# Refs
- extracted from https://github.com/neondatabase/neon/pull/9353
# Problem
Before this PR, when task_mgr shutdown is signalled, e.g. during
pageserver shutdown or Tenant shutdown, initial logical size calculation
stops polling and drops the future that represents the calculation.
This is against the current policy that we poll all futures to
completion.
This became apparent during development of concurrent IO which warns if
we drop a `Timeline::get_vectored` future that still has in-flight IOs.
We may revise the policy in the future, but, right now initial logical
size calculation is the only part of the codebase that doesn't adhere to
the policy, so let's fix it.
## Code Changes
- make sensitive exclusively to `Timeline::cancel`
- This should be sufficient for all cases of shutdowns; the sensitivity
to task_mgr shutdown is unnecessary.
- this broke the various cancel tests in `test_timeline_size.py`, e.g.,
`test_timeline_initial_logical_size_calculation_cancellation`
- the tests would time out because the await point was not sensitive to
cancellation
- to fix this, refactor `pausable_failpoint` so that it accepts a
cancellation token
- side note: we _really_ should write our own failpoint library; maybe
after we get heap-allocated RequestContext, we can plumb failpoints
through there.
Do pull_timeline while WAL is being removed. To this end
- extract pausable_failpoint to utils, sprinkle pull_timeline with it
- add 'checkpoint' sk http endpoint to force WAL removal.
After fixing checking for pull file status code test fails so far which is
expected.
## Problem
The code for tenant create and tenant attach was just a special case of
what upsert_location does.
## Summary of changes
- Use `upsert_location` for create and attach APIs
- Clean up error handling in upsert_location so that it can generate
appropriate HTTP response codes
- Update tests that asserted the old non-idempotent behavior of attach
- Rework the `test_ignore_while_attaching` test, and fix tenant shutdown
during activation, which this test was supposed to cover, but it was
actually just waiting for activation to complete.
