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Date: Thu, 3 Mar 2011 14:00:37 +0000 (UTC)
From: "Kristian Waagan (JIRA)" <jira@apache.org>
To: derby-dev@db.apache.org
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Subject: [jira] Updated: (DERBY-4940) Tune istat operational characteristics
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     [ 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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