36 lines
1.2 KiB
Markdown
36 lines
1.2 KiB
Markdown
# Contracts: PD / Placement RPCs (Multi-Raft)
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Source of truth: `rdb-proto/src/pdpb.proto`
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## Services
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- **Pd**
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- `RegisterStore(RegisterStoreRequest) -> RegisterStoreResponse`
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- `GetRegion(GetRegionRequest) -> GetRegionResponse`
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- `ListRegions(ListRegionsRequest) -> ListRegionsResponse`
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- `MoveRegion(MoveRegionRequest) -> MoveRegionResponse`
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## Messages (selected)
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- `Region`:
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- `id: u64`
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- `start_key: bytes`
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- `end_key: bytes` (empty = infinity)
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- `peers: repeated u64` (store IDs)
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- `leader_id: u64`
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- `Store`:
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- `id: u64`
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- `addr: string`
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- `MoveRegionRequest`:
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- `region_id: u64`
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- `from_store: u64`
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- `to_store: u64`
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## Behaviors / Expectations
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- `ListRegions` is used at bootstrap and periodic refresh to populate routing.
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- `MoveRegion` directs a leader to add a replica on `to_store` (ConfChange Add) and, after catch-up, remove `from_store` (ConfChange Remove). Current implementation keeps source online; removal can be triggered separately.
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- Region key ranges returned by PD must be non-overlapping; nodes validate and fail startup on overlap.
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- Heartbeat: nodes periodically refresh routing via `ListRegions` (30s). A dedicated heartbeat RPC can replace this in a future phase.
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