[gdal-dev] Memory leaks when using SQL queries with shapefiles

[Pierluigi Guasqui]

Hello,

I am experiencing a big memory allocation (with no subsequent memory 
release) when using SQL queries with shapefiles. This is a sample code 
that triggers this problem:

    OGRRegisterAll();

    // opening shapefile data source
    const char *fname = "path/to/shapefile.shp";
    OGRDataSource *poDS;
    poDS = OGRSFDriverRegistrar::Open( fname, FALSE );

    if( poDS == NULL )
    {
        fprintf( stderr, "%s: could not open input file\n", fname );
        return -1;
    }

    // creating the spatial filter
    OGRLineString regionPolygon;
    OGRRawPoint *pointsList = new OGRRawPoint[5];
    pointsList[0].x = -180; pointsList[0].y =  90;
    pointsList[1].x =  180; pointsList[1].y =  90;
    pointsList[2].x =  180; pointsList[2].y = -90;
    pointsList[3].x = -180; pointsList[3].y = -90;
    pointsList[4].x = -180; pointsList[4].y =  90;
    regionPolygon.setPoints(5, pointsList);
    delete[] pointsList;

    // executing the query
    const char *query = "SELECT * FROM table_name WHERE some_field LIKE 
'%bla%' ORDER BY some_other_field";
    OGRLayer *rs = poDS->ExecuteSQL( query, &regionPolygon, NULL );

    // releasing memory
    poDS-> ReleaseResultSet( rs );
    OGRDataSource::DestroyDataSource( poDS );

With a 100.000 records shapefile "ExecuteSQL" has allocated over 300 
MBytes of memory with no deallocation when calling "ReleaseResultSet".

The memory leak is triggered only when "ExecuteSQL" is called with a 
spatial filter (even trivial as shown in the above code) and the SQL 
query contains a 'WHERE' clause and an 'ORDER BY' clause. Is this a bug?

I am using GDAL 1.9.1 under Windows platform.

Any help would be really appreciated!
Thank you,

--
Pierluigi Guasqui
Applied Coherent Technology Corp.


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