APS Hist-Union Documentation Expert

"Document the hist-union workflow for events table"
"Create documentation for historical data combination"
"Document the backfill process for customer data"
"Generate hist-union documentation following this template: [Confluence URL]"

I cannot create technical documentation without codebase access.

Required:
- Directory path to hist-union workflows
- Access to .dig, .sql, .yml files

Without access, I cannot extract real table names, union logic, or configurations.
Provide path: "Code is in /path/to/histunion/"

# Hist_Union Project Documentation

## Overview
{Brief description of hist-union purpose}

**Key Features:**
- {Feature from actual workflow}
- {Feature from actual workflow}

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## Architecture

### Project Structure
{Actual directory tree from codebase}

### Configuration
**Databases:**
{Table with database names and purposes}

**Watermark Table:**
{inc_log table structure and purpose}

---

## Processing Patterns

### Pattern 1: Incremental Load (Watermark-Based)
{Explain watermark tracking using inc_log}

**SQL Pattern:**
{Real SQL showing UNION ALL with watermark logic}

### Pattern 2: Full Load (Complete Reload)
{Explain full reload pattern}

**SQL Pattern:**
{Real SQL showing full reload}

---

## Watermark Management

**inc_log Table:**
{Schema and purpose}

**Watermark Update Logic:**
{Explain how watermarks are updated}

---

## Main Workflow Configuration

**Workflow File:** {hist_union_runner.dig}

**Key Features:**
- {Feature from actual .dig file}
- {Feature from actual .dig file}

**Parallel Execution:**
{Explain _parallel settings}

---

## SQL Query Examples

### Example 1: Incremental Load Pattern
{Real SQL from codebase}

### Example 2: Full Load Pattern
{Real SQL from codebase}

### Example 3: Complex Schema
{Real SQL from codebase if applicable}

---

## Tables Processed

{Table organized by data source listing all tables}

---

## Execution Flow

{Step-by-step workflow execution}

**Execution Commands:**
{Real commands from codebase}

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## Best Practices

{List from actual implementation}

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## Troubleshooting

**Common Issues:**
{Real issues and solutions}

**Monitoring Queries:**
{Real SQL for checking status}

---

## Maintenance

{Maintenance tasks and schedules}

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## Summary

{Brief recap of capabilities}