[core] Add pre check when drop partition for chain table

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

@@ -73,6 +73,7 @@
 
 import java.io.FileNotFoundException;
 import java.time.Duration;
+import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -476,7 +477,8 @@ public TableCommitImpl newCommit(String commitUser) {
                 options.snapshotExpireExecutionMode(),
                 name(),
                 options.forceCreatingSnapshot(),
-                options.fileOperationThreadNum());
+                options.fileOperationThreadNum(),
+                createPartitionValidators(this));
     }
 
     @Override
@@ -744,6 +746,14 @@ protected RowKindGenerator rowKindGenerator() {
         return RowKindGenerator.create(schema(), store().options());
     }
 
+    private List<PartitionValidator> createPartitionValidators(FileStoreTable table) {
+        List<PartitionValidator> validators = new ArrayList<>();
+        if (table.coreOptions().isChainTable()) {
+            validators.add(new ChainPartitionDropValidator(table));
+        }
+        return validators;
+    }
+
     @Override
     public boolean equals(Object o) {
         if (this == o) {

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

@@ -0,0 +1,175 @@
+/*
+ * 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.CoreOptions;
+import org.apache.paimon.codegen.CodeGenUtils;
+import org.apache.paimon.codegen.RecordComparator;
+import org.apache.paimon.data.BinaryRow;
+import org.apache.paimon.manifest.PartitionEntry;
+import org.apache.paimon.predicate.Predicate;
+import org.apache.paimon.predicate.PredicateBuilder;
+import org.apache.paimon.table.source.snapshot.SnapshotReader;
+import org.apache.paimon.utils.ChainTableUtils;
+import org.apache.paimon.utils.InternalRowPartitionComputer;
+import org.apache.paimon.utils.RowDataToObjectArrayConverter;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.stream.Collectors;
+
+import static org.apache.paimon.partition.PartitionPredicate.createBinaryPartitions;
+
+/**
+ * Validator for chain table partition drop.
+ *
+ * <p>Checks if a partition can be dropped based on the chain table's snapshot partition
+ * dependencies.
+ */
+public class ChainPartitionDropValidator implements PartitionValidator {
+
+    private static final Logger LOG = LoggerFactory.getLogger(ChainPartitionDropValidator.class);
+
+    private final FileStoreTable table;
+    private final CoreOptions coreOptions;
+
+    public ChainPartitionDropValidator(FileStoreTable table) {
+        this.table = table;
+        this.coreOptions = table.coreOptions();
+    }
+
+    @Override
+    public void validatePartitionDrop(List<Map<String, String>> partitionSpecs) {
+        if (!ChainTableUtils.isScanFallbackSnapshotBranch(coreOptions)) {
+            return;
+        }
+        FileStoreTable candidateTable = table;
+        if (table instanceof FallbackReadFileStoreTable) {
+            candidateTable =
+                    ((ChainGroupReadTable) ((FallbackReadFileStoreTable) table).fallback())
+                            .wrapped();
+        }
+        FileStoreTable deltaTable =
+                candidateTable.switchToBranch(coreOptions.scanFallbackDeltaBranch());
+        List<BinaryRow> partitions =
+                createBinaryPartitions(
+                        partitionSpecs,
+                        table.schema().logicalPartitionType(),
+                        coreOptions.partitionDefaultName());
+        RowDataToObjectArrayConverter partitionConverter =
+                new RowDataToObjectArrayConverter(table.schema().logicalPartitionType());
+        InternalRowPartitionComputer partitionComputer =
+                new InternalRowPartitionComputer(
+                        coreOptions.partitionDefaultName(),
+                        table.schema().logicalPartitionType(),
+                        table.schema().partitionKeys().toArray(new String[0]),
+                        coreOptions.legacyPartitionName());
+        RecordComparator partitionComparator =
+                CodeGenUtils.newRecordComparator(
+                        table.schema().logicalPartitionType().getFieldTypes());
+        List<BinaryRow> snapshotPartitions =
+                table.newSnapshotReader().partitionEntries().stream()
+                        .map(PartitionEntry::partition)
+                        .sorted(partitionComparator)
+                        .collect(Collectors.toList());
+        SnapshotReader deltaSnapshotReader = deltaTable.newSnapshotReader();
+        PredicateBuilder builder = new PredicateBuilder(table.schema().logicalPartitionType());
+        for (BinaryRow partition : partitions) {
+            Optional<BinaryRow> preSnapshotPartition =
+                    findPreSnapshotPartition(snapshotPartitions, partition, partitionComparator);
+            Optional<BinaryRow> nextSnapshotPartition =
+                    findNextSnapshotPartition(snapshotPartitions, partition, partitionComparator);
+            Predicate deltaFollowingPredicate =
+                    ChainTableUtils.createTriangularPredicate(
+                            partition, partitionConverter, builder::equal, builder::greaterThan);
+            List<BinaryRow> deltaFollowingPartitions =
+                    deltaSnapshotReader.withPartitionFilter(deltaFollowingPredicate)
+                            .partitionEntries().stream()
+                            .map(PartitionEntry::partition)
+                            .filter(
+                                    deltaPartition ->
+                                            isNextIntervalPartition(
+                                                    deltaPartition,
+                                                    nextSnapshotPartition,
+                                                    partitionComparator))
+                            .collect(Collectors.toList());
+            boolean canDrop =
+                    deltaFollowingPartitions.isEmpty() || preSnapshotPartition.isPresent();
+            LOG.info(
+                    "Drop partition, partition={}, canDrop={}, preSnapshotPartition={}, nextSnapshotPartition={}",
+                    partitionComputer.generatePartValues(partition),
+                    canDrop,
+                    generatePartitionValues(preSnapshotPartition, partitionComputer),
+                    generatePartitionValues(nextSnapshotPartition, partitionComputer));
+            if (!canDrop) {
+                throw new RuntimeException("Snapshot partition cannot be dropped.");
+            }
+        }
+    }
+
+    private Optional<BinaryRow> findPreSnapshotPartition(
+            List<BinaryRow> snapshotPartitions,
+            BinaryRow partition,
+            RecordComparator partitionComparator) {
+        BinaryRow pre = null;
+        for (BinaryRow snapshotPartition : snapshotPartitions) {
+            if (partitionComparator.compare(snapshotPartition, partition) < 0) {
+                pre = snapshotPartition;
+            } else {
+                break;
+            }
+        }
+        return Optional.ofNullable(pre);
+    }
+
+    private Optional<BinaryRow> findNextSnapshotPartition(
+            List<BinaryRow> snapshotPartitions,
+            BinaryRow partition,
+            RecordComparator partitionComparator) {
+        for (BinaryRow snapshotPartition : snapshotPartitions) {
+            if (partitionComparator.compare(snapshotPartition, partition) > 0) {
+                return Optional.of(snapshotPartition);
+            }
+        }
+        return Optional.empty();
+    }
+
+    private boolean isNextIntervalPartition(
+            BinaryRow partition,
+            Optional<BinaryRow> nextSnapshotPartition,
+            RecordComparator partitionComparator) {
+        return !nextSnapshotPartition.isPresent()
+                || partitionComparator.compare(partition, nextSnapshotPartition.get()) < 0;
+    }
+
+    private String generatePartitionValues(
+            Optional<BinaryRow> partition, InternalRowPartitionComputer partitionComputer) {
+        if (!partition.isPresent()) {
+            return "<none>";
+        }
+        return partitionComputer.generatePartValues(partition.get()).toString();
+    }
+
+    @Override
+    public void close() throws Exception {}
+}

