[server] Support max partition number of a table

fluss-client/src/test/java/com/alibaba/fluss/client/admin/ClientToServerITCaseBase.java

@@ -115,6 +115,8 @@ private static Configuration initConfig() {
 
         conf.set(ConfigOptions.CLIENT_WRITER_BUFFER_MEMORY_SIZE, MemorySize.parse("1mb"));
         conf.set(ConfigOptions.CLIENT_WRITER_BATCH_SIZE, MemorySize.parse("1kb"));
+
+        conf.set(ConfigOptions.MAX_PARTITION_NUM, 10);
         return conf;
     }
 

fluss-client/src/test/java/com/alibaba/fluss/client/admin/FlussAdminITCase.java

@@ -39,6 +39,7 @@
 import com.alibaba.fluss.exception.SchemaNotExistException;
 import com.alibaba.fluss.exception.TableNotExistException;
 import com.alibaba.fluss.exception.TableNotPartitionedException;
+import com.alibaba.fluss.exception.TooManyPartitionsException;
 import com.alibaba.fluss.fs.FsPath;
 import com.alibaba.fluss.fs.FsPathAndFileName;
 import com.alibaba.fluss.metadata.DataLakeFormat;
@@ -776,6 +777,38 @@ void testBootstrapServerConfigAsTabletServer() throws Exception {
         }
     }
 
+    @Test
+    void testAddTooManyPartitions() throws Exception {
+        String dbName = DEFAULT_TABLE_PATH.getDatabaseName();
+        TableDescriptor partitionedTable =
+                TableDescriptor.builder()
+                        .schema(
+                                Schema.newBuilder()
+                                        .column("id", DataTypes.STRING())
+                                        .column("name", DataTypes.STRING())
+                                        .column("age", DataTypes.STRING())
+                                        .build())
+                        .distributedBy(3, "id")
+                        .partitionedBy("age")
+                        .build();
+        TablePath tablePath = TablePath.of(dbName, "test_add_too_many_partitioned_table");
+        admin.createTable(tablePath, partitionedTable, true).get();
+
+        // add 10 partitions.
+        for (int i = 0; i < 10; i++) {
+            admin.createPartition(tablePath, newPartitionSpec("age", String.valueOf(i)), false)
+                    .get();
+        }
+        // add out of limit partition
+        assertThatThrownBy(
+                        () ->
+                                admin.createPartition(
+                                                tablePath, newPartitionSpec("age", "11"), false)
+                                        .get())
+                .cause()
+                .isInstanceOf(TooManyPartitionsException.class);
+    }
+
     private void assertHasTabletServerNumber(int tabletServerNumber) {
         CoordinatorGateway coordinatorGateway = FLUSS_CLUSTER_EXTENSION.newCoordinatorClient();
         retry(

fluss-common/src/main/java/com/alibaba/fluss/config/ConfigOptions.java

@@ -119,6 +119,14 @@ public class ConfigOptions {
                             "The interval of auto partition check. "
                                     + "The default value is 10 minutes.");
 
+    public static final ConfigOption<Integer> MAX_PARTITION_NUM =
+            key("max.partition.num")
+                    .intType()
+                    .defaultValue(1000)
+                    .withDescription(
+                            "Limits the maximum number of partitions that can be created for a partitioned table "
+                                    + "to avoid creating too many partitions.");
+
     // ------------------------------------------------------------------------
     //  ConfigOptions for Coordinator Server
     // ------------------------------------------------------------------------

fluss-common/src/main/java/com/alibaba/fluss/exception/TooManyPartitionsException.java

@@ -0,0 +1,34 @@
+/*
+ * Copyright (c) 2025 Alibaba Group Holding Ltd.
+ *
+ * Licensed 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 com.alibaba.fluss.exception;
+
+import com.alibaba.fluss.annotation.PublicEvolving;
+
+/**
+ * This exception is thrown if the number of table partitions is exceed max.partition.num.
+ *
+ * @since 0.7
+ */
+@PublicEvolving
+public class TooManyPartitionsException extends ApiException {
+
+    private static final long serialVersionUID = 1L;
+
+    public TooManyPartitionsException(String message) {
+        super(message);
+    }
+}

