Question

As an example, with this script;

mysql_query("LOCK TABLES mytest WRITE;");

for ($i = 1; $i < 100000; ++$i) {
    mysql_query("INSERT INTO mytest (Value, Value2, Value3) VALUES ($i, $i, $i);");
}

mysql_query("UNLOCK TABLES;");

What would happen if the script timed out / the users computer crashed / whatever before the UNLOCK TABLES stage is reached? Will mysql “notice” the client requesting the lock has disconnected and release the lock appropriately, or will it be stuck infinitively?

Answer 1

According to the MySQL docs:

If the connection for a client session terminates, whether normally or
abnormally, the server implicitly releases all table locks held by the
session (transactional and nontransactional). If the client
reconnects, the locks will no longer be in effect.