Profiles / #10
Passed Run of Oct 24, 01:31
Some tests got too few samples to explain their time.
Rerun with
pytest --flakytest-profile --flakytest-rate 2000.
Wall time
33.06 s
1 worker
Test time
26.62 s
sum of test durations
Tests
253
253 passed
Profiler
tachyon
1000 Hz ·
23,670 samples · Python 3.15.1 · flakytest 2026.0b1
Peak memory
183 MB
test process
Where the time goes
Test time by category- Database12.43 s
- Libraries5.14 s
- Migrations2.75 s
- Password hashing2.01 s
- DB schema1.42 s
- Templates1.24 s
- Imports534 ms
- App code311 ms
- Serialization271 ms
- Unsampled208 ms
- pytest150 ms
- Deep copies79 ms
- Test code23 ms
- Factories22 ms
- Waiting22 ms
- Logging6 ms
- Mocking4 ms
- Cache3 ms
Session timeline
Tests
25.42 s
Startup
5.81 s
Collection
303 ms
Between tests
830 ms
Session teardown
524 ms
Test phases
Setup 5.28 s
Call 21.16 s
Teardown 174 ms
Fix next
Ranked by the time each fix saves per run
1
Run tests in parallel on all 2 CPUs
Tests run one at a time: 26.6s of test time on a 2-CPU machine. With pytest-xdist this could take about 13.3s.
High
Parallelism
13.31 s
per run
Fix: pip install pytest-xdist, then run pytest -n auto (add it to addopts, or only in CI). pytest-django creates a separate test database per worker automatically.
Read the guide
Details
Tests must not share state: files in fixed paths, ports, a shared database without per-worker names, or module globals. Run with -p randomly first to shake out order dependencies.
2
Use plain static file storage in tests
Static file storage/manifest handling costs 12.2s.
High
App code
12.18 s
per run
Fix: In test settings use STORAGES["staticfiles"] = {"BACKEND": "django.contrib.staticfiles.storage.StaticFilesStorage"} so templates don't need a manifest.
Read the guide
Details
Where:
- apps/api/tests.py:487 ProfileUploadTest.upload · 605 ms
- apps/guides/content.py:112 render · 467 ms
- apps/mcp/tests.py:67 McpTest.post · 460 ms
- ft/tests.py:204 TestAccountSettings.test_change_password · 433 ms
- apps/projects/urls.py:498 project_profile · 397 ms
- apps/orgs/tests.py:28 SignupTest.test_signing_up_creates_an_organization · 305 ms
- apps/orgs/views.py:33 org_shell · 303 ms
- ft/tests.py:160 TestAccountPages.test_signup · 237 ms
- ft/tests.py:199 TestAccountSettings.test_change_password · 218 ms
- apps/projects/urls.py:49 find_project · 214 ms
Most affected tests:
- apps/api/tests.py::ProfileUploadTest::test_missing_parts_mark_the_profile_incomplete
- ft/tests.py::TestAccountSettings::test_change_password
- apps/orgs/tests.py::SignupTest::test_signing_up_creates_an_organization
- apps/projects/tests.py::ProfilePagePaginationTest::test_slowest_tests_first_then_the_next_page
- apps/projects/tests.py::ProjectPagesTest::test_dashboard_filters
- apps/api/tests.py::TestApiIndex::test_index
- ft/tests.py::TestAccountPages::test_signup
- apps/orgs/tests.py::MembersTest::test_owner_invites_someone_who_signs_up
3
Disable django-debug-toolbar in tests
django-debug-toolbar is installed in the test settings and costs 8.1s.
High
App code
8.09 s
per run
Fix: Only add debug_toolbar to INSTALLED_APPS and MIDDLEWARE when not testing (e.g. `if DEBUG and not TESTING:`).
