diff --git a/mysql_ch_replicator/db_optimizer.py b/mysql_ch_replicator/db_optimizer.py
index 41aea3f..80a4782 100644
--- a/mysql_ch_replicator/db_optimizer.py
+++ b/mysql_ch_replicator/db_optimizer.py
@@ -79,6 +79,7 @@ def optimize_table(self, db_name, table_name):
     def optimize_database(self, db_name):
         self.mysql_api.set_database(db_name)
         tables = self.mysql_api.get_tables()
+        self.mysql_api.close()
         tables = [table for table in tables if self.config.is_table_matches(table)]
 
         self.clickhouse_api.execute_command(f'USE {db_name}')
@@ -97,6 +98,7 @@ def run(self):
         try:
             while not killer.kill_now:
                 db_to_optimize = self.select_db_to_optimize()
+                self.mysql_api.close()
                 if db_to_optimize is None:
                     time.sleep(min(120, self.config.optimize_interval))
                     continue
diff --git a/mysql_ch_replicator/mysql_api.py b/mysql_ch_replicator/mysql_api.py
index 255a3b7..8480933 100644
--- a/mysql_ch_replicator/mysql_api.py
+++ b/mysql_ch_replicator/mysql_api.py
@@ -16,6 +16,7 @@ def __init__(self, database: str, mysql_settings: MysqlSettings):
 
     def close(self):
         self.db.close()
+        self.last_connect_time = 0
 
     def reconnect_if_required(self, force=False):
         curr_time = time.time()
@@ -56,6 +57,7 @@ def execute(self, command, commit=False, args=None):
             self.db.commit()
 
     def set_database(self, database):
+        self.reconnect_if_required()
         self.database = database
         self.cursor = self.db.cursor()
         self.cursor.execute(f'USE {self.database}')