2196 * @param string $expiry DB timestamp field value for expiry
2197 * @param int $format TS_* constant, defaults to TS_MW
2198 * @return string
2199 */
2200 public function decodeExpiry( $expiry, $format = TS_MW );
2201
2202 /**
2203 * Allow or deny "big selects" for this session only. This is done by setting
2204 * the sql_big_selects session variable.
2205 *
2206 * This is a MySQL-specific feature.
2207 *
2208 * @param bool|string $value True for allow, false for deny, or "default" to
2209 * restore the initial value
2210 */
2211 public function setBigSelects( $value = true );
2212
2213 /**
2214 * @return bool Whether this DB is read-only
2215 * @since 1.27
2216 */
2217 public function isReadOnly();
2218
2219 /**
2220 * Make certain table names use their own database, schema, and table prefix
2221 * when passed into SQL queries pre-escaped and without a qualified database name
2222 *
2223 * For example, "user" can be converted to "myschema.mydbname.user" for convenience.
2224 * Appearances like `user`, somedb.user, somedb.someschema.user will used literally.
2225 *
2226 * Calling this twice will completely clear any old table aliases. Also, note that
2227 * callers are responsible for making sure the schemas and databases actually exist.
2228 *
2229 * @param array[] $aliases Map of (table => (dbname, schema, prefix) map)
2230 * @since 1.28
2231 */
2232 public function setTableAliases( array $aliases );
2233
2234 /**
2235 * Convert certain index names to alternative names before querying the DB
2236 *
2237 * Note that this applies to indexes regardless of the table they belong to.
2238 *
2239 * This can be employed when an index was renamed X => Y in code, but the new Y-named
2240 * indexes were not yet built on all DBs. After all the Y-named ones are added by the DBA,
2241 * the aliases can be removed, and then the old X-named indexes dropped.
2242 *
2243 * @param string[] $aliases
2244 * @since 1.31
2245 */
2246 public function setIndexAliases( array $aliases );
2247
2248 /**
2249 * Get a debugging string that mentions the database type, the ID of this instance,
2250 * and the ID of any underlying connection resource or driver object if one is present
2251 *
2252 * @return string "<db type> object #<X>" or "<db type> object #<X> (resource/handle id #<Y>)"
2253 * @since 1.34
2254 */
2255 public function __toString();
2256 }
2257
2258 /**
2259 * @deprecated since 1.29
2260 */
2261 class_alias( IDatabase::class, 'IDatabase' );