1

paimon-common/src/main/java/org/apache/paimon/table/SystemFields.java

@@ -0,0 +1,48 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.paimon.table;
+
+import org.apache.paimon.types.DataField;
+import org.apache.paimon.types.DataTypes;
+
+import java.util.Set;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+/** System columns. */
+public class SystemFields {
+
+    public static final int SYSTEM_FIELD_ID_START = Integer.MAX_VALUE / 2;
+
+    public static final String KEY_FIELD_PREFIX = "_KEY_";
+    public static final int KEY_FIELD_ID_START = SYSTEM_FIELD_ID_START;
+
+    public static final DataField SEQUENCE_NUMBER =
+            new DataField(Integer.MAX_VALUE - 1, "_SEQUENCE_NUMBER", DataTypes.BIGINT().notNull());
+
+    public static final DataField VALUE_KIND =
+            new DataField(Integer.MAX_VALUE - 2, "_VALUE_KIND", DataTypes.TINYINT().notNull());
+
+    public static final DataField LEVEL =
+            new DataField(Integer.MAX_VALUE - 3, "_LEVEL", DataTypes.INT().notNull());
+
+    public static final Set<String> SYSTEM_FIELD_NAMES =
+            Stream.of(SEQUENCE_NUMBER.name(), VALUE_KIND.name(), LEVEL.name())
+                    .collect(Collectors.toSet());
+}

paimon-common/src/main/java/org/apache/paimon/types/RowType.java

@@ -20,6 +20,7 @@
 
 import org.apache.paimon.annotation.Public;
 import org.apache.paimon.data.InternalRow;
+import org.apache.paimon.table.SystemFields;
 import org.apache.paimon.utils.Preconditions;
 import org.apache.paimon.utils.StringUtils;
 
@@ -256,7 +257,10 @@ public static RowType of(DataType[] types, String[] names) {
     public static int currentHighestFieldId(List<DataField> fields) {
         Set<Integer> fieldIds = new HashSet<>();
         new RowType(fields).collectFieldIds(fieldIds);
-        return fieldIds.stream().max(Integer::compareTo).orElse(-1);
+        return fieldIds.stream()
+                .filter(i -> i < SystemFields.SYSTEM_FIELD_ID_START)
+                .max(Integer::compareTo)
+                .orElse(-1);
     }
 
     public static Builder builder() {

paimon-core/src/main/java/org/apache/paimon/KeyValue.java

@@ -21,23 +21,19 @@
 import org.apache.paimon.annotation.VisibleForTesting;
 import org.apache.paimon.data.InternalRow;
 import org.apache.paimon.data.serializer.InternalRowSerializer;
-import org.apache.paimon.types.BigIntType;
 import org.apache.paimon.types.DataField;
-import org.apache.paimon.types.DataTypes;
 import org.apache.paimon.types.RowKind;
 import org.apache.paimon.types.RowType;
-import org.apache.paimon.types.TinyIntType;
 import org.apache.paimon.utils.InternalRowUtils;
 
 import java.util.ArrayList;
 import java.util.List;
 import java.util.stream.Collectors;
 import java.util.stream.IntStream;
 
-import static org.apache.paimon.schema.SystemColumns.LEVEL;
-import static org.apache.paimon.schema.SystemColumns.SEQUENCE_NUMBER;
-import static org.apache.paimon.schema.SystemColumns.VALUE_KIND;
-import static org.apache.paimon.utils.Preconditions.checkState;
+import static org.apache.paimon.table.SystemFields.LEVEL;
+import static org.apache.paimon.table.SystemFields.SEQUENCE_NUMBER;
+import static org.apache.paimon.table.SystemFields.VALUE_KIND;
 
