- [P20260217-224115] 2026-02-17 22:41:15 +0800
  - summary: CONTEXT TRANSFER: We are continuing a conversation that had gotten too long. Here is a summary: --- ## TASK 1: ODS Dedup…
  - prompt:
```text
CONTEXT TRANSFER: We are continuing a conversation that had gotten too long. Here is a summary:

---
## TASK 1: ODS Dedup & Standardize Spec Execution (Run All Tasks)

**STATUS**: done
**USER QUERIES**: Referenced from prior context transfer
**DETAILS**: Executed all 9 tasks from `.kiro/specs/ods-dedup-standardize/tasks.md`. All phases completed including SnapshotMode enum, hash algorithm change, DDL migration, soft-delete refactor, and documentation sync. 32/32 ODS tests passed.
**FILEPATHS**:
- `apps/etl/pipelines/feiqiu/tasks/ods/ods_tasks.py`
- `apps/etl/pipelines/feiqiu/tests/unit/test_ods_dedup_properties.py`
- `db/etl_feiqiu/migrations/2026-02-17__add_ods_latest_version_indexes.sql`
- `db/etl_feiqiu/schemas/ods.sql`
- `.kiro/specs/ods-dedup-standardize/tasks.md`

## TASK 2: ODS Parameter Cleanup

**STATUS**: done
**USER QUERIES**: Referenced from prior context transfer
**DETAILS**: Changed `run.snapshot_missing_delete` default to True, deleted `run.ods_backfill_null_columns` compatibility code, fixed Property 6 test deadline. All 32 ODS tests passed.
**FILEPATHS**:
- `apps/etl/pipelines/feiqiu/tasks/ods/ods_tasks.py`
- `apps/etl/pipelines/feiqiu/tests/unit/test_ods_dedup_properties.py`

## TASK 3: ODS→DWD Processing Flow Report

**STATUS**: in-progress
**USER QUERIES**: "相同的思路，排查ODS - DWD 层数据处理全流程和参数，给我个报告", "报告很好。现在进行优化", multiple follow-up Q&A rounds
**DETAILS**: 
- Generated comprehensive MD report at `apps/etl/pipelines/feiqiu/docs/etl_tasks/ods_to_dwd_flow_report.md`
- Report covers 9 chapters: architecture, main flow with examples, dimension processing (SCD2), fact processing (watermark/increment), parameters, known issues (6 items), data flow diagram, ODS vs DWD comparison, optimization proposals
- Identified 6 known issues: BaseDwdTask dead code, _build_column_mapping undefined variables bug, _pick_order_column unused, FACT_MISSING_FILL_TABLES inconsistency, SCD2 legacy row-by-row methods, Type1 defensive design
- User asked multiple clarifying questions, all answered and incorporated into report:
  - Confirmed: ALL 17 dim tables have SCD2 columns, ALL 23 fact tables do NOT → Type1 branch never triggers
  - Confirmed: ALL ODS tables have content_hash → snapshot_mode always True
  - Clarified: Watermark only applies in auto-watermark mode (no window_override); with explicit window, watermark is not used
  - Clarified: With strict time windows, _insert_missing_by_pk rarely produces actual writes (safety net only)
  - User proposed DWD content_hash optimization → analyzed as feasible, added to report
  - User suggested `dwd.change_detection_mode` parameter ("hash" vs "column") to handle DWD schema changes → incorporated into report section 9.1
- Report was updated with all corrections: section 3.1 (all dims are SCD2), 4.1 (watermark explanation), 4.3/4.4 (simplified since snapshot_mode always True), 4.5 (expanded with 3 scenarios), 9.1 (hash optimization with parameter design)
- ODS index utilization confirmed: 23 `(pk, fetched_at DESC)` indexes exist and are used by DISTINCT ON queries

**NEXT STEPS**:
- User may want to update the report further based on the latest Q&A about watermark modes and strict time windows — the report's section 4.1 still says "水位线之前的数据完全不参与处理" without clarifying this only applies to auto-watermark mode
- Consider updating section 4.5 to note that strict time windows make _insert_missing_by_pk effectively a no-op
- The report is a docs-only change (no code changes), so no `/audit` is needed for this task specifically

**FILEPATHS**:
- `apps/etl/pipelines/feiqiu/docs/etl_tasks/ods_to_dwd_flow_report.md`
- `apps/etl/pipelines/feiqiu/tasks/dwd/dwd_load_task.py`
- `apps/etl/pipelines/feiqiu/tasks/dwd/base_dwd_task.py`
- `apps/etl/pipelines/feiqiu/tasks/base_task.py`
- `db/etl_feiqiu/schemas/dwd.sql`
- `db/etl_feiqiu/schemas/ods.sql`

## USER CORRECTIONS AND INSTRUCTIONS:
- All output text must be in simplified Chinese (per `language-zh.md`)
- Changes to `tasks/`, `db/`, `*.sql` are high-risk and require `/audit` after completion (per `governance.md`)
- Use Python scripts for complex operations, simple shell commands for single commands (per `tech.md`)
- Operating system is Windows with cmd shell
- Cannot use `cd` command in shell — use `cwd` parameter instead
- Test commands: ETL unit tests `python -m pytest tests/unit` (cwd: `apps/etl/pipelines/feiqiu`), monorepo PBT `python -m pytest tests/` (cwd: root)
- Pending `/audit` reminder is active — high-risk paths were modified in earlier tasks (tasks/, db/, *.sql). User needs to manually trigger `/audit`
- User wants reports to be "通俗一点" (plain language) with concrete examples
- User confirmed: all dim tables have SCD2, all fact tables don't; all ODS tables have content_hash; watermark only matters in auto mode
- User proposed `dwd.change_detection_mode` = "hash" | "column" parameter for DWD optimization — this is a design proposal, NOT yet implemented in code

## Files to read
- `apps/etl/pipelines/feiqiu/docs/etl_tasks/ods_to_dwd_flow_report.md`
- `apps/etl/pipelines/feiqiu/tasks/dwd/dwd_load_task.py`
- `apps/etl/pipelines/feiqiu/tasks/base_task.py`

USER QUERIES(most recent first):
1. 我还有问题：- 水位线：所以水位线之前的数据完全不参与处理（除了 _insert_missing_by_pk 回补步骤）。这句话，或者说水位线仅在新增模式下起作用吧？- 回补：缺失主键回补什么时候会发生？如果我的本次任务严格规范了时间窗口，那么就不会有这些问题吧？比如我明确获取8:00 - 10:00的数据。ODS任务从10:01启动的情况下。- HASH对比的风险但有个细节需要注意：ODS 的 content_hash 是基于原始 payload 计算的，而 DWD 的列经过了映射和类型转换。如果直接复用 ODS hash，需要确保"ODS payload 不变 = DWD 列不变"这个等价关系成立。在当前架构下这是成立的（DWD 列都是从 payload 派生的确定性映射），所以可以直接复用。这确实是个问题，那么我建议做一个参数，使用HASH还是使用展平的数据，以便应对DWD表结构改变。后的数据更新。
2. Output:
Command executed successfully with no output.