Read the guide
Details
Where:
- apps/guides/content.py:112 render · 467 ms
- ft/tests.py:204 TestAccountSettings.test_change_password · 433 ms
- apps/projects/urls.py:498 project_profile · 397 ms
- apps/orgs/views.py:33 org_shell · 303 ms
- apps/orgs/tests.py:28 SignupTest.test_signing_up_creates_an_organization · 279 ms
- ft/tests.py:160 TestAccountPages.test_signup · 237 ms
- ft/tests.py:199 TestAccountSettings.test_change_password · 218 ms
- apps/projects/urls.py:49 find_project · 214 ms
- apps/api/urls.py:72 api_request.<locals>.decorator.<locals>.wrapped_view · 179 ms
- ft/urls.py:151 <module> · 174 ms
Most affected tests:
- apps/api/tests.py::ProfileUploadTest::test_missing_parts_mark_the_profile_incomplete
- ft/tests.py::TestAccountSettings::test_change_password
- apps/orgs/tests.py::SignupTest::test_signing_up_creates_an_organization
- apps/projects/tests.py::ProfilePagePaginationTest::test_slowest_tests_first_then_the_next_page
- ft/tests.py::TestAccountPages::test_signup
- apps/projects/tests.py::ProjectPagesTest::test_dashboard_filters
- apps/api/tests.py::TestApiIndex::test_index
- apps/guides/tests.py::TestGuidePages::test_every_guide_renders
4
Make the test database server skip durability work
Tests spend 16.6s (62%) in the database. Test databases don't need to survive a crash, so the server can skip flushing to disk.
High
Database
3.32 s
per run
Fix: For a PostgreSQL test server (Docker/CI service) start it with -c fsync=off -c synchronous_commit=off -c full_page_writes=off, and put its data directory on tmpfs; for MySQL use --innodb-flush-log-at-trx-commit=0 --skip-log-bin. Never on a server with data you need.
Read the guide
Details
Only affects crash safety of the throwaway test server; query behaviour is identical.
Where:
- apps/projects/environments.py:63 get_or_create_environment · 310 ms
- apps/orgs/views.py:33 org_shell · 300 ms
- apps/projects/models.py:466 Profile.save · 298 ms
- apps/projects/profiles.py:334 write_snapshots · 291 ms
- apps/api/tests.py:76 IngestStartEndpointTest.join_workers · 228 ms
- apps/projects/urls.py:49 find_project · 213 ms
- apps/api/urls.py:72 api_request.<locals>.decorator.<locals>.wrapped_view · 179 ms
- apps/projects/tests.py:954 ProjectPagesTest.setUp · 178 ms
- apps/projects/rollups.py:88 add_perfs · 178 ms
- apps/projects/urls.py:40 can_manage_project · 155 ms
Most affected tests:
- apps/api/tests.py::TestApiIndex::test_index
- apps/projects/tests.py::SeedDemoCommandTest::test_seed_demo
- apps/api/tests.py::IngestStartEndpointTest::test_ingest_progress_before_start
- apps/projects/tests.py::ProjectPagesTest::test_configure_page
- apps/api/tests.py::IngestStartEndpointTest::test_ingest_start_progress_end
- apps/api/tests.py::IngestStartEndpointTest::test_results_are_counted_and_the_payload_dropped
- apps/api/tests.py::IngestStartEndpointTest::test_all_test_status_types
- apps/api/tests.py::IngestStartEndpointTest::test_ingest_end_after_progress
5
Repeated queries (N+1) in the code under test
27 tests run the same query 10+ times, e.g. 180x in test_seed_demo. N+1 queries slow the tests and production alike.
High
Database
3.17 s
per run
Fix: Django: fetch related rows in one query with select_related() for foreign keys and prefetch_related() for reverse/many-to-many relations, then lock the count in with assertNumQueries (or pytest-django's django_assert_num_queries).
Read the guide
Details
This changes application code, so it speeds up production too; the tests stay as they are.
