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Posted to derby-dev@db.apache.org by "Øystein Grøvlen (JIRA)" <de...@db.apache.org> on 2006/01/06 16:23:15 UTC

[jira] Created: (DERBY-799) Large response times during checkpointing on disk-bound systems

Large response times during checkpointing on disk-bound systems
---------------------------------------------------------------

         Key: DERBY-799
         URL: http://issues.apache.org/jira/browse/DERBY-799
     Project: Derby
        Type: Improvement
  Components: Performance, Store  
    Versions: 10.0.2.0, 10.0.2.1, 10.1.1.0, 10.1.1.1, 10.1.1.2, 10.1.2.0, 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

I will file another JIRA issue for the related issue of concurrent access to the same file.


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[jira] Updated: (DERBY-799) Large response times during checkpointing on disk-bound systems

Posted by "Dag H. Wanvik (JIRA)" <ji...@apache.org>.
     [ https://issues.apache.org/jira/browse/DERBY-799?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Dag H. Wanvik updated DERBY-799:
--------------------------------

    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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[jira] Updated: (DERBY-799) Large response times during checkpointing on disk-bound systems

Posted by "Øystein Grøvlen (JIRA)" <de...@db.apache.org>.
     [ http://issues.apache.org/jira/browse/DERBY-799?page=all ]

Øystein Grøvlen updated DERBY-799:
----------------------------------

    Description: 
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.


  was:
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

I will file another JIRA issue for the related issue of concurrent access to the same file.



Added a link to another derby-dev thread that discusses this issue.

> Large response times during checkpointing on disk-bound systems
> ---------------------------------------------------------------
>
>          Key: DERBY-799
>          URL: http://issues.apache.org/jira/browse/DERBY-799
>      Project: Derby
>         Type: Improvement
>   Components: Performance, Store
>     Versions: 10.0.2.0, 10.0.2.1, 10.1.1.0, 10.1.1.1, 10.1.1.2, 10.1.2.0, 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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