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https://issues.apache.org/jira/browse/HADOOP-13761?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16321643#comment-16321643
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Aaron Fabbri commented on HADOOP-13761:
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Reminder comment here: We should also:
- Update MetadataStore javadoc to say that implementations *must* implement
their own retries as needed to recover from transient issues like services
unavailable or network connectivity blips. (The most sane design decision IMO..
especially if more backends are added in the future).
- Update any S3Guard-specific retry annotations in S3A FS to assume
MetadataStores do their own retries. e.g. the
{{Retries.OnceTranslated("s3guard not retrying")}} being added to
listLocatedStatus() in HADOOP-15079.
> S3Guard: implement retries for DDB failures and throttling; translate
> exceptions
> --------------------------------------------------------------------------------
>
> Key: HADOOP-13761
> URL: https://issues.apache.org/jira/browse/HADOOP-13761
> Project: Hadoop Common
> Issue Type: Sub-task
> Components: fs/s3
> Affects Versions: 3.0.0-beta1
> Reporter: Aaron Fabbri
> Assignee: Steve Loughran
> Priority: Blocker
>
> Following the S3AFileSystem integration patch in HADOOP-13651, we need to add
> retry logic.
> In HADOOP-13651, I added TODO comments in most of the places retry loops are
> needed, including:
> - open(path). If MetadataStore reflects recent create/move of file path, but
> we fail to read it from S3, retry.
> - delete(path). If deleteObject() on S3 fails, but MetadataStore shows the
> file exists, retry.
> - rename(src,dest). If source path is not visible in S3 yet, retry.
> - listFiles(). Skip for now. Not currently implemented in S3Guard. I will
> create a separate JIRA for this as it will likely require interface changes
> (i.e. prefix or subtree scan).
> We may miss some cases initially and we should do failure injection testing
> to make sure we're covered. Failure injection tests can be a separate JIRA
> to make this easier to review.
> We also need basic configuration parameters around retry policy. There
> should be a way to specify maximum retry duration, as some applications would
> prefer to receive an error eventually, than waiting indefinitely. We should
> also be keeping statistics when inconsistency is detected and we enter a
> retry loop.
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