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https://issues.apache.org/jira/browse/HDFS-12506?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16177811#comment-16177811
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Weiwei Yang commented on HDFS-12506:
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Thanks [~linyiqun] for the review, I have uploaded v5 patch that added test
case to creating volume/bucket with prefix "#". Regarding to your first
comment, about {{KeyType.UNKNOWN}}, I don't think that is necessary. We have
desired format of KSM DB keys, if the key is something else and it is treated
as key and then handed by
{code}
BucketInfo bucketInfo = BucketInfo.parseFrom(value);
{code}
protobuf will throw an exception that parse failed because format not match.
Even we added logic to get a type for unknown, here it still fails but just
with a different error message "Unknown key from ksm.db". That's why I think we
don't need to calculate number of "/"s. A simple protobuf message is
informative enough. Let me know if you disagree. Thanks.
> Ozone: ListBucket is too slow
> -----------------------------
>
> Key: HDFS-12506
> URL: https://issues.apache.org/jira/browse/HDFS-12506
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Components: ozone
> Reporter: Weiwei Yang
> Assignee: Weiwei Yang
> Priority: Blocker
> Labels: ozoneMerge, performance
> Attachments: HDFS-12506-HDFS-7240.001.patch,
> HDFS-12506-HDFS-7240.002.patch, HDFS-12506-HDFS-7240.003.patch,
> HDFS-12506-HDFS-7240.004.patch, HDFS-12506-HDFS-7240.005.patch
>
>
> Generated 3 million keys in ozone, and run {{listBucket}} command to get a
> list of buckets under a volume,
> {code}
> bin/hdfs oz -listBucket http://15oz1.fyre.ibm.com:9864/vol-0-15143 -user wwei
> {code}
> this call spent over *15 seconds* to finish. The problem was caused by the
> inflexible structure of KSM DB. Right now {{ksm.db}} stores keys like
> following
> {code}
> /v1/b1
> /v1/b1/k1
> /v1/b1/k2
> /v1/b1/k3
> /v1/b2
> /v1/b2/k1
> /v1/b2/k2
> /v1/b2/k3
> /v1/b3
> /v1/b4
> {code}
> keys are sorted in nature order so when we do list buckets under a volume e.g
> /v1, we need to seek to /v1 point and start to iterate and filter keys, this
> ends up with scanning all keys under volume /v1. The problem with this design
> is we don't have an efficient approach to locate all buckets without scanning
> the keys.
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