HADOOP-18347. S3A Vectored IO to use bounded thread pool. (#4918)

part of HADOOP-18103.

Also introducing a config fs.s3a.vectored.active.ranged.reads
to configure the maximum number of number of range reads a
single input stream can have active (downloading, or queued)
to the central FileSystem instance's pool of queued operations.
This stops a single stream overloading the shared thread pool.

Contributed by: Mukund Thakur
 Conflicts:
	hadoop-tools/hadoop-aws/src/main/java/org/apache/hadoop/fs/s3a/Constants.java
	hadoop-tools/hadoop-aws/src/main/java/org/apache/hadoop/fs/s3a/S3AFileSystem.java

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/StreamCapabilities.java

@@ -84,7 +84,7 @@ public interface StreamCapabilities {
    * Support for vectored IO api.
    * See {@code PositionedReadable#readVectored(List, IntFunction)}.
    */
-  String VECTOREDIO = "readvectored";
+  String VECTOREDIO = "in:readvectored";
 
   /**
    * Stream abort() capability implemented by {@link Abortable#abort()}.

hadoop-tools/hadoop-aws/src/main/java/org/apache/hadoop/fs/s3a/Constants.java

@@ -1203,4 +1203,23 @@ private Constants() {
    * Default maximum read size in bytes during vectored reads : {@value}.
    */
   public static final int DEFAULT_AWS_S3_VECTOR_READS_MAX_MERGED_READ_SIZE = 1253376; //1M
+
+  /**
+   * Maximum number of range reads a single input stream can have
+   * active (downloading, or queued) to the central FileSystem
+   * instance's pool of queued operations.
+   * This stops a single stream overloading the shared thread pool.
+   * {@value}
+   * <p>
+   * Default is {@link #DEFAULT_AWS_S3_VECTOR_ACTIVE_RANGE_READS}
+   */
+  public static final String AWS_S3_VECTOR_ACTIVE_RANGE_READS =
+          "fs.s3a.vectored.active.ranged.reads";
+
+  /**
+   * Limit of queued range data download operations during vectored
+   * read. Value: {@value}
+   */
+  public static final int DEFAULT_AWS_S3_VECTOR_ACTIVE_RANGE_READS = 4;
+
 }

hadoop-tools/hadoop-aws/src/main/java/org/apache/hadoop/fs/s3a/S3AFileSystem.java

@@ -319,6 +319,12 @@ public class S3AFileSystem extends FileSystem implements StreamCapabilities,
   /** Vectored IO context. */
   private VectoredIOContext vectoredIOContext;
 
+  /**
+   * Maximum number of active range read operation a single
+   * input stream can have.
+   */
+  private int vectoredActiveRangeReads;
+
   private long readAhead;
   private ChangeDetectionPolicy changeDetectionPolicy;
   private final AtomicBoolean closed = new AtomicBoolean(false);
@@ -597,6 +603,8 @@ public void initialize(URI name, Configuration originalConf)
           longBytesOption(conf, ASYNC_DRAIN_THRESHOLD,
                         DEFAULT_ASYNC_DRAIN_THRESHOLD, 0),
           inputPolicy);
+      vectoredActiveRangeReads = intOption(conf,
+              AWS_S3_VECTOR_ACTIVE_RANGE_READS, DEFAULT_AWS_S3_VECTOR_ACTIVE_RANGE_READS, 1);
       vectoredIOContext = populateVectoredIOContext(conf);
     } catch (AmazonClientException e) {
       // amazon client exception: stop all services then throw the translation
@@ -1504,7 +1512,10 @@ private FSDataInputStream executeOpen(
                   createObjectAttributes(path, fileStatus),
                   createInputStreamCallbacks(auditSpan),
                   inputStreamStats,
-                  unboundedThreadPool));
+                  new SemaphoredDelegatingExecutor(
+                          boundedThreadPool,
+                          vectoredActiveRangeReads,
+                          true)));
   }
 
