From 4271e79d7a7bd4121566a5a859161ce4ab86fd53 Mon Sep 17 00:00:00 2001
From: "445092967@qq.com" <445092967@qq.com>
Date: Tue, 17 Oct 2023 23:03:10 +0800
Subject: [PATCH] WIP reuse opened file in worker

---
 .../file/cache/store/LocalPageStore.java      | 23 +++++++++++++++++--
 .../databuffer/CompositeDataBuffer.java       |  2 +-
 .../protocol/databuffer/DataFileChannel.java  | 14 ++++++++---
 .../alluxio/cli/fs/command/CatCommand.java    |  4 ++--
 4 files changed, 35 insertions(+), 8 deletions(-)

diff --git a/dora/core/client/fs/src/main/java/alluxio/client/file/cache/store/LocalPageStore.java b/dora/core/client/fs/src/main/java/alluxio/client/file/cache/store/LocalPageStore.java
index 7bedd9a7e6bd..5dd99a8d7624 100644
--- a/dora/core/client/fs/src/main/java/alluxio/client/file/cache/store/LocalPageStore.java
+++ b/dora/core/client/fs/src/main/java/alluxio/client/file/cache/store/LocalPageStore.java
@@ -215,11 +215,30 @@ public DataFileChannel getDataFileChannel(
     if (pageOffset + bytesToRead > fileLength) {
       bytesToRead = (int) (fileLength - (long) pageOffset);
     }
-
-    DataFileChannel dataFileChannel = new DataFileChannel(pageFile, pageOffset, bytesToRead);
+    DataFileChannel lastDataFileChannel = mLastDataFileChannel;
+    final RandomAccessFile raf;
+    if (lastDataFileChannel != null && lastDataFileChannel.mPageIndex == pageId.getPageIndex()) {
+      raf = lastDataFileChannel.mFile;
+    } else {
+      try {
+        raf = new RandomAccessFile(pageFile, "r") {
+          @Override
+          public void close() throws IOException {
+            super.close();
+          }
+        };
+      } catch (Exception e) {
+        throw new RuntimeException(e);
+      }
+    }
+    DataFileChannel dataFileChannel = new DataFileChannel(
+        pageId.getPageIndex(), raf, pageOffset, bytesToRead);
+    mLastDataFileChannel = dataFileChannel;
     return dataFileChannel;
   }
 
+  volatile DataFileChannel mLastDataFileChannel;
+
   @Override
   public void close() {
     // no-op
diff --git a/dora/core/common/src/main/java/alluxio/network/protocol/databuffer/CompositeDataBuffer.java b/dora/core/common/src/main/java/alluxio/network/protocol/databuffer/CompositeDataBuffer.java
index d803ed7b550e..d2c756b49d0f 100644
--- a/dora/core/common/src/main/java/alluxio/network/protocol/databuffer/CompositeDataBuffer.java
+++ b/dora/core/common/src/main/java/alluxio/network/protocol/databuffer/CompositeDataBuffer.java
@@ -21,7 +21,7 @@
  */
 public final class CompositeDataBuffer implements DataBuffer {
 
-  private final List<DataBuffer> mDataBufferList;
+  public final List<DataBuffer> mDataBufferList;
 
   /**
    * CompositeDataBuffer wraps multiple {@link DataBuffer}.
diff --git a/dora/core/common/src/main/java/alluxio/network/protocol/databuffer/DataFileChannel.java b/dora/core/common/src/main/java/alluxio/network/protocol/databuffer/DataFileChannel.java
index 5a0cab898826..3850495908ff 100644
--- a/dora/core/common/src/main/java/alluxio/network/protocol/databuffer/DataFileChannel.java
+++ b/dora/core/common/src/main/java/alluxio/network/protocol/databuffer/DataFileChannel.java
@@ -17,6 +17,7 @@
 import java.io.File;
 import java.io.IOException;
 import java.io.OutputStream;
+import java.io.RandomAccessFile;
 import java.nio.ByteBuffer;
 import java.nio.channels.FileChannel;
 
@@ -24,9 +25,10 @@
  * A DataBuffer with the underlying data being a {@link FileChannel}.
  */
 public final class DataFileChannel implements DataBuffer {
-  private final File mFile;
+  public final RandomAccessFile mFile;
   private final long mOffset;
   private final long mLength;
+  public final long mPageIndex;
 
   /**
    *
@@ -34,15 +36,21 @@ public final class DataFileChannel implements DataBuffer {
    * @param offset The offset into the FileChannel
    * @param length The length of the data to read
    */
-  public DataFileChannel(File file, long offset, long length) {
+  public DataFileChannel(long pageIndex, RandomAccessFile file, long offset, long length) {
     mFile = Preconditions.checkNotNull(file, "file");
+    try {
+      mFile.seek(offset);
+    } catch (Exception e) {
+      throw new RuntimeException(e);
+    }
     mOffset = offset;
     mLength = length;
+    mPageIndex = pageIndex;
   }
 
   @Override
   public Object getNettyOutput() {
-    return new DefaultFileRegion(mFile, mOffset, mLength);
+    return new DefaultFileRegion(mFile.getChannel(), mOffset, mLength);
   }
 
   @Override
diff --git a/dora/shell/src/main/java/alluxio/cli/fs/command/CatCommand.java b/dora/shell/src/main/java/alluxio/cli/fs/command/CatCommand.java
index 51125212931b..e33652a4f5ca 100644
--- a/dora/shell/src/main/java/alluxio/cli/fs/command/CatCommand.java
+++ b/dora/shell/src/main/java/alluxio/cli/fs/command/CatCommand.java
@@ -54,11 +54,11 @@ protected void runPlainPath(AlluxioURI path, CommandLine cl)
     if (status.isFolder()) {
       throw new FileDoesNotExistException(ExceptionMessage.PATH_MUST_BE_FILE.getMessage(path));
     }
-    byte[] buf = new byte[Constants.MB];
+    byte[] buf = new byte[Constants.MB * 16];
     try (FileInStream is = mFileSystem.openFile(path)) {
       int read = is.read(buf);
       while (read != -1) {
-        System.out.write(buf, 0, read);
+//        System.out.write(buf, 0, read);
         read = is.read(buf);
       }
     }