diff --git a/isthmus-cli/src/main/resources/META-INF/native-image/io.substrait/isthmus-cli/reachability-metadata.json b/isthmus-cli/src/main/resources/META-INF/native-image/io.substrait/isthmus-cli/reachability-metadata.json
index a73d84903..97b8ccdda 100644
--- a/isthmus-cli/src/main/resources/META-INF/native-image/io.substrait/isthmus-cli/reachability-metadata.json
+++ b/isthmus-cli/src/main/resources/META-INF/native-image/io.substrait/isthmus-cli/reachability-metadata.json
@@ -13,6 +13,13 @@
         ]
       }
     },
+    {
+      "type": {
+        "proxy": [
+          "org.apache.calcite.rel.metadata.BuiltInMetadata$AllPredicates"
+        ]
+      }
+    },
     {
       "type": {
         "proxy": [
@@ -20,6 +27,13 @@
         ]
       }
     },
+    {
+      "type": {
+        "proxy": [
+          "org.apache.calcite.rel.metadata.BuiltInMetadata$Collation"
+        ]
+      }
+    },
     {
       "type": {
         "proxy": [
@@ -27,6 +41,13 @@
         ]
       }
     },
+    {
+      "type": {
+        "proxy": [
+          "org.apache.calcite.rel.metadata.BuiltInMetadata$ColumnOrigin"
+        ]
+      }
+    },
     {
       "type": {
         "proxy": [
@@ -34,6 +55,13 @@
         ]
       }
     },
+    {
+      "type": {
+        "proxy": [
+          "org.apache.calcite.rel.metadata.BuiltInMetadata$ColumnUniqueness"
+        ]
+      }
+    },
     {
       "type": {
         "proxy": [
@@ -41,6 +69,13 @@
         ]
       }
     },
+    {
+      "type": {
+        "proxy": [
+          "org.apache.calcite.rel.metadata.BuiltInMetadata$CumulativeCost"
+        ]
+      }
+    },
     {
       "type": {
         "proxy": [
@@ -48,6 +83,13 @@
         ]
       }
     },
+    {
+      "type": {
+        "proxy": [
+          "org.apache.calcite.rel.metadata.BuiltInMetadata$DistinctRowCount"
+        ]
+      }
+    },
     {
       "type": {
         "proxy": [
@@ -55,6 +97,13 @@
         ]
       }
     },
+    {
+      "type": {
+        "proxy": [
+          "org.apache.calcite.rel.metadata.BuiltInMetadata$Distribution"
+        ]
+      }
+    },
     {
       "type": {
         "proxy": [
@@ -62,6 +111,13 @@
         ]
       }
     },
+    {
+      "type": {
+        "proxy": [
+          "org.apache.calcite.rel.metadata.BuiltInMetadata$ExplainVisibility"
+        ]
+      }
+    },
     {
       "type": {
         "proxy": [
@@ -69,6 +125,13 @@
         ]
       }
     },
+    {
+      "type": {
+        "proxy": [
+          "org.apache.calcite.rel.metadata.BuiltInMetadata$ExpressionLineage"
+        ]
+      }
+    },
     {
       "type": {
         "proxy": [
@@ -76,6 +139,13 @@
         ]
       }
     },
+    {
+      "type": {
+        "proxy": [
+          "org.apache.calcite.rel.metadata.BuiltInMetadata$FunctionalDependency"
+        ]
+      }
+    },
     {
       "type": {
         "proxy": [
@@ -83,6 +153,13 @@
         ]
       }
     },
+    {
+      "type": {
+        "proxy": [
+          "org.apache.calcite.rel.metadata.BuiltInMetadata$InputFieldsUsed"
+        ]
+      }
+    },
     {
       "type": {
         "proxy": [
@@ -90,6 +167,13 @@
         ]
       }
     },
+    {
+      "type": {
+        "proxy": [
+          "org.apache.calcite.rel.metadata.BuiltInMetadata$LowerBoundCost"
+        ]
+      }
+    },
     {
       "type": {
         "proxy": [
@@ -97,6 +181,13 @@
         ]
       }
     },
+    {
+      "type": {
+        "proxy": [
+          "org.apache.calcite.rel.metadata.BuiltInMetadata$MaxRowCount"
+        ]
+      }
+    },
     {
       "type": {
         "proxy": [
@@ -104,6 +195,13 @@
         ]
       }
     },
+    {
+      "type": {
+        "proxy": [
+          "org.apache.calcite.rel.metadata.BuiltInMetadata$Measure"
