8.3 KiB
8.3 KiB
name, description
| name | description |
|---|---|
| histunion-create | Create hist-union workflow for combining historical and incremental table data |
Create Hist-Union Workflow
⚠️ CRITICAL: This command enforces strict schema validation and template adherence
I'll help you create a production-ready hist-union workflow to combine historical and incremental table data.
Required Information
Please provide the following details:
1. Table Names
You can provide table names in any of these formats:
- Base name:
client_src.klaviyo_events(I'll derive hist and histunion names) - Hist name:
client_src.klaviyo_events_hist(I'll derive inc and histunion names) - Explicit: Inc:
client_src.klaviyo_events, Hist:client_src.klaviyo_events_hist
2. Lookup Database (Optional)
- Lookup/Config Database: Database for inc_log watermark table
- Default:
client_config(will be used if not specified)
What I'll Do
Step 1: Parse Table Names Intelligently
I will automatically derive all three table names:
From your input, I'll extract:
- Database name
- Base table name (removing _hist or _histunion if present)
- Inc table: {database}.{base_name}
- Hist table: {database}.{base_name}_hist
- Target table: {database}.{base_name}_histunion
Step 2: Get Exact Schemas via MCP Tool (MANDATORY)
I will use MCP tool to get exact column information:
1. Call mcp__treasuredata__describe_table for inc table
- Get complete column list
- Get exact column order
- Get data types
2. Call mcp__treasuredata__describe_table for hist table
- Get complete column list
- Get exact column order
- Get data types
3. Compare schemas:
- Identify columns in inc but not in hist
- Identify any schema differences
- Document column order
Step 3: Check Full Load Status
I will check if table requires full load processing:
IF table_name IN ('klaviyo_lists', 'klaviyo_metric_data'):
Use FULL LOAD template (Case 3)
- DROP TABLE and recreate
- Load ALL data (no WHERE clause)
- Still update watermarks
ELSE:
Use INCREMENTAL template (Case 1 or 2)
- CREATE TABLE IF NOT EXISTS
- Filter using inc_log watermarks
- Update watermarks after insert
Step 4: Select Correct SQL Template
Based on schema comparison:
IF full_load_table:
Template = Case 3 (Full Load)
ELIF inc_schema == hist_schema:
Template = Case 1 (Identical schemas)
ELSE:
Template = Case 2 (Inc has extra columns)
Step 5: Generate SQL File
I will create SQL file with exact schema:
File: hist_union/queries/{base_table_name}.sql
Structure:
- CREATE TABLE (or DROP + CREATE for full load)
- Use EXACT inc table schema
- Maintain exact column order
- INSERT INTO with UNION ALL:
- Historical SELECT
- Add NULL for columns missing in hist
- Use inc_log watermark (skip for full load)
- Incremental SELECT
- Use all columns in exact order
- Use inc_log watermark (skip for full load)
- UPDATE watermarks:
- Update hist table watermark
- Update inc table watermark
Step 6: Create or Update Digdag Workflow
I will update the workflow file:
File: hist_union/hist_union_runner.dig
If file doesn't exist, create with:
- timezone: UTC
- _export section with database and lkup_db
- +create_inc_log_table task
- +hist_union_tasks section with _parallel: true
Add new task:
+hist_union_tasks:
_parallel: true
+{table_name}_histunion:
td>: queries/{table_name}.sql
Step 7: Verify Quality Gates
Before delivering, I will verify:
✅ MCP tool used for both inc and hist table schemas
✅ Schema differences identified and documented
✅ Correct template selected (Case 1, 2, or 3)
✅ All inc table columns present in CREATE TABLE
✅ Exact column order maintained from inc schema
✅ NULL added for columns missing in hist table (if applicable)
✅ Watermark updates present for both hist and inc tables
✅ _parallel: true configured for concurrent execution
✅ No schedule block in workflow file
✅ Correct lkup_db set (client_config or user-specified)
Output
I will generate:
For Single Table:
- hist_union/queries/{table_name}.sql - SQL for combining hist and inc data
- hist_union/hist_union_runner.dig - Updated workflow file
File Contents:
SQL File Structure:
-- CREATE TABLE using exact inc table schema
CREATE TABLE IF NOT EXISTS {database}.{table_name}_histunion (
-- All columns from inc table in exact order
...
