diff --git a/composer.json b/composer.json
index 3e5debca..0555de72 100644
--- a/composer.json
+++ b/composer.json
@@ -27,6 +27,7 @@
         "amphp/dns": "^1",
         "amphp/byte-stream": "^1",
         "amphp/file": "^1",
+        "amphp/mysql": "^2.0",
         "danog/dns-over-https": "^0.2",
         "amphp/http-client-cookies": "^1",
         "danog/tg-file-decoder": "^0.1",
diff --git a/src/danog/MadelineProto/Db/DbArray.php b/src/danog/MadelineProto/Db/DbArray.php
new file mode 100644
index 00000000..263d9a93
--- /dev/null
+++ b/src/danog/MadelineProto/Db/DbArray.php
@@ -0,0 +1,11 @@
+<?php
+
+namespace danog\MadelineProto\Db;
+
+abstract class DbArray extends \ArrayIterator implements DbType
+{
+    protected function __construct($array = [], $flags = 0)
+    {
+        parent::__construct((array) $array, $flags | self::STD_PROP_LIST);
+    }
+}
\ No newline at end of file
diff --git a/src/danog/MadelineProto/Db/DbPropertiesFabric.php b/src/danog/MadelineProto/Db/DbPropertiesFabric.php
new file mode 100644
index 00000000..8ac5754b
--- /dev/null
+++ b/src/danog/MadelineProto/Db/DbPropertiesFabric.php
@@ -0,0 +1,49 @@
+<?php
+
+namespace danog\MadelineProto\Db;
+
+class DbPropertiesFabric
+{
+    /**
+     * @param array $dbSettings
+     * @param string $propertyType
+     * @param string $name
+     * @param $value
+     *
+     * @return mixed
+     *
+     * @uses \danog\MadelineProto\Db\MemoryArray
+     * @uses \danog\MadelineProto\Db\SharedMemoryArray
+     * @uses \danog\MadelineProto\Db\MysqlArray
+     */
+    public static function get(array $dbSettings, string $propertyType, string $name, $value = null): DbType
+    {
+        $class = __NAMESPACE__;
+        switch (strtolower($dbSettings['type'])) {
+            case 'memory':
+                $class .= '\Memory';
+                break;
+            case 'sharedmemory':
+                $class .= '\SharedMemory';
+                break;
+            case 'mysql':
+                $class .= '\Mysql';
+                break;
+            default:
+                throw new \InvalidArgumentException("Unknown dbType: {$dbSettings['type']}");
+
+        }
+
+        switch (strtolower($propertyType)){
+            case 'array':
+                $class .= 'Array';
+                break;
+            default:
+                throw new \InvalidArgumentException("Unknown $propertyType: {$propertyType}");
+        }
+
+        /** @var DbType $class */
+        return $class::getInstance($dbSettings, $name, $value);
+    }
+
+}
\ No newline at end of file
diff --git a/src/danog/MadelineProto/Db/DbType.php b/src/danog/MadelineProto/Db/DbType.php
new file mode 100644
index 00000000..e9bf5dcc
--- /dev/null
+++ b/src/danog/MadelineProto/Db/DbType.php
@@ -0,0 +1,8 @@
+<?php
+
+namespace danog\MadelineProto\Db;
+
+interface DbType
+{
+    static function getInstance(array $settings, string $name, $value): self;
+}
\ No newline at end of file
diff --git a/src/danog/MadelineProto/Db/MemoryArray.php b/src/danog/MadelineProto/Db/MemoryArray.php
new file mode 100644
index 00000000..6cab009b
--- /dev/null
+++ b/src/danog/MadelineProto/Db/MemoryArray.php
@@ -0,0 +1,15 @@
+<?php
+
+namespace danog\MadelineProto\Db;
+
+class MemoryArray extends DbArray
+{
+
+    static function getInstance(array $settings, string $name, $value = []): DbArray
+    {
+        if ($value instanceof DbArray) {
+            $value = $value->getArrayCopy();
+        }
+        return new static($value);
+    }
+}
\ No newline at end of file
diff --git a/src/danog/MadelineProto/Db/Mysql.php b/src/danog/MadelineProto/Db/Mysql.php
new file mode 100644
index 00000000..cada90af
--- /dev/null
