Facing issue in expression while querying the data

It seems you are pulling large data (More than 1 MB) ,there is a support case related to this error , go through it. 

https://community.appian.com/support/w/kb/686/kb-1411-memory-threshold-reached-during-output-conversion

Unnam Nageswara Rao :

You are attempting to retrieve all data from a view in a single QE hit, which is not considered best practice and should generally be avoided. I am not fully aware of the specifics of your use case, but it is necessary to revise your approach, especially as the data in the view will continue to grow and you are using a batch size of -1.

Consider the following alternative approaches:

1. Retrieve only a specific number of rows.
2. Use aggregation to decrease the number of rows.
3. Limit the number of columns in the QE.
4. Execute a stored procedure (SP) and limit the data retrieved.
5. Alternatively, you can transfer the data from the view into a table and perform the QE on that table.

Please provide more details about your use case so that we can suggest a more tailored approach.

For what purpose do you try to load the whole table into memory?

I Need to show all the data into Grid in UI

I would say show few columns in the grid by minimizing the amount of data that you query and try to have a summary where you can display the whole data of that particular selection. That would be a better option. If you have too many columns your grid would look clumsy anyway. So I would consider few points from Rohit's suggestion.

Sorry, but that will never work. That will result in a slow UI and a bad UX. Besides hitting the memory restrictions of Appian.

You will have to implement that in a way you only display a certain subset of the data.

Can you share the code where you are calling this rule in the grid

hi Unnam Nageswara Rao  May I Know the requirement for querying the whole data. filter the columns you need from the data set and display, Calling whole data at once may lead to memory and timeout issues, Also may i know is it a table or view you are using to retrieve the data. Add indexes to the required columns and retrieve the columns you need.

In grid I am passing local data

Can you try calling rule in data keyword in grid and pass fv!paginginfo to paginginfo rule input without using local variable