pg_stat_statements considers a plain select and a select for update tobe equivalent, which seems quite wrong to me as they will have verydifferent performance characteristics due to locking.
The only comment about it in the code is:
/* we ignore rowMarks */
I propose that it should not ignore rowMarks, per the attached patch orsomething similar.
(thanks to Vik Fearing for preliminary testing)
-- Andrew (irc:RhodiumToad)