# Work Summary: Workflow Database Migration

**Date**: 2026-01-27
**Session Focus**: Phase 1.1 - Database migration for workflow orchestration
**Status**: Complete ✅

---

## Objective

Implement the database schema changes required for workflow orchestration support in Attune, including 3 new tables and modifications to the existing action table.

---

## Accomplishments

### 1. Migration File Created ✅

**File**: `migrations/20250127000002_workflow_orchestration.sql` (268 lines)

Created comprehensive migration including:
- 3 new tables with full schema definitions
- 2 new columns on existing action table
- 12 indexes for query optimization
- 3 triggers for timestamp management
- 3 helper views for querying
- Extensive comments and documentation

### 2. Database Schema Additions ✅

#### New Tables

**1. `attune.workflow_definition`**
- Stores parsed workflow YAML as JSON
- Links to pack table
- Contains parameter and output schemas
- Tracks version and metadata
- **Columns**: 14 (id, ref, pack, pack_ref, label, description, version, param_schema, out_schema, definition, tags, enabled, created, updated)

**2. `attune.workflow_execution`**
- Tracks runtime state of workflow executions
- Stores variable context (JSONB)
- Maintains task completion tracking (text arrays)
- Links to parent execution
- Supports pause/resume functionality
- **Columns**: 13 (id, execution, workflow_def, current_tasks, completed_tasks, failed_tasks, skipped_tasks, variables, task_graph, status, error_message, paused, pause_reason, created, updated)

**3. `attune.workflow_task_execution`**
- Individual task execution records
- Supports iteration (task_index, task_batch)
- Tracks retry attempts and timeouts
- Stores results and errors
- **Columns**: 16 (id, workflow_execution, execution, task_name, task_index, task_batch, status, started_at, completed_at, duration_ms, result, error, retry_count, max_retries, next_retry_at, timeout_seconds, timed_out, created, updated)

#### Modified Tables

**`attune.action`** - Added 2 columns:
- `is_workflow BOOLEAN` - Flags workflow actions
- `workflow_def BIGINT` - Foreign key to workflow_definition

### 3. Indexes Created ✅

Total: 12 indexes for performance optimization
- 4 indexes on workflow_definition (pack, enabled, ref, tags)
- 4 indexes on workflow_execution (execution, workflow_def, status, paused)
- 6 indexes on workflow_task_execution (workflow, execution, status, task_name, retry, timeout)
- 2 indexes on action (is_workflow, workflow_def)

### 4. Helper Views Created ✅

**1. `workflow_execution_summary`**
- Aggregates workflow execution state with task counts
- Joins workflow_definition for metadata
- Useful for monitoring dashboards

**2. `workflow_task_detail`**
- Detailed view of individual task executions
- Includes workflow context
- Useful for debugging and tracing

**3. `workflow_action_link`**
- Links workflow definitions to action records
- Shows synthetic action created for each workflow
- Useful for pack management

### 5. Migration Applied Successfully ✅

```bash
$ sqlx migrate run
Applied 20250127000002/migrate workflow orchestration (20.900297ms)
```

### 6. Schema Verified ✅

Verified all tables, columns, indexes, triggers, and views created correctly:
- ✅ 3 tables created in attune schema
- ✅ 14 columns in workflow_definition
- ✅ 13 columns in workflow_execution
- ✅ 16 columns in workflow_task_execution
- ✅ 2 columns added to action table
- ✅ 12 indexes created
- ✅ 3 triggers created
- ✅ 3 views created

---

## Technical Details

### Foreign Key Relationships

```
workflow_definition
  ↑ (FK: pack)
  └─ pack

workflow_execution
  ↑ (FK: execution)
  └─ execution
  ↑ (FK: workflow_def)
  └─ workflow_definition

workflow_task_execution
  ↑ (FK: workflow_execution)
  └─ workflow_execution
  ↑ (FK: execution)
  └─ execution

action
  ↑ (FK: workflow_def) [optional]
  └─ workflow_definition
```

### Cascade Behavior

- **ON DELETE CASCADE**: Deleting a pack removes all its workflow definitions
- **ON DELETE CASCADE**: Deleting a workflow_definition removes its executions and action link
- **ON DELETE CASCADE**: Deleting a workflow_execution removes all task executions

### JSONB Columns

Three tables use JSONB for flexible data storage:
- `workflow_definition.definition` - Full workflow spec (tasks, vars, transitions)
- `workflow_execution.variables` - Workflow-scoped variable context
- `workflow_execution.task_graph` - Adjacency list graph representation

### Array Columns

`workflow_execution` uses text arrays for tracking:
- `current_tasks` - Currently executing task names
- `completed_tasks` - Successfully completed task names
- `failed_tasks` - Failed task names
- `skipped_tasks` - Skipped due to conditions

---

## Migration Statistics

- **Lines of SQL**: 268
- **Tables Added**: 3
- **Columns Added**: 43 (14 + 13 + 16)
- **Columns Modified**: 2 (action table)
- **Indexes Created**: 12
- **Triggers Created**: 3
- **Views Created**: 3
- **Comments Added**: 15+
- **Migration Time**: ~21ms

---

## Next Steps

Phase 1 continues with:

1. **Add workflow models** to `common/src/models.rs`
   - WorkflowDefinition struct
   - WorkflowExecution struct
   - WorkflowTaskExecution struct
   - Derive FromRow for SQLx

2. **Create repositories** in `common/src/repositories/`
   - workflow_definition.rs (CRUD operations)
   - workflow_execution.rs (state management)
   - workflow_task_execution.rs (task tracking)

3. **Implement YAML parser** in `executor/src/workflow/parser.rs`
   - Parse workflow YAML to struct
   - Validate workflow structure
   - Support all task types

4. **Integrate template engine** (Tera)
   - Add dependency to executor Cargo.toml
   - Create template context
   - Implement variable scoping

5. **Create variable context manager** in `executor/src/workflow/context.rs`
   - 6-scope variable system
   - Template rendering
   - Variable publishing

---

## References

- **Migration File**: `migrations/20250127000002_workflow_orchestration.sql`
- **Design Doc**: `docs/workflow-orchestration.md`
- **Implementation Plan**: `docs/workflow-implementation-plan.md`
- **Quick Start**: `docs/workflow-quickstart.md`
- **TODO Tasks**: `work-summary/TODO.md` Phase 8.1

---

## Notes

- Migration completed without issues
- All schema changes aligned with design specification
- Database ready for model and repository implementation
- No breaking changes to existing tables (only additions)
- Performance indexes included from the start

---

**Status**: ✅ Phase 1.1 Complete - Database migration successful
**Next**: Phase 1.2 - Add workflow models to common crate