Definition of columns in metabase_internal.QUERY_EXECUTION table

Hi all:

I would like to get some metrics (like the number of executed queries per day, average query response time, etc.) about how people are using metabase in my company, and found table QUERY_Execution under ‘metabase_internal’.

Is this table the best information sources for tracking queries generated by metabase ?
What is the definition of ‘Id’, ‘Hash’, and ‘Executor Id’ in this table ?
If I identify a long running query in table QUERY_Execution, how can I find the corresponding query statement ?

Thanks !