fluss-rpc/src/main/java/com/alibaba/fluss/rpc/protocol/Errors.java

@@ -58,6 +58,7 @@
 import com.alibaba.fluss.exception.TableNotExistException;
 import com.alibaba.fluss.exception.TableNotPartitionedException;
 import com.alibaba.fluss.exception.TimeoutException;
+import com.alibaba.fluss.exception.TooManyPartitionsException;
 import com.alibaba.fluss.exception.UnknownServerException;
 import com.alibaba.fluss.exception.UnknownTableOrBucketException;
 import com.alibaba.fluss.exception.UnknownWriterIdException;
@@ -187,7 +188,9 @@ public enum Errors {
     LEADER_NOT_AVAILABLE_EXCEPTION(
             44,
             "There is no currently available leader for the given partition.",
-            LeaderNotAvailableException::new);
+            LeaderNotAvailableException::new),
+    PARTITION_MAX_NUM_EXCEPTION(
+            45, "Exceed the maximum number of partitions.", TooManyPartitionsException::new);
 
     private static final Logger LOG = LoggerFactory.getLogger(Errors.class);
 

fluss-server/src/main/java/com/alibaba/fluss/server/coordinator/AutoPartitionManager.java

@@ -23,6 +23,7 @@
 import com.alibaba.fluss.config.Configuration;
 import com.alibaba.fluss.exception.PartitionAlreadyExistsException;
 import com.alibaba.fluss.exception.PartitionNotExistException;
+import com.alibaba.fluss.exception.TooManyPartitionsException;
 import com.alibaba.fluss.metadata.ResolvedPartitionSpec;
 import com.alibaba.fluss.metadata.TableInfo;
 import com.alibaba.fluss.metadata.TablePath;
@@ -245,16 +246,29 @@ private void createPartitions(
             try {
                 metadataManager.createPartition(
                         tablePath, tableId, partitionAssignment, partition, false);
+                currentPartitions.add(partition.getPartitionName());
+                LOG.info(
+                        "Auto partitioning created partition {} for table [{}].",
+                        partition,
+                        tablePath);
             } catch (PartitionAlreadyExistsException e) {
                 LOG.info(
                         "Auto partitioning skip to create partition {} for table [{}] as the partition is exist.",
                         partition,
                         tablePath);
+            } catch (TooManyPartitionsException t) {
+                LOG.warn(
+                        "Auto partitioning skip to create partition {} for table [{}], "
+                                + "because exceed the maximum number of partitions.",
+                        partition,
+                        tablePath);
+            } catch (Exception e) {
+                LOG.error(
+                        "Auto partitioning failed to create partition {} for table [{}].",
+                        partition,
+                        tablePath,
+                        e);
             }
-
-            currentPartitions.add(partition.getPartitionName());
-            LOG.info(
-                    "Auto partitioning created partition {} for table [{}].", partition, tablePath);
         }
     }
 

fluss-server/src/main/java/com/alibaba/fluss/server/coordinator/MetadataManager.java

@@ -16,6 +16,7 @@
 
 package com.alibaba.fluss.server.coordinator;
 
+import com.alibaba.fluss.config.ConfigOptions;
 import com.alibaba.fluss.config.Configuration;
 import com.alibaba.fluss.exception.DatabaseAlreadyExistException;
 import com.alibaba.fluss.exception.DatabaseNotEmptyException;
@@ -27,6 +28,7 @@
 import com.alibaba.fluss.exception.TableAlreadyExistException;
 import com.alibaba.fluss.exception.TableNotExistException;
 import com.alibaba.fluss.exception.TableNotPartitionedException;
+import com.alibaba.fluss.exception.TooManyPartitionsException;
 import com.alibaba.fluss.metadata.DatabaseDescriptor;
 import com.alibaba.fluss.metadata.DatabaseInfo;
 import com.alibaba.fluss.metadata.ResolvedPartitionSpec;
@@ -65,6 +67,7 @@ public class MetadataManager {
 
     private final ZooKeeperClient zookeeperClient;
     private @Nullable final Map<String, String> defaultTableLakeOptions;
+    private final int maxPartitionNum;
 
     /**
      * Creates a new metadata manager.
@@ -75,6 +78,7 @@ public class MetadataManager {
     public MetadataManager(ZooKeeperClient zookeeperClient, Configuration conf) {
         this.zookeeperClient = zookeeperClient;
         this.defaultTableLakeOptions = LakeStorageUtils.generateDefaultTableLakeOptions(conf);
+        maxPartitionNum = conf.get(ConfigOptions.MAX_PARTITION_NUM);
     }
 
     public void createDatabase(
@@ -343,6 +347,24 @@ public void createPartition(
                             partition.getPartitionQualifiedName(), tablePath));
         }
 
