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Cadasta / cadasta-platform

[DEPRECATED] Main repository of the Cadasta platform. Technology to help communities document their land rights around the world.
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Make async spatial requests concurrently #2007

Closed alukach closed 6 years ago

alukach commented 6 years ago

Proposed changes in this pull request

Why I made this change

Improve dashboard view of locations. See #1937

Description of the change

Rather than us only only making our /async/.../spatial requests one-after-another, this PR updates our JS to make all paginated requests at the same time. This will take advantage of the fact that we have multiple webserver processes running, reducing the wait-time for the end-user.

Additionally, I've dropped the number of records on the paginated spatial async endpoint from 1000 to 100, ensuring that the user will more quickly see responses returned from the server.

How someone else can test the change

Unfortunately, I can not get my vagrant machine to serve concurrent requests. I've tried running the django server in --threaded mode and running uwsgi with:

uwsgi \
  --http 0.0.0.0:8000 \
  --chdir /opt/cadasta/cadasta-platform \
  --pythonpath /opt/cadasta/cadasta-platform/cadasta \
  --env DJANGO_SETTINGS_MODULE=config.settings.dev_debug \
  --module "config.wsgi:application" \
  --processes 6 \
  --threads 2 \
  --stats 0.0.0.0:9191 \
  --static-map /static=/opt/cadasta/static

I think this is a limitation of the Vagrant machine's single virtual CPU.

Anyways, if you load the dashboard view of project with many (more than 200 locations), you should see all the pages of data queued up at once. You can additionally drop your paginated size to something low like 3.

When should this PR be merged

Anytime.

Risks

None foreseen. Browsers have builtin throttles on the number of max concurrent requests that can be made to a server, so we won't actually have all requests made to our servers at the same time.

Follow-up actions

[List any possible follow-up actions here; for instance, testing data migrations, software that we need to install on staging and production environments.]

Checklist (for reviewing)

General

Is this PR explained thoroughly? All code changes must be accounted for in the PR description.

Is the PR labeled correctly? It should have the migration label if a new migration is added.

Is the risk level assessment sufficient? The risks section should contain all risks that might be introduced with the PR and which actions we need to take to mitigate these risks. Possible risks are database migrations, new libraries that need to be installed or changes to deployment scripts.

Functionality

Are all requirements met? Compare implemented functionality with the requirements specification.

Does the UI work as expected? There should be no Javascript errors in the console; all resources should load. There should be no unexpected errors. Deliberately try to break the feature to find out if there are corner cases that are not handled.

Code

Do you fully understand the introduced changes to the code? If not ask for clarification, it might uncover ways to solve a problem in a more elegant and efficient way.

Does the PR introduce any inefficient database requests? Use the debug server to check for duplicate requests.

Are all necessary strings marked for translation? All strings that are exposed to users via the UI must be marked for translation.

Is the code documented sufficiently? Large and complex classes, functions or methods must be annotated with comments following our code-style guidelines.

Has the scalability of this change been evaluated?

Is there a maintenance plan in place?

Tests

Are there sufficient test cases? Ensure that all components are tested individually; models, forms, and serializers should be tested in isolation even if a test for a view covers these components.

If this is a bug fix, are tests for the issue in place? There must be a test case for the bug to ensure the issue won’t regress. Make sure that the tests break without the new code to fix the issue.

If this is a new feature or a significant change to an existing feature? has the manual testing spreadsheet been updated with instructions for manual testing?

Security

Confirm this PR doesn't commit any keys, passwords, tokens, usernames, or other secrets.

Are all UI and API inputs run through forms or serializers?

Are all external inputs validated and sanitized appropriately?

Does all branching logic have a default case?

Does this solution handle outliers and edge cases gracefully?

Are all external communications secured and restricted to SSL?

Documentation

Are changes to the UI documented in the platform docs? If this PR introduces new platform site functionality or changes existing ones, the changes must be documented in the Cadasta Platform Documentation.

Are changes to the API documented in the API docs? If this PR introduces new API functionality or changes existing ones, the changes must be documented in the API docs.

Are reusable components documented? If this PR introduces components that are relevant to other developers (for instance a mixin for a view or a generic form) they should be documented in the Wiki.

alukach commented 6 years ago

Thinking this over, I actually think that lowering the apI count from 1000 to 100 was overkill. I'd like for us to re-evaluate if that's needed after observing the impact of this PR and #2006. My hunch is that the change is not needed (or should be lowered less severely, possibly to 500).