feat: support create btree index distributedly

java/.gitignore

@@ -1,2 +1,5 @@
 *.iml
 .java-version
+.classpath
+.project
+.settings

python/python/lance/dataset.py

@@ -2762,8 +2762,38 @@ def prewarm_index(self, name: str):
         """
         return self._ds.prewarm_index(name)
 
-    def merge_index_metadata(self, index_uuid: str):
-        return self._ds.merge_index_metadata(index_uuid)
+    def merge_index_metadata(
+        self,
+        index_uuid: str,
+        index_type: str,
+        batch_readhead: Optional[int] = None,
+    ):
+        """
+        Merge an index which is not commit at present.
+
+        Parameters
+        ----------
+        index_uuid: str
+            The uuid of the index which want to merge.
+        index_type: str
+            The type of the index.
+            Only "BTREE" and "INVERTED" are supported now.
+        batch_readhead: int, optional
+            The number of prefetch batches of sub-page files for merging.
+            Default 1.
+        """
+        index_type = index_type.upper()
+        if index_type not in [
+            "BTREE",
+            "INVERTED",
+        ]:
+            raise NotImplementedError(
+                (
+                    'Only "BTREE" or "INVERTED" are supported for '
+                    f"merge index metadata.  Received {index_type}",
+                )
+            )
+        return self._ds.merge_index_metadata(index_uuid, index_type, batch_readhead)
 
     def session(self) -> Session:
         """

python/python/lance/lance/__init__.pyi

@@ -299,7 +299,9 @@ class _Dataset:
     ): ...
     def drop_index(self, name: str): ...
     def prewarm_index(self, name: str): ...
-    def merge_index_metadata(self, index_uuid: str): ...
+    def merge_index_metadata(
+        self, index_uuid: str, index_type: str, batch_readhead: Optional[int] = None
+    ): ...
     def count_fragments(self) -> int: ...
     def num_small_files(self, max_rows_per_group: int) -> int: ...
     def get_fragments(self) -> List[_Fragment]: ...