mapserver postgis connection

[Frans Knibbe]

An interesting thread.
Shouldn't the connection step go faster if you have FastCGI enabled in 
the MapServer?
Also, I wonder if PostGIS would improve relative to shapefile if you 
have many concurrent users requesting the same data...

Regards,

Frans

Stephen Woodbridge wrote:

> Frances Collier wrote:
>
>> Hello,
>>
>>  
>>
>> I’ve been trying to find out what exactly Mapserver gets back from 
>> Postgis when querying the tables. I haven’t found this to be 
>> documented anywhere. Does Postgis return a shape file, layer, or 
>> simply data rows? The reason I’m asking is that I noticed a huge time 
>> difference between connecting to Postgis and simply calling the shape 
>> files – with the Postgis being significantly slower
>>
>>  
>>
>> I’d appreciate any knowledge, advice, and/or direction.
>
>
> Frances,
>
> PostGIS IS slower than shapefiles because:
>
> 1) You have to make a network of local connection to the database 
> which include some kind of authentication.
> 2) You have to do a query to fetch some data
> 3) The data needs to be transformed from its native PostGIS format 
> into whatever mapserver uses internally
> 4) all the data has to packaged up into packets to transfer from the 
> server to the client (mapserver)
> 5) probably other stuff too
>
> So why would anyone want to use it?
>
> Well you can do lots of cool GIS like things with it. You data might 
> be stored there for other purposes, like it is bing dynamically 
> updated by other process. You need to do thematic mapping, etc, etc
>
> Should you put all or any of your data in PostGIS?
>
> Depends on your need. If all you data is static data and you are only 
> display maps of it then probably not. Use shapefiles as they are most 
> efficient. You can take a hybrid approach of having some static layer 
> in shapefiles and some other layers in postGIS.
>
> If you are doing queries the only look at a small percentage of the 
> data then postGIS queries can be optimized maybe to speed things up. 
> If you are just recalling all you data when zoomed out maybe you need 
> another layer where the data in simplified for that.
>
> -Steve W.
>  http://imaptools.com
>
>