Added indexed availability for deferred outbox work

[jonatansberg]

ref https://linear.app/ghost/issue/BER-3936/raise-mailgun-event-fetch-throughput-concurrent-paging-logs-api

Remote suppression cleanup needs durable retry scheduling so Mailgun delays do not hold up event ingestion. This is the schema foundation: it adds a nullable outbox.available_at timestamp and an index for selecting due work within an event type and status.

outbox
  event_type + status + available_at + id → bounded selection of due work
  existing payload / status / created-at index → retained

Existing rows receive NULL and their payloads are preserved. The migration uses idempotent nontransactional helpers and removes the dependent index before dropping the column on rollback. It adds no producer or worker; the following PR will commit local unsubscribe/complaint safety state with cleanup intents and process them with retries, lease recovery and shutdown draining. Keeping this foundation separate lets us review the database change on its own.

Stacked on #30690 as the next part of the ingestion performance stack. The schema has no logical dependency on prefetch or counter modes. Adding the index can still take time on an existing outbox; no claim is made from the small test database about production DDL duration.

Validation: schema integrity, Core/test types and focused lint pass. Manual MySQL CLI initialization, rollback to 6.63 and forward migration to 6.64 preserved an existing payload and verified the nullable field and index order; the temporary database was removed. SQLite up/up/down/down/up and all four migration integration tests pass. Five independent review passes found no high-confidence issues.

The full unit run is not green: unrelated untracked suites fail and the runner reports source-map parsing errors. A separate tracked-only run reported 8,687 passing tests but still exited with 64 source-map errors. The migration-specific checks above pass. The earlier full repository check also stops on 452 unrelated formatting files.

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[github-actions]

It looks like this PR contains a migration 👀
Here's the checklist for reviewing migrations:

General requirements

• ⚠️ Tested performance on staging database servers, as performance on local machines is not comparable to a production environment
• Satisfies idempotency requirement (both up() and down())
• Does not reference models
• Filename is in the correct format (and correctly ordered)
• Targets the next minor version
• All code paths have appropriate log messages
• Uses the correct utils
• Contains a minimal changeset
• Does not mix DDL/DML operations

Schema changes

• Both schema change and related migration have been implemented
• For index changes: has been performance tested for large tables
• For new tables/columns: fields use the appropriate predefined field lengths
• For new tables/columns: field names follow the appropriate conventions
• Does not drop a non-alpha table outside of a major version

Data changes

• Mass updates/inserts are batched appropriately
• Does not loop over large tables/datasets
• Defends against missing or invalid data
• For settings updates: follows the appropriate guidelines

[nx-cloud]

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☁️ Nx Cloud last updated this comment at 2026-09-10 17:46:08 UTC

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 67.72%. Comparing base (4d53c90) to head (78ed019).

Additional details and impacted files

@@                              Coverage Diff                              @@
##           jonatan-ber-3936-bounded-mailgun-fetching   #30691      +/-   ##
=============================================================================
+ Coverage                                      67.70%   67.72%   +0.01%     
=============================================================================
  Files                                           1674     1674              
  Lines                                          60586    60586              
  Branches                                       10499    10499              
=============================================================================
+ Hits                                           41017    41029      +12     
+ Misses                                         17230    17222       -8     
+ Partials                                        2339     2335       -4     

Flag	Coverage Δ
e2e-tests	70.46% <ø> (+0.02%)	⬆️

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