return $this->__call( __FUNCTION__, func_get_args() );
}
+ public function buildSelectSubquery(
+ $table, $vars, $conds = '', $fname = __METHOD__,
+ $options = [], $join_conds = []
+ ) {
+ return $this->__call( __FUNCTION__, func_get_args() );
+ }
+
public function databasesAreIndependent() {
return $this->__call( __FUNCTION__, func_get_args() );
}
return $this->__call( __FUNCTION__, func_get_args() );
}
- public function wasErrorReissuable() {
+ public function wasConnectionLoss() {
return $this->__call( __FUNCTION__, func_get_args() );
}
return $this->__call( __FUNCTION__, func_get_args() );
}
+ public function wasErrorReissuable() {
+ return $this->__call( __FUNCTION__, func_get_args() );
+ }
+
public function masterPosWait( DBMasterPos $pos, $timeout ) {
return $this->__call( __FUNCTION__, func_get_args() );
}
$ret = $this->doProfiledQuery( $sql, $commentedSql, $isNonTempWrite, $fname );
# Try reconnecting if the connection was lost
- if ( false === $ret && $this->wasErrorReissuable() ) {
+ if ( false === $ret && $this->wasConnectionLoss() ) {
$recoverable = $this->canRecoverFromDisconnect( $sql, $priorWritesPending );
# Stash the last error values before anything might clear them
$lastError = $this->lastError();
}
public function estimateRowCount(
- $table, $vars = '*', $conds = '', $fname = __METHOD__, $options = [], $join_conds = []
+ $table, $var = '*', $conds = '', $fname = __METHOD__, $options = [], $join_conds = []
) {
+ $conds = $this->normalizeConditions( $conds, $fname );
+ $column = $this->extractSingleFieldFromList( $var );
+ if ( is_string( $column ) && !in_array( $column, [ '*', '1' ] ) ) {
+ $conds[] = "$column IS NOT NULL";
+ }
+
$res = $this->select(
$table, [ 'rowcount' => 'COUNT(*)' ], $conds, $fname, $options, $join_conds
);
}
public function selectRowCount(
- $tables, $vars = '*', $conds = '', $fname = __METHOD__, $options = [], $join_conds = []
+ $tables, $var = '*', $conds = '', $fname = __METHOD__, $options = [], $join_conds = []
) {
- $rows = 0;
- $sql = $this->selectSQLText( $tables, '1', $conds, $fname, $options, $join_conds );
- // The identifier quotes is primarily for MSSQL.
- $rowCountCol = $this->addIdentifierQuotes( "rowcount" );
- $tableName = $this->addIdentifierQuotes( "tmp_count" );
- $res = $this->query( "SELECT COUNT(*) AS $rowCountCol FROM ($sql) $tableName", $fname );
+ $conds = $this->normalizeConditions( $conds, $fname );
+ $column = $this->extractSingleFieldFromList( $var );
+ if ( is_string( $column ) && !in_array( $column, [ '*', '1' ] ) ) {
+ $conds[] = "$column IS NOT NULL";
+ }
+
+ $res = $this->select(
+ [
+ 'tmp_count' => $this->buildSelectSubquery(
+ $tables,
+ '1',
+ $conds,
+ $fname,
+ $options,
+ $join_conds
+ )
+ ],
+ [ 'rowcount' => 'COUNT(*)' ],
+ [],
+ $fname
+ );
+ $row = $res ? $this->fetchRow( $res ) : [];
+
+ return isset( $row['rowcount'] ) ? (int)$row['rowcount'] : 0;
+ }
+
+ /**
+ * @param array|string $conds
+ * @param string $fname
+ * @return array
+ */
+ final protected function normalizeConditions( $conds, $fname ) {
+ if ( $conds === null || $conds === false ) {
+ $this->queryLogger->warning(
+ __METHOD__
+ . ' called from '
+ . $fname
+ . ' with incorrect parameters: $conds must be a string or an array'
+ );
+ $conds = '';
+ }
- if ( $res ) {
- $row = $this->fetchRow( $res );
- $rows = ( isset( $row['rowcount'] ) ) ? (int)$row['rowcount'] : 0;
+ if ( !is_array( $conds ) ) {
+ $conds = ( $conds === '' ) ? [] : [ $conds ];
}
- return $rows;
+ return $conds;
+ }
+
+ /**
+ * @param array|string $var Field parameter in the style of select()
+ * @return string|null Column name or null; ignores aliases
+ * @throws DBUnexpectedError Errors out if multiple columns are given
+ */
+ final protected function extractSingleFieldFromList( $var ) {
+ if ( is_array( $var ) ) {
+ if ( !$var ) {
+ $column = null;
+ } elseif ( count( $var ) == 1 ) {
+ $column = isset( $var[0] ) ? $var[0] : reset( $var );
+ } else {
+ throw new DBUnexpectedError( $this, __METHOD__ . ': got multiple columns.' );
+ }
+ } else {
+ $column = $var;
+ }
+
+ return $column;
}
/**
return 'CAST( ' . $field . ' AS INTEGER )';
}
