RewriteDataFileExecutor.java

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// 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
//
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// software distributed under the License is distributed on an
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// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.

package org.apache.doris.datasource.iceberg.rewrite;

import org.apache.doris.catalog.Env;
import org.apache.doris.common.UserException;
import org.apache.doris.datasource.iceberg.IcebergExternalMetaCache.WritableTableLease;
import org.apache.doris.datasource.iceberg.IcebergExternalTable;
import org.apache.doris.datasource.iceberg.IcebergMvccSnapshot;
import org.apache.doris.datasource.iceberg.IcebergTransaction;
import org.apache.doris.datasource.iceberg.IcebergUtils;
import org.apache.doris.datasource.mvcc.MvccSnapshot;
import org.apache.doris.qe.ConnectContext;
import org.apache.doris.resource.computegroup.ComputeGroup;
import org.apache.doris.scheduler.exception.JobException;
import org.apache.doris.scheduler.executor.TransientTaskExecutor;
import org.apache.doris.system.Backend;
import org.apache.doris.transaction.TransactionManager;

import com.google.common.collect.Lists;
// Keep third-party imports lexical to preserve the repository's CustomImportOrder invariant.
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

import java.util.List;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;

/**
 * Executes INSERT-SELECT statements for Iceberg data file rewriting.
 */
public class RewriteDataFileExecutor {
    private static final Logger LOG = LogManager.getLogger(RewriteDataFileExecutor.class);

    private final IcebergExternalTable dorisTable;
    private final ConnectContext connectContext;

    public RewriteDataFileExecutor(IcebergExternalTable dorisTable,
            ConnectContext connectContext) {
        this.dorisTable = dorisTable;
        this.connectContext = connectContext;
    }

    /**
     * Execute rewrite for multiple groups concurrently
     */
    public RewriteResult executeGroupsConcurrently(List<RewriteDataGroup> groups, long targetFileSizeBytes,
            WritableTableLease writableTableLease)
            throws UserException {
        List<RewriteGroupTask> tasks = Lists.newArrayList();
        RewriteResultCollector resultCollector = new RewriteResultCollector(groups.size(), tasks);
        TransactionManager transactionManager = dorisTable.getCatalog().getTransactionManager();
        long transactionId = transactionManager.begin();
        boolean committed = false;
        try {
            IcebergTransaction transaction = (IcebergTransaction) transactionManager.getTransaction(transactionId);
            MvccSnapshot targetSnapshot = new IcebergMvccSnapshot(
                    IcebergUtils.getSnapshotForWritableLease(dorisTable, writableTableLease));
            transaction.beginRewrite(dorisTable, writableTableLease.getTable(), writableTableLease);

            // Register files to delete
            for (RewriteDataGroup group : groups) {
                transaction.updateRewriteFiles(Lists.newArrayList(group.getDataFiles()));
            }

            // Create result collector and tasks
            // Get available BE count once before creating tasks
            // This avoids calling getBackendsNumber() in each task during multi-threaded execution.
            // Use compute group from connect context to align with actual BE selection for queries.
            int availableBeCount = getAvailableBeCount();

            // Create tasks with callbacks
            for (RewriteDataGroup group : groups) {
                RewriteGroupTask task = new RewriteGroupTask(
                        group,
                        transactionId,
                        dorisTable,
                        targetSnapshot,
                        writableTableLease.retain(),
                        connectContext,
                        targetFileSizeBytes,
                        availableBeCount,
                        new RewriteGroupTask.RewriteResultCallback() {
                            @Override
                            public void onTaskCompleted(Long taskId) {
                                resultCollector.onTaskCompleted(taskId);
                            }

                            @Override
                            public void onTaskFailed(Long taskId, Exception error) {
                                resultCollector.onTaskFailed(taskId, error);
                            }
                        });
                tasks.add(task);
            }

            // Submit tasks to TransientTaskManager
            try {
                for (TransientTaskExecutor task : tasks) {
                    Env.getCurrentEnv().getTransientTaskManager().addMemoryTask(task);
                }
            } catch (JobException e) {
                throw new UserException("Failed to submit rewrite tasks: " + e.getMessage(), e);
            }

            // Wait for all tasks to complete
            waitForTasksCompletion(resultCollector, groups.size());

            // Finish rewrite operation
            transaction.finishRewrite();

