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From "Genmao Yu (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HADOOP-14999) AliyunOSS: provide one asynchronous multi-part based uploading mechanism
Date Thu, 08 Mar 2018 08:34:00 GMT

    [ https://issues.apache.org/jira/browse/HADOOP-14999?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16390910#comment-16390910

Genmao Yu commented on HADOOP-14999:

Thanks for [~Sammi] 's review. 
1. comment-1: remove unused config and refine some config
2. comment-2: fixed
3. comment-3: Sorry, any problems?

Preconditions.checkArgument(v >= min,
        String.format("Value of %s: %d is below the minimum value %d",
            key, v, min));
4. comment-4: update unit test
5. comment-5: IMHO, It is too large to test 5GB in integration test. And {{MULTIPART_UPLOAD_SIZE}}
may cover this case as you mentioned.
6. "But they are not cleaned when exception happens during the write() process.": all temp
files are {{deleteOnExit}}, but I also add the resource clean logic in {{try-finally}}

performance test: test file upload

|file size|before patch|after patch (with 4 parallelism)|

> 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, asynchronous_file_uploading.pdf
> 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
> 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´╝Ü
>  - 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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