+++ b/src/danog/MadelineProto/Db/Mysql.php
@@ -0,0 +1,45 @@
+<?php
+
+namespace danog\MadelineProto\Db;
+
+use Amp\Loop;
+use Amp\Mysql\ConnectionConfig;
+use Amp\Mysql\Pool;
+use function Amp\Mysql\Pool;
+
+class Mysql
+{
+    /** @var Pool[] */
+    private static array $connections;
+
+    private static function connect(
+        string $host = '127.0.0.1',
+        int $port = 3306,
+        string $user = 'root',
+        string $password = '',
+        string $db = 'MadelineProto'
+    ) {
+        $config = ConnectionConfig::fromString(
+            "host={$host} port={$port} user={$user} password={$password} db={$db}"
+        );
+
+        return Pool($config);
+    }
+
+    public static function getConnection(
+        string $host = '127.0.0.1',
+        int $port = 3306,
+        string $user = 'root',
+        string $password = '',
+        string $db = 'MadelineProto'
+    ): Pool
+    {
+        $dbKey = "$host:$port:$db";
+        if (empty(static::$connections[$dbKey])) {
+            static::$connections[$dbKey] = static::connect($host, $port, $user, $password, $db);
+        }
+
+        return static::$connections[$dbKey];
+    }
+
+}
\ No newline at end of file
diff --git a/src/danog/MadelineProto/Db/MysqlArray.php b/src/danog/MadelineProto/Db/MysqlArray.php
new file mode 100644
index 00000000..83ec3023
--- /dev/null
+++ b/src/danog/MadelineProto/Db/MysqlArray.php
@@ -0,0 +1,429 @@
+<?php
+
+namespace danog\MadelineProto\Db;
+
+use Amp\Mysql\Pool;
+use Amp\Sql\ResultSet;
+use danog\MadelineProto\Tools;
+use function Amp\call;
+
+class MysqlArray extends DbArray
+{
+    private string $table;
+    private array $settings;
+    private Pool $db;
+    private ?string $key = null;
+
+    public function __serialize(): array
+    {
+        return [
+            'table' => $this->table,
+            'key' => $this->key,
+            'settings' => $this->settings
+        ];
+    }
+
+    public function __unserialize($data): void
+    {
+        foreach ($data as $property => $value) {
+            $this->{$property} = $value;
+        }
+        $this->initDbConnection();
+    }
+
+    public static function getInstance(array $settings, string $name, $value = []): DbType
+    {
+        $instance = new static();
+        $instance->table = $name;
+        $instance->settings = $settings['mysql'];
+        $instance->initDbConnection();
+        $instance->prepareTable();
+
+        if (!empty($value) && !$value instanceof static) {
+            if ($value instanceof DbArray) {
+                $value = $value->getArrayCopy();
+            }
+            foreach ((array) $value as $key => $item) {
+                $instance[$key] = $item;
+            }
+        }
+
+
+        return $instance;
+    }
+
+    /**
+     * Check if offset exists
+     *
+     * @link https://php.net/manual/en/arrayiterator.offsetexists.php
+     *
+     * @param string $index <p>
+     * The offset being checked.
+     * </p>
+     *
+     * @return bool true if the offset exists, otherwise false
+     * @throws \Throwable
+     */
+    public function offsetExists($index)
+    {
+        $row = $this->syncRequest(
+            "SELECT count(`key`) as `count` FROM {$this->table} WHERE `key` = :index LIMIT 1",
+            ['index' => $index]
+        );
+
+        $row = reset($row);
+        return !empty($row['count']);
+    }
+
+    /**
+     * Get value for an offset
+     *
+     * @link https://php.net/manual/en/arrayiterator.offsetget.php
+     *
+     * @param string $index <p>
+     * The offset to get the value from.
+     * </p>
+     *
+     * @return mixed The value at offset <i>index</i>.
