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https://issues.apache.org/jira/browse/DERBY-6809?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14552425#comment-14552425
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Mike Matrigali commented on DERBY-6809:
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i would add that you should make sure to not order by any key/key set that
already has an index as Derby will try it's
best to eliminate sorts by using the index. For a test case easily done just
by not having any indexes. The sample size
seems small to me but depends on data length. I would suggest designing your
test case to be able to generate N rows
of data and then pick whatever order of magnitude number of rows takes seconds
to run. I find that amount of work
significant enough to usually give good results, but not too long so that you
can do iterative debugging easily. Later
longer runs may be interesting.
There are 2 paths through the sorter. One tries to do everything in memory,
the other splits the problem up into groups
and writes/reads merge runs from/to disk. The threshold is based on optimizer
estimate of amount of data. Off hand I do
not remember the default and there is some knob that can be used to bump it up.
The default is likely too small for most
applications that have huge amounts of memory.
> Java 1.8 feature use
> --------------------
>
> Key: DERBY-6809
> URL: https://issues.apache.org/jira/browse/DERBY-6809
> Project: Derby
> Issue Type: Improvement
> Components: Network Server
> Affects Versions: 11.0.0.0
> Reporter: sagar
>
> Suggestion ...
> Is it possible to auto modify the existing source code using tools like
> Netbeans, and take advantage of the new features in JDK 1.8 for better
> multiuser performance and better utilization of current day multicore
> processors?
> Plainly put, can we have from 11.0 onwards a version of derby which takes
> advantage of the advancements and new features in java 1.8 ...
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