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From "Kannan Muthukkaruppan (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (HBASE-3693) isMajorCompaction() check triggers lots of listStatus DFS RPC calls from HBase
Date Wed, 23 Mar 2011 19:20:06 GMT

     [ https://issues.apache.org/jira/browse/HBASE-3693?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Kannan Muthukkaruppan updated HBASE-3693:
-----------------------------------------

    Description: 
We noticed that there are lots of listStatus calls on the ColumnFamily directories within
each region, coming from this codepath:

{code}
compactionSelection()
 --> isMajorCompaction 
    --> getLowestTimestamp()
       -->  FileStatus[] stats = fs.listStatus(p);
{code}

So on every compactionSelection() we're taking this hit. While not immediately an issue, just
from log inspection, this accounts for quite a large number of RPCs to namenode at the moment
and seems like an unnecessary load to be sending to the namenode.

Seems like it would be easy to cache the timestamp for each opened/created StoreFile, in memory,
in the region server, and avoid going to DFS each time for this information.


  was:
We noticed that are lots of listStatus calls on the ColumnFamily directories within each regions,
coming from this codepath:

{code}
compactionSelection()
 --> isMajorCompaction 
    --> getLowestTimestamp()
       -->  FileStatus[] stats = fs.listStatus(p);
{code}

So on every compactionSelection() we're taking this hit. While not immediately an issue, just
from log inspection, this accounts for quite a large number of RPCs to namenode at the moment
and seems like an unnecessary load to be sending to the namenode.

Seems like it would be easy to cache the timestamp for each opened/created StoreFile, in memory,
in the region server, and avoid going to DFS each time for this information.



> isMajorCompaction() check triggers lots of listStatus DFS RPC calls from HBase
> ------------------------------------------------------------------------------
>
>                 Key: HBASE-3693
>                 URL: https://issues.apache.org/jira/browse/HBASE-3693
>             Project: HBase
>          Issue Type: Improvement
>            Reporter: Kannan Muthukkaruppan
>            Assignee: Liyin Tang
>
> We noticed that there are lots of listStatus calls on the ColumnFamily directories within
each region, coming from this codepath:
> {code}
> compactionSelection()
>  --> isMajorCompaction 
>     --> getLowestTimestamp()
>        -->  FileStatus[] stats = fs.listStatus(p);
> {code}
> So on every compactionSelection() we're taking this hit. While not immediately an issue,
just from log inspection, this accounts for quite a large number of RPCs to namenode at the
moment and seems like an unnecessary load to be sending to the namenode.
> Seems like it would be easy to cache the timestamp for each opened/created StoreFile,
in memory, in the region server, and avoid going to DFS each time for this information.

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