dhis2-devs team mailing list archive

[Bob Jolliffe <bobjolliffe@xxxxxxxxx>]

Thanks Lars.  That should help.  Though it is still a bit of mystery
why it worked on one system but not on the other.  Is this alphabetic
ordering post 2.17?

On 28 September 2015 at 12:22, Lars Helge Øverland <larshelge@xxxxxxxxx> wrote:
> Hi Bob,
>
> just to inform - the SQL views are dropped in reversed alphabetical order,
> and generated in alphabetical order based on name. This means there is no
> "intelligence" around detecting view inter-dependencies, but at least gives
> a way to deal with it (make sure that a view which depends on another view
> is alphabetically ordered after it).
>
> regards,
>
> Lars
>
>
>
> On Mon, Sep 28, 2015 at 1:09 PM, Knut Staring <knutst@xxxxxxxxx> wrote:
>>
>> I have a similar problem in 2.19 where backups are not getting generated
>> because of sqlviews.
>>
>> On Mon, Sep 28, 2015 at 11:03 AM, Bob Jolliffe <bobjolliffe@xxxxxxxxx>
>> wrote:
>>>
>>> I am not sure if this is an issue which has been fixed in later
>>> versions, but we recently chanced upon some odd behaviour in 2.17.
>>>
>>> On the production system there are a number of views defined (through
>>> the sql view interface).  A couple of those views depend on other
>>> views.   When resource tables are regenerated the views are dropped
>>> and recreated as expected.
>>>
>>> But ...
>>>
>>> When we restored an exact backup on to a different database on a new
>>> system suddenly the resource table generation was failing because it
>>> was failing to delete views which depended on other views.  It seems
>>> the natural order was changed on the new sqlview table and so the list
>>> of views to be deleted come out in a different order to the source
>>> system.
>>>
>>> So ... either
>>>
>>> 1.  the problem is fixed on a later version; or
>>> 2.  we need to have a "cleverer" way to drop the (potentially
>>> interdependent) views; or
>>> 3.  we need to maintain some sort of ordering/cascading logic which is
>>> restored with the backup; or
>>> 4.  we should issue a cautionary note that creating views which depend
>>> on other views is potentially fragile.  It might work on one system
>>> but cause odd problems on a restored system.
>>>
>>> Maybe 4 is enough.  Anyway I thought I should raise the issue.  Any
>>> thoughts?
>>>
>>> Bob
>>>
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>>
>>
>>
>>
>> --
>> Knut Staring
>> Dept. of Informatics, University of Oslo
>> Norway: +4791880522
>> Skype: knutstar
>> http://dhis2.org
>>
>> _______________________________________________
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>>
>
>
>
> --
> Lars Helge Øverland
> Lead developer, DHIS 2
> University of Oslo
> Skype: larshelgeoverland
> http://www.dhis2.org
>