Bumped to v38

datapoint.go

@@ -162,8 +162,6 @@ func DatapointAdd[T any](name string, value T) (err error) { // {{{
 		return
 	}
 
-	service.Db.Conn.Exec(`UPDATE datapoint SET last_value = NOW(), nodata_is_problem = false WHERE id=$1`, dpID)
-
 	return
 } // }}}
 
@@ -172,30 +170,19 @@ func DatapointsRetrieve() (dps []Datapoint, err error) { // {{{
 	var rows *sqlx.Rows
 	rows, err = service.Db.Conn.Queryx(`
 		SELECT
-			dp.id,
-			dp.name,
-			dp.datatype,
-			dp.last_value,
-			dp.group,
-			dp.comment,
-			dp.nodata_problem_seconds,
-
-			dpv.id AS v_id,
-			dpv.ts,
-			dpv.value_int,
-			dpv.value_string,
-			dpv.value_datetime
-
-		FROM public.datapoint dp
-		LEFT JOIN (
-			SELECT
-				*, 
-				row_number() OVER (PARTITION BY "datapoint_id" ORDER BY ts DESC) AS rn
-			FROM datapoint_value
-		) dpv ON dpv.datapoint_id = dp.id AND rn = 1
+			id, name, datatype, last_value, "group", comment, nodata_problem_seconds,
+			last_value_id AS v_id,
+			CASE
+				WHEN last_value_id IS NULL THEN null
+				ELSE last_value
+			END AS ts,
+			last_value_int AS value_int,
+			last_value_string AS value_string,
+			last_value_datetime AS value_datetime
+		FROM datapoint
 		ORDER BY
-			dp.group ASC,
-			dp.name ASC
+			"group" ASC,
+			name ASC
 	`)
 	if err != nil {
 		err = werr.Wrap(err)

main.go

@@ -29,7 +29,7 @@ import (
 	"time"
 )
 
-const VERSION = "v37"
+const VERSION = "v38"
 
 var (
 	logger              *slog.Logger

sql/00026.sql

@@ -0,0 +1,62 @@
+/* Adding last values to the datapoint table since they are a regularly used value. */
+ALTER TABLE public.datapoint ADD COLUMN last_value_id int4 NULL;
+ALTER TABLE public.datapoint ADD COLUMN last_value_int int8 NULL;
+ALTER TABLE public.datapoint ADD COLUMN last_value_string varchar NULL;
+ALTER TABLE public.datapoint ADD COLUMN last_value_datetime timestamptz NULL;
+
+
+
+/* Once-run query to update it to the latest, to avoid user having to wait for the next entry. */
+UPDATE public.datapoint AS dp
+SET
+    last_value_id = dpv.id,
+    last_value_int = dpv.value_int,
+    last_value_string = dpv.value_string,
+    last_value_datetime = dpv.value_datetime
+FROM (
+	SELECT
+		dp.id AS datapoint_id,
+		dpv.id,
+		dpv.value_int,
+		dpv.value_string,
+		dpv.value_datetime
+	FROM public.datapoint dp
+	LEFT JOIN (
+		SELECT
+			*, 
+			row_number() OVER (PARTITION BY "datapoint_id" ORDER BY ts DESC) AS rn
+		FROM datapoint_value
+	) dpv ON dpv.datapoint_id = dp.id AND rn = 1
+) AS dpv
+WHERE
+	dpv.datapoint_id = dp.id;
+
+
+
+/* A trigger keeps the value current without bugs introduced in software missing the entry. */
+CREATE OR REPLACE FUNCTION datapoint_entry()
+	RETURNS TRIGGER 
+	LANGUAGE PLPGSQL
+	AS
+$$
+BEGIN
+	UPDATE public.datapoint
+	SET
+		nodata_is_problem   = false,
+		last_value          = NEW.ts,
+		last_value_id       = NEW.id,
+		last_value_int      = NEW.value_int,
+		last_value_string   = NEW.value_string,
+		last_value_datetime = NEW.value_datetime
+	WHERE
+		id = NEW.datapoint_id;
+
+	RETURN NEW;
+END;
+$$;
+
+CREATE TRIGGER datapoint_entry
+	AFTER INSERT
+	ON public.datapoint_value
+	FOR EACH ROW
+	EXECUTE PROCEDURE datapoint_entry();