- 180x in test_seed_demo: SELECT "projects_test"."id", "projects_test"."name", "projects_test"."project_id", "projects_test"."slug", "projects_test"."date_last_run", "projects_test"."date_first_seen", "projects_test"."first_commit_id", "projects_test"."muted" FROM "projects_test" WHERE ("projects_test"."name" = %s AND "proj…
- 22x in test_dashboard_filters: SELECT "projects_environment"."id", "projects_environment"."project_id", "projects_environment"."name", "projects_environment"."kind", "projects_environment"."provider", "projects_environment"."details", "projects_environment"."date_first_seen", "projects_environment"."date_last_seen" FROM "project…
- 21x in test_configure_page: SELECT "projects_profile"."id", "projects_profile"."project_id", "projects_profile"."number", "projects_profile"."environment_id", "projects_profile"."session_id", "projects_profile"."run_id", "projects_profile"."commit_id", "projects_profile"."ingest_id", "projects_profile"."external_id", "project…
- 20x in test_index: SELECT "django_content_type"."model" AS "model" FROM "django_content_type" WHERE "django_content_type"."app_label" = %s
- 20x in test_daily_stats_count_a_profile_once_every_part_is_in: SELECT "projects_profilepart"."id", "projects_profilepart"."profile_id", "projects_profilepart"."index", "projects_profilepart"."count", "projects_profilepart"."checksum", "projects_profilepart"."status", "projects_profilepart"."error", "projects_profilepart"."tests_count", "projects_profilepart"."…
Most affected tests:
- apps/projects/tests.py::SeedDemoCommandTest::test_seed_demo
- apps/projects/tests.py::ProjectPagesTest::test_dashboard_filters
- apps/projects/tests.py::ProjectPagesTest::test_configure_page
- apps/api/tests.py::TestApiIndex::test_index
- apps/api/tests.py::ProfileUploadTest::test_daily_stats_count_a_profile_once_every_part_is_in
- apps/api/tests.py::IngestStartEndpointTest::test_all_test_status_types
- apps/api/tests.py::IngestStartEndpointTest::test_details_are_kept_for_failures_only
- apps/api/tests.py::IngestStartEndpointTest::test_ingest_end_after_progress
6
Stop re-running migrations on every test run
Migrations take 2.7s per run, before the first test can start.
Medium
Migrations
2.47 s
per run
Fix: Run with --reuse-db (add it to addopts in pytest.ini/pyproject) so the test database survives between runs; pass --create-db when migrations change. If no test depends on data migrations, --nomigrations builds the schema straight from the models, which is faster still.
Read the guide
Details
CI should still build the database from scratch (no --reuse-db) so broken migrations are caught.
Where:
- apps/projects/migrations/0014_backfill_session_counts.py:23 backfill · 5 ms
- apps/projects/migrations/0012_backfill_session_environments.py:30 backfill · 5 ms
- apps/projects/migrations/0022_backfill_organizations.py:69 forwards · 4 ms
- apps/projects/migrations/0016_profile_parts.py:9 move_documents · 4 ms
- apps/projects/migrations/0025_backfill_slugs_and_numbers.py:35 forwards · 4 ms
- apps/projects/migrations/0025_backfill_slugs_and_numbers.py:28 forwards · 3 ms
- apps/projects/migrations/0015_store_compressed_documents_as_is.py:12 external_storage · 3 ms
- apps/projects/migrations/0018_profile_stats_applied.py:9 mark_applied · 3 ms
- apps/projects/migrations/0009_auto_20240218_1217.py:12 create_mute_objects · 1 ms
- apps/projects/migrations/0012_backfill_session_environments.py:24 backfill · 1 ms
Most affected tests:
- apps/api/tests.py::TestApiIndex::test_index
7
pytest takes a long time before the first test runs
Startup takes 5.8s and collection 303ms on every run, even when you only run one test.
Medium
Imports
2.45 s
per run
Fix: Set testpaths and norecursedirs (node_modules, .venv, build, docs) so pytest doesn't walk unrelated directories; move heavy imports out of module level in test files and conftest.py into fixtures; check `python -X importtime -m pytest --collect-only -q` for the slowest imports.
Read the guide
8
Use a fast password hasher in tests
2.0s (8% of test time) is spent hashing passwords. Slow hashing protects real passwords; in tests it only burns CPU.
Medium
Password hashing
1.91 s
per run
Fix: In your test settings set PASSWORD_HASHERS = ["django.contrib.auth.hashers.MD5PasswordHasher"] (currently PBKDF2PasswordHasher).
Read the guide
Details
Only change the hasher in test settings. Tests that assert on a specific hash format need updating.
