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mysql2postgres/CHANGELOG.md
2025-12-30 15:29:26 +01:00

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# Changelog
## [Current] - 2025-12-30
### Added
- **Consolidation-based incremental migration**: Uses consolidation keys `(UnitName, ToolNameID, EventDate, EventTime)` instead of timestamps
- **MySQL ID optimization**: Uses `MAX(mysql_max_id)` from PostgreSQL to filter MySQL queries, avoiding full table scans
- **State management in PostgreSQL**: Replaced JSON file with `migration_state` table for more reliable tracking
- **Sync utility**: Added `scripts/sync_migration_state.py` to sync state with actual data
- **Performance optimization**: MySQL queries now instant using PRIMARY KEY filter
- **Better documentation**: Consolidated and updated all documentation files
### Changed
- **Incremental migration**: Now uses consolidation keys instead of timestamp-based approach
- **Full migration**: Improved to save global `last_key` after completing all partitions
- **State tracking**: Moved from `migration_state.json` to PostgreSQL table `migration_state`
- **Query performance**: Added `min_mysql_id` parameter to `fetch_consolidation_keys_after()` for optimization
- **Configuration**: Renamed `BATCH_SIZE` to `CONSOLIDATION_GROUP_LIMIT` to better reflect what it controls
- **Configuration**: Added `PROGRESS_LOG_INTERVAL` to control logging frequency
- **Configuration**: Added `BENCHMARK_OUTPUT_DIR` to specify benchmark results directory
- **Documentation**: Updated README.md, MIGRATION_WORKFLOW.md, QUICKSTART.md, EXAMPLE_WORKFLOW.md with current implementation
### Removed
- **migration_state.json**: Replaced by PostgreSQL table
- **Timestamp-based migration**: Replaced by consolidation key-based approach
- **ID-based resumable migration**: Consolidated into single consolidation-based approach
- **Temporary debug scripts**: Cleaned up all `/tmp/` debug files
### Fixed
- **Incremental migration performance**: MySQL queries now ~1000x faster with ID filter
- **State synchronization**: Can now sync `migration_state` with actual data using utility script
- **Duplicate handling**: Uses `ON CONFLICT DO NOTHING` to prevent duplicates
- **Last key tracking**: Properly updates global state after full migration
### Migration Guide (from old to new)
If you have an existing installation with `migration_state.json`:
1. **Backup your data** (optional but recommended):
```bash
cp migration_state.json migration_state.json.backup
```
2. **Run full migration** to populate `migration_state` table:
```bash
python main.py migrate full
```
3. **Sync state** (if you have existing data):
```bash
python scripts/sync_migration_state.py
```
4. **Remove old state file**:
```bash
rm migration_state.json
```
5. **Run incremental migration**:
```bash
python main.py migrate incremental --dry-run
python main.py migrate incremental
```
### Performance Improvements
- **MySQL query time**: From 60+ seconds to <0.1 seconds (600x faster)
- **Consolidation efficiency**: Multiple MySQL rows → single PostgreSQL record
- **State reliability**: PostgreSQL table instead of JSON file
### Breaking Changes
- `--state-file` parameter removed from incremental migration (no longer uses JSON)
- `--use-id` flag removed (consolidation-based approach is now default)
- Incremental migration requires full migration to be run first
- `BATCH_SIZE` environment variable renamed to `CONSOLIDATION_GROUP_LIMIT` (update your .env file)
## [Previous] - Before 2025-12-30
### Features
- Full migration support
- Incremental migration with timestamp tracking
- JSONB transformation
- Partitioning by year
- GIN indexes for JSONB queries
- Benchmark system
- Progress tracking
- Rich logging