Question

I have More than 5000 Record to be loaded from Server to my App and Inserted into Database.
While inserting these records after some successful insertion I am getting this kind of error and my app crashes.

database is malformed in iPhone + error disk i/o error

Following are code snippet that could be useful,Here I am getting Records in 5 Categories One by One and Inserting them into Database

    if (tag==1) {
        NSMutableDictionary *catDic=[dic valueForKeyPath:@"GetAllRecords.results.categories.category"];
        [self performSelectorInBackground:@selector(insertDataInCategoryMaster:) withObject:catDic];

        NSMutableDictionary *levelDic=[dic valueForKeyPath:@"GetAllRecords.results.levels.level"];
        [self performSelectorInBackground:@selector(insertDataInLevelMaster:) withObject:levelDic];

        NSMutableDictionary *queDic=[dic valueForKeyPath:@"GetAllRecords.results.questions.question"];

        [self performSelectorInBackground:@selector(insertDataInQueMaster:) withObject:queDic];

        [self getQueCatLevelData:2];
    }
    else if(tag==2){

        NSMutableDictionary *queDic=[dic valueForKeyPath:@"GetAllRecords.results.questions.question"];
        [self performSelectorInBackground:@selector(insertDataInQueMaster:) withObject:queDic];

        [self getQueCatLevelData:3];

    }
    else if(tag==3){

        NSMutableDictionary *queDic=[dic valueForKeyPath:@"GetAllRecords.results.questions.question"];
        [self performSelectorInBackground:@selector(insertDataInQueMaster:) withObject:queDic];

        [self getQueCatLevelData:4];
    }//and so on for 5 also

in each insertDataInQueMaster I am doing following things.

         NSAutoreleasePool *pool = [[NSAutoreleasePool alloc]init];
        for(NSDictionary *queDictionary in dictionary)
        {

            NSString *strQuery = [NSString stringWithFormat:@"insert into QuestionMaster values(%d,'%@','%@',%d,%d,%d,%d,%d,0,'%@')",[[queDictionary valueForKey:@"questionid"]intValue], [queDictionary valueForKey:@"questiontext"],[queDictionary valueForKey:@"answertext"],[[queDictionary valueForKey:@"categoryid"]intValue],[[queDictionary valueForKey:@"levelid"] intValue],[[queDictionary valueForKey:@"status"]intValue],[[queDictionary valueForKey:@"RangeFrom"]intValue],[[queDictionary valueForKey:@"RangeTo"]intValue],[queDictionary valueForKey:@"Fact"]];

            [NSNumber requestWithSynchronousExcuteQuery:strQuery withReturnningError:&error];

            if(error)
            {
                NSLog(@"error description:%@",[[error userInfo] description]);
                [[NSUserDefaults standardUserDefaults]setBool:NO forKey:@"FirstTime"];
            }

        }

        count++;
        [[NSUserDefaults standardUserDefaults]setInteger:count forKey:@"CheckCount"];
        [[NSUserDefaults standardUserDefaults]synchronize];
        [pool drain];

I am doing These all things while App is Loading in AppDelegate.m , that too in Background
The Error Comes After successfully inserting few records in Database so I think there is no problem with Database opening and Inserting.

I hope I am clear,
Please comment if any confusion.
Waiting for reply.
Thanks in advance.

Answer 1

hurray, I got the Simple Solution to this

I just Placed

  @synchronized(self)
  {
      //My Whole Code  for Background methods goes here
  }

and that’s it, it solved my error and crash too.

The @synchronized()directive locks a section of code for use by a single thread. Other threads are blocked until the thread exits the protected code—that is, when execution continues past the last statement in the @synchronized() block.

The @synchronized() directive takes as its only argument any Objective-C object, including self.