[mapserver-dev] incorrect layer drawing order issue

Tamas Szekeres szekerest at gmail.com
Fri Nov 7 03:49:17 PST 2014

We could also extend the DATA section with a SORTBY clause for the mssql
Adding this feature to MSSQL (as per RFC 105) would anyway be fairly easy.


2014-11-07 11:24 GMT+01:00 geographika <geographika at gmail.com>:

>  Hi list,
> I have come across an issue that is critical to the project I am working
> on and wondered if it applies to all database drivers or just the SQL
> Server 2008 one.
> I have logged the issue on GitHub at:
> https://github.com/mapserver/mapserver/issues/5008
> I will try some tests over the weekend to see if the Postgres driver works
> the same way, but there seems to be no way of guaranteeing feature display
> order - even if all documentation suggests it can be achieved in a database
> layer using "ORDER BY"
> Whilst for a low number of records the order seems ordered, with 150+
> features I get different images returned each time by my WMS service. No
> use of clustered indexes, partition statements etc. can get around this as
> SQL result sets can only be guaranteed with an ORDER BY in the outermost
> statement.
> I note that in http://mapserver.org/fr/development/rfc/ms-rfc-105.html
> there is a new function msLayerBuildSQLOrderBy() that allows sorting to be
> done outside of the layer's DATA statement for WFS requests with a SORTBY
> parameter. Maybe this could also be used by a new LAYER "SORT" config
> keyword?
> I see the above is only implemented for a few drivers. The client would be
> willing to fund adding this to the SQL Server driver if there are any core
> devs interested in doing this.
> Regards,
> Seth
>  --
> web: http://geographika.co.uk
> twitter: @geographika
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