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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.
https://demo.cadasta.org
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Improve async locations endpoint response speed #2006

Closed alukach closed 6 years ago

alukach commented 6 years ago

Proposed changes in this pull request

Why I made this change

In #1937, I attempted to improve the async locations API endpoint by introducing the following optimizations:

  1. Use query-fu to handle the awkward relationship between the SpatialUnit.location_type_label property and the QuestionOption. label_xlat field.
  2. Reduce API response side by reducing precision (and additionally redundant points) on geometries
  3. Making API requests from front-end concurrently.

This felt like too many disparate changes. Fix 1 was particularly poorly implemented. This PR is a re-implementation of addressing the issue of the awkward relationship between the SpatialUnit.location_type_label property and the QuestionOption. label_xlat field.

Description of the change

Rather than doing some crazy queries to work around the awkward relationship between the SpatialUnit.location_type_label property and the QuestionOption. label_xlat field, this PR denormalizes the data by syncing the value of the QuestionOption. label_xlat on a new SpatialUnit.label field. This is managed by signals. We now update related SpatialUnit instances whenever a relevant QuestionOption is saved. Additionally, we query for a relevant QuestionOption instance when a new SpatialUnit is created.

By denormalizing the relationship between the two, the lookup for a label when listing SpatialUnit instances is not needed. Therefore, the API is considerably faster:

Before:

screen shot 2018-03-06 at 9 45 02 pm

After:

screen shot 2018-03-06 at 9 27 14 pm

How someone else can test the change

I think the unit tests are pretty comprehensive.

When should this PR be merged

Anytime.

Risks

Minimal. The signal can be skipped by using the QuestionOption.objects.update() method, however I don't believe this is used anywhere within our codebase.

Follow-up actions

The fixes for reducing geometry precision and making API requests concurrently should still be made.

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

@oliverroick @seav okay, this PR is finally good to go.

oliverroick commented 6 years ago

[ch28]

(Ignore — testing the Clubhouse integration)