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https://issues.apache.org/jira/browse/HADOOP-19139?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17867196#comment-17867196
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ASF GitHub Bot commented on HADOOP-19139:
-----------------------------------------
saxenapranav commented on code in PR #6699:
URL: https://github.com/apache/hadoop/pull/6699#discussion_r1683883811
##########
hadoop-tools/hadoop-azure/src/main/java/org/apache/hadoop/fs/azurebfs/services/AbfsInputStream.java:
##########
@@ -385,32 +434,74 @@ private int readLastBlock(final byte[] b, final int off,
final int len)
// data need to be copied to user buffer from index bCursor,
// AbfsInutStream buffer is going to contain data from last block start. In
// that case bCursor will be set to fCursor - lastBlockStart
- long lastBlockStart = max(0, contentLength - footerReadSize);
+ if (!getFileStatusInformationPresent()) {
+ long lastBlockStart = max(0, (fCursor + len) - footerReadSize);
+ bCursor = (int) (fCursor - lastBlockStart);
+ return optimisedRead(b, off, len, lastBlockStart, min(fCursor + len,
footerReadSize), true);
+ }
+ long lastBlockStart = max(0, getContentLength() - footerReadSize);
bCursor = (int) (fCursor - lastBlockStart);
// 0 if contentlength is < buffersize
- long actualLenToRead = min(footerReadSize, contentLength);
- return optimisedRead(b, off, len, lastBlockStart, actualLenToRead);
+ long actualLenToRead = min(footerReadSize, getContentLength());
+ return optimisedRead(b, off, len, lastBlockStart, actualLenToRead, false);
}
private int optimisedRead(final byte[] b, final int off, final int len,
- final long readFrom, final long actualLen) throws IOException {
+ final long readFrom, final long actualLen,
+ final boolean isOptimizedReadWithoutContentLengthInformation) throws
IOException {
fCursor = readFrom;
int totalBytesRead = 0;
int lastBytesRead = 0;
try {
buffer = new byte[bufferSize];
+ boolean fileStatusInformationPresentBeforeRead =
getFileStatusInformationPresent();
+ /*
+ * Content length would not be available for the first optimized read in
case
+ * of lazy head optimization in inputStream. In such case, read of the
first optimized read
+ * would be done without the contentLength constraint. Post first call,
the contentLength
+ * would be present and should be used for further reads.
+ */
for (int i = 0;
- i < MAX_OPTIMIZED_READ_ATTEMPTS && fCursor < contentLength; i++) {
+ i < MAX_OPTIMIZED_READ_ATTEMPTS &&
(!getFileStatusInformationPresent()
+ || fCursor < getContentLength()); i++) {
lastBytesRead = readInternal(fCursor, buffer, limit,
(int) actualLen - limit, true);
if (lastBytesRead > 0) {
totalBytesRead += lastBytesRead;
limit += lastBytesRead;
fCursor += lastBytesRead;
fCursorAfterLastRead = fCursor;
+
+ /*
+ * In non-lazily opened inputStream, the contentLength would be
available before
+ * opening the inputStream. In such case, optimized read would
always be done
+ * on the last part of the file.
+ *
+ * In lazily opened inputStream, the contentLength would not be
available before
+ * opening the inputStream. In such case, contentLength conditioning
would not be
+ * applied to execute optimizedRead. Hence, the optimized read may
not be done on the
+ * last part of the file. If the optimized read is done on the
non-last part of the
+ * file, inputStream should read only the amount of data requested
by optimizedRead,
+ * as the buffer supplied would be only of the size of the data
requested by optimizedRead.
+ */
+ boolean shouldBreak = !fileStatusInformationPresentBeforeRead
+ && totalBytesRead == (int) actualLen;
+ if (shouldBreak) {
+ break;
+ }
}
}
} catch (IOException e) {
+ if (e instanceof FileNotFoundException) {
Review Comment:
Good point. Taken.
> [ABFS]: No GetPathStatus call for opening AbfsInputStream
> ---------------------------------------------------------
>
> Key: HADOOP-19139
> URL: https://issues.apache.org/jira/browse/HADOOP-19139
> Project: Hadoop Common
> Issue Type: Sub-task
> Components: fs/azure
> Reporter: Pranav Saxena
> Assignee: Pranav Saxena
> Priority: Major
> Labels: pull-request-available
>
> Read API gives contentLen and etag of the path. This information would be
> used in future calls on that inputStream. Prior information of eTag is of not
> much importance.
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