diff --git a/.github/funding.yml b/.github/funding.yml
new file mode 100644
index 000000000..25adc9520
--- /dev/null
+++ b/.github/funding.yml
@@ -0,0 +1,2 @@
+github: dg
+custom: "https://nette.org/donate"
diff --git a/composer.json b/composer.json
index 46ebba32d..4380a83d9 100644
--- a/composer.json
+++ b/composer.json
@@ -40,7 +40,7 @@
 	},
 	"extra": {
 		"branch-alias": {
-			"dev-master": "3.0-dev"
+			"dev-master": "3.1-dev"
 		}
 	}
 }
diff --git a/src/Bridges/DatabaseDI/DatabaseExtension.php b/src/Bridges/DatabaseDI/DatabaseExtension.php
index 1272a1259..5b0737b6e 100644
--- a/src/Bridges/DatabaseDI/DatabaseExtension.php
+++ b/src/Bridges/DatabaseDI/DatabaseExtension.php
@@ -38,6 +38,7 @@ public function getConfigSchema(): Nette\Schema\Schema
 				'options' => Expect::array(),
 				'debugger' => Expect::bool(true),
 				'explain' => Expect::bool(true),
+				'connectionTimeout' => Expect::int()->min(0),
 				'reflection' => Expect::string(), // BC
 				'conventions' => Expect::string('discovered'), // Nette\Database\Conventions\DiscoveredConventions
 				'autowired' => Expect::bool(),
@@ -75,6 +76,10 @@ private function setupDatabase(\stdClass $config, string $name): void
 			}
 		}
 
+		if ($config->connectionTimeout !== null) {
+			$config->options[\PDO::ATTR_TIMEOUT] = $config->connectionTimeout;
+		}
+
 		$connection = $builder->addDefinition($this->prefix("$name.connection"))
 			->setFactory(Nette\Database\Connection::class, [$config->dsn, $config->user, $config->password, $config->options])
 			->setAutowired($config->autowired);
diff --git a/src/Bridges/DatabaseTracy/ConnectionPanel.php b/src/Bridges/DatabaseTracy/ConnectionPanel.php
index 5bd58bab8..6d6392966 100644
--- a/src/Bridges/DatabaseTracy/ConnectionPanel.php
+++ b/src/Bridges/DatabaseTracy/ConnectionPanel.php
@@ -34,6 +34,9 @@ class ConnectionPanel implements Tracy\IBarPanel
 	/** @var bool */
 	public $disabled = false;
 
+	/** @var float */
+	public $performanceScale = 0.25;
+
 	/** @var float logged time */
 	private $totalTime = 0;
 
@@ -46,11 +49,11 @@ class ConnectionPanel implements Tracy\IBarPanel
 
 	public function __construct(Connection $connection)
 	{
-		$connection->onQuery[] = [$this, 'logQuery'];
+		$connection->onQuery[] = \Closure::fromCallable([$this, 'logQuery']);
 	}
 
 
-	public function logQuery(Connection $connection, $result): void
+	private function logQuery(Connection $connection, $result): void
 	{
 		if ($this->disabled) {
 			return;
@@ -138,6 +141,7 @@ public function getPanel(): ?string
 			$name = $this->name;
 			$count = $this->count;
 			$totalTime = $this->totalTime;
+			$performanceScale = $this->performanceScale;
 			require __DIR__ . '/templates/ConnectionPanel.panel.phtml';
 		});
 	}
diff --git a/src/Bridges/DatabaseTracy/templates/ConnectionPanel.panel.phtml b/src/Bridges/DatabaseTracy/templates/ConnectionPanel.panel.phtml
index ef83eddf9..a31f7b9cb 100644
--- a/src/Bridges/DatabaseTracy/templates/ConnectionPanel.panel.phtml
+++ b/src/Bridges/DatabaseTracy/templates/ConnectionPanel.panel.phtml
@@ -29,7 +29,7 @@ use Tracy\Helpers;
 			[$connection, $sql, $params, $source, $time, $rows, $error, $command, $explain] = $query;
 		?>
 		<tr>
-		<td>
+		<td style="background:rgba(255, 95, 23, <?= sprintf('%0.3f', log($time * 1000 + 1, 10) * $performanceScale) ?>)">
 		<?php if ($error): ?>
 			<span title="<?= Helpers::escapeHtml($error) ?>">ERROR</span>
 		<?php elseif ($time !== null): echo sprintf('%0.3f', $time * 1000); endif ?>
diff --git a/src/Database/Connection.php b/src/Database/Connection.php
index 18ffe26ac..7b589983e 100644
--- a/src/Database/Connection.php
+++ b/src/Database/Connection.php
@@ -152,6 +152,23 @@ public function rollBack(): void
 	}
 