);
-- INSERT with UNION ALL
INSERT INTO {database}.{table_name}_histunion
-- Historical data (with NULL for missing columns if needed)
SELECT ...
FROM {database}.{table_name}_hist
WHERE time > COALESCE((SELECT MAX(inc_value) FROM {lkup_db}.inc_log ...), 0)
UNION ALL
-- Incremental data
SELECT ...
FROM {database}.{table_name}
WHERE time > COALESCE((SELECT MAX(inc_value) FROM {lkup_db}.inc_log ...), 0);
-- Update watermarks
INSERT INTO {lkup_db}.inc_log ...
Workflow File Structure:
timezone: UTC
_export:
td:
database: {database}
lkup_db: {lkup_db}
+create_inc_log_table:
td>:
query: |
CREATE TABLE IF NOT EXISTS ${lkup_db}.inc_log (...)
+hist_union_tasks:
_parallel: true
+{table_name}_histunion:
td>: queries/{table_name}.sql
Special Cases
Full Load Tables
For klaviyo_lists and klaviyo_metric_data:
-- DROP TABLE (fresh start each run)
DROP TABLE IF EXISTS {database}.{table_name}_histunion;
-- CREATE TABLE (no IF NOT EXISTS)
CREATE TABLE {database}.{table_name}_histunion (...);
-- INSERT with NO WHERE clause (load all data)
INSERT INTO {database}.{table_name}_histunion
SELECT ... FROM {database}.{table_name}_hist
UNION ALL
SELECT ... FROM {database}.{table_name};
-- Still update watermarks (for tracking)
INSERT INTO {lkup_db}.inc_log ...
Schema Differences
When inc table has columns that hist table doesn't:
-- CREATE uses inc schema (includes all columns)
CREATE TABLE IF NOT EXISTS {database}.{table_name}_histunion (
incremental_date varchar, -- Extra column from inc
...other columns...
);
-- Hist SELECT adds NULL for missing columns
SELECT
NULL as incremental_date, -- NULL for missing column
...other columns...
FROM {database}.{table_name}_hist
UNION ALL
-- Inc SELECT uses all columns
SELECT
incremental_date, -- Actual value
...other columns...
FROM {database}.{table_name}
Next Steps After Generation
-
Review Generated Files:
cat hist_union/queries/{table_name}.sql cat hist_union/hist_union_runner.dig -
Verify SQL Syntax:
cd hist_union td wf check hist_union_runner.dig -
Run Workflow:
td wf run hist_union_runner.dig -
Verify Results:
-- Check row counts SELECT COUNT(*) FROM {database}.{table_name}_histunion; -- Check watermarks SELECT * FROM {lkup_db}.inc_log WHERE project_name = 'hist_union' ORDER BY table_name; -- Sample data SELECT * FROM {database}.{table_name}_histunion LIMIT 10;
Examples
Example 1: Simple Table Name
User: "Create hist-union for client_src.shopify_products"
I will derive:
- Inc: client_src.shopify_products
- Hist: client_src.shopify_products_hist
- Target: client_src.shopify_products_histunion
- Lookup DB: client_config (default)
Example 2: Hist Table Name
User: "Add client_src.klaviyo_events_hist to hist_union"
I will derive:
- Inc: client_src.klaviyo_events
- Hist: client_src.klaviyo_events_hist
- Target: client_src.klaviyo_events_histunion
- Lookup DB: client_config (default)
Example 3: Custom Lookup DB
User: "Create hist-union for mc_src.users with lookup db mc_config"
I will use:
- Inc: mc_src.users
- Hist: mc_src.users_hist
- Target: mc_src.users_histunion
- Lookup DB: mc_config (user-specified)
Production-Ready Guarantee
All generated code will:
- ✅ Use exact schemas from MCP tool (no guessing)
- ✅ Handle schema differences correctly
- ✅ Use correct template based on full load check
- ✅ Maintain exact column order
- ✅ Include proper NULL handling
- ✅ Update watermarks correctly
- ✅ Use parallel execution for efficiency
- ✅ Follow Presto/Trino SQL syntax
- ✅ Be production-tested and proven
Ready to proceed? Please provide the table name(s) and I'll generate your complete hist-union workflow using exact schemas from MCP tool and production-tested templates.