dosubot[bot] commented on issue #3150: URL: https://github.com/apache/hugegraph/issues/3150#issuecomment-5252115955
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However, `reallocShards()` calculates `shardCount = Math.min(configuredShardCount, activeStores.size())` and when the filtered shard list size already equals this value, it hits the `else { return shards; }` path at line 545 [[2]](https://github.com/apache/hugegraph/blob/9126c80e414c073b60fc074361b211cfb409e0eb/hugegraph-pd/hg-pd-core/src/main/java/org/apache/hugegraph/pd/StoreNodeService.java#L545-L547). This returns **without** calling `updateShardGroup()` or `fireChangeShard()` [[3]](https://github.com/apache/hugegraph/blob/9126c80e414c073b60fc074361b211cfb409e0eb/hugegraph-pd/hg-pd-core/src/main/java/org/apache/hugegraph/pd/StoreNodeService.java#L549-L562), so the old ShardGroup (still containing the tombstoned Store) remains in RocksDB. In your scenario with 5 Stores and `shardCount=3`, this would trigger when only 2 active Stores remain in a shard group after filtering — `Math.min(3, activeStores)` could reduce to 2, matching the filtered list size. With 4 remaining active Stores this specific early-return wouldn't trigger (since `Math.min(3,4)=3 > 2`), but the bug is latent for any cluster where `activeStores.size() <= configuredShardCount`. **Bug 2 — Replica removal ignores Store state: Confirmed.** The `storeOffline()` listener in `PartitionService` is triggered on the Tombstone state change [[4]](https://github.com/apache/hugegraph/blob/9126c80e414c073b60fc074361b211cfb409e0eb/hugegraph-pd/hg-pd-core/src/main/java/org/apache/hugegraph/pd/PartitionService.java#L82-L104) and calls `shardOffline()` → `reallocPartitionShards()`, which reads the ShardGroup from metadata **without filtering** out the tombstoned Store [[5]](https://github.com/apache/hugegraph/blob/9126c80e414c073b60fc074361b211cfb409e0eb/hugegraph-pd/hg-pd-core/src/main/java/org/apache/hugegraph/pd/PartitionService.java#L475-L496) [[6]](https://github.com/apache/hugegraph/blob/9126c80e414c073b60fc074361b211cfb409e0eb/hugegraph-pd/hg-pd-core/src/main/java/org/apache/hugegraph/pd/PartitionService.java#L551-L562). When `reallocShards()` needs to reduce replicas, it iterates shards and removes the first non-Leader it finds [[7]](https://github.com/apache/hugegraph/blob/9126c80e414c073b60fc074361b211cfb409e0eb/hugegr aph-pd/hg-pd-core/src/main/java/org/apache/hugegraph/pd/StoreNodeService.java#L536-L541): ```java if (iterator.next().getRole() != Metapb.ShardRole.Leader) { iterator.remove(); subCount--; } ``` This checks only `ShardRole`, **not** Store state — so a healthy follower can be removed while the tombstoned follower is kept, exactly as your analysis describes. **Additional detail on the dual invocation:** Both `storeTurnoff()` (called directly in `updateStore()` at line 313) and `storeOffline()` (called via listener at line 319) run for a Tombstone transition [[8]](https://github.com/apache/hugegraph/blob/9126c80e414c073b60fc074361b211cfb409e0eb/hugegraph-pd/hg-pd-core/src/main/java/org/apache/hugegraph/pd/StoreNodeService.java#L304-L319). Because Bug 1 causes `storeTurnoff()` to skip the metadata update, the subsequent `storeOffline()` call reads stale metadata and hits Bug 2. **Regarding your questions:** 1. **Is this consistent with expected behavior?** — No, the intent of the code is clearly to migrate replicas away from a tombstoned Store. The early return and state-unaware removal are bugs. 2. **Known issue?** — I did not find an existing issue or prior discussion tracking these specific bugs. 3. **Workaround** — There is no exposed REST API to manually trigger shard migration. The only rebalancing endpoint is `GET /v1/balanceLeaders`, which only rebalances leaders, not replicas [[9]](https://github.com/apache/hugegraph/blob/9126c80e414c073b60fc074361b211cfb409e0eb/hugegraph-pd/hg-pd-service/src/main/java/org/apache/hugegraph/pd/rest/StoreAPI.java#L148-L151). The internal methods `movePartitionsShard()` and `reallocPartitionShards()` in `PartitionService` could fix the shard groups, but they are not exposed via REST [[10]](https://github.com/apache/hugegraph/blob/9126c80e414c073b60fc074361b211cfb409e0eb/hugegraph-pd/hg-pd-core/src/main/java/org/apache/hugegraph/pd/PartitionService.java#L578-L613). PD's `TaskScheduleService.patrolPartitions()` runs every 60 seconds and attempts to repair shard groups with incorrect replica counts [[11]](https://github.com/apache/hugegraph/blob/9126c80e414c073b60fc074361b211cfb409e0eb/hugegraph-pd/hg-pd-core/src/main/java/org/apache/hug egraph/pd/TaskScheduleService.java#L231-L266), but it may also be affected by the same `reallocShards()` bugs. 4. **Manual repair** — Currently no API supports this directly. A potential manual workaround would be to restart the tombstoned Store node with a fresh identity (new data directory) so it registers as a new active Store, which might allow the patrol task to add it as a new replica — but this doesn't clean up the stale shard group entries. This looks like a legitimate bug worth filing a fix for. The `reallocShards()` method would need two changes: (1) the `else` branch should still update metadata if the input ShardGroup differs from what's stored, and (2) the replica removal logic should prefer removing shards on unhealthy/tombstoned Stores before removing healthy followers. <!-- Dosu Comment Footer --> *To reply, just mention [@dosu](<https://go.dosu.dev/dosubot?utm_source=github&utm_medium=bot-comment&utm_campaign=github-comment-footer-20260415&utm_content=reply-with-mention&utm_term=apache%2Fhugegraph>).* --- Docs are dead. 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