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https://issues.apache.org/jira/browse/HADOOP-19139?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17838477#comment-17838477
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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_r1570043455
##########
hadoop-tools/hadoop-azure/src/main/java/org/apache/hadoop/fs/azurebfs/services/AbfsInputStream.java:
##########
@@ -376,32 +439,48 @@ 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 (!fileStatusInformationPresent.get()) {
+ 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 isReadWithoutContentLengthInformation) throws IOException {
fCursor = readFrom;
int totalBytesRead = 0;
int lastBytesRead = 0;
try {
buffer = new byte[bufferSize];
+ boolean fileStatusInformationPresentBeforeRead =
fileStatusInformationPresent.get();
for (int i = 0;
- i < MAX_OPTIMIZED_READ_ATTEMPTS && fCursor < contentLength; i++) {
+ i < MAX_OPTIMIZED_READ_ATTEMPTS &&
(!fileStatusInformationPresent.get()
+ || fCursor < getContentLength()); i++) {
lastBytesRead = readInternal(fCursor, buffer, limit,
(int) actualLen - limit, true);
if (lastBytesRead > 0) {
totalBytesRead += lastBytesRead;
+ boolean shouldBreak = !fileStatusInformationPresentBeforeRead
Review Comment:
In a non-lazily opened InputStream, the contentLength is available before
opening the InputStream. In this case, the optimizedRead will always be done on
the last part of the file.
In a lazily opened InputStream, the contentLength is not available before
opening the InputStream. In this case, the optimizedRead may not be done on the
last part of the file. If the optimizedRead is done on a non-last part of the
file, the 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
Added as a comment.
> [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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