+        try {
+            int partitionNumber = zookeeperClient.getPartitionNumber(tablePath);
+            if (partitionNumber + 1 > maxPartitionNum) {
+                throw new TooManyPartitionsException(
+                        String.format(
+                                "Exceed the maximum number of partitions for table %s, only allow %s partitions.",
+                                tablePath, maxPartitionNum));
+            }
+        } catch (TooManyPartitionsException e) {
+            throw e;
+        } catch (Exception e) {
+            throw new FlussRuntimeException(
+                    String.format(
+                            "Get the number of partition from zookeeper failed for table %s",
+                            tablePath),
+                    e);
+        }
+
         try {
             long partitionId = zookeeperClient.getPartitionIdAndIncrement();
             // register partition assignments to zk first
@@ -352,10 +374,10 @@ public void createPartition(
             LOG.info(
                     "Register partition {} to zookeeper for table [{}].", partitionName, tablePath);
         } catch (Exception e) {
-            LOG.error(
-                    "Register partition to zookeeper failed to create partition {} for table [{}]",
-                    partitionName,
-                    tablePath,
+            throw new FlussRuntimeException(
+                    String.format(
+                            "Register partition to zookeeper failed to create partition %s for table [%s]",
+                            partitionName, tablePath),
                     e);
         }
     }

fluss-server/src/main/java/com/alibaba/fluss/server/zk/ZooKeeperClient.java

@@ -408,6 +408,16 @@ public Optional<TablePartition> getPartition(TablePath tablePath, String partiti
         return getOrEmpty(path).map(PartitionZNode::decode);
     }
 
+    /** Get partition num of a table in ZK. */
+    public int getPartitionNumber(TablePath tablePath) throws Exception {
+        String path = PartitionsZNode.path(tablePath);
+        Stat stat = zkClient.checkExists().forPath(path);
+        if (stat == null) {
+            return 0;
+        }
+        return stat.getNumChildren();
+    }
+
     /** Create a partition for a table in ZK. */
     public void registerPartition(
             TablePath tablePath, long tableId, String partitionName, long partitionId)

fluss-server/src/test/java/com/alibaba/fluss/server/coordinator/AutoPartitionManagerTest.java

@@ -38,6 +38,7 @@
 
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.RegisterExtension;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.Arguments;
@@ -191,7 +192,7 @@ void testAddPartitionedTable(TestParams params) throws Exception {
                         periodicExecutor);
         autoPartitionManager.start();
 
-        TableInfo table = createPartitionedTable(params.timeUnit);
+        TableInfo table = createPartitionedTable(2, 4, params.timeUnit);
         TablePath tablePath = table.getTablePath();
         autoPartitionManager.addAutoPartitionTable(table);
         // the first auto-partition task is a non-periodic task
@@ -244,6 +245,80 @@ void testAddPartitionedTable(TestParams params) throws Exception {
         assertThat(partitions.keySet()).containsExactlyInAnyOrder(params.expectedPartitionsFinal);
     }
 
