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PODistance Function for SQLite in iOS 5 is very slow
 

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    <p>I have been using for a long time a C function that calculates the distance between coordinates in SQLLite.</p> <p>The thing is that for the very same database and different iOS devices (4 and 5) the time for executing the same query is 5 times longer when running iOS 5.</p> <p>Does anybody knows why?</p> <p>Here's the code for the distance:</p> <pre><code>static void distanceFunc(sqlite3_context *context, int argc, sqlite3_value **argv){ // check that we have four arguments (lat1, lon1, lat2, lon2) assert(argc == 4); // check that all four arguments are non-null if (sqlite3_value_type(argv[0]) == SQLITE_NULL || sqlite3_value_type(argv[1]) == SQLITE_NULL || sqlite3_value_type(argv[2]) == SQLITE_NULL || sqlite3_value_type(argv[3]) == SQLITE_NULL) { sqlite3_result_null(context); return; } // get the four argument values double lat1 = sqlite3_value_double(argv[0]); double lon1 = sqlite3_value_double(argv[1]); double lat2 = sqlite3_value_double(argv[2]); double lon2 = sqlite3_value_double(argv[3]); // convert lat1 and lat2 into radians now, to avoid doing it twice below double lat1rad = DEG2RAD(lat1); double lat2rad = DEG2RAD(lat2); // apply the spherical law of cosines to our latitudes and longitudes, and set the result appropriately // 6378.1 is the approximate radius of the earth in kilometres sqlite3_result_double(context, (acos(sin(lat1rad) * sin(lat2rad) + cos(lat1rad) * cos(lat2rad) * cos(DEG2RAD(lon2) - DEG2RAD(lon1))) * 6378.1) * 1000); } </code></pre> <p>and here's a example on how I am using it:</p> <pre><code>Select distance(Latitude, Longitude,-22.89095,-47.05134) from TABLE </code></pre> <p>Please, any help will be very appreciated</p> <p>Thanks</p>
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