FTS Index creation fails with transaction conflict (version 3010)

[tryweb]

Bug Description

FTS (Full-Text Search) index creation fails with a transaction conflict error. The system falls back to BM25-only mode.

Error Message

lance error: Retryable commit conflict for version 3010: This CreateIndex transaction was preempted by concurrent transaction CreateIndex at version 3010. Please retry.

Environment

• Plugin: lancedb-opencode-pro
• Database: LanceDB
• Search Mode: BM25-only (fallback)
• Embedding Model: nomic-embed-text (via Ollama)
• Embedder Health: Healthy, lastSuccess: 2026-04-05

Reproduction Steps

1. Configure plugin with LanceDB provider
2. Use Ollama as embedding provider
3. Perform memory operations (search/insert)
4. Observe FTS index fails to initialize

Expected Behavior

FTS index should be created successfully, enabling full-text search capabilities.

Actual Behavior

• FTS index creation fails after 3 retry attempts
• System falls back to BM25-only mode
• Vector index also fails with similar conflict

Analysis

The error indicates a concurrent transaction conflict in LanceDB when attempting to create an index. This appears to be related to:

1. Multiple operations attempting to create indexes simultaneously
2. Lack of proper transaction locking/synchronization
3. Possible race condition in the index creation workflow

Related Issues

• LanceDBError: Commit conflict for version 8: Failed to commit the transaction after 5 retries. lancedb/lancedb#725 - Commit conflict error
• bug(node): Fail to optimize table when there is a FTS index available lancedb/lancedb#1987 - FTS index optimization fails
• bug(python): Async Lancedb table optimize breakes FTS lancedb/lancedb#2193 - Async LanceDB table optimize breaks FTS

Workaround

Use BM25-only search mode as fallback.

[tryweb]

已修復 ✓

此問題已於 v0.6.1 中修復。修復內容：

根本原因

TOCTOU (Time-Of-Check-Time-Of-Use) race condition：
當多個 OpenCode 進程同時啟動時，都會呼叫 ensureIndexes()，兩者都看到沒有 index，兩者都嘗試建立，第二個會收到 Retryable commit conflict 錯誤。

修復內容

1. 新增 isCommitConflict() helper - 偵測 LanceDB 的 commit conflict 錯誤訊息
2. 衝突後重新驗證 - 在 catch block 中呼叫 listIndices()，若另一個 process 已建立 index，則採用該 index
3. 加入 jitter - baseDelay * 2^attempt + Math.random() * baseDelay 防止 thundering-herd re-collision
4. 最終檢查 - 所有重試失敗後，再次呼叫 listIndices() 確認 index 是否存在

驗證結果

• Docker npm run verify: 34 tests pass ✓
• Unit tests: 6 tests pass ✓
• TypeScript: 0 errors ✓

PR

#65

相關變更

• src/store.ts - isCommitConflict(), createVectorIndexWithRetry(), createFtsIndexWithRetry()
• test/unit/index-race-condition.test.ts - 新增 6 個單元測試
• openspec/specs/index-retry/spec.md - 新增 3 個 requirements, 7 個 scenarios
• docs/backlog.md - 新增 BL-051
• docs/roadmap.md - 新增 BL-051 到 P1 清單