Re: CellTable with AsyncDataProvider - load performance issue

2012-10-21 Thread Jens 
1.) Can't you use SQL Limit/Offset keywords to select the range? Would 
probably simplify your server code a bit and your DB knows what you want to 
do.

2.) Some (if not all) databases should be able to log slow queries if 
configured. If thats not possible add some time tracking and logging code 
where you think it makes sense. That way you can verify if its a server 
issue or a network/client issue.

-- J.

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Re: CellTable with AsyncDataProvider - load performance issue

2012-10-21 Thread Magnus 
Hi!

Am Freitag, 19. Oktober 2012 11:41:40 UTC+2 schrieb Ümit Seren:
>
> I would debug it using Chrome Developer Tools. You can check the HTTP 
> request and see where most of the time is spent. I guess there must be an 
> issue with the backend. 
> Do you also get the slowdowns in production mode?
>
>>
>>  
I see the delays in production mode only. 

In debug mode I always have a nearly empty database, because it gets 
extremely slow otherwise.

The AsyncDataProvider uses the same RPC calls to fetch the data as the 
simple table that I used before, except that the AsyncDataProvider never 
loads all records at once. It specifies a record interval with a start and 
end index. On the database level I realize this as follows:

  ResultSet r = dbs.query (...);
...   
  if (filter.ix0 != -1)
   r.relative (filter.ix0 - 1); // fast forward to the first wanted record

  int n = filter.ix1 - filter.ix0 + 1; // number of records to load
  int i = 0;
  ...
  while (i++ < n)
  {
   if (!r.next ())
break;

   Game g = loadGame (r);
   l.add (g);
  }

The only difference with AsyncDataProvider I see is that I make a jump in 
the result set to the index of the first wanted record (r.relative above). 
Maybe the database is slow at this point.
But I cannot verify this. The delay occurrs not always, just sometimes...

Magnus

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Re: CellTable with AsyncDataProvider - load performance issue

2012-10-19 Thread Ümit Seren 
I would debug it using Chrome Developer Tools. You can check the HTTP 
request and see where most of the time is spent. I guess there must be an 
issue with the backend. 
Do you also get the slowdowns in production mode?


On Wednesday, October 17, 2012 1:16:53 PM UTC+2, Magnus wrote:
>
> Hello,
>
> I changed all the simple lists of my application into CellTables with an 
> AsyncDataProvider.
>
> Before the change, I always loaded the whole list via RPC and also showed 
> the whole list in the GUI.
> After the change, I always load a portion according to the page size and 
> always show one page only.
>
> However, it sometimes lasts very long, up to 10 sec, to fetch the data. 
> During this time the CellTable shows its loading animation. This does not 
> happen most of the time, but when it happens it looks like a problem to the 
> user.
>
> How can it be that fetching the whole list has a good constant 
> performance, while fetching the small portions with AsyncDataProvider is 
> that slow *sometimes*?
>
> See below how I create the AsyncDataProvider.
>
> Thanks
> Magnus
>
> -
>
>  protected void createDataProvider ()
>  {
>   pvd = new AsyncDataProvider()
>   {
>@Override
>protected void onRangeChanged(HasData display)
>{
> Range r = display.getVisibleRange();
> int start = r.getStart() + 1;
> int end = start + r.getLength() - 1;
>
> onRangeChange (start,end);
>}
>   };
>   
>  }
>
>  public void onRangeChange (int i0,int i1)
>  {
>   // load list and record count via RPC call
>  }
>
>

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CellTable with AsyncDataProvider - load performance issue

2012-10-17 Thread Magnus 
Hello,

I changed all the simple lists of my application into CellTables with an 
AsyncDataProvider.

Before the change, I always loaded the whole list via RPC and also showed 
the whole list in the GUI.
After the change, I always load a portion according to the page size and 
always show one page only.

However, it sometimes lasts very long, up to 10 sec, to fetch the data. 
During this time the CellTable shows its loading animation. This does not 
happen most of the time, but when it happens it looks like a problem to the 
user.

How can it be that fetching the whole list has a good constant performance, 
while fetching the small portions with AsyncDataProvider is that slow 
*sometimes*?

See below how I create the AsyncDataProvider.

Thanks
Magnus

-

 protected void createDataProvider ()
 {
  pvd = new AsyncDataProvider()
  {
   @Override
   protected void onRangeChanged(HasData display)
   {
Range r = display.getVisibleRange();
int start = r.getStart() + 1;
int end = start + r.getLength() - 1;

onRangeChange (start,end);
   }
  };
  
 }

 public void onRangeChange (int i0,int i1)
 {
  // load list and record count via RPC call
 }

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