+ public function buildSelectSubquery(
+ $table, $vars, $conds = '', $fname = __METHOD__,
+ $options = [], $join_conds = []
+ ) {
+ return new Subquery(
+ $this->selectSQLText( $table, $vars, $conds, $fname, $options, $join_conds )
+ );
+ }
+
public function databasesAreIndependent() {
return false;
}
}
public function tableName( $name, $format = 'quoted' ) {
+ if ( $name instanceof Subquery ) {
+ throw new DBUnexpectedError(
+ $this,
+ __METHOD__ . ': got Subquery instance when expecting a string.'
+ );
+ }
+
# Skip the entire process when we have a string quoted on both ends.
# Note that we check the end so that we will still quote any use of
# use of `database`.table. But won't break things if someone wants
# any remote case where a word like on may be inside of a table name
# surrounded by symbols which may be considered word breaks.
if ( preg_match( '/(^|\s)(DISTINCT|JOIN|ON|AS)(\s|$)/i', $name ) !== 0 ) {
+ $this->queryLogger->warning(
+ __METHOD__ . ": use of subqueries is not supported this way.",
+ [ 'trace' => ( new RuntimeException() )->getTraceAsString() ]
+ );
+
return $name;
}
/**
* Get an aliased table name
- * e.g. tableName AS newTableName
*
- * @param string $name Table name, see tableName()
- * @param string|bool $alias Alias (optional)
+ * This returns strings like "tableName AS newTableName" for aliased tables
+ * and "(SELECT * from tableA) newTablename" for subqueries (e.g. derived tables)
+ *
+ * @see Database::tableName()
+ * @param string|Subquery $table Table name or object with a 'sql' field
+ * @param string|bool $alias Table alias (optional)
* @return string SQL name for aliased table. Will not alias a table to its own name
*/
- protected function tableNameWithAlias( $name, $alias = false ) {
- if ( !$alias || $alias == $name ) {
- return $this->tableName( $name );
+ protected function tableNameWithAlias( $table, $alias = false ) {
+ if ( is_string( $table ) ) {
+ $quotedTable = $this->tableName( $table );
+ } elseif ( $table instanceof Subquery ) {
+ $quotedTable = (string)$table;
+ } else {
+ throw new InvalidArgumentException( "Table must be a string or Subquery." );
+ }
+
+ if ( !strlen( $alias ) || $alias === $table ) {
+ if ( $table instanceof Subquery ) {
+ throw new InvalidArgumentException( "Subquery table missing alias." );
+ }
+
+ return $quotedTable;
} else {
- return $this->tableName( $name ) . ' ' . $this->addIdentifierQuotes( $alias );
+ return $quotedTable . ' ' . $this->addIdentifierQuotes( $alias );
}
}
return false;
}
- public function wasErrorReissuable() {
- return false;
+ public function wasConnectionLoss() {
+ return $this->wasConnectionError( $this->lastErrno() );
}
public function wasReadOnlyError() {
return false;
}
+ public function wasErrorReissuable() {
+ return (
+ $this->wasDeadlock() ||
+ $this->wasLockTimeout() ||
+ $this->wasConnectionLoss()
+ );
+ }
+
/**
* Do not use this method outside of Database/DBError classes
*
$msg = "$fname: Explicit transaction already active (from {$this->trxFname}).";
throw new DBUnexpectedError( $this, $msg );
} else {
- // @TODO: make this an exception at some point
$msg = "$fname: Implicit transaction already active (from {$this->trxFname}).";
- $this->queryLogger->error( $msg );
- return; // join the main transaction set
+ throw new DBUnexpectedError( $this, $msg );
}
} elseif ( $this->getFlag( self::DBO_TRX ) && $mode !== self::TRANSACTION_INTERNAL ) {
- // @TODO: make this an exception at some point
$msg = "$fname: Implicit transaction expected (DBO_TRX set).";
- $this->queryLogger->error( $msg );
- return; // let any writes be in the main transaction
+ throw new DBUnexpectedError( $this, $msg );
}
// Avoid fatals if close() was called
"$fname: No transaction to commit, something got out of sync." );
return; // nothing to do
} elseif ( $this->trxAutomatic ) {
- // @TODO: make this an exception at some point
- $msg = "$fname: Explicit commit of implicit transaction.";
- $this->queryLogger->error( $msg );
- return; // wait for the main transaction set commit round
+ throw new DBUnexpectedError(
+ $this,
+ "$fname: Expected mass commit of all peer transactions (DBO_TRX set)."
