On 05/10/2010 12:35, Harwarth, Stefan (Bundeswehr) wrote:
> Hi Markus,
>
> I'd like to point out something I noticed recently as I think it might by a 
> related implementation issue: We have a number of pages that were created, 
> renamed, deleted and sometimes re-created in the last months and several 
> times we had strange result sets in our queries. I looked them up in the 
> smw_ids table and in all cases (~20) they had :smw_redi in the smw_iw column 
> even though they were real articles.

There has been a bug in SMW 1.5.0 that caused problems on moving pages. 
To fix this, a new version needs to be installed and the affected pages 
need to be moved to another name and back again. Or you can *completely* 
rebuild the SMW tables as described online.

Regards,

Markus

>
> Is it possible that SMW is not always able to track the change of an article 
> to a redirectpage and vice versa?
>
> Stefan
>
>> -----Original Message-----
>> From: Markus Krötzsch [mailto:[email protected]]
>> Sent: Tuesday, October 05, 2010 12:25 PM
>> To: Kevin Jones
>> Cc: smw dev list
>> Subject: Re: [SMW-devel] Deleted pages still showing up in
>> query results
>>
>> == Why and when non-existing pages may occur in SMW query results ==
>>
>> In principle, it is possible that SMW queries show pages that
>> do not have text (that is "don't exist"). The reason is that
>> SMW needs to consider non-existing pages as well, for
>> instance if some property of Type:Page is assigned a value of
>> a page that does not exist, then the assignment still must be
>> stored. This is one reason why SMW creates internal IDs for
>> non-existing pages as well.
>>
>> Normally, these pages should not appear in any query, since
>> they do not satisfy normal query conditions. They have no
>> properties (not even a Modification date) and they have no
>> categories either. The only way in which they can be selected
>> is by issuing namespace queries: they have a namespace based
>> on their page title. The easiest current workaround to
>> protect namespace queries against such results is to add the
>> condition [[Modification date::+]] which is true exactly for
>> those pages that exist.
>>
>> If non-existing pages still appear in a query that has
>> conditions beyond namespace filters, then there is an
>> inconsistency in the database that should be fixed by
>> repairing the data (using the web interface, and possibly
>> runJobs.php for speeding things up).
>>
>> Completely purging all non-existing pages from SMW's tables
>> is currently only possible by deleting and rebuilding the
>> tables as described on the "repairing SMW" documentation page
>> (this requires a command line script). Since SMW needs
>> internal page IDs for numerous purposes, it is not easy to
>> see if a page is really no longer needed anywhere, and this
>> is why SMW does not purge obsolete page ID records during its
>> normal operation.
>>
>> I remark that this behaviour is specific to the SMWSQLStore2
>> storage backend. It is an implementation issue of this
>> particular DB organisation which uses internal IDs for more
>> efficient querying.
>>
>> Cheers,
>>
>> Markus
>>
>>
>


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