Update Mode

Update mode syncs changed tables from source to destination without touching unchanged data.

When to Use

• Destination already has a complete copy and you want to refresh stale tables
• Periodic sync from production to staging
• After schema changes that only affected certain tables

What Happens

1. Skips DDL — assumes schema is already correct on destination
2. Compares row counts for every table
3. Truncates and re-copies only tables where counts differ
4. Leaves matching tables untouched

Difference from Resume

	Resume	Update
Intent	Finish an interrupted copy	Refresh stale data
Schema assumption	Created by previous Full run	Already correct
Practical difference	Same behavior	Same behavior

Note

Resume and Update currently use the same logic. The distinction is semantic — Resume implies "I was interrupted" while Update implies "destination is stale". Future versions may add more intelligent diffing for Update mode.

Limitations

• Does not detect schema changes (new columns, dropped tables)
• Does not handle row-level deletes — if source has fewer rows than destination, it won't remove the extras (use Full mode for that)
• For structural changes, run a Full copy instead
• Requires the "All Tables" selection — Update is blocked with an explanation while a non-default table selection is active

Tips

• Pair Update mode with Checksum verification to catch content differences beyond just row counts
• For tables with frequent updates but stable row counts, consider Full mode periodically