Where:
- ft/tests.py:204 TestAccountSettings.test_change_password · 426 ms
- ft/tests.py:231 TestAccountSettings.test_projects_only_lists_your_own_even_for_superusers · 258 ms
- apps/orgs/tests.py:194 SuperuserTest.test_superusers_can_open_any_project_but_dont_list_them · 241 ms
- apps/orgs/tests.py:28 SignupTest.test_signing_up_creates_an_organization · 226 ms
- ft/tests.py:160 TestAccountPages.test_signup · 220 ms
- ft/tests.py:214 TestAccountSettings.test_change_password · 214 ms
- ft/tests.py:199 TestAccountSettings.test_change_password · 214 ms
- ft/tests.py:176 TestAccountSettings.setUpTestData · 212 ms
- apps/projects/tests.py:139 ProjectEditPage.setUpTestData · 1 ms
- apps/projects/tests.py:407 TestProjectTestPage.setUpTestData · 0.94 ms
Most affected tests:
- ft/tests.py::TestAccountSettings::test_change_password
- ft/tests.py::TestAccountSettings::test_projects_only_lists_your_own_even_for_superusers
- apps/orgs/tests.py::SuperuserTest::test_superusers_can_open_any_project_but_dont_list_them
- apps/orgs/tests.py::SignupTest::test_signing_up_creates_an_organization
- ft/tests.py::TestAccountPages::test_signup
- apps/projects/tests.py::ProjectEditPage::test_invalid_form
- apps/projects/tests.py::TestProjectTestPage::test_not_logged_in
9
Use TestCase instead of TransactionTestCase
1.2s goes to flushing every table after tests in 11 TransactionTestCase / transaction=True / live_server tests.
Medium
DB schema
1.06 s
per run
Fix: Use django.test.TestCase (or @pytest.mark.django_db without transaction=True): it wraps each test in a transaction and rolls back instead of truncating every table. Keep TransactionTestCase only for tests that need real commits (on_commit hooks can use TestCase.captureOnCommitCallbacks).
Read the guide
Details
Tests that rely on commit behaviour, multiple connections or a live server still need a transactional test case.
Most affected tests:
- apps/api/tests.py::IngestStartEndpointTest::test_ingest_start_progress_end
- apps/api/tests.py::IngestStartEndpointTest::test_details_are_kept_for_failures_only
- apps/api/tests.py::IngestStartEndpointTest::test_ingest_valid
- apps/api/tests.py::IngestStartEndpointTest::test_ingest_start_with_git
- apps/api/tests.py::IngestStartEndpointTest::test_ingest_end_after_progress
- apps/api/tests.py::IngestStartEndpointTest::test_results_are_counted_and_the_payload_dropped
- apps/api/tests.py::ProfileUploadLockTest::test_upload_while_a_part_is_being_processed
- apps/api/tests.py::IngestStartEndpointTest::test_ingest_multiple_sessions
10
Tests open new database connections over and over
Connecting to the database takes 1.0s.
Medium
Database
806 ms
per run
Fix: Reuse connections: create the engine once per session (not per test) and keep the default pool (NullPool reconnects on every checkout); in Django avoid closing connections in tests (connection.close()/close_old_connections).
Read the guide
Details
Where:
- apps/api/tests.py:76 IngestStartEndpointTest.join_workers · 184 ms
- apps/api/tests.py:73 IngestStartEndpointTest.setUp · 91 ms
- apps/api/tasks.py:266 warm_reports · 50 ms
- apps/api/urls.py:72 api_request.<locals>.decorator.<locals>.wrapped_view · 44 ms
- apps/api/tests.py:331 IngestStartEndpointTest.test_results_are_counted_and_the_payload_dropped · 29 ms
- apps/api/tests.py:928 ProfileUploadLockTest.setUp · 21 ms
- apps/api/tests.py:257 IngestStartEndpointTest.test_ingest_end_after_progress · 12 ms
- apps/api/tasks.py:237 process_profile · 11 ms
- apps/api/tests.py:212 IngestStartEndpointTest.test_ingest_start_progress_end · 11 ms
- apps/api/tests.py:235 IngestStartEndpointTest.test_ingest_progress_before_start · 11 ms
Most affected tests:
- apps/api/tests.py::IngestStartEndpointTest::test_ingest_start_progress_end
- apps/api/tests.py::IngestStartEndpointTest::test_results_are_counted_and_the_payload_dropped
- apps/api/tests.py::IngestStartEndpointTest::test_ingest_end_after_progress
- apps/api/tests.py::IngestStartEndpointTest::test_all_test_status_types
- apps/api/tests.py::IngestStartEndpointTest::test_ingest_progress_before_start
- apps/api/tests.py::ProfileUploadQueueTest::test_upload_is_processed_by_the_worker
- apps/api/tests.py::IngestStartEndpointTest::test_details_are_kept_for_failures_only
- apps/projects/tests.py::FlakyReportTest::test_report
11
Create shared test data in setUpTestData instead of setUp
setUp() runs before every test and takes 933ms in total (db 874ms, library 47ms, factories 6ms) in 14 classes: SettingsTest (3 tests), ProjectsPageTest (5 tests), ProjectEditPage (6 tests), ProjectDeletePage (4 tests).
