Re: queryId constant squashing does not support prepared statements

> I also agree with Alvaro that this discussion doesn't justify a
> revert. If the pre-v18 behavior wasn't chiseled on stone tablets,
> the new behavior isn't either. We can improve it some more later.

As I was looking further into what we currently have in v18 and HEAD
the normalization could break if we pass a function.

For example,
"""
select where 1 in (1, 2, int4(1));
"""
the normalized string is,

"""
select where $1 in ($2 /*, ... */))
"""

Notice the extra close parenthesis that is added after the comment. This is
because although int4(1) is a function call it is rewritten as a Const
and that breaks the assumptions being made by the location of the
last expression.

Also, something like:
"""
select where 1 in (1, 2, cast(4 as int));
"""
is normalized as:
"""
select where $1 in ($2 /*, ... */ as int))
"""

I don't think the current state is acceptable, if it results in pg_s_s
storing an invalid normalized version of the sql.

Now, with the attached v2 supporting external params, we see other normalization
anomalies such as

"""
postgres=# select where $1 in ($3, $2) and 1 in ($4, cast($5 as int))
\bind 0 1 2 3 4
postgres-# ;
--
(0 rows)

postgres=# select toplevel, query, calls from pg_stat_statements;
toplevel | query
| calls
----------+-------------------------------------------------------------------------+-------
t | select where $1 in ($2 /*, ... */) and $3 in ($4 /*, ...
*/($5 as int)) | 1
(1 row)
"""

Without properly accounting for the boundaries of the list of expressions, i.e.,
the start and end positions of '(' and ')' or '[' and ']' and normalizing the
expressions in between, it will be very difficult for the normalization to
behave sanely.

thoughts?

--
Sami Imseih
Amazon Web Services (AWS)