+     * @throws \Throwable
+     */
+    public function offsetGet($index)
+    {
+        $row = $this->syncRequest(
+            "SELECT `value` FROM {$this->table} WHERE `key` = :index LIMIT 1",
+            ['index' => $index]
+        );
+        $row = reset($row);
+        if ($row) {
+            return unserialize($row['value']);
+        }
+        return null;
+
+    }
+
+    /**
+     * Set value for an offset
+     *
+     * @link https://php.net/manual/en/arrayiterator.offsetset.php
+     *
+     * @param string $index <p>
+     * The index to set for.
+     * </p>
+     * @param $value
+     *
+     * @return void
+     * @throws \Throwable
+     */
+    public function offsetSet($index, $value)
+    {
+        $this->syncRequest("
+                INSERT INTO `{$this->table}` 
+                SET `key` = :index, `value` = :value 
+                ON DUPLICATE KEY UPDATE `value` = :value
+            ",
+            [
+                'index' => $index,
+                'value' => serialize($value),
+            ]
+        );
+    }
+
+    /**
+     * Unset value for an offset
+     *
+     * @link https://php.net/manual/en/arrayiterator.offsetunset.php
+     *
+     * @param string $index <p>
+     * The offset to unset.
+     * </p>
+     *
+     * @return void
+     * @throws \Throwable
+     */
+    public function offsetUnset($index)
+    {
+        $this->syncRequest("
+                    DELETE FROM `{$this->table}`
+                    WHERE `key` = :index
+                ",
+            ['index' => $index]
+        );
+    }
+
+    /**
+     * Append an element
+     * @link https://php.net/manual/en/arrayiterator.append.php
+     * @param mixed $value <p>
+     * The value to append.
+     * </p>
+     * @return void
+     */
+    public function append($value)
+    {
+        throw new \BadMethodCallException('Append operation does not supported');
+    }
+
+    /**
+     * Get array copy
+     *
+     * @link https://php.net/manual/en/arrayiterator.getarraycopy.php
+     * @return array A copy of the array, or array of public properties
+     * if ArrayIterator refers to an object.
+     * @throws \Throwable
+     */
+    public function getArrayCopy(): array
+    {
+        $rows = $this->syncRequest("SELECT `key`, `value` FROM {$this->table}");
+        $result = [];
+        foreach ($rows as $row) {
+            $result[$row['key']] = unserialize($row['value']);
+        }
+        return $result;
+    }
+
+    /**
+     * Count elements
+     *
+     * @link https://php.net/manual/en/arrayiterator.count.php
+     * @return int The number of elements or public properties in the associated
+     * array or object, respectively.
+     * @throws \Throwable
+     */
+    public function count(): int
+    {
+        return $this->syncRequest("SELECT count(`key`) as `count` FROM {$this->table}")['count'] ?? 0;
+    }
+
+    /**
+     * Sort array by values
+     * @link https://php.net/manual/en/arrayiterator.asort.php
+     * @return void
+     */
+    public function asort()
+    {
+        throw new \BadMethodCallException('Sort operation does not supported');
+    }
+
+    /**
+     * Sort array by keys
+     * @link https://php.net/manual/en/arrayiterator.ksort.php
+     * @return void
+     */
+    public function ksort()
+    {
+        throw new \BadMethodCallException('Sort operation does not supported');
+    }
+
+    /**
+     * User defined sort
+     * @link https://php.net/manual/en/arrayiterator.uasort.php
+     * @param string $cmp_function <p>
+     * The compare function used for the sort.
+     * </p>
+     * @return void
+     */
+    public function uasort($cmp_function)
+    {
+        throw new \BadMethodCallException('Sort operation does not supported');
+    }
+
+    /**
+     * User defined sort
+     * @link https://php.net/manual/en/arrayiterator.uksort.php
+     * @param string $cmp_function <p>
+     * The compare function used for the sort.
