Paging about cdrs-tokio HOT 13 CLOSED

Paging is supported: https://docs.rs/cdrs-tokio/latest/cdrs_tokio/cluster/session/struct.Session.html#method.paged

from cdrs-tokio.

Thank you!

When I try to use it like here:

from cdrs-tokio.

That method has been available for 2 years: https://github.com/krojew/cdrs-tokio/blame/master/cdrs-tokio/src/cluster/pager.rs#L76 . You would need to show your whole code to see what's wrong.

from cdrs-tokio.

Sorry I missed that the regular query function is query_with_params while the one for pager is query_with_param (without the s). Do you think it will be a good thought to make them the same?

I looked at the example here:

I tried:

loop {
        futures.push(tokio::spawn(query_pager.next()));
        if !query_pager.has_more() {
            break;
        }
    }

but could not be done due borrowing.

from cdrs-tokio.

Of course - pager is 100% async. The problem with your loop is that you spawn a task for each next call. That''s not how async in Rust should be used - simply call query_pager.next().await in your loop.

from cdrs-tokio.

But then it will await for each iteration to be done. it is not concurrent in this way

from cdrs-tokio.

No - that's not how async works. Each await point switches to another task to proceed concurrently (at least in most runtimes). You can read more about async here: https://rust-lang.github.io/async-book/

from cdrs-tokio.

I have this code:

loop {
        let now = Instant::now();
        for row in query_pager.next().await? {
              results.push(row);
        }

        println!("inside: {}", now.elapsed().as_millis());
        if !query_pager.has_more() {
            break;
        }
    }

which doesn't seem to execute concurrently. the sum of the time in each iteration is the total of the whole loop.

from cdrs-tokio.

It executes concurrently with other tasks run by the async executor. What you seem to want is having a parallel pager, which is not possible, since the pager needs to store current state.

from cdrs-tokio.

The performance is very similar to the the one without the pager. Isn't it should be different?

from cdrs-tokio.

That depends on the situation. If the performance is the same, that suggests it's not very dependent on the amount of data, but other factors. Pager will usually not give you better performance in itself - its main goal is to split the data when it gets large enough. You can use the pager in combination with async tasks to process rows concurrently as they come, instead of processing on single data set. That should give you a performance boost.

from cdrs-tokio.

I see. Thank you so much it was very helpful!

from cdrs-tokio.

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

from cdrs-tokio.