[gdal-dev] double delay getting feature count

[Clay, Bruce]

I have tried several different arrangements trying to get the feature
count from a user selection and I am getting a delay two times for each
query.

 

My current arrangement is

 

OGRLayer *queryLayer = dataSource->ExecuteSQL(fullQueryString, NULL,
"generic");

 

if (queryLayer != NULL)

{

      queryLayer->ResetReading();

      OGRFeature *feature = queryLayer->GetNextFeature();

 

      int numFeatures = queryLayer->GetFeatureCount();

 

. . .Display progress meter then loop reading the features from Oracle

 

 

 

 

I have tried putting the call to GetFeatureCount first and there is no
apparent difference.

 

I am reading data from an Oracle database and using GDAL version 1.6.2
on Windows XP

 

The call to ExecuteSql returns right away but the call to the first
GetNextFeature and the call to GetFeatureCount both have a long delay
depending on the size of the dataset.

 

I need the feature count to use in a progress popup window to let the
user know what is happening.

 

Is there a way to only pay for the query time once and still get the
feature count?

 

 

Bruce




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