Vlad Lazar 6f0046b688 storage_controller: ensure mutual exclusion for imports and shard splits (#11632) ...

## Problem

Shard splits break timeline imports.

## Summary of Changes

Ensure mutual exclusion for imports and shard splits.

On the shard split code path:
1. Right before shard splitting, check the database to ensure that
no-import is on-going for the tenant. Exclusion is guaranteed because
this validation is done while holding the exclusive tenant lock.
Timeline creation (and import creation implicitly) requires a shared
tenant lock.
2. When selecting a shard to split, use the in-mem state to exclude
shards with an on-going import. This is opportunistic since an import
might start after the check, but allows shard splits to make progres
instead of continously retrying to split the same shard.

On the timeline creation code path:
1. Check the in-memory splitting flag on all shards of the tenant. If
any of them are splitting, error out asking the client to retry. On the
happy path this is not required, due to the tenant lock set-up described
above, but it covers the case where we restart with a pending
shard-split.

Closes https://github.com/neondatabase/neon/issues/11567

2025-04-25 11:46:15 +00:00

..

src

storage_controller: ensure mutual exclusion for imports and shard splits (#11632)

2025-04-25 11:46:15 +00:00

Cargo.toml

cover direct IO + concurrent IO in unit, regression & perf tests (#11585)

2025-04-17 15:53:10 +00:00