chaoqin-li1123 commented on code in PR #45023:
URL: https://github.com/apache/spark/pull/45023#discussion_r1489903039
##########
python/pyspark/sql/datasource.py:
##########
@@ -298,6 +320,104 @@ def read(self, partition: InputPartition) ->
Iterator[Union[Tuple, Row]]:
...
+class DataSourceStreamReader(ABC):
+ """
+ A base class for streaming data source readers. Data source stream readers
are responsible
+ for outputting data from a streaming data source.
+
+ .. versionadded: 4.0.0
+ """
+
+ def initialOffset(self) -> dict:
+ """
+ Return the initial offset of the streaming data source.
+ A new streaming query starts reading data from the initial offset.
+ If Spark is restarting an existing query, it will restart from the
check-pointed offset
+ rather than the initial one.
+
+ Returns
+ -------
+ dict
+ A dict whose key and values are str type.
Review Comment:
The serialization is easy, but deserialization will be tricky. We don't have
runtime type information to deserialize a plain json text back to python
object.(because we don't even know what python type the json is serialized from
unless we keep extra type information in the json)
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: [email protected]
For queries about this service, please contact Infrastructure at:
[email protected]
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
