pixelsdb · gengdy1545 · Mar 16, 2026 · Mar 16, 2026 · Mar 17, 2026
diff --git a/pixels-cli/src/main/java/io/pixelsdb/pixels/cli/executor/CompactExecutor.java b/pixels-cli/src/main/java/io/pixelsdb/pixels/cli/executor/CompactExecutor.java
@@ -32,15 +32,18 @@
 import io.pixelsdb.pixels.common.physical.StorageFactory;
 import io.pixelsdb.pixels.common.retina.RetinaService;
 import io.pixelsdb.pixels.common.utils.ConfigFactory;
-import io.pixelsdb.pixels.common.utils.DateUtil;
+import io.pixelsdb.pixels.common.utils.NetUtils;
+import io.pixelsdb.pixels.common.utils.PixelsFileNameUtils;
 import io.pixelsdb.pixels.core.compactor.CompactLayout;
 import io.pixelsdb.pixels.core.compactor.PixelsCompactor;
 import net.sourceforge.argparse4j.inf.Namespace;
 
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Iterator;
+import java.util.LinkedHashMap;
 import java.util.List;
+import java.util.Map;
 import java.util.concurrent.ConcurrentLinkedQueue;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
@@ -114,16 +117,52 @@ public void execute(Namespace ns, String command) throws Exception
             }
         }
 
+        // Issue #1305: obtain local hostname for the unified compact file naming.
+        String hostName = NetUtils.getLocalHostName();
+
+        /**
+         * Issue #1305:
+         * Group files by virtualNodeId before compaction.
+         * GC-eligible files (retina/ordered/compact) carry a real virtualNodeId and must
+         * not be mixed across groups to preserve create_ts/delete_ts monotonicity.
+         * single-type files fall into the VNODE_ID_NONE (-1) bucket and are compacted freely.
+         * copy-type files and unrecognised-format files are skipped.
+         */
+        Map<Integer, List<Status>> groupedStatuses = new LinkedHashMap<>();
+        for (Status status : statuses)
+        {
+            String path = status.getPath();
+            PixelsFileNameUtils.PxlFileType fileType = PixelsFileNameUtils.extractFileType(path);
+            if (fileType == null)
+            {
+                System.err.println("Skipping file with unrecognized naming format: " + path);
+                continue;
+            }
+            if (fileType == PixelsFileNameUtils.PxlFileType.COPY)
+            {
+                System.err.println("Skipping copy file (test/benchmark data, not for compaction): " + path);
+                continue;
+            }
+            int vNodeId = PixelsFileNameUtils.extractVirtualNodeId(path);
+            groupedStatuses.computeIfAbsent(vNodeId, k -> new ArrayList<>()).add(status);
+        }
+
         List<Path> targetPaths = layout.getCompactPaths();
         ConcurrentLinkedQueue<File> compactFiles = new ConcurrentLinkedQueue<>();
         ConcurrentLinkedQueue<Path> compactPaths = new ConcurrentLinkedQueue<>();
         int targetPathId = 0;
 
-        // compact
+        // Issue #1305: iterate over each virtualNodeId group independently to preserve
+        // the monotonicity invariants required by Storage GC.
         long startTime = System.currentTimeMillis();
-        for (int i = 0, thdId = 0; i < statuses.size(); i += numRowGroupInBlock, ++thdId)
+        int thdId = 0;
+        for (Map.Entry<Integer, List<Status>> entry : groupedStatuses.entrySet())
         {
-            if (i + numRowGroupInBlock > statuses.size())
+            int vNodeId = entry.getKey();
+            List<Status> groupStatuses = entry.getValue();
+            int groupSize = groupStatuses.size();
+
+            for (int i = 0; i < groupSize; ++thdId)
             {
                 /**
                  * Issue #160:
@@ -136,34 +175,38 @@ public void execute(Namespace ns, String command) throws Exception
                  * and rebuild a pure compactLayout for the tail files as the
                  * compactLayout in metadata does not work for the tail files.
                  */
-                numRowGroupInBlock = statuses.size() - i;
-                compactLayout = CompactLayout.buildPure(numRowGroupInBlock, numColumn);
-            }
+                // Issue #1305: use local batchSize/batchLayout instead of mutating
+                // numRowGroupInBlock/compactLayout, so they stay unchanged across batches and groups.
+                int batchSize = Math.min(numRowGroupInBlock, groupSize - i);
+                CompactLayout batchLayout = (batchSize < numRowGroupInBlock)
+                        ? CompactLayout.buildPure(batchSize, numColumn)
+                        : compactLayout;
 
