avoid buffer

Author: dnhatn

server/src/main/java/org/elasticsearch/index/codec/tsdb/es819/ES819TSDBDocValuesProducer.java

@@ -1897,7 +1897,6 @@ static BlockLoader.SingletonLongBuilder singletonLongs(
     static final class SingletonLongToDoubleDelegate implements BlockLoader.SingletonLongBuilder {
         private final BlockLoader.SingletonDoubleBuilder doubleBuilder;
         private final BlockDocValuesReader.ToDouble toDouble;
-        private final double[] buffer = new double[ES819TSDBDocValuesFormat.NUMERIC_BLOCK_SIZE];
 
         // The passed builder is used to store the converted double values and produce the final block containing them.
         SingletonLongToDoubleDelegate(BlockLoader.SingletonDoubleBuilder doubleBuilder, BlockDocValuesReader.ToDouble toDouble) {
@@ -1912,11 +1911,7 @@ public BlockLoader.SingletonLongBuilder appendLong(long value) {
 
         @Override
         public BlockLoader.SingletonLongBuilder appendLongs(long[] values, int from, int length) {
-            assert length <= buffer.length : "length " + length + " > " + buffer.length;
-            for (int i = 0; i < length; i++) {
-                buffer[i] = toDouble.convert(values[from + i]);
-            }
-            doubleBuilder.appendDoubles(buffer, 0, length);
+            doubleBuilder.appendLongs(toDouble, values, from, length);
             return this;
         }
 

server/src/main/java/org/elasticsearch/index/mapper/BlockLoader.java

@@ -575,6 +575,8 @@ interface SingletonDoubleBuilder extends Builder {
         SingletonDoubleBuilder appendDouble(double value);
 
         SingletonDoubleBuilder appendDoubles(double[] values, int from, int length);
+
+        SingletonDoubleBuilder appendLongs(BlockDocValuesReader.ToDouble toDouble, long[] values, int from, int length);
     }
 
     interface LongBuilder extends Builder {

test/framework/src/main/java/org/elasticsearch/index/mapper/TestBlock.java

@@ -286,6 +286,20 @@ public BlockLoader.SingletonDoubleBuilder appendDouble(double value) {
                         return this;
                     }
 
+                    @Override
+                    public BlockLoader.SingletonDoubleBuilder appendLongs(
+                        BlockDocValuesReader.ToDouble toDouble,
+                        long[] longValues,
+                        int from,
+                        int length
+                    ) {
+                        for (int i = 0; i < length; i++) {
+                            values[count + i] = toDouble.convert(longValues[from + i]);
+                        }
+                        this.count += length;
+                        return this;
+                    }
+
                     @Override
                     public BlockLoader.Builder appendNull() {
                         throw new UnsupportedOperationException();

x-pack/plugin/esql/compute/src/main/java/org/elasticsearch/compute/lucene/read/SingletonDoubleBuilder.java

@@ -10,6 +10,7 @@
 import org.elasticsearch.compute.data.Block;
 import org.elasticsearch.compute.data.BlockFactory;
 import org.elasticsearch.core.Releasable;
+import org.elasticsearch.index.mapper.BlockDocValuesReader;
 import org.elasticsearch.index.mapper.BlockLoader;
 
 /**
@@ -84,6 +85,15 @@ public BlockLoader.SingletonDoubleBuilder appendDoubles(double[] values, int fro
         return this;
     }
 
+    @Override
+    public BlockLoader.SingletonDoubleBuilder appendLongs(BlockDocValuesReader.ToDouble toDouble, long[] longValues, int from, int length) {
+        for (int i = 0; i < length; i++) {
+            values[count + i] = toDouble.convert(longValues[from + i]);
+        }
+        this.count += length;
+        return this;
+    }
+
     @Override
     public void close() {
         blockFactory.adjustBreaker(-valuesSize(values.length));

x-pack/plugin/esql/compute/src/test/java/org/elasticsearch/compute/lucene/read/SingletonDoubleBuilderTests.java

@@ -72,6 +72,8 @@ private void testRead(BlockFactory factory) throws IOException {
                             double value = Double.longBitsToDouble(docValues.longValue());
                             if (randomBoolean()) {
                                 builder.appendDoubles(new double[] { value }, 0, 1);
+                            } else if (randomBoolean()) {
+                                builder.appendLongs(Double::longBitsToDouble, new long[] { docValues.longValue() }, 0, 1);
                             } else {
                                 builder.appendDouble(value);
                             }