add doc for lance

Author: xx789633

website/docs/streaming-lakehouse/integrate-data-lakes/lance.md

@@ -0,0 +1,98 @@
+---
+title: Lance
+sidebar_position: 1
+---
+
+# Lance
+
+[Lance](https://lancedb.github.io/lance/) is a modern table format optimized for machine learning and AI applications. 
+To integrate Fluss with Lance, you must enable lakehouse storage and configure Lance as the lakehouse storage. For more details, see [Enable Lakehouse Storage](maintenance/tiered-storage/lakehouse-storage.md#enable-lakehouse-storage).
+
+## Introduction
+
+To configure Lance as the lakehouse storage, you must configure the following configurations in `server.yaml`:
+```yaml
+# Lance configuration
+datalake.format: lance
+
+datalake.lance.warehouse: /tmp/lance
+
+# To S3 as Lance storage backend, you need to specify the following properties
+# datalake.lance.warehouse: s3://<bucket>
+# datalake.lance.endpoint: <endpoint>
+# datalake.lance.allow_http: true
+# datalake.lance.access_key_id: <access_key_id>
+# datalake.lance.secret_access_key: <secret_access_key>
+```
+
+When a table is created or altered with the option `'table.datalake.enabled' = 'true'`, Fluss will automatically create a corresponding Lance table with path `<warehouse_path>/<database_name>/<table_name>.lance`.
+The schema of the Lance table matches that of the Fluss table.
+
+```sql title="Flink SQL"
+USE CATALOG fluss_catalog;
+
+CREATE TABLE fluss_order_with_lake (
+    `order_id` BIGINT,
+    `item_id` BIGINT,
+    `amount` INT,
+    `address` STRING
+) WITH (
+     'table.datalake.enabled' = 'true',
+     'table.datalake.freshness' = '30s'
+);
+```
+
+Then, the datalake tiering service continuously tiers data from Fluss to Lance. The parameter `table.datalake.freshness` controls the frequency that Fluss writes data to Lance tables. By default, the data freshness is 3 minutes.  
+
+> **NOTE**: Fluss v0.8 only supports tiering log tables.
+
+You can also specify Lance table properties when creating a datalake-enabled Fluss table by using the `lance.` prefix within the Fluss table properties clause.
+
+```sql title="Flink SQL"
+CREATE TABLE fluss_order_with_lake (
+    `order_id` BIGINT,
+    `item_id` BIGINT,
+    `amount` INT,
+    `address` STRING
+ ) WITH (
+     'table.datalake.enabled' = 'true',
+     'table.datalake.freshness' = '30s',
+     'lance.max_row_per_file' = '512'
+);
+```
+
+For example, you can specify the property `max_row_per_file` to control the writing behavior when Fluss tiers data to Lance.
+
+### Reading with Lance ecosystem tools
+
+Since the data tiered to Lance from Fluss is stored as a standard Lance table, you can use any tool that supports Lance to read it. Below is an example using [pylance](https://pypi.org/project/pylance/):
+
+```python title="Lance Python"
+import lance
+ds = lance.dataset("<warehouse_path>/<database_name>/<table_name>.lance")
+```
+
+## Data Type Mapping
+
+Lance internally stores data in Arrow format.
+When integrating with Lance, Fluss automatically converts between Fluss data types and Lance data types.  
+The following table shows the mapping between [Fluss data types](table-design/data-types.md) and Lance data types:
+
+| Fluss Data Type               | Lance Data Type |
+|-------------------------------|-----------------|
+| BOOLEAN                       | BOOLEAN         |
+| TINYINT                       | Int8            |
+| SMALLINT                      | Int16           |
+| INT                           | Int32           |
+| BIGINT                        | Int64           |
+| FLOAT                         | Float32         |
+| DOUBLE                        | Float64         |
+| DECIMAL                       | Decimal128      |
+| STRING                        | Utf8            |
+| CHAR                          | Utf8            |
+| DATE                          | Date            |
+| TIME                          | TIME            |
+| TIMESTAMP                     | TIMESTAMP       |
+| TIMESTAMP WITH LOCAL TIMEZONE | TIMESTAMP       |
+| BINARY                        | FixedSizeBinary |
+| BYTES                         | BINARY          |