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https://issues.apache.org/jira/browse/HADOOP-14999?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16396605#comment-16396605
]
SammiChen commented on HADOOP-14999:
------------------------------------
Hi [~uncleGen], some comments,
1.
{quote}
Preconditions.checkArgument(v >= min,
String.format("Value of %s: %d is below the minimum value %d",
key, v, min));
{quote}
Ignore the comment. String.format with %d is OK.
2.
bq. Asynchronous multi-part based uploading mechanism to support huge file*
which is larger than 5GB.
Please give a detail explain about where does 5GB threshold comes from?
3.
{quote}
if (partSize < MULTIPART_MIN_SIZE) {
LOG.warn("{} must be at least 5 MB; configured value is {}",
property, partSize);
partSize = MULTIPART_MIN_SIZE;
{quote}
MULTIPART_MIN_SIZE is 100K. The threshold in warning message is 5 MB.
4.
bq. long partSize = AliyunOSSUtils.getMultipartSizeProperty(getConf(),
MULTIPART_UPLOAD_PART_SIZE_DEFAULT);
can we use uploadPartSize instead here?
5.
bq. I also add the resource clean logic in try-finally
{quote}
try {
blockStream.write(b, off, len);
blockWritten += len;
if (blockWritten >= blockSize) {
uploadCurrentPart();
blockWritten = 0L;
}
} finally {
for (File tFile: blockFiles) {
if (tFile.exists() && !tFile.delete()) {
LOG.warn("Failed to delete temporary file {}", tFile);
}
}
}
{quote}
I see you add the temp file delete in finally no matter the above operation
succeeds or not . When store.uploadPart() returns, is the upload finished
already? If it's
an async operation, delete the temp file in normal case may have trouble.
6. the performance data looks good.
> AliyunOSS: provide one asynchronous multi-part based uploading mechanism
> ------------------------------------------------------------------------
>
> Key: HADOOP-14999
> URL: https://issues.apache.org/jira/browse/HADOOP-14999
> Project: Hadoop Common
> Issue Type: Sub-task
> Components: fs/oss
> Affects Versions: 3.0.0-beta1
> Reporter: Genmao Yu
> Assignee: Genmao Yu
> Priority: Major
> Attachments: HADOOP-14999.001.patch, HADOOP-14999.002.patch,
> HADOOP-14999.003.patch, HADOOP-14999.004.patch, HADOOP-14999.005.patch,
> HADOOP-14999.006.patch, HADOOP-14999.007.patch, HADOOP-14999.008.patch,
> HADOOP-14999.009.patch, asynchronous_file_uploading.pdf,
> diff-between-patch7-and-patch8.txt
>
>
> This mechanism is designed for uploading file in parallel and asynchronously:
> - improve the performance of uploading file to OSS server. Firstly, this
> mechanism splits result to multiple small blocks and upload them in parallel.
> Then, getting result and uploading blocks are asynchronous.
> - avoid buffering too large result into local disk. To cite an extreme
> example, there is a task which will output 100GB or even larger, we may need
> to output this 100GB to local disk and then upload it. Sometimes, it is
> inefficient and limited to disk space.
> This patch reuse {{SemaphoredDelegatingExecutor}} as executor service and
> depends on HADOOP-15039.
> Attached {{asynchronous_file_uploading.pdf}} illustrated the difference
> between previous {{AliyunOSSOutputStream}} and
> {{AliyunOSSBlockOutputStream}}, i.e. this asynchronous multi-part based
> uploading mechanism.
> 1. {{AliyunOSSOutputStream}}: we need to output the whole result to local
> disk before we can upload it to OSS. This will poses two problems：
> - if the output file is too large, it will run out of the local disk.
> - if the output file is too large, task will wait long time to upload result
> to OSS before finish, wasting much compute resource.
> 2. {{AliyunOSSBlockOutputStream}}: we cut the task output into small blocks,
> i.e. some small local file, and each block will be packaged into a uploading
> task. These tasks will be submitted into {{SemaphoredDelegatingExecutor}}.
> {{SemaphoredDelegatingExecutor}} will upload this blocks in parallel, this
> will improve performance greatly.
> 3. Each task will retry 3 times to upload block to Aliyun OSS. If one of
> those tasks failed, the whole file uploading will failed, and we will abort
> current uploading.
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