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https://issues.apache.org/jira/browse/DERBY-6075?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13612457#comment-13612457
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Knut Anders Hatlen commented on DERBY-6075:
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I reran the experiment with more data points and more iterations (ran the test
100 times per revision). Averages are shown below. Numbers are in milliseconds,
so lower is better.
10.9.1.0 - 12936 (baseline)
r1398952 - 13017 (baseline + 0.6%) - before DERBY-5947
r1412577 - 12402 (baseline - 4.1%) - after DERBY-5947
r1413586 - 11761 (baseline - 9.1%) - before DERBY-6003
r1426151 - 11275 (baseline - 12.8%) - after DERBY-6003
r1448025 - 11065 (baseline - 14.5%) - before DERBY-6075
10.10.1.1 - 11054 (baseline - 14.5%) - including most of DERBY-6075
It looks like DERBY-5947 and DERBY-6003 indeed did improve compilation speed.
The numbers also suggest that some other changes may have contributed to the
improvements in 10.10. And any improvements caused by the changes in this issue
are indistinguishable from noise.
In any case, it looks like we're heading in the right direction with 10.10. :)
> Use modern collections in impl/sql/compile
> ------------------------------------------
>
> Key: DERBY-6075
> URL: https://issues.apache.org/jira/browse/DERBY-6075
> Project: Derby
> Issue Type: Bug
> Components: SQL
> Affects Versions: 10.10.1.1
> Reporter: Knut Anders Hatlen
> Assignee: Knut Anders Hatlen
> Priority: Minor
> Attachments: Compile.java, d6075-10a-aggregate-vectors.diff,
> d6075-11a-remaining-vectors.diff, d6075-12a-stack.diff,
> d6075-13a-unused-properties.diff, d6075-14a-dead-syntax.diff,
> d6075-15a-sqlgrammar-vectors.diff, d6075-16a-negative-test.diff,
> d6075-17a-rename-aggregate-vectors.diff, d6075-1a-CollectNodesVisitor.diff,
> d6075-2a-bindExpression.diff, d6075-3a-javadoc.diff,
> d6075-4a-parameterList.diff, d6075-5a-ordering.diff,
> d6075-6a-DMLModStatementNode.diff, d6075-7a-more-signatures.diff,
> d6075-8a-local-hashtables.diff, d6075-9a-hashtable-fields.diff
>
>
> The code in the org.apache.derby.impl.sql.compile package predates the Java
> Collections Framework and uses old-style collections like java.util.Vector
> and java.util.Hashtable. Since the old-style collection classes are used in
> many method signatures, it's difficult to use modern collection classes when
> adding new code.
> I suggest we switch to using interfaces (like java.util.List and
> java.util.Map) instead of specific classes in the signatures, so that we have
> more flexibility in choosing the right collection class for the job.
> Only changing the signatures would allow us to continue using Vector and
> Hashtable, since they implement the interfaces. However, I think it would be
> good to switch to ArrayList and HashMap in a second step. The instances in
> impl/sql/compile are not shared between threads, so we don't need the
> synchronization provided by the old-style classes. Switching to
> unsynchronized classes may make compilation slightly faster.
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