Restore the fix for AvgDoubleGroupByFunction

puzpuzpuz · puzpuzpuz · commit bcd0a23eec92 · 2026-03-04T22:54:07.000+02:00
diff --git a/core/src/main/java/io/questdb/griffin/engine/functions/groupby/AvgDoubleGroupByFunction.java b/core/src/main/java/io/questdb/griffin/engine/functions/groupby/AvgDoubleGroupByFunction.java
@@ -52,7 +52,7 @@ public void computeBatch(MapValue mapValue, long ptr, int count, long startRowId
             final double batchSum = Vect.sumDoubleAcc(ptr, count, countPtr);
             if (!Numbers.isNull(batchSum)) {
                 final double prevSum = mapValue.getDouble(valueIndex);
-                if (Numbers.isFinite(prevSum)) {
+                if (!Double.isNaN(prevSum)) {
                     mapValue.putDouble(valueIndex, prevSum + batchSum);
                 } else {
                     mapValue.putDouble(valueIndex, batchSum);
diff --git a/core/src/test/java/io/questdb/test/griffin/engine/functions/groupby/DoubleGroupByFunctionBatchTest.java b/core/src/test/java/io/questdb/test/griffin/engine/functions/groupby/DoubleGroupByFunctionBatchTest.java
@@ -58,9 +58,10 @@ public void tearDown() {
     }
 
     // Verify that computeBatch is consistent with computeNext: when the running sum
-    // overflows to +Infinity, the next finite batch overwrites it (resets the accumulator).
+    // overflows to +Infinity, it is preserved. AvgDouble's computeNext uses addDouble
+    // with no inner guard, so Infinity + finite = Infinity naturally.
     @Test
-    public void testAvgDoubleBatchAccumulatedInfinityIsOverwritten() {
+    public void testAvgDoubleBatchAccumulatedInfinityIsPreserved() {
         AvgDoubleGroupByFunction function = new AvgDoubleGroupByFunction(DoubleColumn.newInstance(COLUMN_INDEX));
         try (SimpleMapValue value = prepare(function)) {
             // Batch 1: running sum = MAX_VALUE (finite)
@@ -71,12 +72,12 @@ public void testAvgDoubleBatchAccumulatedInfinityIsOverwritten() {
             ptr = allocateDoubles(Double.MAX_VALUE);
             function.computeBatch(value, ptr, 1, 0);
 
-            // Batch 3: Infinity is not finite, so the accumulator resets to 1.0
+            // Batch 3: Infinity is preserved, not overwritten
             ptr = allocateDoubles(1.0);
             function.computeBatch(value, ptr, 1, 0);
 
-            // avg = 1.0 / 3 (count is still 3)
-            Assert.assertEquals(1.0 / 3.0, function.getDouble(value), 1e-15);
+            // avg = Infinity / 3 = Infinity
+            Assert.assertTrue(Double.isInfinite(function.getDouble(value)));
         }
     }
 
