[rrd4j] Reuse the state for identical values (openhab#16379)

Signed-off-by: Jörg Sautter <joerg.sautter@gmx.net> Signed-off-by: Jørgen Austvik <jaustvik@acm.org>
austvik · Mar 27, 2024 · 283c884 · 283c884
1 parent 2dc420b
commit 283c884
Showing 1 changed file with 13 additions and 1 deletion.
diff --git a/...e.rrd4j/src/main/java/org/openhab/persistence/rrd4j/internal/RRD4jPersistenceService.java b/...e.rrd4j/src/main/java/org/openhab/persistence/rrd4j/internal/RRD4jPersistenceService.java
@@ -491,9 +491,21 @@ public Iterable<HistoricItem> query(FilterCriteria filter) {
             long ts = result.getFirstTimestamp();
             ZonedDateTime zdt = ZonedDateTime.ofInstant(Instant.ofEpochSecond(ts), ZoneId.systemDefault());
             long step = result.getRowCount() > 1 ? result.getStep() : 0;
+
+            double prevValue = Double.NaN;
+            State prevState = null;
             for (double value : result.getValues(DATASOURCE_STATE)) {
                 if (!Double.isNaN(value) && (((ts >= start) && (ts <= end)) || (start == end))) {
-                    RRD4jItem rrd4jItem = new RRD4jItem(itemName, toState.apply(value), zdt);
+                    State state;
+
+                    if (prevValue == value) {
+                        state = prevState;
+                    } else {
+                        prevState = state = toState.apply(value);
+                        prevValue = value;
+                    }
+
+                    RRD4jItem rrd4jItem = new RRD4jItem(itemName, state, zdt);
                     items.add(rrd4jItem);
                 }
                 zdt = zdt.plusSeconds(step);