 
+	/**
+	 * @return mixed
+	 */
+	public function transaction(callable $callback)
+	{
+		$this->beginTransaction();
+		try {
+			$res = $callback();
+		} catch (\Throwable $e) {
+			$this->rollBack();
+			throw $e;
+		}
+		$this->commit();
+		return $res;
+	}
+
+
 	/**
 	 * Generates and executes SQL query.
 	 */
diff --git a/src/Database/Context.php b/src/Database/Context.php
index 280bd16f5..9cf68c1b4 100644
--- a/src/Database/Context.php
+++ b/src/Database/Context.php
@@ -60,6 +60,15 @@ public function rollBack(): void
 	}
 
 
+	/**
+	 * @return mixed
+	 */
+	public function transaction(callable $callback)
+	{
+		return $this->connection->transaction($callback);
+	}
+
+
 	public function getInsertId(string $sequence = null): string
 	{
 		return $this->connection->getInsertId($sequence);
diff --git a/src/Database/SqlPreprocessor.php b/src/Database/SqlPreprocessor.php
index 0517f8dcc..1fbdbd422 100644
--- a/src/Database/SqlPreprocessor.php
+++ b/src/Database/SqlPreprocessor.php
@@ -19,18 +19,26 @@ class SqlPreprocessor
 {
 	use Nette\SmartObject;
 
-	/** @var array */
-	private const MODE_LIST = ['and', 'or', 'set', 'values', 'order'];
+	private const
+		MODE_AND = 'and',       // (key [operator] value) AND ...
+		MODE_OR = 'or',         // (key [operator] value) OR ...
+		MODE_SET = 'set',       // key=value, key=value, ...
+		MODE_VALUES = 'values', // (key, key, ...) VALUES (value, value, ...)
+		MODE_ORDER = 'order',   // key, key DESC, ...
+		MODE_LIST = 'list',     // value, value, ...  |  (tuple), (tuple), ...
+		MODE_AUTO = 'auto';     // arrayMode for arrays
+
+	private const MODES = [self::MODE_AND, self::MODE_OR, self::MODE_SET, self::MODE_VALUES, self::MODE_ORDER, self::MODE_LIST];
 
 	private const ARRAY_MODES = [
-		'INSERT' => 'values',
-		'REPLACE' => 'values',
-		'KEY UPDATE' => 'set',
-		'SET' => 'set',
-		'WHERE' => 'and',
-		'HAVING' => 'and',
-		'ORDER BY' => 'order',
-		'GROUP BY' => 'order',
+		'INSERT' => self::MODE_VALUES,
+		'REPLACE' => self::MODE_VALUES,
+		'KEY UPDATE' => self::MODE_SET,
+		'SET' => self::MODE_SET,
+		'WHERE' => self::MODE_AND,
+		'HAVING' => self::MODE_AND,
+		'ORDER BY' => self::MODE_ORDER,
+		'GROUP BY' => self::MODE_ORDER,
 	];
 
 	private const PARAMETRIC_COMMANDS = [
@@ -60,7 +68,7 @@ class SqlPreprocessor
 	/** @var bool */
 	private $useParams;
 
-	/** @var string|null values|set|and|order */
+	/** @var string|null values|set|and|order|items */
 	private $arrayMode;
 
 
@@ -88,16 +96,15 @@ public function process(array $params, bool $useParams = false): array
 			$param = $params[$this->counter++];
 
 			if (($this->counter === 2 && count($params) === 2) || !is_scalar($param)) {
-				$res[] = $this->formatValue($param, 'auto');
-				$this->arrayMode = null;
+				$res[] = $this->formatValue($param, self::MODE_AUTO);
 
