First, take a look at the RequestMode and AMPCpuTime columns for the two rows in DBQL. Chances are, the first time is only doing a "Prepare" to parse the query and retrieve metadata about the result set. The second time is executing the (prepared) query. This is common behavior for many tools, not just WebI.
if the same query ran for the first time its not showing any results second time that is after 10 mins its showing results ?
Not sure why it is happeneing for the same query .