Thanks Jonathan,
as for the bug on Linq I hope this can help to improve performance of mono.
At 16.01 23/12/2009, Jonathan Chambers wrote:
Hello,
Here is some summarized profiler output in case
anyone is interested in where the time is going.
This is the above sample for 1000 rows instead
of 10000, and with --profiler=default:time.
Thanks,
Jonathan
On Wed, Dec 9, 2009 at 9:20 AM, Oskar Berggren
<<mailto:oskar.bergg...@gmail.com>oskar.bergg...@gmail.com> wrote:
2009/12/9 APS <<mailto:dev.ma...@apsystems.it>dev.ma...@apsystems.it>:
> For sure I can pass a test case, is better
that I file a bug report? I think
> that Mono team already knows where datasets
are slower than MS.Net and maybe
> can suggest me some "best practice".
> Btw with the code provided below with MS.Net
on a standard developer machine
> and Mono on a bi-processor testing machine (with 2GB of ram):
>
> 1000 rows
> MS.Net: 130ms
> Mono 2.4.3: 1.2s
> Mono 2.0.1: 3.5s
>
> 10.000 rows
> MS.Net: less than a second
> Mono 2.4.3: 114s
> Mono 2.0.1: 361s
So when the data size increase by a factor of
10, on <http://ms.net>ms.net the time
taken also seem to increase by a factor of 10, but on mono by a factor
of 100. Seems like an an O(N) versus an O(N²) algorithm.
The code below contains a loop and you claim the Select part is taking
the most time. If that is true, it seems to
indicate that <http://ms.net>ms.net
Select() for this case is O(1) but mono's O(N), with N being the
number of rows in the table.
/Oskar
> I have tables with more than 50.000 rows...I
don't know how much it takes to
> perform the elaboration. RowFilter speed up only if applied on small
> rowsets.
> The problem is in the .Select method, removing those lines the elaboration
> is quicker in Mono. Testing machines are not
with the same resources but the
> difference is too much to think to an hardware difference.
> Here is the code...
>
> DataSet ds1 = new DataSet();
> ds1.Tables.Add();
> ds1.Tables[0].Columns.Add("COL1", typeof(string));
> ds1.Tables[0].Columns.Add("COL2", typeof(int));
> ds1.Tables[0].Columns.Add("COL3", typeof(bool));
> for (int i = 0; i < 10000; i++) {
> ds1.Tables[0].Rows.Add(new object[] { "test", i, true });
> }
> DataSet ds2 = new DataSet();
> ds2.Tables.Add();
> ds2.Tables[0].Columns.Add("COL1", typeof(string));
> ds2.Tables[0].Columns.Add("COL2", typeof(int));
> ds2.Tables[0].Columns.Add("COL3", typeof(bool));
> for (int i = 0; i < 10000; i++) {
> ds2.Tables[0].Rows.Add(new object[] { "test", i, true });
> }
> DataSet ds3 = new DataSet();
> ds3.Tables.Add();
> ds3.Tables[0].Columns.Add("COL1", typeof(string));
> ds3.Tables[0].Columns.Add("COL2", typeof(int));
> ds3.Tables[0].Columns.Add("COL3", typeof(bool));
> for (int i = 0; i < 10000; i++) {
> ds3.Tables[0].Rows.Add(new object[] { "test", i, true });
> }
> int idx=0;
> foreach (DataRow dr in ds1.Tables[0].Rows) {
> DataRow[] dr2 = ds2.Tables[0].Select("COL2=" + idx);
> DataRow[] dr3 = ds3.Tables[0].Select("COL2=" + idx);
>
> idx++;
> }
>
>
>
>
> At 21.59 02/12/2009, Nagappan Alagappan wrote:
>
> Hello,
>
> Do you have a test case to reproduce this issue, which you could share with
> the Mono team ?
>
> Thanks
> Nagappan
>
> On Wed, Dec 2, 2009 at 4:05 AM, APS
<<mailto:dev.ma...@apsystems.it>dev.ma...@apsystems.it > wrote:
> Hi,
>
> I'm testing some old elaboration that cycles on a large datatable and
> for every rows makes several selections on separated datatables.
> This elaboration is really slow on mono and
fast on <http://MS.NET>MS.NET, let say
> 400secs vs 4 secs.
> It seems that last rows are slower that first rows.
> I made some test on datasets scroll and I saw that mono performance
> is better than <http://MS.NET>MS.NET so the
delay is due to inner selections.
> I changed datatable.select in defaultview.sort and I gained 200secs,
> still too slow.
> Now I've identified some datatable.compute as the main delay source.
> I'll try to change them using Linq but the question is: there's some
> known performance problem in dataset heavy usage, there's some best
> pratice that you can suggest to speed up elaborations?
> Thanks in advance.
>
>
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>
>
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> http://nagappanal.blogspot.com
>
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