hbase-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "ramkrishna.s.vasudevan (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HBASE-15205) Do not find the replication scope for every WAL#append()
Date Tue, 09 Feb 2016 05:12:18 GMT

    [ https://issues.apache.org/jira/browse/HBASE-15205?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15138363#comment-15138363
] 

ramkrishna.s.vasudevan commented on HBASE-15205:
------------------------------------------------

bq.When then is the scope checked? When we go to replicate after reading the WAL? We'd be
trading CPU for i/o?
Actually in the current code we check the scope both on writes and reads. So when we try to
replicate we once again try to iterate the scope that was persisted and check against the
families associated with every cell and only then decide on which one to be replicated. 
bq.We'd be trading CPU for i/o?
Yes but on the write path only. But now may be more data is written per WAL Key for a multiCF
case. 

> 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, 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. 



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)

Mime
View raw message