Code Optimization

Hi friends,

have you noticed that, if you have windows 10 and Intel graphics chip, moving mouse over video or just moving mouse makes video lagging in a web video player?

I have Intel processor with built-in video card and I have noticed this problem. To solve it you need to do two simple steps under the Intel HD Graphics control panel:

- maximize performance on the plugged in mode

- maximize performance and disable power setting for the on-battery mode

more over, after I disabled it all I have noticed that YouTube video player started to work great in the full-screen (before this it didn't show video in full-screen mode) mode and whole laptop performance has been increased.

Enjoy it :)

1vqHSTrq1GEoEF7QsL8dhmJfRMDVxhv2y

Hi friends,

today I'm going to show you one possible way to speed up the COUNT(*)  performance in case when you need to know the total amount of rows of your select query with paging.

Here is the example of my first and slow query:

Select

    COUNT(*) OVER () as TotalCount

    , ID

    , OwnerID

    , Name

    , [Description]

    , keywords

From [dbo].[tblData]

    and (@FilterBy = 0 OR @FilterBy = TypeID)

Order By DateAdded Desc

OFFSET @p0 ROWS FETCH NEXT @p1 ROWS ONLY;

this query did take from 4 seconds up to 9 seconds selecting 315000 rows from about 450000 rows -

that is really slow. It seems like OVER () overloads the query itself (but this is just my guess).

Also converting from nchar to char takes a lot of time, so I did change it (notice the N letter before string)

After some time of thinking and playing with that around, I did come to the following solution:

select @rowstotal = count(*)

From [dbo].[tblData]

where pState = 'a' and [status] <> 'P'

     and (@FilterBy = 0 OR @FilterBy = TypeID)

select

      @rowstotal as TotalCount

(pay attention that to calculate total number of rows to be selected you do not need ordering. I think count(*) with ordering works much slower)

Now this query takes up to 1 second to select the same 315000 rows from about 450000 that is minimum 4 times faster :) 

I'm not sure if this is really best solution as I'm not a DBA master :)

but in my case it sped up the query enough.

Thank you.

1vqHSTrq1GEoEF7QsL8dhmJfRMDVxhv2y

Hello my friends,

Did you have a need to populate the DataGridView control with a lot of data? I'm sure you did have.

If you have a huge amount of rows, like 10 000 and more, you will see a huge problem in performance.

To avoid performance leak - you need to set proper value into the RowHeadersWidthSizeMode property.

So the best way is to disable auto resizing during data binding:

dataGridView1.RowHeadersWidthSizeMode = DataGridViewRowHeadersWidthSizeMode.DisableResizing;

you actually can set EnableResizing but avoid to use the DataGridViewRowHeadersWidthSizeMode.AutoSizeToAllHeaders

The AutoSizeToAllHeaders is most time consumable parameter.

In addition would be better to set the RowHeadersVisible to false

dataGridView1.RowHeadersVisible = false;

Now you can bind data source, and enable it all or set what you want it to be 

Thank you, see you next time.

1vqHSTrq1GEoEF7QsL8dhmJfRMDVxhv2y