+     * </p>
+     * @return void
+     */
+    public function uksort($cmp_function)
+    {
+        throw new \BadMethodCallException('Sort operation does not supported');
+    }
+
+    /**
+     * Sort an array naturally
+     * @link https://php.net/manual/en/arrayiterator.natsort.php
+     * @return void
+     */
+    public function natsort()
+    {
+        throw new \BadMethodCallException('Sort operation does not supported');
+    }
+
+    /**
+     * Sort an array naturally, case insensitive
+     * @link https://php.net/manual/en/arrayiterator.natcasesort.php
+     * @return void
+     */
+    public function natcasesort()
+    {
+        throw new \BadMethodCallException('Sort operation does not supported');
+    }
+
+    /**
+     * Rewind array back to the start
+     *
+     * @link https://php.net/manual/en/arrayiterator.rewind.php
+     * @return void
+     * @throws \Throwable
+     */
+    public function rewind()
+    {
+        $this->key = null;
+        $this->key();
+    }
+
+    /**
+     * Return current array entry
+     *
+     * @link https://php.net/manual/en/arrayiterator.current.php
+     * @return mixed The current array entry.
+     * @throws \Throwable
+     */
+    public function current()
+    {
+        return $this->offsetGet($this->key());
+    }
+
+    /**
+     * Return current array key
+     *
+     * @link https://php.net/manual/en/arrayiterator.key.php
+     * @return string|float|int|bool|null The current array key.
+     * @throws \Throwable
+     */
+    public function key(): ?string
+    {
+        if ($this->key === null) {
+            $row = $this->syncRequest(
+                "SELECT `key` FROM {$this->table} ORDER BY `key` LIMIT 1"
+            );
+            if ($row) {
+                $row = reset($row);
+                $this->key = $row['key'] ?? null;
+            }
+
+        }
+        return $this->key;
+    }
+
+    /**
+     * Move to next entry
+     *
+     * @link https://php.net/manual/en/arrayiterator.next.php
+     * @return void
+     * @throws \Throwable
+     */
+    public function next() {
+        $row = $this->syncRequest(
+            "SELECT `key` FROM {$this->table} WHERE `key` > :key LIMIT 1",
+            ['key' => $this->key()]
+        );
+        $row = reset($row);
+        $this->key = $row['key'] ?? null;
+    }
+
+    /**
+     * Check whether array contains more entries
+     *
+     * @link https://php.net/manual/en/arrayiterator.valid.php
+     * @return bool
+     * @throws \Throwable
+     */
+    public function valid() {
+        if ($this->key() === null) {
+            return false;
+        }
+
+        $row = $this->syncRequest(
+            "SELECT `key` FROM {$this->table} WHERE `key` > :key LIMIT 1",
+            ['key' => $this->key()]
+        );
+
+        return $row !== null;
+    }
+
+    /**
+     * Seek to position
+     * @link https://php.net/manual/en/arrayiterator.seek.php
+     * @param int $position <p>
+     * The position to seek to.
+     * </p>
+     * @return void
+     */
+    public function seek($position)
+    {
+        $row = $this->syncRequest(
+            "SELECT `key` FROM {$this->table} ORDER BY `key` LIMIT 1, :position",
+            ['offset' => $position]
+        );
+        $row = reset($row);
+        if (isset($row['key'])) {
+            $this->key = $row['key'];
+        }
+    }
+
+    private function initDbConnection()
+    {
+        $this->db = Mysql::getConnection(
+            $this->settings['host'],
+            $this->settings['port'],
+            $this->settings['user'],
+            $this->settings['password'],
+            $this->settings['database'],
+        );
+    }
+
+    /**
+     * Create table for property
+     *
+     * @return array|null
+     * @throws \Throwable
+     */
+    private function prepareTable()
+    {
+        return $this->syncRequest("
+            CREATE TABLE IF NOT EXISTS `{$this->table}`
+            (
+                `key` VARCHAR(255) NOT NULL,
+                `value` LONGTEXT NULL,
+                `ts` TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
+                PRIMARY KEY (`key`)
+            )
+        ");
+    }
+
+    /**
+     * Perform blocking request to db
+     *
