Postgres filtering by tstzrange not ended - postgresql

Question

I have a trigger function using a temporal postgres table. Which is versioned by a 'sys_period' variable defined as a tstzrange. I can see my trigger fails since it does not approriate filter only the active rows in the table.
CREATE OR REPLACE FUNCTION update_analysis_{0}_function()
RETURNS trigger
LANGUAGE 'plpgsql'
AS
$$
BEGIN
UPDATE analysis
SET finish_date = (
SELECT STRICT_MAX(performed_on)
FROM task
WHERE analysis_id = NEW.analysis_id
)
WHERE id = NEW.analysis_id;
return NEW;
END;
$$;
CREATE TRIGGER update_analysis_{0}
AFTER INSERT OR DELETE OR UPDATE OF performed_on
ON task
FOR EACH ROW
EXECUTE PROCEDURE update_analysis_{0}_function();
Both the analysis table and the task table has versioning with sysperiod. (The strict_max is from https://wiki.postgresql.org/wiki/Aggregate_strict_min_and_max)
The current version gets bugs which could be fixed if I could filter on sys_period not ended. making the body look something like this:
BEGIN
UPDATE analysis
SET finish_date = (
SELECT STRICT_MAX(performed_on)
FROM task
WHERE analysis_id = NEW.analysis_id
AND task.sys_period.end = NULL
)
WHERE id = NEW.analysis_id;
AND Analysis.sys_period.end = NULL
return NEW;
END;

Answer 1

The function I was looking for was upper_inf. Giving the following solution:
UPDATE analysis
SET finish_date = (
SELECT STRICT_MAX(performed_on)
FROM task
WHERE analysis_id = NEW.analysis_id
AND upper_inf(task.sys_period)
)
WHERE id = NEW.analysis_id;
AND upper_inf(task.sys_period)
return NEW;
END;