+        ]
+      }
+    },
     {
       "type": {
         "proxy": [
@@ -111,6 +209,13 @@
         ]
       }
     },
+    {
+      "type": {
+        "proxy": [
+          "org.apache.calcite.rel.metadata.BuiltInMetadata$Memory"
+        ]
+      }
+    },
     {
       "type": {
         "proxy": [
@@ -118,6 +223,13 @@
         ]
       }
     },
+    {
+      "type": {
+        "proxy": [
+          "org.apache.calcite.rel.metadata.BuiltInMetadata$MinRowCount"
+        ]
+      }
+    },
     {
       "type": {
         "proxy": [
@@ -125,6 +237,13 @@
         ]
       }
     },
+    {
+      "type": {
+        "proxy": [
+          "org.apache.calcite.rel.metadata.BuiltInMetadata$NodeTypes"
+        ]
+      }
+    },
     {
       "type": {
         "proxy": [
@@ -132,6 +251,13 @@
         ]
       }
     },
+    {
+      "type": {
+        "proxy": [
+          "org.apache.calcite.rel.metadata.BuiltInMetadata$NonCumulativeCost"
+        ]
+      }
+    },
     {
       "type": {
         "proxy": [
@@ -139,6 +265,13 @@
         ]
       }
     },
+    {
+      "type": {
+        "proxy": [
+          "org.apache.calcite.rel.metadata.BuiltInMetadata$Parallelism"
+        ]
+      }
+    },
     {
       "type": {
         "proxy": [
@@ -146,6 +279,13 @@
         ]
       }
     },
+    {
+      "type": {
+        "proxy": [
+          "org.apache.calcite.rel.metadata.BuiltInMetadata$PercentageOriginalRows"
+        ]
+      }
+    },
     {
       "type": {
         "proxy": [
@@ -153,6 +293,13 @@
         ]
       }
     },
+    {
+      "type": {
+        "proxy": [
+          "org.apache.calcite.rel.metadata.BuiltInMetadata$PopulationSize"
+        ]
+      }
+    },
     {
       "type": {
         "proxy": [
@@ -160,6 +307,13 @@
         ]
       }
     },
+    {
+      "type": {
+        "proxy": [
+          "org.apache.calcite.rel.metadata.BuiltInMetadata$Predicates"
+        ]
+      }
+    },
     {
       "type": {
         "proxy": [
@@ -167,6 +321,13 @@
         ]
       }
     },
+    {
+      "type": {
+        "proxy": [
+          "org.apache.calcite.rel.metadata.BuiltInMetadata$RowCount"
+        ]
+      }
+    },
     {
       "type": {
         "proxy": [
@@ -174,6 +335,13 @@
         ]
       }
     },
+    {
+      "type": {
+        "proxy": [
+          "org.apache.calcite.rel.metadata.BuiltInMetadata$Selectivity"
+        ]
+      }
+    },
     {
       "type": {
         "proxy": [
@@ -181,6 +349,13 @@
         ]
       }
     },
+    {
+      "type": {
+        "proxy": [
+          "org.apache.calcite.rel.metadata.BuiltInMetadata$Size"
+        ]
+      }
+    },
     {
       "type": {
         "proxy": [
@@ -188,6 +363,13 @@
         ]
       }
     },
+    {
+      "type": {
+        "proxy": [
+          "org.apache.calcite.rel.metadata.BuiltInMetadata$TableReferences"
+        ]
+      }
+    },
     {
       "type": {
         "proxy": [
@@ -195,6 +377,13 @@
         ]
       }
     },
+    {
+      "type": {
+        "proxy": [
+          "org.apache.calcite.rel.metadata.BuiltInMetadata$UniqueKeys"
+        ]
+      }
+    },
     {
       "type": {
         "proxy": [
diff --git a/isthmus-cli/src/test/script/smoke.sh b/isthmus-cli/src/test/script/smoke.sh
index 8a25ef0b3..9b7fd84cb 100755
--- a/isthmus-cli/src/test/script/smoke.sh
+++ b/isthmus-cli/src/test/script/smoke.sh
@@ -18,6 +18,13 @@ echo "${LINEITEM}"
 # SQL Query - Aggregate
 "${CMD}" 'select l_orderkey, count(l_partkey) from lineitem group by l_orderkey' --create "${LINEITEM}"
 
+# SQL Query - Grouping-only aggregate (no aggregate function; exercises the column-uniqueness
+# metadata query that must not fall back to Janino runtime codegen in the native image)