 			} elseif (is_string($param) && $this->counter > $prev + 1) {
 				$prev = $this->counter;
 				$this->arrayMode = null;
 				$res[] = Nette\Utils\Strings::replace(
 					$param,
-					'~\'[^\']*+\'|"[^"]*+"|\?[a-z]*|^\s*+(?:\(?\s*SELECT|INSERT|UPDATE|DELETE|REPLACE|EXPLAIN)\b|\b(?:SET|WHERE|HAVING|ORDER BY|GROUP BY|KEY UPDATE)(?=\s*$|\s*\?)|/\*.*?\*/|--[^\n]*~Dsi',
-					[$this, 'callback']
+					'~\'[^\']*+\'|"[^"]*+"|\?[a-z]*|^\s*+(?:\(?\s*SELECT|INSERT|UPDATE|DELETE|REPLACE|EXPLAIN)\b|\b(?:SET|WHERE|HAVING|ORDER BY|GROUP BY|KEY UPDATE)(?=\s*$|\s*\?)|\bIN\s+\(\?\)|/\*.*?\*/|--[^\n]*~Dsi',
+					\Closure::fromCallable([$this, 'callback'])
 				);
 			} else {
 				throw new Nette\InvalidArgumentException('There are more parameters than placeholders.');
@@ -108,19 +115,24 @@ public function process(array $params, bool $useParams = false): array
 	}
 
 
-	/** @internal */
-	public function callback(array $m): string
+	private function callback(array $m): string
 	{
 		$m = $m[0];
 		if ($m[0] === '?') { // placeholder
 			if ($this->counter >= count($this->params)) {
 				throw new Nette\InvalidArgumentException('There are more placeholders than passed parameters.');
 			}
-			return $this->formatValue($this->params[$this->counter++], substr($m, 1) ?: 'auto');
+			return $this->formatValue($this->params[$this->counter++], substr($m, 1) ?: self::MODE_AUTO);
 
 		} elseif ($m[0] === "'" || $m[0] === '"' || $m[0] === '/' || $m[0] === '-') { // string or comment
 			return $m;
 
+		} elseif (substr($m, -3) === '(?)') { // IN (?)
+			if ($this->counter >= count($this->params)) {
+				throw new Nette\InvalidArgumentException('There are more placeholders than passed parameters.');
+			}
+			return 'IN (' . $this->formatValue($this->params[$this->counter++], self::MODE_LIST) . ')';
+
 		} else { // command
 			$cmd = ltrim(strtoupper($m), "\t\n\r (");
 			$this->arrayMode = self::ARRAY_MODES[$cmd] ?? null;
@@ -132,7 +144,7 @@ public function callback(array $m): string
 
 	private function formatValue($value, string $mode = null): string
 	{
-		if (!$mode || $mode === 'auto') {
+		if (!$mode || $mode === self::MODE_AUTO) {
 			if (is_scalar($value) || is_resource($value)) {
 				if ($this->useParams) {
 					$this->remaining[] = $value;
@@ -187,16 +199,16 @@ private function formatValue($value, string $mode = null): string
 			$value = iterator_to_array($value);
 		}
 
-		if (is_array($value)) {
+		if ($mode && is_array($value)) {
 			$vx = $kx = [];
-			if ($mode === 'auto') {
-				$mode = $this->arrayMode;
+			if ($mode === self::MODE_AUTO) {
+				$mode = $this->arrayMode ?? self::MODE_LIST;
 			}
 
-			if ($mode === 'values') { // (key, key, ...) VALUES (value, value, ...)
+			if ($mode === self::MODE_VALUES) { // (key, key, ...) VALUES (value, value, ...)
 				if (array_key_exists(0, $value)) { // multi-insert
 					if (!is_array($value[0]) && !$value[0] instanceof Row) {
-						throw new Nette\InvalidArgumentException('Automaticaly detected multi-insert, but values aren\'t array. If you need try to change mode like "?[' . implode('|', self::MODE_LIST) . ']". Mode "' . $mode . '" was used.');
+						throw new Nette\InvalidArgumentException('Automaticaly detected multi-insert, but values aren\'t array. If you need try to change mode like "?[' . implode('|', self::MODES) . ']". Mode "' . $mode . '" was used.');
 					}
 					foreach ($value[0] as $k => $v) {
 						$kx[] = $this->delimite($k);
@@ -219,10 +231,10 @@ private function formatValue($value, string $mode = null): string
 				}
 				return '(' . implode(', ', $kx) . ') VALUES (' . implode(', ', $vx) . ')';
 
