One thing that I know for sure can be a killer is if you open your Live table into a new mapper and the bounds for the table in the MAPINFO_MAPCATALOG are wide, MapInfo tries - more or less - to get every single record from your database.
If you are querying on attribute information you might want to turn of the MBRSEARCH (Can as far as I know only be done thru MapBasic, or by altering the TAB-file directly). If this has been turned of MapInfo doesn't use the spatial index when figuring out which records to return. This can boost the performance, espacially if the attribute condition only returns a few (hundred or thousand) records. Another thing that annoys me when using the live connection is "when does MapInfo actual refresh the data" ? When you download the data you can allways push the Refresh button, but is not the case when using live connection. Peter Horsbøll Møller GIS Developer Geographical Information & IT COWI A/S Rugårdsvej 55 DK-5000 Odense Denmark Tel +45 6313 5013 Direct +45 6313 5008 Mob +45 5156 1045 Fax +45 6313 5090 E-mail [EMAIL PROTECTED] http://www.cowi.dk > -----Original Message----- > From: Christof Kaiser [mailto:[EMAIL PROTECTED] > Sent: Monday, October 27, 2003 9:06 PM > To: [EMAIL PROTECTED] > Subject: MI-L MI "live" on Oracle Spatial:how is the querying done? > > > Hi, > > as we know, MapInfo (I am using 7.0) cann connect to an Oracle > (Spatial) Database (using 9 and 9.2). > You can either choose to get a copy of the data in a MapInfo relation > which is updated every now and then if you want to. > Or you get the data live from Oracle just when it is > displayed. The second, of course, is the cooler choise > (database guys hate > redunancy). > > I works ok for smaller datasets, but when in comes to mass data (a > couple of million lines), it stalls. > I suspect that MI is doing some silly query on the whole data > initially. > Maybe it wants to index the objects or something like that. > I havnt done a trace on the database yet, but i was wondering if > somebody already knows what MI > tries to do to the poor database and how I can prevent that. > > Actually, I just want it to do a decent spatial query for the > needed small > window. > That doesnt take so long (if i do it manually). > > I know that there was a problem if attributes are queried as > well. In this > case, MI get all the data and sorts > it out locally rather than shipping a eleborate sql query. > Not too clever in > terms of performance. > > tia > Christof > > > --------------------------------------------------------------------- > List hosting provided by Directions Magazine | > www.directionsmag.com | To unsubscribe, e-mail: > [EMAIL PROTECTED] > For additional commands, e-mail: > [EMAIL PROTECTED] > Message number: 8884 > > --------------------------------------------------------------------- List hosting provided by Directions Magazine | www.directionsmag.com | To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] Message number: 8885