+"${CMD}" 'select l_orderkey from lineitem group by l_orderkey' --create "${LINEITEM}"
+
+# SQL Query - DISTINCT (same metadata-query path as grouping-only aggregate)
+"${CMD}" 'select distinct l_orderkey from lineitem' --create "${LINEITEM}"
+
 # SQL Expression - Literal expression
 "${CMD}" --expression '10'
 
diff --git a/isthmus/src/main/java/io/substrait/isthmus/ConverterProvider.java b/isthmus/src/main/java/io/substrait/isthmus/ConverterProvider.java
index f8b4b130e..cce2741fa 100644
--- a/isthmus/src/main/java/io/substrait/isthmus/ConverterProvider.java
+++ b/isthmus/src/main/java/io/substrait/isthmus/ConverterProvider.java
@@ -343,11 +343,14 @@ public ExpressionRexConverter getExpressionRexConverter(
    * @return a new RelBuilder instance
    */
   public RelBuilder getRelBuilder(CalciteSchema schema) {
-    return RelBuilder.create(
-        Frameworks.newConfigBuilder()
-            .defaultSchema(schema.plus())
-            .typeSystem(getTypeSystem())
-            .build());
+    RelBuilder relBuilder =
+        RelBuilder.create(
+            Frameworks.newConfigBuilder()
+                .defaultSchema(schema.plus())
+                .typeSystem(getTypeSystem())
+                .build());
+    Utils.useReflectiveMetadataProvider(relBuilder.getCluster());
+    return relBuilder;
   }
 
   // Utility Getters
diff --git a/isthmus/src/main/java/io/substrait/isthmus/SqlConverterBase.java b/isthmus/src/main/java/io/substrait/isthmus/SqlConverterBase.java
index 30938403e..d6b30a7c3 100644
--- a/isthmus/src/main/java/io/substrait/isthmus/SqlConverterBase.java
+++ b/isthmus/src/main/java/io/substrait/isthmus/SqlConverterBase.java
@@ -6,9 +6,6 @@
 import org.apache.calcite.plan.RelOptCluster;
 import org.apache.calcite.plan.RelOptCostImpl;
 import org.apache.calcite.plan.volcano.VolcanoPlanner;
-import org.apache.calcite.rel.metadata.DefaultRelMetadataProvider;
-import org.apache.calcite.rel.metadata.ProxyingMetadataHandlerProvider;
-import org.apache.calcite.rel.metadata.RelMetadataQuery;
 import org.apache.calcite.rel.type.RelDataTypeFactory;
 import org.apache.calcite.rex.RexBuilder;
 import org.apache.calcite.sql.parser.SqlParser;
@@ -57,12 +54,7 @@ protected SqlConverterBase(ConverterProvider converterProvider) {
     this.converterConfig = converterProvider.getSqlToRelConverterConfig();
     VolcanoPlanner planner = new VolcanoPlanner(RelOptCostImpl.FACTORY, Contexts.of("hello"));
     this.relOptCluster = RelOptCluster.create(planner, new RexBuilder(factory));
-    relOptCluster.setMetadataQuerySupplier(
-        () -> {
-          ProxyingMetadataHandlerProvider handler =
-              new ProxyingMetadataHandlerProvider(DefaultRelMetadataProvider.INSTANCE);
-          return new RelMetadataQuery(handler);
-        });
+    Utils.useReflectiveMetadataProvider(relOptCluster);
     parserConfig = converterProvider.getSqlParserConfig();
   }
 }
diff --git a/isthmus/src/main/java/io/substrait/isthmus/SubstraitRelNodeConverter.java b/isthmus/src/main/java/io/substrait/isthmus/SubstraitRelNodeConverter.java
index 26f063c7b..1fe0f8515 100644
--- a/isthmus/src/main/java/io/substrait/isthmus/SubstraitRelNodeConverter.java
+++ b/isthmus/src/main/java/io/substrait/isthmus/SubstraitRelNodeConverter.java
@@ -164,6 +164,7 @@ public static RelNode convert(
                 .typeSystem(converterProvider.getTypeSystem())
                 .programs()
                 .build());
+    Utils.useReflectiveMetadataProvider(relBuilder.getCluster());
     // Normalize any offset-based outer references (steps_out) to the id-based form (rel_anchor /
     // rel_reference) so the conversion below resolves correlations purely by anchor. Plans that are
     // already id-based are left unchanged.
