extended events rpc_completed duration does not matching with rpc_starting
My question is &quot;which one tell me how much time the query actually took? Is it Duration in sp_statement_completed or the difference between starting and completed?&quot;

&quot;Duration&quot; in the sp_statement_completed event is how long the query actually took at the server.  It doesn't include the time spent sending results to the client (usually, see here for details).
I'm not 100% sure why the Extended Events timestamp column shows such a large discrepancy between the &quot;starting&quot; and &quot;completed&quot; events, but that's not where you want to focus your attention.