Enable streaming executor by default

python/ray/data/context.py

@@ -76,7 +76,7 @@
 # Whether to use the streaming executor. This only has an effect if the new execution
 # backend is enabled.
 DEFAULT_USE_STREAMING_EXECUTOR = bool(
-    int(os.environ.get("RAY_DATASET_USE_STREAMING_EXECUTOR", "0"))
+    int(os.environ.get("RAY_DATASET_USE_STREAMING_EXECUTOR", "1"))
 )
 
 # Whether to eagerly free memory (new backend only).