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https://issues.apache.org/jira/browse/FLUME-3149?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16142698#comment-16142698
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ASF GitHub Bot commented on FLUME-3149:
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GitHub user zyfo2 opened a pull request:
https://github.com/apache/flume/pull/159
FLUME-3149 reduce cpu cost for taildir file source while still maintaining
reliability by using posFile in memory channel
File channel tracks transferred events and use transnational mechanism to
make transfer recoverable. However, it increases CPU cost due to frequent
system calls like write, read, etc. The Cpu cost could be very high if the
transfer rate is high.
In contrast, Memory channel has no such issue which requires only about 10%
of CPU cost in the same environment but it's not recovered if the system is
down accidentally.
For sources like taildir, I propose we could write position file in memory
channel to achieve reliability and reduce CPU cost.
After testing on my own production environment, CPU usage dropped from 13%
to 3% and still maintain reliability. （Transfer rate: 1Mb/s , kafka sink,
file channel -> memory channel with pos file)
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/zyfo2/flume FLUME-3149
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/flume/pull/159.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #159
----
commit cbdc0ac1f4ad6708e1b17fb6d392910a508e895d
Author: zhangyifeng01 <zhangyifen...@baidu.com>
Date: 2017-08-26T08:28:52Z
FLUME-3149 reduce cpu cost for taildir file source while still maintaining
reliability by using posFile in memory channel
----
> reduce cpu cost for file source transfer while still maintaining reliability
> ----------------------------------------------------------------------------
>
> Key: FLUME-3149
> URL: https://issues.apache.org/jira/browse/FLUME-3149
> Project: Flume
> Issue Type: Improvement
> Components: File Channel
> Reporter: will zhang
>
> File channel tracks transferred events and use transnational mechanism to
> make transfer recoverable. However, it increases CPU cost due to frequent
> system calls like write, read, etc. The Cpu cost could be very high if the
> transfer rate is high. In contrast, Memory channel has no such issue which
> requires only about 10% of CPU cost in the same environment but it's not
> recovered if the system is down accidentally.
> For sources like taildir/spooldir, I propose we could track offsets of file
> and store them locally to achieve reliability while still using memory
> channel to reduce CPU cost. Actually, I have already implemented this feature
> by storing the offsets in event headers and passing it to my own
> "offsetMemoryChannel" and store theses offsets in local disk in our
> production which reduces CPU cost by about 90 percent.
> Please let me know if it's worthwhile to have this feature in community
> version. Thank you.
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