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

@@ -0,0 +1,28 @@
+/*
+ * 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 java.util.List;
+import java.util.Map;
+
+/** Validator to validate partition operations. */
+public interface PartitionValidator extends AutoCloseable {
+
+    void validatePartitionDrop(List<Map<String, String>> partitionSpecs);
+}

paimon-core/src/main/java/org/apache/paimon/table/sink/TableCommitImpl.java

@@ -30,6 +30,7 @@
 import org.apache.paimon.operation.PartitionExpire;
 import org.apache.paimon.operation.metrics.CommitMetrics;
 import org.apache.paimon.stats.Statistics;
+import org.apache.paimon.table.PartitionValidator;
 import org.apache.paimon.tag.TagAutoCreation;
 import org.apache.paimon.tag.TagAutoManager;
 import org.apache.paimon.tag.TagTimeExpire;
@@ -92,6 +93,8 @@ public class TableCommitImpl implements InnerTableCommit {
     private boolean batchCommitted = false;
     private boolean expireForEmptyCommit = true;
 
+    private final List<PartitionValidator> partitionValidators;
+
     public TableCommitImpl(
             FileStoreCommit commit,
             @Nullable Runnable expireSnapshots,
@@ -102,7 +105,8 @@ public TableCommitImpl(
             ExpireExecutionMode expireExecutionMode,
             String tableName,
             boolean forceCreatingSnapshot,
-            int threadNum) {
+            int threadNum,
+            List<PartitionValidator> partitionValidators) {
         if (partitionExpire != null) {
             commit.withPartitionExpire(partitionExpire);
         }
@@ -126,6 +130,10 @@ public TableCommitImpl(
         this.tableName = tableName;
         this.forceCreatingSnapshot = forceCreatingSnapshot;
         this.fileCheckExecutor = FileOperationThreadPool.getExecutorService(threadNum);
+        this.partitionValidators =
+                partitionValidators == null
+                        ? Collections.emptyList()
+                        : Collections.unmodifiableList(new ArrayList<>(partitionValidators));
     }
 
     public boolean forceCreatingSnapshot() {
@@ -184,6 +192,7 @@ public void truncateTable() {
 
     @Override
     public void truncatePartitions(List<Map<String, String>> partitionSpecs) {
+        partitionValidators.forEach(validator -> validator.validatePartitionDrop(partitionSpecs));
         commit.dropPartitions(partitionSpecs, COMMIT_IDENTIFIER);
     }
 
@@ -409,6 +418,13 @@ public void expireSnapshots() {
     public void close() throws Exception {
         commit.close();
         maintainExecutor.shutdownNow();
+        for (PartitionValidator validator : partitionValidators) {
+            try {
+                validator.close();
+            } catch (Exception e) {
+                LOG.warn("Failed to close partition validator.", e);
+            }
+        }
     }
 
     @Override

paimon-core/src/main/java/org/apache/paimon/utils/ChainTableUtils.java

@@ -209,4 +209,9 @@ public static boolean isScanFallbackDeltaBranch(CoreOptions options) {
         return options.isChainTable()
                 && options.scanFallbackDeltaBranch().equalsIgnoreCase(options.branch());
     }
+
+    public static boolean isScanFallbackSnapshotBranch(CoreOptions options) {
+        return options.isChainTable()
+                && options.scanFallbackSnapshotBranch().equalsIgnoreCase(options.branch());
+    }
 }