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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

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