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https://issues.apache.org/jira/browse/APEXMALHAR-2223?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15537578#comment-15537578
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ASF GitHub Bot commented on APEXMALHAR-2223:
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GitHub user chandnisingh opened a pull request:
https://github.com/apache/apex-malhar/pull/438
APEXMALHAR-2223 ability to buffer data up to a threshold and write it…
… to wal when the threshold is reached.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/chandnisingh/apex-malhar APEXMALHAR-2223
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/apex-malhar/pull/438.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 #438
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commit 7383f8b4eac04902e5365a60d683f07c85d05a8d
Author: Chandni Singh <[email protected]>
Date: 2016-09-30T21:15:51Z
APEXMALHAR-2223 ability to buffer data up to a threshold and write it to
wal when the threshold is reached.
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> Managed state should parallelize WAL writes
> -------------------------------------------
>
> Key: APEXMALHAR-2223
> URL: https://issues.apache.org/jira/browse/APEXMALHAR-2223
> Project: Apache Apex Malhar
> Issue Type: Improvement
> Affects Versions: 3.4.0
> Reporter: Thomas Weise
> Assignee: Chandni Singh
>
> Currently, data is accumulated in memory and written to the WAL on checkpoint
> only. This causes a write spike on checkpoint and does not utilize the HDFS
> write pipeline. The other extreme is writing to the WAL as soon as data
> arrives and then only flush in beforeCheckpoint. The downside of this is that
> when the same key is written many times, all duplicates will be in the WAL.
> Need to find a balances approach, that the user can potentially fine tune.
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