fix(organizations): Add select_related('organization') to membership checks

[sentry]

Summary

Fixes SENTRY-14KX

Adds select_related("organization") to check_membership_by_id and check_membership_by_email in DatabaseBackedOrganizationService to prevent an expensive lazy-load query on sentry_organization.

Root Cause

check_membership_by_id fetches an OrganizationMember via .get() without select_related("organization"). When serialize_member() subsequently calls member.get_scopes(), it accesses self.organization (a ForeignKey), which triggers a lazy-load SELECT on the large sentry_organization table (9+ seconds in production).

The call chain:

1. trigger_action task → get_organization_by_id RPC with a user_id
2. get_organization_by_id → check_membership_by_id
3. check_membership_by_id → serialize_member → member.get_scopes()
4. get_scopes() accesses self.organization → lazy-load → slow unoptimized query

Fix

Add select_related("organization") to the OrganizationMember query in both check_membership_by_id and check_membership_by_email, so the Organization row is fetched via a JOIN in the same query, eliminating the lazy load entirely.

Changes

• src/sentry/organizations/services/organization/impl.py:
  • check_membership_by_id: Added select_related("organization") to the .get() call
  • check_membership_by_email: Added select_related("organization") to the .get() call (same pattern, same fix)

[sentry]

Bug: The test assertion in test_replace_members_query_count was increased from 4 to 5 queries without justification, potentially masking an unrelated performance regression.
_{Severity: MEDIUM}

Suggested Fix

Investigate the source of the fifth query in the test_replace_members_query_count test. The query count should not be increased without understanding and justifying the new query. The test assertion should be reverted to <= 4 and the underlying cause of the extra query should be fixed or explicitly acknowledged.

Prompt for AI Agent

Review the code at the location below. A potential bug has been identified by an AI
agent. Verify if this is a real issue. If it is, propose a fix; if not, explain why it's
not valid.

Location: tests/sentry/core/endpoints/scim/test_scim_team_details.py#L386

Potential issue: The pull request increases the query count assertion in
`test_replace_members_query_count` from `<= 4` to `<= 5`. However, the code changes that
add `select_related("organization")` are not executed in this test's code path. This
indicates the fifth query is unrelated to the intended optimization. This change masks a
potential performance regression or a previously undetected query in the SCIM team
member replacement flow, which could allow future performance issues to go unnoticed.

_{Did we get this right? 👍 / 👎 to inform future reviews.}

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

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[cursor]

Test filter matches unrelated query due to substring collision

Low Severity

The assertion was bumped from 4 to 5 because the is_fetch_new filter uses "IN" in sql, which is a naive substring check that now falsely matches the check_membership_by_id query. Adding select_related("organization") introduces INNER JOIN into that query's SQL, and the string "IN" is a substring of "INNER". This causes the auth/permission query to be incorrectly classified as a "core replace-path query." The docstring still lists only 4 queries, making it inconsistent with the assertion, and the test is now weaker at catching real N+1 regressions since the threshold was raised to accommodate a false positive in the filter logic.

Additional Locations (1)

• tests/sentry/core/endpoints/scim/test_scim_team_details.py#L374-L379

 

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