   /**

hadoop-tools/hadoop-aws/src/main/java/org/apache/hadoop/fs/s3a/S3AInputStream.java

@@ -27,7 +27,7 @@
 import java.nio.ByteBuffer;
 import java.util.List;
 import java.util.concurrent.CompletableFuture;
-import java.util.concurrent.ThreadPoolExecutor;
+import java.util.concurrent.ExecutorService;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.function.IntFunction;
 
@@ -139,7 +139,7 @@ public class S3AInputStream extends FSInputStream implements  CanSetReadahead,
   /**
    * Thread pool used for vectored IO operation.
    */
-  private final ThreadPoolExecutor unboundedThreadPool;
+  private final ExecutorService boundedThreadPool;
   private final String bucket;
   private final String key;
   private final String pathStr;
@@ -196,13 +196,13 @@ public class S3AInputStream extends FSInputStream implements  CanSetReadahead,
    * @param s3Attributes object attributes
    * @param client S3 client to use
    * @param streamStatistics stream io stats.
-   * @param unboundedThreadPool thread pool to use.
+   * @param boundedThreadPool thread pool to use.
    */
   public S3AInputStream(S3AReadOpContext ctx,
                         S3ObjectAttributes s3Attributes,
                         InputStreamCallbacks client,
                         S3AInputStreamStatistics streamStatistics,
-                        ThreadPoolExecutor unboundedThreadPool) {
+                        ExecutorService boundedThreadPool) {
     Preconditions.checkArgument(isNotEmpty(s3Attributes.getBucket()),
         "No Bucket");
     Preconditions.checkArgument(isNotEmpty(s3Attributes.getKey()), "No Key");
@@ -224,7 +224,7 @@ public S3AInputStream(S3AReadOpContext ctx,
     setInputPolicy(ctx.getInputPolicy());
     setReadahead(ctx.getReadahead());
     this.asyncDrainThreshold = ctx.getAsyncDrainThreshold();
-    this.unboundedThreadPool = unboundedThreadPool;
+    this.boundedThreadPool = boundedThreadPool;
     this.vectoredIOContext = context.getVectoredIOContext();
     this.threadIOStatistics = requireNonNull(ctx.getIOStatisticsAggregator());
   }
@@ -882,7 +882,7 @@ public void readVectored(List<? extends FileRange> ranges,
       streamStatistics.readVectoredOperationStarted(sortedRanges.size(), sortedRanges.size());
       for (FileRange range: sortedRanges) {
         ByteBuffer buffer = allocate.apply(range.getLength());
-        unboundedThreadPool.submit(() -> readSingleRange(range, buffer));
+        boundedThreadPool.submit(() -> readSingleRange(range, buffer));
       }
     } else {
       LOG.debug("Trying to merge the ranges as they are not disjoint");
@@ -893,7 +893,7 @@ public void readVectored(List<? extends FileRange> ranges,
       LOG.debug("Number of original ranges size {} , Number of combined ranges {} ",
               ranges.size(), combinedFileRanges.size());
       for (CombinedFileRange combinedFileRange: combinedFileRanges) {
-        unboundedThreadPool.submit(
+        boundedThreadPool.submit(
             () -> readCombinedRangeAndUpdateChildren(combinedFileRange, allocate));
       }
     }

hadoop-tools/hadoop-aws/src/site/markdown/tools/hadoop-aws/performance.md

@@ -82,6 +82,15 @@ on the client requirements.
       that we group ranges together during vectored read.
       Setting this value to 0 will disable merging of ranges.
    </description>
+<property>
+   <name>fs.s3a.vectored.active.ranged.reads</name>
+   <value>4</value>
+   <description>
+      Maximum number of range reads a single input stream can have
+      active (downloading, or queued) to the central FileSystem
+      instance's pool of queued operations.
+      This stops a single stream overloading the shared thread pool.
+   </description>
 </property>
 ```