            // Collect statistics from transaction after all tasks are completed
            int rewrittenDataFilesCount = groups.stream().mapToInt(group -> group.getDataFiles().size()).sum();
            // this should after finishRewrite
            int addedDataFilesCount = transaction.getFilesToAddCount();
            long rewrittenBytesCount = groups.stream().mapToLong(group -> group.getTotalSize()).sum();
            int removedDeleteFilesCount = groups.stream().mapToInt(group -> group.getDeleteFileCount()).sum();

            transactionManager.commit(transactionId);
            committed = true;
            Env.getCurrentEnv().getExtMetaCacheMgr().invalidateTableCache(dorisTable);

            return new RewriteResult(rewrittenDataFilesCount, addedDataFilesCount,
                    rewrittenBytesCount, removedDeleteFilesCount);
        } finally {
            if (!committed) {
                resultCollector.cancelAllTasks();
                transactionManager.rollback(transactionId);
            }
        }
    }

    /**
     * Wait for all tasks to complete using notification mechanism
     */
    private void waitForTasksCompletion(RewriteResultCollector collector, int totalTasks)
            throws UserException {
        LOG.info("Waiting for {} rewrite tasks to complete using notification mechanism", totalTasks);

        int maxWaitTime = connectContext.getSessionVariable().getInsertTimeoutS();

        try {
            boolean completed = collector.await(maxWaitTime, TimeUnit.SECONDS);

            if (!completed) {
                LOG.warn("Rewrite tasks did not complete within timeout of {} seconds", maxWaitTime);
                throw new UserException("Rewrite tasks did not complete within timeout");
            }

            // Check if any task failed
            if (collector.getFirstError() != null) {
                LOG.warn("Rewrite tasks failed: {}", collector.getFirstError().getMessage());
                throw new UserException("Some rewrite tasks failed: " + collector.getFirstError().getMessage(),
                        collector.getFirstError());
            }

            LOG.info("All {} rewrite tasks completed successfully", totalTasks);

        } catch (InterruptedException e) {
            Thread.currentThread().interrupt();
            LOG.warn("Wait for tasks completion was interrupted", e);
            throw new UserException("Wait for tasks completion was interrupted", e);
        }
    }

    private int getAvailableBeCount() throws UserException {
        ComputeGroup computeGroup = connectContext.getComputeGroup();
        List<Backend> backends = computeGroup.getBackendList();
        int availableBeCount = 0;
        for (Backend backend : backends) {
            if (backend.isAlive()) {
                availableBeCount++;
            }
        }
        return availableBeCount;
    }

    /**
     * Result collector for concurrent rewrite tasks
     */
    static class RewriteResultCollector {
        private final int expectedTasks;
        private final AtomicInteger completedTasks = new AtomicInteger(0);
        private final AtomicInteger failedTasks = new AtomicInteger(0);
        private volatile Exception firstError = null;
        private final CountDownLatch completionLatch;
        private final List<RewriteGroupTask> allTasks;

        public RewriteResultCollector(int expectedTasks, List<RewriteGroupTask> tasks) {
            this.expectedTasks = expectedTasks;
            this.completionLatch = new CountDownLatch(expectedTasks);
            this.allTasks = tasks;
        }

        public synchronized void onTaskCompleted(Long taskId) {
            int completed = completedTasks.incrementAndGet();
            LOG.info("Task {} completed ({}/{})", taskId, completed, expectedTasks);
            completionLatch.countDown();
        }

        public synchronized void onTaskFailed(Long taskId, Exception error) {
            int failed = failedTasks.incrementAndGet();
            if (firstError == null) {
                firstError = error;

                // Cancel all other tasks immediately when first failure occurs
                LOG.warn("Task {} failed, cancelling all other tasks", taskId);
                cancelAllOtherTasks(taskId);
            }
            LOG.warn("Task {} failed ({}/{}): {}", taskId, failed, expectedTasks, error.getMessage());
            completionLatch.countDown();
        }

        private void cancelAllOtherTasks(Long failedTaskId) {
            for (RewriteGroupTask task : allTasks) {
                if (!task.getId().equals(failedTaskId)) {
                    cancelTask(task);
                }
            }
        }

        void cancelAllTasks() {
            for (RewriteGroupTask task : allTasks) {
                cancelTask(task);
            }
        }

        private void cancelTask(RewriteGroupTask task) {
            try {
                // addMemoryTask registers before publishing. Remove first so a failed or
                // suppressed publish cannot retain a table-bearing snapshot in the manager map.
                Env.getCurrentEnv().getTransientTaskManager().removeMemoryTask(task.getId());
                task.cancel();
                LOG.info("Cancelled task {}", task.getId());
            } catch (Exception e) {
                LOG.warn("Failed to cancel task {}: {}", task.getId(), e.getMessage());
            }
        }

        public boolean await(long timeout, TimeUnit unit) throws InterruptedException {
            return completionLatch.await(timeout, unit);
        }

        public Exception getFirstError() {
            return firstError;
        }
    }
}