Performance GRID computed columns

omnius

Hi,

i have a report with 2 tables on 1 dataset.
This query returns aprox. 300 rows and takes 16ms. The generation of the report takes about 10 seconds.
So far so good.

But then i added a second dataset, with a number of computed columns. These computed columns are displayed in a grid. But from this moment on the generation of the report takes 85 seconds.
The strange thing is: when i preview the result of the dataset (in the dataset editor) the data is generated in a few seconds. So my guess is that the computed columns are not the problem?
As soon as i remove the grid(but leave the dataset with the computed columns), my report generation is back to 10 seconds. I've tested this both local in the report designer, as on tomcat. Both have the same results.

Any ideas?

omnius

hmm, it kinda looks like the query is rerun for every time one of the computed columns is used....
So when i add 1 of the computed columns to my report it takes for example 2 seconds. When i add a second computed column it takes 4 sec, for the third it takes 6 sec and so on...

Virgil Dodson

Hi omnius,

I'm pretty sure you will see different results if you use a table instead of a grid and then bind the table to the dataset and not the individual controls.

Basically, if you drag a dataset field into a grid, that control will be individually bound to the dataset, which may run the query again... so if you drag several different fields like this they may each run the query. Instead, put a table where you need it, and drag the fields from the dataset into the table. Make sure that the table is bound to the data set and check that the individual controls have their binding set to None. This should run the query only once for the entire table.

omnius

thanks, that solved the problem.