+ );
}
}
} elseif ( $this->getFlag( self::DBO_TRX ) ) {
throw new DBUnexpectedError(
$this,
- "$fname: Expected mass rollback of all peer databases (DBO_TRX set)."
+ "$fname: Expected mass rollback of all peer transactions (DBO_TRX set)."
);
}
}
* Takes same arguments as Database::select()
*
* @param string|array $table
- * @param string|array $vars
+ * @param string|array $var
* @param string|array $conds
* @param string $fname
* @param string|array $options
* @param array $join_conds
* @return bool|int
*/
- public function estimateRowCount( $table, $vars = '*', $conds = '',
+ public function estimateRowCount( $table, $var = '*', $conds = '',
$fname = __METHOD__, $options = [], $join_conds = []
) {
+ $conds = $this->normalizeConditions( $conds, $fname );
+ $column = $this->extractSingleFieldFromList( $var );
+ if ( is_string( $column ) && !in_array( $column, [ '*', '1' ] ) ) {
+ $conds[] = "$column IS NOT NULL";
+ }
+
$options['EXPLAIN'] = true;
- $res = $this->select( $table, $vars, $conds, $fname, $options, $join_conds );
+ $res = $this->select( $table, $var, $conds, $fname, $options, $join_conds );
if ( $res === false ) {
return false;
}
return $this->lastErrno() == 1205;
}
- public function wasErrorReissuable() {
- return $this->lastErrno() == 2013 || $this->lastErrno() == 2006;
- }
-
/**
* Determines if the last failure was due to the database being read-only.
*
* Takes same arguments as Database::select()
*
* @param string $table
- * @param string $vars
+ * @param string $var
* @param string $conds
* @param string $fname
* @param array $options
* @param array $join_conds
* @return int
*/
- public function estimateRowCount( $table, $vars = '*', $conds = '',
+ public function estimateRowCount( $table, $var = '*', $conds = '',
$fname = __METHOD__, $options = [], $join_conds = []
) {
+ $conds = $this->normalizeConditions( $conds, $fname );
+ $column = $this->extractSingleFieldFromList( $var );
+ if ( is_string( $column ) && !in_array( $column, [ '*', '1' ] ) ) {
+ $conds[] = "$column IS NOT NULL";
+ }
+
$options['EXPLAIN'] = true;
- $res = $this->select( $table, $vars, $conds, $fname, $options, $join_conds );
+ $res = $this->select( $table, $var, $conds, $fname, $options, $join_conds );
$rows = -1;
if ( $res ) {
$row = $this->fetchRow( $res );
}
public function wasDeadlock() {
- return $this->lastErrno() == '40P01';
+ // https://www.postgresql.org/docs/8.2/static/errcodes-appendix.html
+ return $this->lastErrno() === '40P01';
+ }
+
+ public function wasLockTimeout() {
+ // https://www.postgresql.org/docs/8.2/static/errcodes-appendix.html
+ return $this->lastErrno() === '55P03';
}
public function duplicateTableStructure(
* Run an SQL query and return the result. Normally throws a DBQueryError
* on failure. If errors are ignored, returns false instead.
*
+ * If a connection loss is detected, then an attempt to reconnect will be made.
