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From Mike Matrigali <mikem_...@sbcglobal.net>
Subject Re: [jira] Commented: (DERBY-2493) Use unsynchronized collections in BackingStoreHashtable
Date Wed, 28 Mar 2007 16:48:30 GMT
it depends on what the test is testing, but I usually consider these 
ordering dependencies a test bug - ie. they are counting on an order not
specified by SQL.  For .sql tests there are usually 2 possible fixes:
1) If what is being tested is not affected by adding an order by to
    the query, I just add the order by to the select.
2) If you feel that adding the order by changes what is being tested 
then, select all rows into a temp table and then verify the result by
doing an order by select on the temp table.

Knut Anders Hatlen (JIRA) wrote:
>     [ https://issues.apache.org/jira/browse/DERBY-2493?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12484860
> Knut Anders Hatlen commented on DERBY-2493:
> -------------------------------------------
> It seems like the ordering is already a problem in lang/distinct.sql. That's why it has
different canons for different JVMs.
>>Use unsynchronized collections in BackingStoreHashtable
>>                Key: DERBY-2493
>>                URL: https://issues.apache.org/jira/browse/DERBY-2493
>>            Project: Derby
>>         Issue Type: Improvement
>>         Components: Performance, Store
>>   Affects Versions:
>>           Reporter: Knut Anders Hatlen
>>        Assigned To: Knut Anders Hatlen
>>           Priority: Minor
>>BackingStoreHashtable uses a Vector and a Hashtable, but doesn't need the synchronization
provided by these classes (I think). Replacing them with ArrayList and HashMap could improve
performance for some kinds of operations.

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