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From Mike Matrigali <mikem_...@sbcglobal.net>
Subject Re: Soft Upgrade and Downgrade
Date Wed, 22 Mar 2006 21:40:34 GMT
The way I look at it, derby has a very nice default.  We call it soft
upgrade, but in my mind it really is "no upgrade".  We guarantee that
if you do nothing to your existing app, then you can run it and the
database against your current version of the derby software and all
future versions of the derby software.  I think this is a reasonable
"automatic"  default.

Because we provide no way to "go back" with database versions I believe
it is reasonable to require the very slight user intervention of 
connecting and requiring the upgrade=true flag.  If you want to use new
stuff then you proactively tell us.  This model is really important if
we ever decide to do some sort of major data upgrade where the cost
of hard upgrade may be hours depending on the size of the db and number
of rows touched.

Oystein Grovlen - Sun Norway wrote:
> I agree that soft upgrade has a value, but I think you give soft upgrade 
> credit for things that are actual not provided by soft upgrade.  More 
> comments below.
> Kathey Marsden wrote:
>> Rick Hillegas wrote:
>>> 4) What is the customer problem solved by Soft Upgrade?
>> Soft upgrade solves  many  problems for users , support and
>> development.  It:
>> -  Minimizes end  user intervention in accordance with  Derby's charter
>> http://db.apache.org/derby/derby_charter.html.
>>     which calls for ease of use and zero administration for end users.
> It is not soft upgrade that minimizes end user intervention.  That is 
> provided by automatic upgrade (soft or hard).  In fact, soft upgrade 
> increases user intervention since you will need to explicitly state that 
> you want to do a hard upgrade.  Without soft upgrade, hard upgrades 
> could have been done automatically.
>> -  Encourages upgrade and reduces the need to port fixes to old releases.
> I agree that people will probably be less hesistant to upgrade to new 
> releases if they are able to revert to their old release.  In my 
> opinion, that is the only value of soft upgrade.  In itself, I would not 
> think that using the old data format should make it much less risky to 
> upgrade than using a new data format.  And if I had to downgrade due to 
> problems with the new release, how do I know that this new faulty 
> release has not corrupted my database?
>> -  Provides applications, embedding  or including Derby  a scalable
>> deployment option for distributing  new versions of Derby.
> How is soft upgrade provide more scalable deployment than hard upgrade?

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