diff --git a/core/trino-main/src/main/java/io/trino/operator/output/SlicePositionsAppender.java b/core/trino-main/src/main/java/io/trino/operator/output/SlicePositionsAppender.java
index 63f8ddb3e30a..7b7e4e5f7b13 100644
--- a/core/trino-main/src/main/java/io/trino/operator/output/SlicePositionsAppender.java
+++ b/core/trino-main/src/main/java/io/trino/operator/output/SlicePositionsAppender.java
@@ -196,12 +196,18 @@ private void duplicateBytes(Block block, int position, int count, int startOffse
     {
         int length = block.getSliceLength(position);
         int newByteCount = count * length;
-        ensureBytesCapacity(currentOffset + newByteCount);
+        if (length == 0) {
+            // empty Slice, there is no need to copy anything
+            Arrays.fill(offsets, positionCount + 1, positionCount + count + 1, startOffset);
+        }
+        else {
+            ensureBytesCapacity(currentOffset + newByteCount);
 
-        Slice slice = block.getSlice(position, 0, length);
-        for (int i = 0; i < count; i++) {
-            slice.getBytes(0, bytes, startOffset + (i * length), length);
-            offsets[positionCount + i + 1] = startOffset + ((i + 1) * length);
+            Slice slice = block.getSlice(position, 0, length);
+            for (int i = 0; i < count; i++) {
+                slice.getBytes(0, bytes, startOffset + (i * length), length);
+                offsets[positionCount + i + 1] = startOffset + ((i + 1) * length);
+            }
         }
 
         positionCount += count;
diff --git a/core/trino-main/src/test/java/io/trino/operator/output/TestPositionsAppender.java b/core/trino-main/src/test/java/io/trino/operator/output/TestPositionsAppender.java
index c9ec00c5effa..929eb7c70841 100644
--- a/core/trino-main/src/test/java/io/trino/operator/output/TestPositionsAppender.java
+++ b/core/trino-main/src/test/java/io/trino/operator/output/TestPositionsAppender.java
@@ -61,6 +61,7 @@
 import static io.trino.spi.type.TimestampType.createTimestampType;
 import static io.trino.spi.type.TinyintType.TINYINT;
 import static io.trino.spi.type.VarbinaryType.VARBINARY;
+import static io.trino.spi.type.VarcharType.VARCHAR;
 import static io.trino.spi.type.VarcharType.createUnboundedVarcharType;
 import static java.util.Objects.requireNonNull;
 import static org.testng.Assert.assertEquals;
@@ -215,6 +216,21 @@ public void testConsecutiveBuilds(Type type)
         assertEquals(positionsAppender.build().getPositionCount(), 0);
     }
 
+    // testcase for jit bug described https://github.com/trinodb/trino/issues/12821
+    @Test(priority = Integer.MIN_VALUE)
+    public void testSliceRle()
+    {
+        PositionsAppender positionsAppender = POSITIONS_APPENDER_FACTORY.create(VARCHAR, 10, DEFAULT_MAX_PAGE_SIZE_IN_BYTES);
+
+        // first append some not empty value to avoid RleAwarePositionsAppender for the empty value
+        positionsAppender.appendRle(new RunLengthEncodedBlock(singleValueBlock("some value"), 1));
+        // append empty value multiple times to trigger jit compilation
+        Block emptyStringBlock = singleValueBlock("");
+        for (int i = 0; i < 1000; i++) {
+            positionsAppender.appendRle(new RunLengthEncodedBlock(emptyStringBlock, 2000));
+        }
+    }
+
     @DataProvider(name = "nullRleTypes")
     public static Object[][] nullRleTypes()
     {
@@ -254,6 +270,13 @@ public static Object[][] types()
                 };
     }
 
+    private static Block singleValueBlock(String value)
+    {
+        BlockBuilder blockBuilder = VARCHAR.createBlockBuilder(null, 1);
+        VARCHAR.writeSlice(blockBuilder, Slices.utf8Slice(value));
+        return blockBuilder.build();
+    }
+
     private IntArrayList allPositions(int count)
     {
         return new IntArrayList(IntStream.range(0, count).toArray());