Parse local data store performance

Question

I am using parse as cloud storage, combined with local data store for general access. I do find that querying the local data storage takes a lot longer than I expected. This is particularly noticeable when using the data to populate tables or update graphical views. Equivalent functions in coredata are near instantaneous and the results are very good. Whilst I do not expect the performance of coredata, it is much slower than I might expect for offline access and I wonder if I am doing something wrong?

Here is an example query :

PFQuery *query = [PFQuery queryWithClassName:LOCATION_OBJECT];
[query fromLocalDatastore];
[query whereKey:MESSAGE_TO_FIELD equalTo:user.username];
[query orderByDescending:CREATED_FIELD];
NSLog(@"Query started");
NSArray* res = [query findObjects];
NSLog(@"Query finished, found %lu objects", (unsigned long)[res count]);

Executing on a 2015 iPad mini the sort of timings I see are as follows :

2015-06-16 18:56:38.883 app[1744:1668474] Query started
2015-06-16 18:56:38.885 app[1744:1668474] Warning: A long-running operation is being executed on the main thread. 
Break on warnBlockingOperationOnMainThread() to debug.
2015-06-16 18:56:39.177 app[1744:1668474] Query finished, found 17 objects

I do understand that Parse is offering much more than just a database, nevertheless this query takes 0.292secs which seems an age. For my app, I use this sort of operation fairly frequently as a user navigates across the screen. With coredata the results were excellent, with Parse the lag is very noticeable. It is worth mentioning that results are similar on the simulator. The warning parse issues when you do this sort of thing is not encouraging, but in any case, my questions are two fold :

1) Have I missed any performance adjustments/settings in Parse? 2) Have other people who have used Parse found similar performance or have any advice?

At this point, it looks like I will need to use coredata in the app and write my own routines to push that data to Parse's cloud, which is a lot more work than I was hoping for.

Thanks for your time.

Update 30Jun15

Thanks for the comments, as per those comments, here is example performance from doing it the way Parse wants you to do it. As before, performance is still poor when compared with coredata. Example code :

PFQuery *query = [PFQuery queryWithClassName:LOCATION_OBJECT];
[query fromLocalDatastore];
[query whereKey:MESSAGE_TO_FIELD equalTo:user.username];
[query orderByDescending:CREATED_FIELD];
NSLog(@"Query started ... ");
[query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
    NSLog(@"Query finished ... ");
    if(!error)
        NSLog(@"Found %lu message records in local datastore", (unsigned long)[objects count]);
    else
        NSLog(@"Parse error pulling messages from datastore: %@ %@", error, [error userInfo]);
}];

Performance in same iPad :

2015-06-30 10:32:09.633 MvBii[205:5172] Query started ... 
2015-06-30 10:32:09.948 MvBii[205:5172] Query finished ... 
2015-06-30 10:32:09.948 MvBii[205:5172] Found 100 message records in local datastore

Query takes 0.315 seconds. Now, as before, I'm not saying this is bad per se and probably for many applications it is just fine, but it is orders of magnitude worse than coredata and is too slow for my app. As the user navigates around the screen graphics are drawn as a result of this query, and I can't update the screen quick enough, using parse, in response to the user input. Using coredata the results are very good.

My main question is simply whether this query time is in accord with any one else's experience? I wonder if there is anything peculiar to my app or data set? The data set is not large (< 200 items), the parse object is just strings and ints. I still really want to use Parse for all of the other facilities it provides. Maybe it is simply my expectations are off, but it seems a long time for a basic query.

Parse local data store performance

Answers (1)

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