[Data] Add read_json docs example for setting PyArrow block size wh…

…en reading large files (#40533)

Adds an example for a workaround when reading large files with ray.data.read_json, which involves setting the block size used by PyArrow's JSON loader. Generated docs page

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Signed-off-by: Scott Lee <sjl@anyscale.com>

python/ray/data/read_api.py

@@ -1028,6 +1028,21 @@ def read_json(
         >>> ds.take(1)
         [{'order_number': 10107, 'quantity': 30, 'year': '2022', 'month': '09'}]
 
+        When reading large files, the default block size configured in PyArrow can be too small,
+        resulting in the following error:
+        ``pyarrow.lib.ArrowInvalid: straddling object straddles two block boundaries
+        (try to increase block size?)``.
+
+        To resolve this, use the ``read_options`` parameter to set a larger block size:
+
+        >>> import pyarrow.json as pajson
+        >>> block_size = 10 << 20 # Set block size to 10MB
+        >>> ray.data.read_json(
+        ...     "s3://anonymous@ray-example-data/log.json",
+        ...     read_options=pajson.ReadOptions(block_size=block_size)
+        ... )
+        Dataset(num_blocks=8, num_rows=1, schema={timestamp: timestamp[s], size: int64})
+
     Args:
         paths: A single file or directory, or a list of file or directory paths.
             A list of paths can contain both files and directories.