Low
Database
653 ms
per run
Fix: Move object creation that tests only read from setUp() into `@classmethod def setUpTestData(cls)`: it runs once per class and each test still sees the original rows (TestCase rolls back to a savepoint).
Read the guide
Details
Since Django 3.2 attributes assigned in setUpTestData are deep-copied per test, so in-memory changes don't leak between tests. Keep objects a test modifies in the database (or re-fetches) as before.
Where:
- apps/projects/tests.py:954 ProjectPagesTest.setUp · 199 ms
- apps/api/tests.py:73 IngestStartEndpointTest.setUp · 134 ms
- apps/projects/tests.py:143 ProjectEditPage.setUp · 82 ms
- apps/projects/tests.py:101 ProjectsPageTest.setUp · 58 ms
- apps/projects/tests.py:338 ProjectTestsPage.setUp · 58 ms
- ft/tests.py:180 TestAccountSettings.setUp · 57 ms
- apps/projects/tests.py:413 TestProjectTestPage.setUp · 55 ms
- apps/projects/tests.py:1413 MemoryTest.setUp · 48 ms
- apps/projects/tests.py:308 ProjectRunPage.setUp · 40 ms
- apps/projects/tests.py:269 ProjectRunsPage.setUp · 39 ms
Most affected tests:
- apps/projects/tests.py::TestProjectTestPage::test_project_test_page
- apps/projects/tests.py::ProjectEditPage::test_project
- apps/api/tests.py::ProfileUploadLockTest::test_upload_while_a_part_is_being_processed
- apps/projects/tests.py::ProjectEditPage::test_project_submit
- apps/projects/tests.py::ProjectPagesTest::test_runs_page
- apps/projects/tests.py::ProjectsPageTest::test_other_peoples_project
- ft/tests.py::TestAccountSettings::test_email
- apps/projects/tests.py::ProjectCreatePage::test_not_logged_in
Tests
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Memory
The test process peaked at 215 MBSlowest fixtures
Exact setup time across the session| Fixture | Scope | Calls | Total |
|---|---|---|---|
| _django_setup_unittest | class | 54 | 3.03 s |
| django_db_setup | session | 1 | 3.02 s |
| _unittest_setUpClass_fixture_ProjectPagesTest | class | 1 | 287 ms |
| _unittest_setUpClass_fixture_TestAccountSettings | class | 1 | 224 ms |
| _unittest_setUpClass_fixture_ProfilePagePaginationTest | class | 1 | 209 ms |
| _unittest_setUpClass_fixture_McpTest | class | 1 | 183 ms |
| _unittest_setUpClass_fixture_AnalyticsTest | class | 1 | 178 ms |
| _unittest_setUpClass_fixture_RealProfileDocumentTest | class | 1 | 136 ms |
| _unittest_setUpClass_fixture_MemoryTest | class | 1 | 86 ms |
| _unittest_setUpClass_fixture_StorageTest | class | 1 | 80 ms |
| _unittest_setUpClass_fixture_FlakyReportTest | class | 1 | 69 ms |
| _unittest_setUpClass_fixture_LegacyUrlTest | class | 1 | 60 ms |
| _unittest_setUpClass_fixture_UnstorableCharactersTest | class | 1 | 52 ms |
| _unittest_setUpClass_fixture_FlakyReportCacheTest | class | 1 | 50 ms |
| _unittest_setUpClass_fixture_TestProjectTestPage | class | 1 | 22 ms |