+    @Test
+    void testMaxPartitions() throws Exception {
+        int expectPartitionNumber = 10;
+        Configuration config = new Configuration();
+        config.set(ConfigOptions.MAX_PARTITION_NUM, expectPartitionNumber);
+        MetadataManager metadataManager = new MetadataManager(zookeeperClient, config);
+
+        ZonedDateTime startTime =
+                LocalDateTime.parse("2024-09-10T00:00:00").atZone(ZoneId.systemDefault());
+        long startMs = startTime.toInstant().toEpochMilli();
+        ManualClock clock = new ManualClock(startMs);
+        ManuallyTriggeredScheduledExecutorService periodicExecutor =
+                new ManuallyTriggeredScheduledExecutorService();
+
+        AutoPartitionManager autoPartitionManager =
+                new AutoPartitionManager(
+                        new TestingMetadataCache(3),
+                        metadataManager,
+                        new Configuration(),
+                        clock,
+                        periodicExecutor);
+        autoPartitionManager.start();
+
+        // create a partitioned with -1 retention to never auto-drop partitions
+        TableInfo table = createPartitionedTable(-1, 4, AutoPartitionTimeUnit.DAY);
+        TablePath tablePath = table.getTablePath();
+        autoPartitionManager.addAutoPartitionTable(table);
+        // the first auto-partition task is a non-periodic task
+        periodicExecutor.triggerPeriodicScheduledTasks();
+
+        Map<String, Long> partitions = zookeeperClient.getPartitionNameAndIds(tablePath);
+        // pre-create 4 partitions including current partition
+        assertThat(partitions.keySet())
+                .containsExactlyInAnyOrder("20240910", "20240911", "20240912", "20240913");
+
+        // manually create 4 future partitions.
+        int replicaFactor = table.getTableConfig().getReplicationFactor();
+        Map<Integer, BucketAssignment> bucketAssignments =
+                TableAssignmentUtils.generateAssignment(
+                                table.getNumBuckets(), replicaFactor, new int[] {0, 1, 2})
+                        .getBucketAssignments();
+        long tableId = table.getTableId();
+        PartitionAssignment partitionAssignment =
+                new PartitionAssignment(tableId, bucketAssignments);
+        for (int i = 20250101; i <= 20250104; i++) {
+            metadataManager.createPartition(
+                    tablePath,
+                    tableId,
+                    partitionAssignment,
+                    fromPartitionName(table.getPartitionKeys(), i + ""),
+                    false);
+            // mock the partition is created in zk.
+            autoPartitionManager.addPartition(tableId, i + "");
+        }
+
+        clock.advanceTime(Duration.ofDays(4));
+        periodicExecutor.triggerPeriodicScheduledTasks();
+        partitions = zookeeperClient.getPartitionNameAndIds(tablePath);
+        assertThat(partitions.keySet())
+                .containsExactlyInAnyOrder(
+                        "20240910",
+                        "20240911",
+                        "20240912",
+                        "20240913",
+                        // only 20240914, 20240915 are created in this round
+                        "20240914",
+                        "20240915",
+                        // 20250101 ~ 20250102 are retained
+                        "20250101",
+                        "20250102",
+                        "20250103",
+                        "20250104");
+    }
+
     private static class TestParams {
         final AutoPartitionTimeUnit timeUnit;
         final long startTimeMs;
@@ -365,7 +440,9 @@ public TestParams build() {
 
     // -------------------------------------------------------------------------------------------
 
-    private TableInfo createPartitionedTable(AutoPartitionTimeUnit timeUnit) throws Exception {
+    private TableInfo createPartitionedTable(
+            int partitionRetentionNum, int partitionPreCreateNum, AutoPartitionTimeUnit timeUnit)
+            throws Exception {
         long tableId = 1;
         TablePath tablePath = TablePath.of("db", "test_partition_" + UUID.randomUUID());
         TableDescriptor descriptor =
@@ -384,8 +461,12 @@ private TableInfo createPartitionedTable(AutoPartitionTimeUnit timeUnit) throws
                         .property(ConfigOptions.TABLE_REPLICATION_FACTOR, 3)
                         .property(ConfigOptions.TABLE_AUTO_PARTITION_ENABLED, true)
                         .property(ConfigOptions.TABLE_AUTO_PARTITION_TIME_UNIT, timeUnit)
-                        .property(ConfigOptions.TABLE_AUTO_PARTITION_NUM_RETENTION, 2)
-                        .property(ConfigOptions.TABLE_AUTO_PARTITION_NUM_PRECREATE, 4)
+                        .property(
+                                ConfigOptions.TABLE_AUTO_PARTITION_NUM_RETENTION,
+                                partitionRetentionNum)
+                        .property(
+                                ConfigOptions.TABLE_AUTO_PARTITION_NUM_PRECREATE,
+                                partitionPreCreateNum)
                         .build();
         long currentMillis = System.currentTimeMillis();
         TableInfo tableInfo =

website/docs/maintenance/configuration.md

@@ -50,6 +50,7 @@ during the Fluss cluster working.
 | remote.fs.write-buffer-size                      | MemorySize | 4kb                                                                                                                                                                   | The default size of the write buffer for writing the local files to remote file systems.                                                                                                                                                                                         |
 | plugin.classloader.parent-first-patterns.default | String     | java.,<br/>com.alibaba.fluss.,<br/>javax.annotation.,<br/>org.slf4j,<br/>org.apache.log4j,<br/>org.apache.logging,<br/>org.apache.commons.logging,<br/>ch.qos.logback | A (semicolon-separated) list of patterns that specifies which classes should always be resolved through the plugin parent ClassLoader first. A pattern is a simple prefix that is checked against the fully qualified class name. This setting should generally not be modified. |
 | auto-partition.check.interval                    | Duration   | 10min                                                                                                                                                                 | The interval of auto partition check. The default value is 10 minutes.                                                                                                                                                                                                           |
+| max.partition.num                                | Integer    | 1000                                                                                                                                                                  | Limits the maximum number of partitions that can be created for a partitioned table to avoid creating too many partitions.                                                                                                                                                       |
 
 ## CoordinatorServer