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From Mike Matrigali <mikem_...@sbcglobal.net>
Subject Re: [jira] Updated: (DERBY-3330) provide support for unique constraint over nullable columns
Date Thu, 21 Feb 2008 17:40:44 GMT
In what situation will it be necessary to run hard upgrade.  My 
understanding was that only new software would create these "new"
types of indexes.  All old index behavior was to remain the same
and thus would not need the new functionality.  So all existing
unique indexes should continue to throw errors for multiple nulls.
New unique constraints on nullable columns should be the only indexes
that use the new code.

Why are you upgrading all existing conglomerates?  If at all possible
I believe we should avoid an upgrade process that touches all 
conglomerates at upgrade time.  We have not ever done that in the past.

What I was expecting for hard upgrade code was code that only allowed
use of the new feature if the database was upgraded.  Because derby 
supports soft upgrade the software already has to recognize and function
with existing conglomerates without change.  So with similar changes
to yours in the past store usually just continues to read the old 
format.  Under hard upgrade when the store decides it is necessary to
write the new format then it can write the new format if db has been
hard upgraded, or it must write the old format if it is still soft
upgrade.


Anurag Shekhar (JIRA) wrote:
>      [ https://issues.apache.org/jira/browse/DERBY-3330?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
> 
> Anurag Shekhar updated DERBY-3330:
> ----------------------------------
> 
>     Attachment: derby-3330v6.diff
> 
> This patch includes hard upgrade (Upgrade test from 10.3.1.4 and  10.1.3.1runs without
fails).
> 
> Description of Hard upgrade
> 
> Hard upgrade makes following changes 
> 1. Updates B2I class by adding extra attribute (uniquewhenNotNull)
> 2. Updates format id.
> 3. Updates ConglomerateDescriptor of all updated Conglomerates to 
> user new version of IndexDescriptorImpl
> 
> Unique index meant to be backing index of UniqueConstraint is updated to 
> become UniqueWhenNotNull index (nUniqueColumn is set to nKeyFields - 1
>  and uniquewhen not null is set to true). For other indexes uniqueWhenNotNull
>  attribute is set to false.
> 
> Hard upgrade is initiated from DataDictionaryImpl.upgradeConglomerate 
> (new method). This method calles another newly intoroduced method 
> getAllConglomerates to get the list of conglomerate and updates them 
> by calling TransaCtioncontroller.updateUniquenessOfConglomerate 
> which internally calls Conglomerate.updateUniqueness to 
> conglomerate attributes.
> 
> 
> I will be posting one more patch after introducing multipage page 
> scan while checking for duplicates.
> 
> 
>> provide support for unique constraint over nullable columns
>> -----------------------------------------------------------
>>
>>                 Key: DERBY-3330
>>                 URL: https://issues.apache.org/jira/browse/DERBY-3330
>>             Project: Derby
>>          Issue Type: New Feature
>>          Components: Store
>>    Affects Versions: 10.4.0.0
>>         Environment: all
>>            Reporter: Anurag Shekhar
>>            Assignee: Anurag Shekhar
>>         Attachments: BTreeController.diff, derby-3330-testcase.diff, derby-3330.diff,
derby-3330v2.diff, derby-3330v3.diff, derby-3330v4.diff, derby-3330v5.diff, derby-3330v6.diff,
FunctionalSpec_DERBY-3330-V2.html, FunctionalSpec_DERBY-3330.html, UniqueConstraint_Implementation.html
>>
>>
>> Allow unique constraint over nullable field. Right now derby support unique constraint
only over not null columns.
> 


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