Exit Code: 0
3. Output:
Command executed successfully with no output.

Exit Code: 0
4. 我还有问题：- 水位线：所以水位线之前的数据完全不参与处理（除了 _insert_missing_by_pk 回补步骤）。这句话，或者说水位线仅在新增模式下起作用吧？- 回补：缺失主键回补什么时候会发生？如果我的本次任务严格规范了时间窗口，那么就不会有这些问题吧？比如我明确获取8:00 - 10:00的数据。ODS任务从10:01启动的情况下。- HASH对比的风险但有个细节需要注意：ODS 的 content_hash 是基于原始 payload 计算的，而 DWD 的列经过了映射和类型转换。如果直接复用 ODS hash，需要确保"ODS payload 不变 = DWD 列不变"这个等价关系成立。在当前架构下这是成立的（DWD 列都是从 payload 派生的确定性映射），所以可以直接复用。这确实是个问题，那么我建议做一个参数，使用HASH还是使用展平的数据，以便应对DWD表结构改变。后的数据更新。
5. Output:
Hook execution failed with exit code 1.

Error output:
[AUDIT REMINDER] Pending audit detected (root-file, dir:admin-web, dir:backend, dir:etl, dir:miniprogram, dir:db, db-schema-change). Run /audit (Manual: Run /audit hook) to sync docs & write audit artifacts. (rate limit: 15min)



Exit Code: 1
6. Output:
Command executed successfully with no output.

Exit Code: 0
7. Output:
Command executed successfully with no output.

Exit Code: 0
8. 问题：- 维表都有SCD2吧？相应的，事实表都没有吧？- 水位线作用是区分新数据和老数据么？新数据直接写入，老数据进行对比？- 4.4 写入策略矩阵 dwd.fact_upsert 配置ODS 有 content_hash？ODS都有HASH吧？- 缺失主键回补（_insert_missing_by_pk），这个章节中，假设的情况可能发生么？什么情况下发生？给我举例说明。我的以下想法是否合理？以及是否可以优化性能：- 既然上游每条ODS数据都有ID，hash，和fetched_at。那么，DWD可不可以也增加一个HASH(并建设好相应索引等事务)，ODS to DWD时，不用逐一对比，只对比fetched_at最晚的ID，对应的HASH即可知道数据是否被修改了。- 更新逻辑：知道数据缺失或修改后：SCD2做数据新增，并修改SCD2相关信息。而事实表直接修改所有字段即可。我认为ODS已经存储了快照，DWD层的事实数据，只保证最新信息即可。- ODS应该建立了索引，现在ODS to DWD时，通过索引了么？
9. Output:
Hook execution failed with exit code 1.

Error output:
[AUDIT REMINDER] Pending audit detected (root-file, dir:admin-web, dir:backend, dir:etl, dir:miniprogram, dir:db, db-schema-change). Run /audit (Manual: Run /audit hook) to sync docs & write audit artifacts. (rate limit: 15min)



Exit Code: 1
10. Output:
Command executed successfully with no output.

Exit Code: 0
11. Output:
Command executed successfully with no output.

Exit Code: 0
12. 报告很好。现在进行优化：- 仔细检查有没有漏的逻辑和方面？- 通俗一点的解释，以及举例说明流程。- 输出为md文档。
13. Output:
Hook execution failed with exit code 1.

Error output:
[AUDIT REMINDER] Pending audit detected (root-file, dir:admin-web, dir:backend, dir:etl, dir:miniprogram, dir:db, db-schema-change). Run /audit (Manual: Run /audit hook) to sync docs & write audit artifacts. (rate limit: 15min)



Exit Code: 1
14. Output:
Command executed successfully with no output.

Exit Code: 0
15. Output:
Command executed successfully with no output.

Exit Code: 0
---

METADATA:
The previous conversation had 8 messages.

INSTRUCTIONS:
Continue working until the user query has been fully addressed. Do not ask for clarification - proceed with the work based on the context provided.
IMPORTANT: you need to read from the files to Read section
```
