Incremental-Export.md

## Incremental Export

#### Background
Incremental export allows for export of entities after a specified timestamp. This allows for synchronization capability to be built as it makes payloads lighter.

#### Export Options
New _fetchType_ added to indicate incremental export. This option can be used with any _matchType_. When _fetchType_ is _incremental_, it is necessary to specify the _changeMarker_ option for incremental export to function, else full export will be performed.

```json
{
 "itemsToExport": [
 { "typeName": "hive_db", "uniqueAttributes": { "qualifiedName": "stocks@cl1" } }
 ],
"options": {
 "fetchType": "incremental",
 "changeMarker": 10000
 }
}
```

#### Getting Change Marker

The very first call to export with _fetchType_ set to _incremental_ should be made with _changeMarker_ set to 0. This will perform a full export. The _AtlasExportResult_ will have the _changeMarker_ set to a value. This is the value that should be used for subsequent call to Export.

#### Skip Lineage Option

Export can be performed by skipping lineage information. This avoids all lineage information getting into the exported file.

#### Benefit of Incremental Export

The real benefit of incremental export comes when export is done with _skipLineage_ option set to _true_. This greatly improves performance when fetching entities that have changed since the last export.