-            List<String> sourcePaths = new ArrayList<>();
-            for (int j = 0; j < numRowGroupInBlock; ++j)
-            {
-                if (!statuses.get(i+j).getPath().endsWith("/"))
+                List<String> sourcePaths = new ArrayList<>();
+                for (int j = 0; j < batchSize; ++j)
                 {
-                    sourcePaths.add(statuses.get(i + j).getPath());
+                    if (!groupStatuses.get(i + j).getPath().endsWith("/"))
+                    {
+                        sourcePaths.add(groupStatuses.get(i + j).getPath());
+                    }
                 }
-            }
 
-            Path targetPath = targetPaths.get(targetPathId++);
-            String targetDirPath = targetPath.getUri();
-            targetPathId %= targetPaths.size();
-            if (!targetDirPath.endsWith("/"))
-            {
-                targetDirPath += "/";
-            }
-            String targetFileName = DateUtil.getCurTime() + "_compact.pxl";
-            String targetFilePath = targetDirPath + targetFileName;
+                Path targetPath = targetPaths.get(targetPathId++);
+                String targetDirPath = targetPath.getUri();
+                targetPathId %= targetPaths.size();
+                if (!targetDirPath.endsWith("/"))
+                {
+                    targetDirPath += "/";
+                }
+                // Issue #1305: use unified naming format (hostName + vNodeId) instead of DateUtil timestamp only.
+                String targetFileName = PixelsFileNameUtils.buildCompactFileName(hostName, vNodeId);
+                String targetFilePath = targetDirPath + targetFileName;
 
-            System.out.println("(" + thdId + ") " + sourcePaths.size() +
-                    " ordered files to be compacted into '" + targetFilePath + "'.");
+                System.out.println("(" + thdId + ") vNodeId=" + vNodeId + ", " + sourcePaths.size() +
+                        " ordered files to be compacted into '" + targetFilePath + "'.");
 
-            PixelsCompactor.Builder compactorBuilder = PixelsCompactor.newBuilder()
-                    .setSourcePaths(sourcePaths)
+                PixelsCompactor.Builder compactorBuilder = PixelsCompactor.newBuilder()
+                        .setSourcePaths(sourcePaths)
                     /**
                      * Issue #192:
                      * No need to deep copy compactLayout as it is never modified in-place
@@ -173,40 +216,46 @@ public void execute(Namespace ns, String command) throws Exception
                      *
                      * Deep copy it if it is in-place modified in the future.
                      */
-                    .setCompactLayout(compactLayout)
-                    .setInputStorage(orderStorage)
-                    .setOutputStorage(compactStorage)
-                    .setPath(targetFilePath)
-                    .setBlockSize(blockSize)
-                    .setReplication(replication)
-                    .setBlockPadding(false)
-                    .setHasHiddenColumn(true);
-
-            long threadStart = System.currentTimeMillis();
-            compactExecutor.execute(() -> {
-                // Issue #192: run compaction in threads.
-                try
-                {
-                    // build() spends some time to read file footers and should be called inside sub-thread.
-                    PixelsCompactor pixelsCompactor = compactorBuilder.build();
-                    pixelsCompactor.compact();
-                    pixelsCompactor.close();
-                    File compactFile = new File();
-                    compactFile.setName(targetFileName);
-                    compactFile.setType(File.Type.REGULAR);
-                    compactFile.setNumRowGroup(pixelsCompactor.getNumRowGroup());
-                    compactFile.setPathId(targetPath.getId());
-                    compactFiles.offer(compactFile);
-                    compactPaths.offer(targetPath);
-                } catch (IOException e)
-                {
-                    System.err.println("write compact file '" + targetFilePath + "' failed");
-                    e.printStackTrace();
-                    return;
-                }
-                System.out.println("Compact file '" + targetFilePath + "' is built in " +
-                        ((System.currentTimeMillis() - threadStart) / 1000.0) + "s");
-            });
+                        .setCompactLayout(batchLayout)
+                        .setInputStorage(orderStorage)
+                        .setOutputStorage(compactStorage)
+                        .setPath(targetFilePath)
+                        .setBlockSize(blockSize)
+                        .setReplication(replication)
+                        .setBlockPadding(false)
+                        .setHasHiddenColumn(true);
+
+                final String finalTargetFileName = targetFileName;
+                final String finalTargetFilePath = targetFilePath;
+                final Path finalTargetPath = targetPath;
+                long threadStart = System.currentTimeMillis();
+
+                compactExecutor.execute(() -> {
+                    // Issue #192: run compaction in threads.
+                    try
+                    {
+                        PixelsCompactor pixelsCompactor = compactorBuilder.build();
+                        pixelsCompactor.compact();
+                        pixelsCompactor.close();
+                        File compactFile = new File();
+                        compactFile.setName(finalTargetFileName);
+                        compactFile.setType(File.Type.REGULAR);
+                        compactFile.setNumRowGroup(pixelsCompactor.getNumRowGroup());
+                        compactFile.setPathId(finalTargetPath.getId());
+                        compactFiles.offer(compactFile);
+                        compactPaths.offer(finalTargetPath);
+                    } catch (IOException e)
+                    {
+                        System.err.println("write compact file '" + finalTargetFilePath + "' failed");
+                        e.printStackTrace();
+                        return;
+                    }
+                    System.out.println("Compact file '" + finalTargetFilePath + "' is built in " +
+                            ((System.currentTimeMillis() - threadStart) / 1000.0) + "s");
+                });
+
+                i += batchSize;
+            }
         }
 
