log / capture all the queries executed in drupal I want to log / capture all the queries executed by the drupal?
update, select, insert any query,
is there any hook or what will be the method to do this.
You want Devel. 

It has a lot of helpful tools for Drupal developers, including a helper function to print a summary of all database queries for each page request at the bottom of each page. The summary includes how many times each query was executed on a page (shouldn't run same query multiple times), and how long each query took.