The built-in Protobuf extension conflicts with the Protobuf on which Tablestore depends in PHP. As a result, the built-in Tablestore PHP SDKs in the PHP runtime environment cannot be used. For more information, see Dynamically load and unload built-in extensions in the PHP runtime environment. In addition, PHP runtimes dynamically load and unload built-in extensions. We recommend that you use environment variables to remove unnecessary extensions to optimize the startup speed of the runtime environment.