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https://issues.apache.org/jira/browse/DERBY-799?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Dag H. Wanvik updated DERBY-799:
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Derby Categories: [Performance]
> Large response times during checkpointing on disk-bound systems
> ---------------------------------------------------------------
>
> Key: DERBY-799
> URL: https://issues.apache.org/jira/browse/DERBY-799
> Project: Derby
> Issue Type: Improvement
> Components: Store
> Affects Versions: 10.0.2.0, 10.0.2.1, 10.1.1.0, 10.1.2.1
> Environment: Observed on both Solaris and Linux with Sun VM.
> Reporter: Øystein Grøvlen
>
> We have observed that during checkpointing, transaction response times for
> small transactions may become very long. Extra trace output in the log
> showed that this was due to long response times for disk I/O. I observed
> that some read and write operations took more than 20 seconds.
> The believed reason for the long response times is that the file system
> buffer may be overflowed during checkpointing. During checkpointing, Derby
> writes all dirty pages to the file system buffer and then syncs at the end.
> I tried syncing a file for every 100th write and that improved the situation
> a bit.
> The following derby-dev threads discusses this issue:
> http://www.nabble.com/-jira-Created%3A-%28DERBY-733%29-Starvation-in-RAFContainer.readPage%28%29-t646257.html#a1975574
> http://www.nabble.com/Derby-I-O-issues-during-checkpointing-t473523.html#a1294290
> I will file another JIRA issue for the related issue of concurrent access to
> the same file.
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