---
title: "MySQL to HeliosDB Migration Guide"
---

# MySQL to HeliosDB Migration Guide

**Version:** 1.0

---

## Pre-Migration Checklist

- [ ] Backup MySQL database
- [ ] Review schema for unsupported features
- [ ] Estimate data volume
- [ ] Plan downtime (if any)
- [ ] Test on development environment

---

## Step 1: Export MySQL Schema

```bash
# Export schema without data
mysqldump -h localhost -u root -p database_name \
  --no-data \
  --routines \
  --triggers \
  > schema.sql

# Review for compatibility
grep -E "ENGINE=|AUTO_INCREMENT|COLLATE" schema.sql
```

---

## Step 2: Migrate Schema

```sql
-- Import MySQL schema into HeliosDB
-- Note: Some SQL syntax may need adjustment

-- Example adjustments:
-- MySQL: `column_name` → PostgreSQL: "column_name"
-- MySQL: INT AUTO_INCREMENT → PostgreSQL: SERIAL
-- MySQL: VARCHAR(255) → PostgreSQL: VARCHAR or TEXT
```

---

## Step 3: Export and Import Data

```bash
# Export from MySQL as CSV
mysql -h localhost -u root -p database_name \
  -e "SELECT * FROM table_name" \
  | sed 's/\t/,/g' > table_name.csv

# Import into HeliosDB using COPY
psql -h heliosdb.host -U user -d database_name \
  -c "COPY table_name FROM STDIN WITH (FORMAT csv)" \
  < table_name.csv
```

---

## Step 4: Validate Data

```sql
-- Check row counts
SELECT COUNT(*) FROM table_name;

-- Verify data integrity
SELECT * FROM table_name LIMIT 100;

-- Check for NULL values unexpectedly introduced
SELECT * FROM table_name WHERE column_name IS NULL;
```

---

## Step 5: Create Indexes

> **`ANALYZE` in the current release:** `ANALYZE` (including `VACUUM ANALYZE`) is accepted for PostgreSQL compatibility and returns immediately; it does not collect planner statistics yet. Statistics collection is planned. `EXPLAIN ANALYZE`, which runs the query and reports actual rows and timing, works today.

```sql
-- Recreate indexes
CREATE INDEX idx_name ON table_name(column_name);

-- Analyze for query optimization
ANALYZE table_name;
```

---

## Common Compatibility Issues

| MySQL | HeliosDB Solution |
|-------|------------------|
| `ENUM` type | Use `VARCHAR` with `CHECK` constraint |
| `UNSIGNED INT` | Use `INTEGER` or `BIGINT` |
| `JSON` | Use `JSONB` type |
| `FULL TEXT` | Use HeliosDB full-text search |
| `SPATIAL` | Use PostGIS-compatible geospatial |

---

## Zero-Downtime Migration

```bash
# 1. Set up replication
mysql> CHANGE MASTER TO MASTER_HOST='heliosdb.host', ...
mysql> START SLAVE;

# 2. Verify sync
mysql> SHOW SLAVE STATUS;

# 3. Switch applications
# Point connection strings to HeliosDB

# 4. Clean up MySQL
mysql> STOP SLAVE;
```

---

## Rollback Plan

```bash
# Keep MySQL running in read-only mode
mysql> SET GLOBAL read_only = ON;

# If rollback needed
mysql> SET GLOBAL read_only = OFF;
# Point applications back to MySQL
```

---

## Performance Tuning

```sql
-- After migration, optimize indexes
ANALYZE;
VACUUM;

-- Enable query cache for hot tables
ALTER TABLE frequently_accessed ENABLE INTELLIGENT_CACHING;
```

---

## Post-Migration

- [ ] Verify all data migrated
- [ ] Test application queries
- [ ] Validate performance
- [ ] Monitor error logs
- [ ] Clean up old MySQL database (after verification)

---

**Related Documentation:**