+     * @param string $query
+     * @param array $params
+     *
+     * @return array|null
+     * @throws \Throwable
+     */
+    private function syncRequest(string $query, array $params = []): array
+    {
+        return Tools::wait(
+            call(
+                function() use($query, $params) {
+                    $request = yield $this->db->execute($query, $params);
+                    $result = [];
+                    if ($request instanceof ResultSet) {
+                        while (yield $request->advance()) {
+                            $row = $request->getCurrent();
+                            if (isset($row['key'])) {
+                                $result[$row['key']] = $row;
+                            } else {
+                                $result[] = $row;
+                            }
+
+                        }
+                    }
+                    return $result;
+                }
+            )
+        );
+    }
+
+}
\ No newline at end of file
diff --git a/src/danog/MadelineProto/Db/SharedMemoryArray.php b/src/danog/MadelineProto/Db/SharedMemoryArray.php
new file mode 100644
index 00000000..2252556c
--- /dev/null
+++ b/src/danog/MadelineProto/Db/SharedMemoryArray.php
@@ -0,0 +1,25 @@
+<?php
+
+namespace danog\MadelineProto\Db;
+
+class SharedMemoryArray extends DbArray
+{
+    private static SharedMemoryArray $instance;
+
+    public static function getInstance(array $settings, string $name, $value = []): DbArray
+    {
+        if (empty(static::$instance)) {
+            static::$instance = new static($value);
+        } else {
+            if ($value instanceof DbArray) {
+                $value = $value->getArrayCopy();
+            }
+            $value = array_replace_recursive(static::$instance->getArrayCopy(), (array) $value);
+            foreach ($value as $key => $item) {
+                static::$instance[$key] = $item;
+            }
+        }
+
+        return static::$instance;
+    }
+}
\ No newline at end of file
diff --git a/src/danog/MadelineProto/MTProto.php b/src/danog/MadelineProto/MTProto.php
index 3a17eda4..a6c43204 100644
--- a/src/danog/MadelineProto/MTProto.php
+++ b/src/danog/MadelineProto/MTProto.php
@@ -23,6 +23,12 @@ use Amp\Dns\Resolver;
 use Amp\File\StatCache;
 use Amp\Http\Client\HttpClient;
 use danog\MadelineProto\Async\AsyncConstruct;
+use danog\MadelineProto\Db\DbArray;
+use danog\MadelineProto\Db\DbType;
+use danog\MadelineProto\Db\Engines\DbInterface;
+use danog\MadelineProto\Db\DbPropertiesFabric;
+use danog\MadelineProto\Db\Mysql;
+use danog\MadelineProto\Db\Types\ArrayType;
 use danog\MadelineProto\Loop\Generic\PeriodicLoop;
 use danog\MadelineProto\Loop\Update\FeedLoop;
 use danog\MadelineProto\Loop\Update\SeqLoop;
@@ -85,7 +91,7 @@ class MTProto extends AsyncConstruct implements TLCallback
      *
      * @var int
      */
-    const V = 138;
+    const V = 139;
     /**
      * String release version.
      *
@@ -278,15 +284,15 @@ class MTProto extends AsyncConstruct implements TLCallback
     /**
      * Internal peer database.
      *
-     * @var array
+     * @var DbArray
      */
-    public $chats = [];
+    public $chats;
     /**
      * Cached parameters for fetching channel participants.
      *
-     * @var array
+     * @var DbArray
      */
-    public $channel_participants = [];
+    public $channel_participants;
     /**
      * When we last stored data in remote peer database (now doesn't exist anymore).
      *
@@ -302,9 +308,9 @@ class MTProto extends AsyncConstruct implements TLCallback
     /**
      * Full chat info database.
      *
-     * @var array
+     * @var DbArray
      */
-    public $full_chats = [];
+    public $full_chats;
     /**
      * Latest chat message ID map for update handling.
      *
@@ -407,6 +413,18 @@ class MTProto extends AsyncConstruct implements TLCallback
      * @var \danog\MadelineProto\TL\TL
      */
     private $TL;
+
+    /**
+     * List of properties stored in database (memory or external)
+     * @see DbPropertiesFabric
+     * @var array
+     */
+    private array $dbProperies = [
+        'chats' => 'array',
+        'full_chats' => 'array',
+        'channel_participants' => 'array'
+    ];
+
     /**
      * Constructor function.