-			} elseif (!$mode || $mode === 'set') {
+			} elseif ($mode === self::MODE_SET) {
 				foreach ($value as $k => $v) {
-					if (is_int($k)) { // value, value, ... OR (1, 2), (3, 4)
-						$vx[] = is_array($v) ? '(' . $this->formatValue($v) . ')' : $this->formatValue($v);
+					if (is_int($k)) { // value, value, ...
+						$vx[] = $this->formatValue($v);
 					} elseif (substr($k, -1) === '=') { // key+=value, key-=value, ...
 						$k2 = $this->delimite(substr($k, 0, -2));
 						$vx[] = $k2 . '=' . $k2 . ' ' . substr($k, -2, 1) . ' ' . $this->formatValue($v);
@@ -232,7 +244,13 @@ private function formatValue($value, string $mode = null): string
 				}
 				return implode(', ', $vx);
 
-			} elseif ($mode === 'and' || $mode === 'or') { // (key [operator] value) AND ...
+			} elseif ($mode === self::MODE_LIST) { // value, value, ...  |  (tuple), (tuple), ...
+				foreach ($value as $k => $v) {
+					$vx[] = is_array($v) ? '(' . $this->formatValue($v, self::MODE_LIST) . ')' : $this->formatValue($v);
+				}
+				return implode(', ', $vx);
+
+			} elseif ($mode === self::MODE_AND || $mode === self::MODE_OR) { // (key [operator] value) AND ...
 				foreach ($value as $k => $v) {
 					if (is_int($k)) {
 						$vx[] = $this->formatValue($v);
@@ -242,7 +260,7 @@ private function formatValue($value, string $mode = null): string
 					$k = $this->delimite($k);
 					if (is_array($v)) {
 						if ($v) {
-							$vx[] = $k . ' ' . ($operator ? $operator . ' ' : '') . 'IN (' . $this->formatValue(array_values($v)) . ')';
+							$vx[] = $k . ' ' . ($operator ? $operator . ' ' : '') . 'IN (' . $this->formatValue(array_values($v), self::MODE_LIST) . ')';
 						} elseif ($operator === 'NOT') {
 						} else {
 							$vx[] = '1=0';
@@ -257,7 +275,7 @@ private function formatValue($value, string $mode = null): string
 				}
 				return $value ? '(' . implode(') ' . strtoupper($mode) . ' (', $vx) . ')' : '1=1';
 
-			} elseif ($mode === 'order') { // key, key DESC, ...
+			} elseif ($mode === self::MODE_ORDER) { // key, key DESC, ...
 				foreach ($value as $k => $v) {
 					$vx[] = $this->delimite($k) . ($v > 0 ? '' : ' DESC');
 				}
@@ -267,11 +285,11 @@ private function formatValue($value, string $mode = null): string
 				throw new Nette\InvalidArgumentException("Unknown placeholder ?$mode.");
 			}
 
-		} elseif (in_array($mode, self::MODE_LIST, true)) {
+		} elseif (in_array($mode, self::MODES, true)) {
 			$type = gettype($value);
 			throw new Nette\InvalidArgumentException("Placeholder ?$mode expects array or Traversable object, $type given.");
 
-		} elseif ($mode && $mode !== 'auto') {
+		} elseif ($mode && $mode !== self::MODE_AUTO) {
 			throw new Nette\InvalidArgumentException("Unknown placeholder ?$mode.");
 
 		} else {
diff --git a/src/Database/Structure.php b/src/Database/Structure.php
index b2bc08ca4..5ec06790b 100644
--- a/src/Database/Structure.php
+++ b/src/Database/Structure.php
@@ -177,14 +177,11 @@ protected function needStructure(): void
 			return;
 		}
 
-		$this->structure = $this->cache->load('structure', [$this, 'loadStructure']);
+		$this->structure = $this->cache->load('structure', \Closure::fromCallable([$this, 'loadStructure']));
 	}
 
