Configuration improvements:
- Set read_timeout=300 (5 minutes) to handle long queries
- Set write_timeout=300 (5 minutes) for writes
- Set max_allowed_packet=64MB to handle larger data transfers
Retry logic:
- Added retry mechanism with max 3 retries on fetch failure
- Auto-reconnect on connection loss before retry
- Better error messages showing retry attempts
This fixes the 'connection is lost' error that occurs during
long-running migrations by:
1. Giving MySQL queries more time to complete
2. Allowing larger packet sizes for bulk data
3. Automatically recovering from connection drops
Fixes: 'Connection is lost' error during full migration