 /**
  * A key value, including user key, sequence number, value kind and value. This object can be
@@ -115,70 +111,29 @@ public KeyValue setLevel(int level) {
     }
 
     public static RowType schema(RowType keyType, RowType valueType) {
-        List<DataField> fields = new ArrayList<>(keyType.getFields());
-        fields.add(new DataField(0, SEQUENCE_NUMBER, new BigIntType(false)));
-        fields.add(new DataField(1, VALUE_KIND, new TinyIntType(false)));
-        fields.addAll(valueType.getFields());
-        return new RowType(fields);
+        return new RowType(createKeyValueFields(keyType.getFields(), valueType.getFields()));
     }
 
     public static RowType schemaWithLevel(RowType keyType, RowType valueType) {
-        RowType.Builder builder = RowType.builder();
-        schema(keyType, valueType)
-                .getFields()
-                .forEach(f -> builder.field(f.name(), f.type(), f.description()));
-        builder.field(LEVEL, DataTypes.INT().notNull());
-        return builder.build();
+        List<DataField> fields = new ArrayList<>(schema(keyType, valueType).getFields());
+        fields.add(LEVEL);
+        return new RowType(fields);
     }
 
     /**
-     * Create key-value fields, we need to add a const value to the id of value field to ensure that
-     * they are consistent when compared by field id. For example, there are two table with key
-     * value fields as follows
-     *
-     * <ul>
-     *   <li>Table1 key fields: 1->a, 2->b, 3->c; value fields: 0->value_count
-     *   <li>Table2 key fields: 1->c, 3->d, 4->a, 5->b; value fields: 0->value_count
-     * </ul>
-     *
-     * <p>We will use 5 as maxKeyId, and create fields for Table1/Table2 as follows
-     *
-     * <ul>
-     *   <li>Table1 fields: 1->a, 2->b, 3->c, 6->seq, 7->kind, 8->value_count
-     *   <li>Table2 fields: 1->c, 3->d, 4->a, 5->b, 6->seq, 7->kind, 8->value_count
-     * </ul>
-     *
-     * <p>Then we can compare these two table fields with the field id.
+     * Create key-value fields
      *
      * @param keyFields the key fields
      * @param valueFields the value fields
-     * @param maxKeyId the max key id
      * @return the table fields
      */
     public static List<DataField> createKeyValueFields(
-            List<DataField> keyFields, List<DataField> valueFields, final int maxKeyId) {
-        checkState(maxKeyId >= keyFields.stream().mapToInt(DataField::id).max().orElse(0));
-
+            List<DataField> keyFields, List<DataField> valueFields) {
         List<DataField> fields = new ArrayList<>(keyFields.size() + valueFields.size() + 2);
         fields.addAll(keyFields);
-        fields.add(
-                new DataField(
-                        maxKeyId + 1,
-                        SEQUENCE_NUMBER,
-                        new org.apache.paimon.types.BigIntType(false)));
-        fields.add(
-                new DataField(
-                        maxKeyId + 2, VALUE_KIND, new org.apache.paimon.types.TinyIntType(false)));
-        for (DataField valueField : valueFields) {
-            DataField newValueField =
-                    new DataField(
-                            valueField.id() + maxKeyId + 3,
-                            valueField.name(),
-                            valueField.type(),
-                            valueField.description());
-            fields.add(newValueField);
-        }
-
+        fields.add(SEQUENCE_NUMBER);
+        fields.add(VALUE_KIND);
+        fields.addAll(valueFields);
         return fields;
     }
 

paimon-core/src/main/java/org/apache/paimon/schema/SchemaEvolutionUtil.java

@@ -217,14 +217,9 @@ public static IndexCastMapping createIndexCastMapping(
             int[] dataProjection,
             List<DataField> dataKeyFields,
             List<DataField> dataValueFields) {
-        int maxKeyId =
-                Math.max(
-                        tableKeyFields.stream().mapToInt(DataField::id).max().orElse(0),
-                        dataKeyFields.stream().mapToInt(DataField::id).max().orElse(0));
         List<DataField> tableFields =
-                KeyValue.createKeyValueFields(tableKeyFields, tableValueFields, maxKeyId);
-        List<DataField> dataFields =
-                KeyValue.createKeyValueFields(dataKeyFields, dataValueFields, maxKeyId);
+                KeyValue.createKeyValueFields(tableKeyFields, tableValueFields);
+        List<DataField> dataFields = KeyValue.createKeyValueFields(dataKeyFields, dataValueFields);
         return createIndexCastMapping(tableProjection, tableFields, dataProjection, dataFields);
     }
 

