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https://issues.apache.org/jira/browse/HADOOP-19389?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17914180#comment-17914180
]
ASF GitHub Bot commented on HADOOP-19389:
-----------------------------------------
cnauroth commented on code in PR #7291:
URL: https://github.com/apache/hadoop/pull/7291#discussion_r1920473054
##########
hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/shell/Display.java:
##########
@@ -286,31 +326,98 @@ public AvroFileInputStream(FileStatus status) throws
IOException {
writer = new GenericDatumWriter<Object>(schema);
output = new ByteArrayOutputStream();
encoder = EncoderFactory.get().jsonEncoder(schema, output);
+ finalSeparator =
System.getProperty("line.separator").getBytes(StandardCharsets.UTF_8);
}
/**
* Read a single byte from the stream.
*/
@Override
public int read() throws IOException {
+ if (buffer == null) {
+ return -1;
+ }
+
if (pos < buffer.length) {
return buffer[pos++];
}
+
if (!fileReader.hasNext()) {
+ // Unset buffer to signal EOF on future calls.
+ buffer = null;
return -1;
}
+
writer.write(fileReader.next(), encoder);
encoder.flush();
+
if (!fileReader.hasNext()) {
- // Write a new line after the last Avro record.
- output.write(System.getProperty("line.separator")
- .getBytes(StandardCharsets.UTF_8));
- output.flush();
+ if (buffer.length > 0) {
+ // Write a new line after the last Avro record.
+ output.write(finalSeparator);
+ output.flush();
+ }
+ }
+
+ swapBuffer();
+ return read();
+ }
+
+ @Override
+ public int read(byte[] dest, int destPos, int destLen) throws IOException {
+ if (dest == null) {
Review Comment:
Done.
> Optimize shell -text command I/O with multi-byte read.
> ------------------------------------------------------
>
> Key: HADOOP-19389
> URL: https://issues.apache.org/jira/browse/HADOOP-19389
> Project: Hadoop Common
> Issue Type: Improvement
> Components: command, fs, fs/azure, fs/gcs, fs/s3
> Affects Versions: 3.4.1
> Reporter: Chris Nauroth
> Assignee: Chris Nauroth
> Priority: Minor
> Labels: pull-request-available
>
> {{hadoop fs -text}} reads Avro files and sequence files by internally
> wrapping the stream in
> [{{AvroFileInputStream}}|https://github.com/apache/hadoop/blob/rel/release-3.4.1/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/shell/Display.java#L270]
> or
> [{{TextRecordInputStream}}|https://github.com/apache/hadoop/blob/rel/release-3.4.1/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/shell/Display.java#L217].
> These classes implement the required single-byte
> [{{read()}}|https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/io/InputStream.html#read()],
> but not the optional multi-byte buffered [{{read(byte[], int,
> int)}}|https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/io/InputStream.html#read(byte%5B%5D,int,int)].
> The default implementation in the JDK is a [loop over single-byte
> read|https://github.com/openjdk/jdk11u-dev/blob/a47c72fad455bfdf9053cb8e94c99e73965ab50d/src/java.base/share/classes/java/io/InputStream.java#L280],
> which causes sub-optimal I/O and method call overhead. We can optimize this
> by overriding the multi-byte read method.
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