Changes between Version 1 and Version 2 of MapGuideRfc46

Timestamp:

03/14/08 15:00:22 (17 years ago)

Author:

ronnielouie

Comment:

--

MapGuideRfc46

@@ -29 +29 @@
 This is the most important part of the RFC.  It describes the problem domain in detail.  Focusing on this will allow reviewers to fully understand why the proposed change is being made, and potentially suggest different/better ways of accomplishing the desired results.  The more time we spend on understanding the problem, the better our solution will be.
 
+The current MgSelectionBase::GenerateFilter() API returns a string representing a filter for a set of selected features.  This filter string would look something like: "FeatId = 1109 OR FeatId = 1130 OR FeatId = 2065" such that each of the IDs of the selected features is explicitly specified.  The string is then passed as the filter to MgFeatureService::SelectFeatures() to query the datastore.   
+
+A selection can contain an unlimited number of features, which means that the filter will contain an unlimited number of OR conditions.  However, most datastores have a finite number of OR's that can be supported, and some data sources, such as Access databases, are limited to a relatively small number or OR conditions.  
+
+Results can be unpredictable when the limit is exceeded due to buffer overruns and/or memory corruption leading to instability in the MapGuide Server.  In an effort to improve stability, GenerateFilter() was modified to return a string representing a smaller subset of the total selected features.
+
 == Proposed Solution ==