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Migration Guides

This directory contains version-specific migration guides for upgrading between ThemisDB versions.

Available Migration Guides

Current Guides

  • v1.7.x to v1.8.0 - Wire Protocol V2, versioned API routing, ZSTD compression, SAGA engine
  • v1.3.x to v1.4.x - Extended context, LLM features, pagination
  • (Guides for v1.4→v1.5, v1.5→v1.6, v1.6→v1.7 will be added retroactively)

Migration Guide Template

When creating a new migration guide, follow this structure:

# Migration Guide: vX.Y to vX.Y+1

## Overview

Brief summary of changes and why upgrade is beneficial.

## Breaking Changes

List of breaking changes (if any).

## New Features

Highlight new features available after upgrade.

## Deprecated Features

List of newly deprecated features.

## Step-by-Step Migration

1. Pre-migration checks
2. Backup procedures
3. Upgrade steps
4. Post-migration validation
5. Rollback procedure (if needed)

## Code Changes Required

Example code changes needed.

## Testing

How to test the migration.

## Support

Where to get help.

General Migration Best Practices

Before Migration

  1. Review Release Notes: Read CHANGELOG.md for the target version
  2. Check Compatibility: Review API Compatibility Matrix
  3. Backup Data: Always backup before major upgrades
  4. Test in Staging: Test migration in non-production environment
  5. Review Deprecations: Check Deprecation Registry

During Migration

  1. Follow Guide: Use version-specific migration guide
  2. Monitor Logs: Watch for errors and warnings
  3. Incremental Approach: Upgrade one minor version at a time
  4. Document Issues: Note any unexpected behavior
  5. Keep Rollback Ready: Have rollback plan prepared

After Migration

  1. Verify Functionality: Run integration tests
  2. Check Performance: Compare metrics before/after
  3. Update Configuration: Apply new recommended settings
  4. Update Dependencies: Upgrade client libraries
  5. Monitor Production: Watch metrics for first 48 hours

Migration Strategies

Blue-Green Deployment

[Production v1.3.x] ←→ Load Balancer ←→ [Staging v1.4.x]
                                ↓
                         Switch traffic gradually
                                ↓
[Staging v1.3.x] ←→ Load Balancer ←→ [Production v1.4.x]

Rolling Update

Node 1: v1.3.x → v1.4.x (upgrade first)
Node 2: v1.3.x (still running)
Node 3: v1.3.x (still running)
   ↓
Node 1: v1.4.x (running)
Node 2: v1.3.x → v1.4.x (upgrade second)
Node 3: v1.3.x (still running)
   ↓
Node 1: v1.4.x (running)
Node 2: v1.4.x (running)
Node 3: v1.3.x → v1.4.x (upgrade last)

Canary Deployment

95% traffic → v1.3.x (stable)
5% traffic  → v1.4.x (canary)
    ↓
Monitor metrics, error rates
    ↓
80% traffic → v1.3.x
20% traffic → v1.4.x
    ↓
Continue gradually
    ↓
100% traffic → v1.4.x

Version-Specific Migration Paths

Upgrading Multiple Versions

When upgrading across multiple versions, follow this path:

v1.0.x → v1.1.x → v1.2.x → v1.3.x → v1.4.x → v1.5.x → v1.6.x → v1.7.x → v1.8.x

Important: Do not skip minor versions. Upgrade sequentially to ensure proper migration of data structures and configurations.

Skip-Level Migration (Not Recommended)

If you must skip versions:

  1. Review all intermediate CHANGELOGs
  2. Combine all migration steps
  3. Test extensively in staging
  4. Have rollback plan ready
  5. Consider professional support

Rollback Procedures

When to Rollback

Rollback if:

  • Critical bugs discovered
  • Performance degradation >20%
  • Data integrity issues
  • Incompatibility with critical systems
  • Failed validation tests

How to Rollback

  1. Stop ThemisDB services
  2. Restore backup (data + config)
  3. Reinstall previous version
  4. Verify data integrity
  5. Resume services
  6. Document issues for future attempts

Rollback Time Limits

  • <1 hour since upgrade: Easy rollback
  • 1-24 hours: Moderate complexity
  • >24 hours: May require data reconciliation
  • >7 days: Rollback not recommended

Support Resources

Documentation

Community Support

Professional Support

For enterprise customers:

  • Email: enterprise@themisdb.com
  • Priority support with SLA
  • Dedicated migration assistance
  • Custom migration planning

Contribution

Found an issue in a migration guide?

  1. Open an issue: https://github.com/makr-code/ThemisDB/issues
  2. Submit a PR with corrections
  3. Share your migration experience

License

All migration guides are released under the same license as ThemisDB. See LICENSE for details.