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https://issues.apache.org/jira/browse/HBASE-15205?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15144298#comment-15144298
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Ashish Singhi commented on HBASE-15205:
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bq. For which we have to disable and enable the table. So this should workout.
It need not. It is configurable with {{hbase.online.schema.update.enable}} by
default it is {{true}} which means we do not enable and disable the table by
default on alter table command. Irrespective of that on alter table command the
HRegion constructor will be called and map will be updated accordingly.
bq. Is there any chance that the replication scope of a table can be changed
without using the alter_table command?
AFAIK no other way it is possible.
> Do not find the replication scope for every WAL#append()
> --------------------------------------------------------
>
> Key: HBASE-15205
> URL: https://issues.apache.org/jira/browse/HBASE-15205
> Project: HBase
> Issue Type: Sub-task
> Components: regionserver
> Reporter: ramkrishna.s.vasudevan
> Assignee: ramkrishna.s.vasudevan
> Priority: Minor
> Fix For: 2.0.0
>
> Attachments: HBASE-15205.patch, HBASE-15205_1.patch,
> ScopeWALEdits.jpg, ScopeWALEdits_afterpatch.jpg
>
>
> After the byte[] and char[] the other top contributor for lot of GC (though
> it is only 2.86%) is the UTF_8.newDecoder.
> This happens because for every WAL append we try to calculate the replication
> scope associate with the families associated with the TableDescriptor. I
> think per WAL append doing this is very costly and creates lot of garbage.
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