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From Rick Hillegas <Richard.Hille...@Sun.COM>
Subject unsubscribing from an Apache list, was: [jira] Commented: (DERBY-4520) Refactor and extend data type cloning facilities
Date Mon, 25 Jan 2010 13:51:33 GMT
Hi Srinivasa,

Instructions for unsubscribing from an Apache list can be found here: 

Hope this helps,

SrinivasaRao.Nalleboyina@cognizant.com wrote:
> Hi All,
> Could you please unsubscribe from the list or let me know what are all steps to be followed
for unsubscribe.
> -----Original Message-----
> From: Kristian Waagan (JIRA) [mailto:jira@apache.org] 
> Sent: Monday, January 25, 2010 4:20 PM
> To: derby-dev@db.apache.org
> Subject: [jira] Commented: (DERBY-4520) Refactor and extend data type cloning facilities
>     [ https://issues.apache.org/jira/browse/DERBY-4520?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12804499#action_12804499
> Kristian Waagan commented on DERBY-4520:
> ----------------------------------------
> I wonder if we should just remove the same asserts for init-, close- and resetStream
in FormatIdInputStream as well?
>> Refactor and extend data type cloning facilities
>> ------------------------------------------------
>>                 Key: DERBY-4520
>>                 URL: https://issues.apache.org/jira/browse/DERBY-4520
>>             Project: Derby
>>          Issue Type: Improvement
>>          Components: Store
>>    Affects Versions:
>>            Reporter: Kristian Waagan
>>            Assignee: Kristian Waagan
>>         Attachments: derby-4520-1a-RowLocation_cloning.diff, derby-4520-1a-RowLocation_cloning.diff,
derby-4520-2a-remove_CloneableObject_iface.diff, derby-4520-2a-remove_CloneableObject_iface.stat,
derby-4520-3a-CloneableStream_and_delayed_fill.diff, derby-4520-3a-CloneableStream_and_delayed_fill.stat,
derby-4520-3b-CloneableStream_and_delayed_fill.diff, derby-4520-3b-CloneableStream_and_delayed_fill.stat
>> With the increased use of streams to represent data values, the cloning facilities
needs to be improved.
>> Unless I get pushback, I will proceed by producing patches to reach the following
>>  - move the functionality provided by CloneableObject into DataValueDescriptor
>>    (all classes implementing CloneableObject also implements DataValueDescriptor)
>>  - introduce the cloning methods cloneValue, cloneState and cloneHolder (all in DataValueDescriptor,
see description below)
>>    Note that they all return a usable DVD. I'm all ears for better names for the
clone methods (another suggestion mentioned is cloneDeep, cloneHalfDeep, and cloneShallow).
>> cloneValue <deep> (new method, functionality was present through combined calls
to the DVD public interface) 
>>  - a DVD obtained through cloneValue is independent of other DVDs and the state of
the Derby store
>>  - the data value will be materialized
>> cloneState <halfDeep> (~= DataValueDescriptor.getClone)
>>  - a DVD obtained through cloneState is independent of other DVDs, but may depend
on the state of the Derby store (due to references to store streams)
>>  - the data value will be materialized if the value is represented by a non-cloneable
stream or if Derby believes materializing the value is more appropriate than keeping the stream
>> cloneHolder <shallow> (~= CloneableObject.cloneObject)
>>  -  a DVD obtained through cloneHolder is dependent on the original DVD and its clones
made through cloneHolder. If one of the DVDs changes its state, all of them will be affected.
Will also be dependent on the state of the Derby store if there are references to store streams.
>>  - the data value will never be materialized due to cloneHolder being invoked
>> For many of the data types, cloneState and cloneHolder will forward to cloneValue.
>> cloneState will be used the most. cloneValue is currently only required in the sorter.
cloneHolder is required (for performance reasons and maybe to avoid OOME) when DVDs pass through
temporary holders (BackingStoreHashtable, TemporaryRowHolderImpl). I have not gone through
all the usages of cloneState to see if any of them can be, or has to be, replaced with another
>> The ability to clone store streams will be added by Mike's patch attached to DERBY-3650.

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