Re: query_id, pg_stat_activity, extended query protocol

> I discovered the current state of queryId reporting and found that it
> may be unlogical: Postgres resets queryId right before query execution
> in simple protocol and doesn't reset it at all in extended protocol and
> other ways to execute queries.

In exec_parse_message, exec_bind_message  and exec_execute_message,
the queryId is reset via pgstat_report_activity

> I think we should generally report it when the backend executes a job
> related to the query with that queryId. This means it would reset the
> queryId at the end of the query execution.

When the query completes execution and the session goes into a state 
other than "active", both the query text and the queryId should be of the 
last executed statement. This is the documented behavior, and I believe
it's the correct behavior.

If we reset queryId at the end of execution, this behavior breaks. Right?

> This seems logical, but
> what about the planning process? If an extension plans a query without
> the intention to execute it for speculative reasons, should we still
> show the queryId? Perhaps we should reset the state right after planning
> to accurately reflect the current queryId.

I think you are suggesting that during planning, the queryId
of the current statement being planned should not be reported.
 
If my understanding is correct, I don't think that is a good idea. Tools that 
snasphot pg_stat_activity will not be able to account for the queryId during
planning. This could mean that certain load on the database cannot be tied
back to a specific queryId.

Regards,

Sami