issue: #45881
Add persistent task management for external collections with automatic
detection of external_source and external_spec changes. When source
changes, the system aborts running tasks and creates new ones, ensuring
only one active task per collection. Tasks validate their source on
completion to prevent superseded tasks from committing results.
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- Core invariant: at most one active UpdateExternalCollection task
exists per collection — tasks are serialized by collectionID
(collection-level locking) and any change to external_source or
external_spec aborts superseded tasks and causes a new task creation
(externalCollectionManager + external_collection_task_meta
collection-based locks enforce this).
- What was simplified/removed: per-task fine-grained locking and
concurrent multi-task acceptance per collection were replaced by
collection-level synchronization (external_collection_task_meta.go) and
a single persistent task lifecycle in DataCoord/Index task code;
redundant double-concurrent update paths were removed by checking
existing task presence in AddTask/LoadOrStore and aborting/overwriting
via Drop/Cancel flows.
- Why this does NOT cause data loss or regress behavior: task state
transitions and commit are validated against the current external
source/spec before applying changes — UpdateStateWithMeta and SetJobInfo
verify task metadata and persist via catalog only under matching
collection-state; DataNode externalCollectionManager persists task
results to in-memory manager and exposes Query/Drop flows (services.go)
without modifying existing segment data unless a task successfully
finishes and SetJobInfo atomically updates segments via meta/catalog
calls, preventing superseded tasks from committing stale results.
- New capability added: end-to-end external collection update workflow —
DataCoord Index task + Cluster RPC helpers + DataNode external task
runner and ExternalCollectionManager enable creating, querying,
cancelling, and applying external collection updates
(fragment-to-segment balancing, kept/updated segment handling, allocator
integration); accompanying unit tests cover success, failure,
cancellation, allocator errors, and balancing logic.
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Signed-off-by: sunby <sunbingyi1992@gmail.com>
1. Add global scheduler for datacoord.
2. Define and implement new CreateTask, QueryTask, DropTask interfaces.
3. Refine Import, Compaction, Stats, Index task.
issue: https://github.com/milvus-io/milvus/issues/41123
Co-authored-by: Cai Zhang <cai.zhang@zilliz.com>
