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Posted to derby-dev@db.apache.org by "Kristian Waagan (JIRA)" <ji...@apache.org> on 2010/12/07 22:21:09 UTC
[jira] Created: (DERBY-4940) Tune istat operational characteristics
Tune istat operational characteristics
--------------------------------------
Key: DERBY-4940
URL: https://issues.apache.org/jira/browse/DERBY-4940
Project: Derby
Issue Type: Sub-task
Components: SQL
Affects Versions: 10.8.0.0
Reporter: Kristian Waagan
The istat feature relies in a few tuning parameters to work properly.
The main goals of the feature is to avoid stale statistics degrading query performance, and at the same time not interfere too much with user activity. Some study of applications "in the field" is necessary to properly size the set of parameters.
It is also clear that it is impossible to make the feature behave exactly as wanted for all types of applications. Users that want full control of their statistics, can disable the istat daemon and manually monitor and update the statistics.
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[jira] [Closed] (DERBY-4940) Tune istat operational characteristics
Posted by "Kristian Waagan (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/DERBY-4940?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Kristian Waagan closed DERBY-4940.
----------------------------------
Resolution: Won't Fix
Given that we haven't gotten much feedback from users, I assume the current defaults are ok.
I'm resolving this issue as Won't Fix and closing it, but users should feel free to reopen it or log a new issue at a later time if the defaults turn out to be problematic.
> Tune istat operational characteristics
> --------------------------------------
>
> Key: DERBY-4940
> URL: https://issues.apache.org/jira/browse/DERBY-4940
> Project: Derby
> Issue Type: Improvement
> Components: SQL
> Affects Versions: 10.8.1.2
> Reporter: Kristian Waagan
> Labels: derby_triage10_10
> Attachments: derby-4940-1a-absdiff_to_1k.diff
>
>
> The istat feature relies in a few tuning parameters to work properly.
> The main goals of the feature is to avoid stale statistics degrading query performance, and at the same time not interfere too much with user activity. Some study of applications "in the field" is necessary to properly size the set of parameters.
> It is also clear that it is impossible to make the feature behave exactly as wanted for all types of applications. Users that want full control of their statistics, can disable the istat daemon and manually monitor and update the statistics.
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[jira] [Updated] (DERBY-4940) Tune istat operational
characteristics
Posted by "Mamta A. Satoor (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/DERBY-4940?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Mamta A. Satoor updated DERBY-4940:
-----------------------------------
Labels: derby_triage10_10 (was: )
> Tune istat operational characteristics
> --------------------------------------
>
> Key: DERBY-4940
> URL: https://issues.apache.org/jira/browse/DERBY-4940
> Project: Derby
> Issue Type: Improvement
> Components: SQL
> Affects Versions: 10.8.1.2
> Reporter: Kristian Waagan
> Labels: derby_triage10_10
> Attachments: derby-4940-1a-absdiff_to_1k.diff
>
>
> The istat feature relies in a few tuning parameters to work properly.
> The main goals of the feature is to avoid stale statistics degrading query performance, and at the same time not interfere too much with user activity. Some study of applications "in the field" is necessary to properly size the set of parameters.
> It is also clear that it is impossible to make the feature behave exactly as wanted for all types of applications. Users that want full control of their statistics, can disable the istat daemon and manually monitor and update the statistics.
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[jira] Updated: (DERBY-4940) Tune istat operational characteristics
Posted by "Kristian Waagan (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/DERBY-4940?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Kristian Waagan updated DERBY-4940:
-----------------------------------
Attachment: derby-4940-1a-absdiff_to_1k.diff
Attaching patch 1a, which changes the default setting of the absdiff threshold to 1000. This will hopefully stop the tinderbox and the nightlies to fail due to failures in the various updatelocks tests.
Whether the absdiff mechanism will be kept or not is up for discussion, this commit is primarily to try to stabilize the regression tests.
Committed to trunk with revision 1071588.
> Tune istat operational characteristics
> --------------------------------------
>
> Key: DERBY-4940
> URL: https://issues.apache.org/jira/browse/DERBY-4940
> Project: Derby
> Issue Type: Sub-task
> Components: SQL
> Affects Versions: 10.8.0.0
> Reporter: Kristian Waagan
> Attachments: derby-4940-1a-absdiff_to_1k.diff
>
>
> The istat feature relies in a few tuning parameters to work properly.
> The main goals of the feature is to avoid stale statistics degrading query performance, and at the same time not interfere too much with user activity. Some study of applications "in the field" is necessary to properly size the set of parameters.
> It is also clear that it is impossible to make the feature behave exactly as wanted for all types of applications. Users that want full control of their statistics, can disable the istat daemon and manually monitor and update the statistics.
