diff --git a/core/src/main/scala/org/apache/spark/storage/StorageLevel.scala b/core/src/main/scala/org/apache/spark/storage/StorageLevel.scala
index 755f1a760ee051dfd9c94ce6efb5d7765609060d..632ff047d10428dbcc1ab055e2d23bf1a5753b66 100644
--- a/core/src/main/scala/org/apache/spark/storage/StorageLevel.scala
+++ b/core/src/main/scala/org/apache/spark/storage/StorageLevel.scala
@@ -23,9 +23,9 @@ import java.io.{Externalizable, IOException, ObjectInput, ObjectOutput}
* Flags for controlling the storage of an RDD. Each StorageLevel records whether to use memory,
* whether to drop the RDD to disk if it falls out of memory, whether to keep the data in memory
* in a serialized format, and whether to replicate the RDD partitions on multiple nodes.
- * The [[org.apache.spark.storage.StorageLevel$]] singleton object contains some static constants for
- * commonly useful storage levels. To create your own storage level object, use the factor method
- * of the singleton object (`StorageLevel(...)`).
+ * The [[org.apache.spark.storage.StorageLevel$]] singleton object contains some static constants
+ * for commonly useful storage levels. To create your own storage level object, use the
+ * factory method of the singleton object (`StorageLevel(...)`).
*/
class StorageLevel private(
private var useDisk_ : Boolean,
diff --git a/python/pyspark/__init__.py b/python/pyspark/__init__.py
index fd5972d381a80c7a118ede5201c06eda513318b5..1f35f6f939d8e70c16ec3ebaff5d0b70df59c7bc 100644
--- a/python/pyspark/__init__.py
+++ b/python/pyspark/__init__.py
@@ -30,6 +30,8 @@ Public classes:
An "add-only" shared variable that tasks can only add values to.
- L{SparkFiles<pyspark.files.SparkFiles>}
Access files shipped with jobs.
+ - L{StorageLevel<pyspark.storagelevel.StorageLevel>}
+ Finer-grained cache persistence levels.
"""
import sys
import os
@@ -39,6 +41,7 @@ sys.path.insert(0, os.path.join(os.environ["SPARK_HOME"], "python/lib/py4j0.7.eg
from pyspark.context import SparkContext
from pyspark.rdd import RDD
from pyspark.files import SparkFiles
+from pyspark.storagelevel import StorageLevel
-__all__ = ["SparkContext", "RDD", "SparkFiles"]
+__all__ = ["SparkContext", "RDD", "SparkFiles", "StorageLevel"]
diff --git a/python/pyspark/context.py b/python/pyspark/context.py
index 8fbf2965097d925fb62d835e89945fa17bfeaa4f..597110321a86370c29063052eb892f9213a4bfb3 100644
--- a/python/pyspark/context.py
+++ b/python/pyspark/context.py
@@ -27,6 +27,7 @@ from pyspark.broadcast import Broadcast
from pyspark.files import SparkFiles
from pyspark.java_gateway import launch_gateway
from pyspark.serializers import dump_pickle, write_with_length, batched
+from pyspark.storagelevel import StorageLevel
from pyspark.rdd import RDD
from py4j.java_collections import ListConverter
@@ -279,6 +280,16 @@ class SparkContext(object):
"""
self._jsc.sc().setCheckpointDir(dirName, useExisting)
+ def _getJavaStorageLevel(self, storageLevel):
+ """
+ Returns a Java StorageLevel based on a pyspark.StorageLevel.
+ """
+ if not isinstance(storageLevel, StorageLevel):
+ raise Exception("storageLevel must be of type pyspark.StorageLevel")
+
+ newStorageLevel = self._jvm.org.apache.spark.storage.StorageLevel
+ return newStorageLevel(storageLevel.useDisk, storageLevel.useMemory,
+ storageLevel.deserialized, storageLevel.replication)
def _test():
import atexit
diff --git a/python/pyspark/rdd.py b/python/pyspark/rdd.py
index 914118ccdd92b7560514e13e118b18dbd947659c..58e1849cadac8611c0a4e85681cc67ea6bb7ca25 100644
--- a/python/pyspark/rdd.py
+++ b/python/pyspark/rdd.py
@@ -70,6 +70,25 @@ class RDD(object):
self._jrdd.cache()
return self
+ def persist(self, storageLevel):
+ """
+ Set this RDD's storage level to persist its values across operations after the first time
+ it is computed. This can only be used to assign a new storage level if the RDD does not
+ have a storage level set yet.
+ """
+ self.is_cached = True
+ javaStorageLevel = self.ctx._getJavaStorageLevel(storageLevel)
+ self._jrdd.persist(javaStorageLevel)
+ return self
+
+ def unpersist(self):
+ """
+ Mark the RDD as non-persistent, and remove all blocks for it from memory and disk.
+ """
+ self.is_cached = False
+ self._jrdd.unpersist()
+ return self
+
def checkpoint(self):
"""
Mark this RDD for checkpointing. It will be saved to a file inside the
diff --git a/python/pyspark/shell.py b/python/pyspark/shell.py
index 54823f80378787ff5c73c78f6b8ab8d336d52975..dc205b306f0a93d398d4b18c95da6f888a93ec6e 100644
--- a/python/pyspark/shell.py
+++ b/python/pyspark/shell.py
@@ -24,6 +24,7 @@ import os
import platform
import pyspark
from pyspark.context import SparkContext
+from pyspark.storagelevel import StorageLevel
# this is the equivalent of ADD_JARS
add_files = os.environ.get("ADD_FILES").split(',') if os.environ.get("ADD_FILES") != None else None
diff --git a/python/pyspark/storagelevel.py b/python/pyspark/storagelevel.py
new file mode 100644
index 0000000000000000000000000000000000000000..b31f4762e69bc42cad009183004c0349fcf5e798
--- /dev/null
+++ b/python/pyspark/storagelevel.py
@@ -0,0 +1,43 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements. See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License. You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+__all__ = ["StorageLevel"]
+
+class StorageLevel:
+ """
+ Flags for controlling the storage of an RDD. Each StorageLevel records whether to use memory,
+ whether to drop the RDD to disk if it falls out of memory, whether to keep the data in memory
+ in a serialized format, and whether to replicate the RDD partitions on multiple nodes.
+ Also contains static constants for some commonly used storage levels, such as MEMORY_ONLY.
+ """
+
+ def __init__(self, useDisk, useMemory, deserialized, replication = 1):
+ self.useDisk = useDisk
+ self.useMemory = useMemory
+ self.deserialized = deserialized
+ self.replication = replication
+
+StorageLevel.DISK_ONLY = StorageLevel(True, False, False)
+StorageLevel.DISK_ONLY_2 = StorageLevel(True, False, False, 2)
+StorageLevel.MEMORY_ONLY = StorageLevel(False, True, True)
+StorageLevel.MEMORY_ONLY_2 = StorageLevel(False, True, True, 2)
+StorageLevel.MEMORY_ONLY_SER = StorageLevel(False, True, False)
+StorageLevel.MEMORY_ONLY_SER_2 = StorageLevel(False, True, False, 2)
+StorageLevel.MEMORY_AND_DISK = StorageLevel(True, True, True)
+StorageLevel.MEMORY_AND_DISK_2 = StorageLevel(True, True, True, 2)
+StorageLevel.MEMORY_AND_DISK_SER = StorageLevel(True, True, False)
+StorageLevel.MEMORY_AND_DISK_SER_2 = StorageLevel(True, True, False, 2)