         // Issue #192: wait for the compaction to complete.

diff --git a/pixels-cli/src/main/java/io/pixelsdb/pixels/cli/executor/CopyExecutor.java b/pixels-cli/src/main/java/io/pixelsdb/pixels/cli/executor/CopyExecutor.java
@@ -24,7 +24,7 @@
 import io.pixelsdb.pixels.common.physical.StorageFactory;
 import io.pixelsdb.pixels.common.utils.ConfigFactory;
 import io.pixelsdb.pixels.common.utils.Constants;
-import io.pixelsdb.pixels.common.utils.DateUtil;
+import io.pixelsdb.pixels.common.utils.PixelsFileNameUtils;
 import net.sourceforge.argparse4j.inf.Namespace;
 import org.apache.hadoop.io.IOUtils;
 
@@ -82,8 +82,7 @@ public void execute(Namespace ns, String command) throws Exception
                     continue;
                 }
                 String destPath = destination_ +
-                        sourceName.substring(0, sourceName.indexOf(postfix)) +
-                        "_copy_" + DateUtil.getCurTime() + postfix;
+                        PixelsFileNameUtils.buildCopyFileName(sourceName);
                 copyExecutor.execute(() -> {
                     try
                     {

diff --git a/pixels-cli/src/main/java/io/pixelsdb/pixels/cli/load/IndexedPixelsConsumer.java b/pixels-cli/src/main/java/io/pixelsdb/pixels/cli/load/IndexedPixelsConsumer.java
@@ -34,8 +34,8 @@
  import io.pixelsdb.pixels.common.physical.Storage;
  import io.pixelsdb.pixels.common.physical.StorageFactory;
  import io.pixelsdb.pixels.common.utils.ConfigFactory;
- import io.pixelsdb.pixels.common.utils.DateUtil;
  import io.pixelsdb.pixels.common.utils.IndexUtils;
+ import io.pixelsdb.pixels.common.utils.PixelsFileNameUtils;
  import io.pixelsdb.pixels.common.utils.RetinaUtils;
  import io.pixelsdb.pixels.core.PixelsWriter;
  import io.pixelsdb.pixels.core.TypeDescription;
@@ -183,7 +183,7 @@ private PerVirtualNodeWriter initializeRetinaWriter(int bucketId) throws IOExcep
          {
              targetDirPath += "/";
          }
-         String targetFileName = targetNode.getAddress() + "_" + DateUtil.getCurTime() + "_" + bucketId + ".pxl";
+         String targetFileName = PixelsFileNameUtils.buildOrderedFileName(targetNode.getAddress(), targetNode.getVirtualNodeId());
          String targetFilePath = targetDirPath + targetFileName;
 
