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https://issues.apache.org/jira/browse/HBASE-17161?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15711733#comment-15711733
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Jingcheng Du edited comment on HBASE-17161 at 12/1/16 11:36 AM:
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Thanks Ram. For a mob cell, I think it is important.
In scan of each cell in a mob-enabled cf, we try to read the ref tag. So it
helps if the ref tag is in the first one.
was (Author: jingcheng...@intel.com):
Thanks Ram. For a mob cell, I think it is important.
In each scan of a mob-enabled cf, we try to read the ref tag. So it helps if
the ref tag is in the first one.
> MOB : Make ref cell creation more efficient
> -------------------------------------------
>
> Key: HBASE-17161
> URL: https://issues.apache.org/jira/browse/HBASE-17161
> Project: HBase
> Issue Type: Improvement
> Reporter: Anoop Sam John
> Assignee: Anoop Sam John
> Fix For: 2.0.0
>
> Attachments: HBASE-17161.patch, HBASE-17161.patch
>
>
> When we flush MOB data, ref cells are created per actual MOB cell. This
> creates lots of garbage
> Refer MobUtils#createMobRefCell
> We need to add 2 tags into the ref cell. An ArrayList is created with default
> size creating ref array. Call to CellUtil.getTags will create a new ArrayList
> even if the original cell is having no tags.
> A new KV is created which will create a new backing byte[] and do copy. Also
> along with each of the flush/compaction op, a fresh Tag object is created for
> TableName tag.
> Fixes include
> 1. A table name tag is not going to change per HStore. Even both the new
> tags to be added. Will keep a byte[] of these 2 tags at MobHStore level so
> that all flush and compactions in this store can use it.
> 2. Create a new MobRefCell just like TagRewriteCell where only value and tags
> part will be diff from the original cell.
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