> ## Documentation Index
> Fetch the complete documentation index at: https://docs.mantrixflow.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Incremental sync

> Use Incremental sync with a stable replication key and stored checkpoint state.

`INCREMENTAL` sync uses a replication key and checkpoint state to process newer source rows after each successful run.

## Requirements

* PostgreSQL source table
* stable replication key such as `updated_at`, `created_at`, or an increasing id
* destination table that already exists
* saved SQL model output that matches the destination columns

## How to configure

1. Open the **Destination** panel.
2. Switch **Sync mode** to `INCREMENTAL`.
3. Enter the replication key.
4. Save the destination.
5. Run manually once.
6. Review run history.
7. Add a schedule if the manual run succeeds.

## Checkpoint state

After a successful run, MantrixFlow extracts checkpoint state before deleting the temporary staging file. The next Incremental run resumes from that stored state.

## Good replication keys

Use columns that move forward predictably and are populated on every row. Timestamp columns should be indexed when tables are large.