          PixelsWriter pixelsWriter = getPixelsWriter(targetStorage, targetFilePath);

diff --git a/pixels-cli/src/main/java/io/pixelsdb/pixels/cli/load/SimplePixelsConsumer.java b/pixels-cli/src/main/java/io/pixelsdb/pixels/cli/load/SimplePixelsConsumer.java
@@ -26,9 +26,9 @@
  import io.pixelsdb.pixels.common.metadata.domain.Path;
  import io.pixelsdb.pixels.common.physical.Storage;
  import io.pixelsdb.pixels.common.physical.StorageFactory;
- import io.pixelsdb.pixels.common.utils.Constants;
- import io.pixelsdb.pixels.common.utils.DateUtil;
- import io.pixelsdb.pixels.core.PixelsWriter;
+import io.pixelsdb.pixels.common.utils.NetUtils;
+import io.pixelsdb.pixels.common.utils.PixelsFileNameUtils;
+import io.pixelsdb.pixels.core.PixelsWriter;
  import io.pixelsdb.pixels.core.PixelsWriterImpl;
  import io.pixelsdb.pixels.core.TypeDescription;
  import io.pixelsdb.pixels.core.vector.VectorizedRowBatch;
@@ -126,7 +126,7 @@ private void initializePixelsWriter() throws MetadataException, IOException
          {
              targetDirPath += "/";
          }
-         String targetFileName = Constants.LOAD_DEFAULT_RETINA_PREFIX + "_" + DateUtil.getCurTime() + ".pxl";
+         String targetFileName = PixelsFileNameUtils.buildSingleFileName(NetUtils.getLocalHostName());
          String targetFilePath = targetDirPath + targetFileName;
 
          pixelsWriter = PixelsWriterImpl.newBuilder()

diff --git a/pixels-common/src/main/java/io/pixelsdb/pixels/common/utils/NetUtils.java b/pixels-common/src/main/java/io/pixelsdb/pixels/common/utils/NetUtils.java
@@ -0,0 +1,69 @@
+/*
+ * Copyright 2026 PixelsDB.
+ *
+ * This file is part of Pixels.
+ *
+ * Pixels is free software: you can redistribute it and/or modify
+ * it under the terms of the Affero GNU General Public License as
+ * published by the Free Software Foundation, either version 3 of
+ * the License, or (at your option) any later version.
+ *
+ * Pixels is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * Affero GNU General Public License for more details.
+ *
+ * You should have received a copy of the Affero GNU General Public
+ * License along with Pixels.  If not, see
+ * <https://www.gnu.org/licenses/>.
+ */
+package io.pixelsdb.pixels.common.utils;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+
+/**
+ * Common network utilities.
+ *
+ * @author hank
+ * @create 2026-03-16
+ */
+public final class NetUtils
+{
+    private static final Logger logger = LogManager.getLogger(NetUtils.class);
+
+    private NetUtils() {}
+
+    /**
+     * Returns the hostname of the local machine.
+     *
+     * <p>Resolution order:
+     * <ol>
+     *   <li>The {@code HOSTNAME} environment variable — reliable in container / k8s environments
+     *       where {@link InetAddress#getLocalHost()} may return an unpredictable pod address.</li>
+     *   <li>{@link InetAddress#getLocalHost()#getHostName()} — standard JVM resolution.</li>
+     *   <li>{@code "localhost"} — last-resort fallback; a warning is logged.</li>
+     * </ol>
+     *
+     * @return the local hostname, never {@code null}
+     */
+    public static String getLocalHostName()
+    {
+        String hostName = System.getenv("HOSTNAME");
+        if (hostName != null && !hostName.isEmpty())
+        {
+            return hostName;
+        }
+        try
+        {
+            return InetAddress.getLocalHost().getHostName();
+        } catch (UnknownHostException e)
+        {
+            logger.warn("Failed to resolve local hostname via InetAddress, falling back to 'localhost'", e);
+            return "localhost";
+        }
+    }
+}