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https://issues.apache.org/jira/browse/DERBY-6305?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13789569#comment-13789569
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Kim Haase commented on DERBY-6305:
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Nobody seems to have gotten around to updating the wiki page, unless they did
so on a page I couldn't find. I added information about the undocumented
properties to the following page, which is linked to from the front page of the
wiki:
https://wiki.apache.org/db-derby/UndocumentedDerbyBehavior
It includes what I found in the source code about valid argument values, but
doesn't explain what the properties actually do, since that info isn't there.
I'm guessing that "bulkFetch" has to do with changing the default value
described in "About the optimizer's selection of bulk fetch"
(http://db.apache.org/derby/docs/10.10/tuning/ctunoptimz29384.html) and that
the hash properties have to do with "Join strategies"
(http://db.apache.org/derby/docs/10.10/tuning/ctunoptimz23173.html),
particularly since the latter mentions setting a property but doesn't say what
the property is or how to set it. The useStatistics property should have
something to do with runtime statistics, but I can't guess what.
Does anyone else know?
> Tuning Derby information on optimizer overrides needs improvement
> -----------------------------------------------------------------
>
> Key: DERBY-6305
> URL: https://issues.apache.org/jira/browse/DERBY-6305
> Project: Derby
> Issue Type: Bug
> Components: Documentation
> Affects Versions: 10.10.1.1
> Reporter: Kim Haase
> Assignee: Kim Haase
> Attachments: ctundepthoptover.html, DERBY-6305.diff,
> DerbyDashProperties.html
>
>
> The topic "Optimizer overrides" in the Tuning Derby manual talks about using
> the "-- DERBY-PROPERTIES" clause to specify overrides but doesn't include a
> link to the topic later in the manual, "Overriding the default optimizer
> behavior", that explains how to use the clause. This undoubtedly results in
> user confusion.
> The first topic is
> http://db.apache.org/derby/docs/10.10/tuning/ctundepthoptover.html; the
> second is
> http://db.apache.org/derby/docs/10.10/tuning/ctunoptimzoverride.html.
> I'll add the link, and I welcome additional suggestions on how to improve
> these topics.
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