Skip to main content

Very slow query where table have many records



I' m using sqlite on iphone. I have table with 200 000 records. It' s size is small, only 2 MB. I' m doing standard select(3 collumns) with two simple condtions. I' m operating only on integer values( in return and condtion). All data are unique. I'm get usually only 10-50 records from database.





In spite of that my query take 3 sec. It' s a lot of time. How i can improve this ?





Edit: I can't load my table with other thread.







NSString * query = [ NSString stringWithFormat:@"SELECT rRozklad.hour, rRozklad.minute, rRozklad.marks FROM rRozklad.idOkres=%i AND rRozklad.idPolaczeniaLinie=2 ORDER by rRozklad.hour, rRozklad.minute", okres];



NSLog(@"%@", query);



const char * querystring = [ query UTF8String ];

sqlite3_stmt * statment;



if(sqlite3_prepare_v2(database, querystring, -1, &statment, nil) == SQLITE_OK){

while(sqlite3_step(statment) == SQLITE_ROW){

NSMutableArray * temp = [[NSMutableArray alloc] initWithCapacity:2];

[temp addObject:[NSNumber numberWithInt: sqlite3_column_int(statment, 0)]];

[temp addObject:[NSNumber numberWithInt: sqlite3_column_int(statment, 1)] ];

[temp addObject:[ NSString stringWithUTF8String: (const char *)sqlite3_column_text(statment, 2)]];



[wyniki addObject:temp];

[temp release];



}

}




Comments

  1. It looks like your SQL is missing the table name and the WHERE keyword.

    SELECT rRozklad.hour, rRozklad.minute, rRozklad.marks
    FROM rRozklad.idOkres=%i AND rRozklad.idPolaczeniaLinie=2
    ORDER by rRozklad.hour, rRozklad.minute


    Do you have your columns indexed? Especially idOkres, idPolaczeniaLinie, hour, and minute?

    ReplyDelete

Post a Comment

Popular posts from this blog

[韓日関係] 首相含む大幅な内閣改造の可能性…早ければ来月10日ごろ=韓国

div not scrolling properly with slimScroll plugin

I am using the slimScroll plugin for jQuery by Piotr Rochala Which is a great plugin for nice scrollbars on most browsers but I am stuck because I am using it for a chat box and whenever the user appends new text to the boxit does scroll using the .scrollTop() method however the plugin's scrollbar doesnt scroll with it and when the user wants to look though the chat history it will start scrolling from near the top. I have made a quick demo of my situation http://jsfiddle.net/DY9CT/2/ Does anyone know how to solve this problem?

Why does this javascript based printing cause Safari to refresh the page?

The page I am working on has a javascript function executed to print parts of the page. For some reason, printing in Safari, causes the window to somehow update. I say somehow, because it does not really refresh as in reload the page, but rather it starts the "rendering" of the page from start, i.e. scroll to top, flash animations start from 0, and so forth. The effect is reproduced by this fiddle: http://jsfiddle.net/fYmnB/ Clicking the print button and finishing or cancelling a print in Safari causes the screen to "go white" for a sec, which in my real website manifests itself as something "like" a reload. While running print button with, let's say, Firefox, just opens and closes the print dialogue without affecting the fiddle page in any way. Is there something with my way of calling the browsers print method that causes this, or how can it be explained - and preferably, avoided? P.S.: On my real site the same occurs with Chrome. In the ex