      *
@@ -540,6 +558,18 @@ class MTProto extends AsyncConstruct implements TLCallback
             'reportDest'
         ];
     }
+
+    public function initDb(bool $reset = false): void
+    {
+        foreach ($this->dbProperies as $property => $type) {
+            if ($reset) {
+                unset($this->{$property});
+            } else {
+                $this->{$property} = DbPropertiesFabric::get($this->settings['db'], $type, $property, $this->{$property});
+            }
+        }
+    }
+
     /**
      * Cleanup memory and session file.
      *
@@ -751,6 +781,9 @@ class MTProto extends AsyncConstruct implements TLCallback
             }
             $this->TL->init($this->settings['tl_schema']['src'], $callbacks);
         }
+
+        $this->initDb();
+
     }
     /**
      * Upgrade MadelineProto instance.
@@ -777,9 +810,9 @@ class MTProto extends AsyncConstruct implements TLCallback
         if (isset($settings['authorization']['rsa_key'])) {
             unset($settings['authorization']['rsa_key']);
         }
-        if (!isset($this->full_chats)) {
-            $this->full_chats = [];
-        }
+
+        $this->initDb();
+
         if (!isset($this->secret_chats)) {
             $this->secret_chats = [];
         }
@@ -799,6 +832,8 @@ class MTProto extends AsyncConstruct implements TLCallback
                 $chat['mtproto'] = 1;
             }
         }
+        unset($chat);
+
         foreach ($settings['connection_settings'] as $key => &$connection) {
             if (\in_array($key, ['default_dc', 'media_socket_count', 'robin_period'])) {
                 continue;
@@ -821,6 +856,8 @@ class MTProto extends AsyncConstruct implements TLCallback
                 $connection['obfuscated'] = true;
             }
         }
+        unset($connection);
+
         $this->resetMTProtoSession(true, true);
         $this->config = ['expires' => -1];
         $this->dh_config = ['version' => 0];
@@ -1244,6 +1281,23 @@ class MTProto extends AsyncConstruct implements TLCallback
             'run_callback' => true,
         ], 'secret_chats' => ['accept_chats' => true],
         'serialization' => ['serialization_interval' => 30, 'cleanup_before_serialization' => false],
+        /**
+         * Where internal database will be stored?
+         *      memory - session file
+         *      sharedMemory - multiples instances share db if run in single process
+         *      mysql - mysql database, shared by all instances in all processes.
+         */
+        'db' => [
+            'type' => 'memory',
+            /** @see Mysql */
+            'mysql' => [
+                'host' => '127.0.0.1',
+                'port' => 3306,
+                'user' => 'root',
+                'password' => '',
+                'database' => 'MadelineProto'
+            ]
+        ],
         'upload' => ['allow_automatic_upload' => true, 'part_size' => 512 * 1024, 'parallel_chunks' => 20], 'download' => ['report_broken_media' => true, 'part_size' => 1024 * 1024, 'parallel_chunks' => 20], 'pwr' => [
             'pwr' => false,
             // Need info ?
@@ -1469,13 +1523,13 @@ class MTProto extends AsyncConstruct implements TLCallback
         $this->authorization = null;
         $this->updates = [];
         $this->secret_chats = [];
-        $this->chats = [];
-        $this->users = [];
+
+        $this->initDb(true);
+
         $this->tos = ['expires' => 0, 'accepted' => true];
         $this->referenceDatabase = new ReferenceDatabase($this);
         $this->minDatabase = new MinDatabase($this);
         $this->dialog_params = ['_' => 'MadelineProto.dialogParams', 'limit' => 0, 'offset_date' => 0, 'offset_id' => 0, 'offset_peer' => ['_' => 'inputPeerEmpty'], 'count' => 0];
-        $this->full_chats = [];
     }
     /**
      * Reset the update state and fetch all updates from the beginning.