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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 Mon, 05 Feb 2018 04:33:02 GMT

    [ https://issues.apache.org/jira/browse/HADOOP-14999?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16352026#comment-16352026

Genmao Yu commented on HADOOP-14999:

cc [~stevel@apache.org]

> 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,
> 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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