 
-	/**
-	 * @internal
-	 */
-	public function loadStructure(): array
+	protected function loadStructure(): array
 	{
 		$driver = $this->connection->getSupplementalDriver();
 
diff --git a/tests/Database/Context.transaction.phpt b/tests/Database/Context.transaction.phpt
index c5d293845..b5f9f4a3e 100644
--- a/tests/Database/Context.transaction.phpt
+++ b/tests/Database/Context.transaction.phpt
@@ -23,6 +23,18 @@ test(function () use ($context) {
 });
 
 
+test(function () use ($context) {
+	Assert::exception(function () use ($context) {
+		$context->transaction(function () use ($context) {
+			$context->query('DELETE FROM book');
+			throw new Exception('my exception');
+		});
+	}, Exception::class, 'my exception');
+
+	Assert::same(3, $context->fetchField('SELECT id FROM book WHERE id = ', 3));
+});
+
+
 test(function () use ($context) {
 	$context->beginTransaction();
 	$context->query('DELETE FROM book');
diff --git a/tests/Database/SqlPreprocessor.phpt b/tests/Database/SqlPreprocessor.phpt
index d6cf7314d..75392dae4 100644
--- a/tests/Database/SqlPreprocessor.phpt
+++ b/tests/Database/SqlPreprocessor.phpt
@@ -80,6 +80,11 @@ test(function () use ($preprocessor) { // IN
 
 	Assert::same(reformat('SELECT id FROM author WHERE ([a] IN (NULL, ?, ?, ?)) AND (1=0) AND ([c] NOT IN (NULL, ?, ?, ?))'), $sql);
 	Assert::same([1, 2, 3, 1, 2, 3], $params);
+
+
+	[$sql, $params] = $preprocessor->process(['SELECT * FROM table WHERE ? AND id IN (?) AND ?', ['a' => 111], [3, 4], ['b' => 222]]);
+	Assert::same(reformat('SELECT * FROM table WHERE ([a] = ?) AND id IN (?, ?) AND ([b] = ?)'), $sql);
+	Assert::same([111, 3, 4, 222], $params);
 });
 
 
@@ -332,7 +337,7 @@ test(function () use ($preprocessor) { // insert
 	[$sql, $params] = $preprocessor->process(['/* comment */  INSERT INTO author',
 		['name' => 'Catelyn Stark'],
 	]);
-	Assert::same(reformat("/* comment */  INSERT INTO author [name]='Catelyn Stark'"), $sql); // autodetection not used
+	Assert::same(reformat("/* comment */  INSERT INTO author 'Catelyn Stark'"), $sql); // autodetection not used
 	Assert::same([], $params);
 });
 
@@ -347,10 +352,10 @@ test(function () use ($preprocessor) { // ?values
 });
 
 
-test(function () use ($preprocessor) { // automatic detection faild
+test(function () use ($preprocessor) { // automatic detection failed
 	Assert::exception(function () use ($preprocessor) {
-		$preprocessor->process(['INSERT INTO author (name) SELECT name FROM user WHERE id IN (?)', [11, 12]]);
-	}, Nette\InvalidArgumentException::class, 'Automaticaly detected multi-insert, but values aren\'t array. If you need try to change mode like "?[and|or|set|values|order]". Mode "values" was used.');
+		dump($preprocessor->process(['INSERT INTO author (name) SELECT name FROM user WHERE id ?', [11, 12]])); // invalid sql
+	}, Nette\InvalidArgumentException::class, 'Automaticaly detected multi-insert, but values aren\'t array. If you need try to change mode like "?[and|or|set|values|order|list]". Mode "values" was used.');
 });
 
 
@@ -440,10 +445,10 @@ test(function () use ($preprocessor) { // update
 	Assert::same([12, 'John Doe'], $params);
 
 
-	[$sql, $params] = $preprocessor->process(['UPDATE author SET a=1,',
+	[$sql, $params] = $preprocessor->process(['UPDATE author SET a=1,', // autodetection not used
 		['id' => 12, 'name' => 'John Doe'],
 	]);
-	Assert::same(reformat('UPDATE author SET a=1, [id]=?, [name]=?'), $sql);
+	Assert::same(reformat('UPDATE author SET a=1, ?, ?'), $sql);
 	Assert::same([12, 'John Doe'], $params);
 });