paimon-core/src/main/java/org/apache/paimon/schema/SchemaValidation.java

@@ -68,8 +68,8 @@
 import static org.apache.paimon.CoreOptions.SNAPSHOT_NUM_RETAINED_MIN;
 import static org.apache.paimon.CoreOptions.STREAMING_READ_OVERWRITE;
 import static org.apache.paimon.mergetree.compact.PartialUpdateMergeFunction.SEQUENCE_GROUP;
-import static org.apache.paimon.schema.SystemColumns.KEY_FIELD_PREFIX;
-import static org.apache.paimon.schema.SystemColumns.SYSTEM_FIELD_NAMES;
+import static org.apache.paimon.table.SystemFields.KEY_FIELD_PREFIX;
+import static org.apache.paimon.table.SystemFields.SYSTEM_FIELD_NAMES;
 import static org.apache.paimon.types.DataTypeRoot.ARRAY;
 import static org.apache.paimon.types.DataTypeRoot.MAP;
 import static org.apache.paimon.types.DataTypeRoot.MULTISET;

paimon-core/src/main/java/org/apache/paimon/table/PrimaryKeyTableUtils.java

@@ -34,7 +34,8 @@
 import java.util.List;
 import java.util.stream.Collectors;
 
-import static org.apache.paimon.schema.SystemColumns.KEY_FIELD_PREFIX;
+import static org.apache.paimon.table.SystemFields.KEY_FIELD_ID_START;
+import static org.apache.paimon.table.SystemFields.KEY_FIELD_PREFIX;
 
 /** Utils for creating changelog table with primary keys. */
 public class PrimaryKeyTableUtils {
@@ -45,7 +46,7 @@ public static RowType addKeyNamePrefix(RowType type) {
 
     public static List<DataField> addKeyNamePrefix(List<DataField> keyFields) {
         return keyFields.stream()
-                .map(f -> f.newName(KEY_FIELD_PREFIX + f.name()))
+                .map(f -> f.newName(KEY_FIELD_PREFIX + f.name()).newId(f.id() + KEY_FIELD_ID_START))
                 .collect(Collectors.toList());
     }
 

paimon-core/src/test/java/org/apache/paimon/table/SchemaEvolutionTest.java

@@ -57,8 +57,8 @@
 import java.util.UUID;
 import java.util.function.Consumer;
 
-import static org.apache.paimon.schema.SystemColumns.KEY_FIELD_PREFIX;
-import static org.apache.paimon.schema.SystemColumns.SYSTEM_FIELD_NAMES;
+import static org.apache.paimon.table.SystemFields.KEY_FIELD_PREFIX;
+import static org.apache.paimon.table.SystemFields.SYSTEM_FIELD_NAMES;
 import static org.apache.paimon.testutils.assertj.PaimonAssertions.anyCauseMatches;
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
@@ -424,23 +424,6 @@ public void testDropAllFields() throws Exception {
 
     @Test
     public void testCreateAlterSystemField() throws Exception {
-        Schema schema1 =
-                new Schema(
-                        RowType.of(
-                                        new DataType[] {DataTypes.INT(), DataTypes.BIGINT()},
-                                        new String[] {"f0", "_VALUE_COUNT"})
-                                .getFields(),
-                        Collections.emptyList(),
-                        Collections.emptyList(),
-                        new HashMap<>(),
-                        "");
-        assertThatThrownBy(() -> schemaManager.createTable(schema1))
-                .isInstanceOf(IllegalStateException.class)
-                .hasMessage(
-                        String.format(
-                                "Field name[%s] in schema cannot be exist in %s",
-                                "_VALUE_COUNT", SYSTEM_FIELD_NAMES));
-
         Schema schema2 =
                 new Schema(
                         RowType.of(