diff --git a/isthmus/src/main/java/io/substrait/isthmus/Utils.java b/isthmus/src/main/java/io/substrait/isthmus/Utils.java
index 9804954eb..92f56e7a8 100644
--- a/isthmus/src/main/java/io/substrait/isthmus/Utils.java
+++ b/isthmus/src/main/java/io/substrait/isthmus/Utils.java
@@ -10,6 +10,10 @@
 import java.util.function.BiFunction;
 import java.util.stream.Stream;
 import org.apache.calcite.jdbc.CalciteSchema;
+import org.apache.calcite.plan.RelOptCluster;
+import org.apache.calcite.rel.metadata.DefaultRelMetadataProvider;
+import org.apache.calcite.rel.metadata.ProxyingMetadataHandlerProvider;
+import org.apache.calcite.rel.metadata.RelMetadataQuery;
 import org.jspecify.annotations.NonNull;
 
 /**
@@ -99,4 +103,28 @@ public static CalciteSchema createCalciteSchemaFromNames(
 
     return schema;
   }
+
+  /**
+   * Configures {@code cluster} to answer relational-metadata queries with handlers built via {@link
+   * java.lang.reflect.Proxy reflection} rather than runtime code generation.
+   *
+   * <p>Calcite's default {@link RelMetadataQuery} obtains its handlers from {@code
+   * JaninoRelMetadataProvider}, which compiles a handler class at runtime with Janino. Runtime code
+   * generation is unavailable in a GraalVM native image (closed-world, ahead-of-time compiled), so
+   * any metadata query — e.g. the column-uniqueness check {@code RelBuilder} runs for a grouping
+   * {@code aggregate} or {@code DISTINCT} — fails there. {@link ProxyingMetadataHandlerProvider}
+   * builds the same handlers with dynamic proxies, which are supported in native images once the
+   * handler interfaces are registered.
+   *
+   * <p>Apply this to every {@link RelOptCluster} used while converting to or from Calcite so the
+   * native image never reaches the Janino-backed path.
+   *
+   * @param cluster the cluster to configure
+   */
+  public static void useReflectiveMetadataProvider(final RelOptCluster cluster) {
+    cluster.setMetadataQuerySupplier(
+        () ->
+            new RelMetadataQuery(
+                new ProxyingMetadataHandlerProvider(DefaultRelMetadataProvider.INSTANCE)));
+  }
 }
diff --git a/isthmus/src/main/java/io/substrait/isthmus/sql/SubstraitSqlToCalcite.java b/isthmus/src/main/java/io/substrait/isthmus/sql/SubstraitSqlToCalcite.java
index 82650291b..29c0f93cf 100644
--- a/isthmus/src/main/java/io/substrait/isthmus/sql/SubstraitSqlToCalcite.java
+++ b/isthmus/src/main/java/io/substrait/isthmus/sql/SubstraitSqlToCalcite.java
@@ -2,6 +2,7 @@
 
 import io.substrait.isthmus.ConverterProvider;
 import io.substrait.isthmus.SubstraitTypeSystem;
+import io.substrait.isthmus.Utils;
 import io.substrait.isthmus.calcite.rel.DdlSqlToRelConverter;
 import java.util.List;
 import java.util.stream.Collectors;
@@ -256,6 +257,8 @@ static RelOptCluster createDefaultRelOptCluster() {
         new RexBuilder(new JavaTypeFactoryImpl(SubstraitTypeSystem.TYPE_SYSTEM));
     HepProgram program = HepProgram.builder().build();
     RelOptPlanner emptyPlanner = new HepPlanner(program);
-    return RelOptCluster.create(emptyPlanner, rexBuilder);
+    RelOptCluster cluster = RelOptCluster.create(emptyPlanner, rexBuilder);
+    Utils.useReflectiveMetadataProvider(cluster);
+    return cluster;
   }
 }