FMDB - Improve FMResultSet speed

Question

This code take a very long time to run. I have roughly 100,000 records. Each step takes roughly the same mount of time.... get the result from FMResultSet and reading it into the 3 arrays. I tried using two select statements. One to get the result count and then allocating that amount in the mutableArray. No performance difference. Any suggestions to improve speed?

FMResultSet *results = [database executeQuery:@"SELECT FriendlyName, Serial, Barcode FROM Inventory, Company WHERE Inventory.friendlyName <> '' AND Company.CompanyID = Inventory.companyID AND Company.CompanyName = ?", selectedCompany];

arrayFriendlyName =[[NSMutableArray alloc]init];
arraySerial = [[NSMutableArray alloc]init];
arrayBarcode = [[NSMutableArray alloc]init];


while([results next]) {

    [arrayFriendlyName addObject:[results stringForColumn:@"FriendlyName"]];
    [arrayBarcode addObject:[results stringForColumn:@"Barcode"]];
    [arraySerial addObject:[results stringForColumn:@"Serial"]];

}

[database close];

Answer 1

Depending on your database structure any object-oriented wrapper around sqlite can be quite slow when it comes to thousands of rows. You can try to speed it up by directly accessing the sqlite database, without using any object oriented wrapper. As you don't need any relations (at least in your example code), you won't loose any relevant functionality - and it will be as fast as it can get.

As always, Ray Wenderlich is a good resource to look at: http://www.raywenderlich.com/913/sqlite-tutorial-for-ios-making-our-app

In case you didn't do it already, you can also have a look whether you have your indexes set right on your query - as you are joining two tables, having no indexes on the joined columns can seriously impact your performance.