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[jira] [Commented] (DERBY-4940) Tune istat operational
characteristics
Posted by "Mamta A. Satoor (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/DERBY-4940?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13465744#comment-13465744 ]
Mamta A. Satoor commented on DERBY-4940:
----------------------------------------
Hi Kristian, I noticed that you committed a patch which was for regression tests. Do we plan on doing more work on this jira?
> Tune istat operational characteristics
> --------------------------------------
>
> Key: DERBY-4940
> URL: https://issues.apache.org/jira/browse/DERBY-4940
> Project: Derby
> Issue Type: Improvement
> Components: SQL
> Affects Versions: 10.8.1.2
> Reporter: Kristian Waagan
> Labels: derby_triage10_10
> Attachments: derby-4940-1a-absdiff_to_1k.diff
>
>
> The istat feature relies in a few tuning parameters to work properly.
> The main goals of the feature is to avoid stale statistics degrading query performance, and at the same time not interfere too much with user activity. Some study of applications "in the field" is necessary to properly size the set of parameters.
> It is also clear that it is impossible to make the feature behave exactly as wanted for all types of applications. Users that want full control of their statistics, can disable the istat daemon and manually monitor and update the statistics.
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[jira] [Updated] (DERBY-4940) Tune istat operational
characteristics
Posted by "Mamta A. Satoor (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/DERBY-4940?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Mamta A. Satoor updated DERBY-4940:
-----------------------------------
Urgency: Normal
> Tune istat operational characteristics
> --------------------------------------
>
> Key: DERBY-4940
> URL: https://issues.apache.org/jira/browse/DERBY-4940
> Project: Derby
> Issue Type: Improvement
> Components: SQL
> Affects Versions: 10.8.1.2
> Reporter: Kristian Waagan
> Labels: derby_triage10_10
> Attachments: derby-4940-1a-absdiff_to_1k.diff
>
>
> The istat feature relies in a few tuning parameters to work properly.
> The main goals of the feature is to avoid stale statistics degrading query performance, and at the same time not interfere too much with user activity. Some study of applications "in the field" is necessary to properly size the set of parameters.
> It is also clear that it is impossible to make the feature behave exactly as wanted for all types of applications. Users that want full control of their statistics, can disable the istat daemon and manually monitor and update the statistics.
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[jira] Updated: (DERBY-4940) Tune istat operational characteristics
Posted by "Kristian Waagan (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/DERBY-4940?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Kristian Waagan updated DERBY-4940:
-----------------------------------
Issue Type: Improvement (was: Sub-task)
Parent: (was: DERBY-4934)
> Tune istat operational characteristics
> --------------------------------------
>
> Key: DERBY-4940
> URL: https://issues.apache.org/jira/browse/DERBY-4940
> Project: Derby
> Issue Type: Improvement
> Components: SQL
> Affects Versions: 10.8.0.0
> Reporter: Kristian Waagan
> Attachments: derby-4940-1a-absdiff_to_1k.diff
>
>
> The istat feature relies in a few tuning parameters to work properly.
> The main goals of the feature is to avoid stale statistics degrading query performance, and at the same time not interfere too much with user activity. Some study of applications "in the field" is necessary to properly size the set of parameters.
> It is also clear that it is impossible to make the feature behave exactly as wanted for all types of applications. Users that want full control of their statistics, can disable the istat daemon and manually monitor and update the statistics.
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[jira] Commented: (DERBY-4940) Tune istat operational
characteristics
Posted by "Rick Hillegas (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/DERBY-4940?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12995441#comment-12995441 ]
Rick Hillegas commented on DERBY-4940:
--------------------------------------
There is a discussion about reasonable defaults for the undocumented istat knobs and about whether additional knobs are needed: http://old.nabble.com/forum/Search.jtp?forum=105&local=y&query=question+about+istats+thresholds
This issue is a place to continue those discussions and, if necessary, to hang patches. At the moment, we are still planning to not document these knobs. Instead, we would like to gain experience about how istat behaves in the wild. From that experience, we hope to figure out whether these are the right knobs, how to set reasonable defaults for them, and whether we should document how to override Derby's defaults.
> Tune istat operational characteristics
> --------------------------------------
>
> Key: DERBY-4940
> URL: https://issues.apache.org/jira/browse/DERBY-4940
> Project: Derby
> Issue Type: Sub-task
> Components: SQL
> Affects Versions: 10.8.0.0
> Reporter: Kristian Waagan
>
> The istat feature relies in a few tuning parameters to work properly.
> The main goals of the feature is to avoid stale statistics degrading query performance, and at the same time not interfere too much with user activity. Some study of applications "in the field" is necessary to properly size the set of parameters.
> It is also clear that it is impossible to make the feature behave exactly as wanted for all types of applications. Users that want full control of their statistics, can disable the istat daemon and manually monitor and update the statistics.
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