Memory not decreasing after a series of insertions in the database - ios

Question

I have simple code that inserts values into my database:
-(void)inserirBd:(NSString *)valores{
sqlite3_stmt *statement;
// Get the documents directory
NSArray *dirPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *docsDir = dirPaths[0];
// Build the path to the database file
databasePath = [[NSString alloc] initWithString: [docsDir stringByAppendingPathComponent:#"fazerbem.sqlite"]];
const char *dbpath = [databasePath UTF8String];
if (sqlite3_open(dbpath, &myDatabase) == SQLITE_OK) {
NSString *insertSQL = valores;
const char *insert_stmt = [insertSQL UTF8String];
sqlite3_prepare_v2(myDatabase, insert_stmt,
-1, &statement, NULL);
if (sqlite3_step(statement) == SQLITE_DONE) {
} else {
NSLog(#"Error -> %s", sqlite3_errmsg(myDatabase));
}
sqlite3_finalize(statement);
sqlite3_close(myDatabase);
}
}
and I am calling this function in this way:
cInsert = [NSString stringWithFormat:#"INSERT INTO fazerbem_products (value) Values ('%#')", p1_1.text,];
InsertBD *insert = [[InsertBD alloc] init];
[insert inserirBd:cInsert];
To perform some tests of memory, I put the above command in a loop that will insert a repeat this 85,000 times, in debug memory, before inserting the values ​​into the database the memory was 1.1 MB, after performing the loop the memory rose to around 500 MB.
But after that, why not the memory lowered to 1.1 MB again? since the loop was already processed and in this case the memory should be released ? (I'm using ARC, and my app only have a button to do this)

Answer 1

The Xcode Debug Memory report is not what either you want nor what you think it is.
The Debug Navigator shows the same things as the "Activity Monitor" instrument. It is not showing current live memory by your app, it's showing current memory allocated to your app by the OS. The OS will reclaim unused but allocated memory as needs arise.
The concept is to avoid allocation memory blocks from the system, deallocating only to need to re-allocate later. There is a difference between the system allocation memory (large blocks) to an app and the app allocation memory to an object (portions of the large blocks). You care about the second, the system cares about the first.
See this SO Answer Here by #Putz1103 for complete details.
Use Instruments and look at Live Bytes to see the actual memory usage.