+ * For queries that involve no larger transactions or locks, they will be re-issued
+ * for convenience, provided the connection was re-established.
+ *
* In new code, the query wrappers select(), insert(), update(), delete(),
* etc. should be used where possible, since they give much better DBMS
* independence and automatically quote or validate user input in a variety
* This includes the user table in the query, with the alias "a" available
* for use in field names (e.g. a.user_name).
*
+ * A derived table, defined by the result of selectSQLText(), requires an alias
+ * key and a Subquery instance value which wraps the SQL query, for example:
+ *
+ * [ 'c' => new Subquery( 'SELECT ...' ) ]
+ *
* Joins using parentheses for grouping (since MediaWiki 1.31) may be
* constructed using nested arrays. For example,
*
* doing UNION queries, where the SQL text of each query is needed. In general,
* however, callers outside of Database classes should just use select().
*
+ * @see IDatabase::select()
+ *
* @param string|array $table Table name
* @param string|array $vars Field names
* @param string|array $conds Conditions
* @param string $fname Caller function name
* @param string|array $options Query options
* @param string|array $join_conds Join conditions
- *
- * @return string SQL query string.
- * @see IDatabase::select()
+ * @return string SQL query string
*/
public function selectSQLText(
$table, $vars, $conds = '', $fname = __METHOD__,
* Takes the same arguments as IDatabase::select().
*
* @param string $table Table name
- * @param string $vars Unused
+ * @param string $var Column for which NULL values are not counted [default "*"]
* @param array|string $conds Filters on the table
* @param string $fname Function name for profiling
* @param array $options Options for select
* @throws DBError
*/
public function estimateRowCount(
- $table, $vars = '*', $conds = '', $fname = __METHOD__, $options = [], $join_conds = []
+ $table, $var = '*', $conds = '', $fname = __METHOD__, $options = [], $join_conds = []
);
/**
* @since 1.27 Added $join_conds parameter
*
* @param array|string $tables Table names
- * @param string $vars Unused
+ * @param string $var Column for which NULL values are not counted [default "*"]
* @param array|string $conds Filters on the table
* @param string $fname Function name for profiling
* @param array $options Options for select
* @throws DBError
*/
public function selectRowCount(
- $tables, $vars = '*', $conds = '', $fname = __METHOD__, $options = [], $join_conds = []
+ $tables, $var = '*', $conds = '', $fname = __METHOD__, $options = [], $join_conds = []
);
/**
*/
public function buildIntegerCast( $field );
+ /**
+ * Equivalent to IDatabase::selectSQLText() except wraps the result in Subqyery
+ *
+ * @see IDatabase::selectSQLText()
+ *
+ * @param string|array $table Table name
+ * @param string|array $vars Field names
+ * @param string|array $conds Conditions
+ * @param string $fname Caller function name
+ * @param string|array $options Query options
+ * @param string|array $join_conds Join conditions
+ * @return Subquery
+ * @since 1.31
+ */
+ public function buildSelectSubquery(
+ $table, $vars, $conds = '', $fname = __METHOD__,
+ $options = [], $join_conds = []
+ );
+
/**
* Returns true if DBs are assumed to be on potentially different servers
*
/**
* Determines if the last failure was due to a deadlock
*
+ * Note that during a deadlock, the prior transaction will have been lost
+ *
* @return bool
*/
public function wasDeadlock();
/**
* Determines if the last failure was due to a lock timeout
*
+ * Note that during a lock wait timeout, the prior transaction will have been lost
+ *
* @return bool
*/
public function wasLockTimeout();
/**
- * Determines if the last query error was due to a dropped connection and should
- * be dealt with by pinging the connection and reissuing the query.
+ * Determines if the last query error was due to a dropped connection
+ *
+ * Note that during a connection loss, the prior transaction will have been lost
*
* @return bool
+ * @since 1.31
*/
- public function wasErrorReissuable();
+ public function wasConnectionLoss();
/**
* Determines if the last failure was due to the database being read-only.
*/
public function wasReadOnlyError();
+ /**
+ * Determines if the last query error was due to something outside of the query itself
+ *
+ * Note that the transaction may have been lost, discarding prior writes and results
+ *
+ * @return bool
+ */
+ public function wasErrorReissuable();
+
/**
* Wait for the replica DB to catch up to a given master position
*