[mapserver-dev] RFC 52 updated, call for vote...

[Steve Lime]

When drawing msLayersWhichItems() can still build an item list based on what's in the mapfile just as
it does currently. Queries have always retrieved all items, that's the new functionality. I propose making
sure various index tracking are complete in both cases so you could draw immediately after querying, for 
example.

The RDMS sources have the ability to restrict attributes in SQL.

Your processing block seems like a shortcut in msLayerGetItems() which should return an array of items for
a layer. We could have that function check for the ITEMS processing tag and return that instead of going
to the data (which could be expensive I suppose).

Steve

>>> On 6/17/2009 at 3:52 PM, in message
<f3b73b7d0906171352t189cb344ofaa23434e4f1fed7 at mail.gmail.com>, Tamas Szekeres
<szekerest at gmail.com> wrote:
> +1
> 
> One minor issue I wonder about is how should we handle the OGR special
> attributes (like OGR:LabelAngle) which currently haven't been retrieved only
> when an explicit reference is used for the attribute in the mapfile. It
> would be unwise to retrieve all the special fields along with the other
> attributes if it's not required by the user.
> We should probably have those attributes enumerated explicitly for the
> driver by using a driver specific parameter in the query functions or a
> driver specific processing option should be established for this purpose.
> The latter is already there for the inline layers, which could be extended
> here easily:
> 
> PROCESSING "ITEMS=itemname1,itemname2,itemname3"
> 
> This would also be essential if the user would define a subset of the
> attributes to be retrieved so as to gain further performance increment of
> the queries with certain data sources.
> 
> 
> Best regards,
> 
> Tamas
> 
> 
> 
> 2009/6/17 Steve Lime <Steve.Lime at dnr.state.mn.us>
> 
>> New version that proposes to retain msLayerGetShape() for MapScript and
>> instead create a
>> new msLayerResultsGetShape() should be on the website shortly.
>>
>>  http://www.mapserver.org/development/rfc/ms-rfc-52.html 
>>
>> Steve
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>>