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Posted to commits@spark.apache.org by da...@apache.org on 2016/09/14 20:37:32 UTC

spark git commit: [SPARK-17472] [PYSPARK] Better error message for serialization failures of large objects in Python

Repository: spark
Updated Branches:
  refs/heads/master e33bfaed3 -> dbfc7aa4d


[SPARK-17472] [PYSPARK] Better error message for serialization failures of large objects in Python

## What changes were proposed in this pull request?

For large objects, pickle does not raise useful error messages. However, we can wrap them to be slightly more user friendly:

Example 1:
```
def run():
  import numpy.random as nr
  b = nr.bytes(8 * 1000000000)
  sc.parallelize(range(1000), 1000).map(lambda x: len(b)).count()

run()
```

Before:
```
error: 'i' format requires -2147483648 <= number <= 2147483647
```

After:
```
pickle.PicklingError: Object too large to serialize: 'i' format requires -2147483648 <= number <= 2147483647
```

Example 2:
```
def run():
  import numpy.random as nr
  b = sc.broadcast(nr.bytes(8 * 1000000000))
  sc.parallelize(range(1000), 1000).map(lambda x: len(b.value)).count()

run()
```

Before:
```
SystemError: error return without exception set
```

After:
```
cPickle.PicklingError: Could not serialize broadcast: SystemError: error return without exception set
```

## How was this patch tested?

Manually tried out these cases

cc davies

Author: Eric Liang <ek...@databricks.com>

Closes #15026 from ericl/spark-17472.


Project: http://git-wip-us.apache.org/repos/asf/spark/repo
Commit: http://git-wip-us.apache.org/repos/asf/spark/commit/dbfc7aa4
Tree: http://git-wip-us.apache.org/repos/asf/spark/tree/dbfc7aa4
Diff: http://git-wip-us.apache.org/repos/asf/spark/diff/dbfc7aa4

Branch: refs/heads/master
Commit: dbfc7aa4d0d5457bc92e1e66d065c6088d476843
Parents: e33bfae
Author: Eric Liang <ek...@databricks.com>
Authored: Wed Sep 14 13:37:35 2016 -0700
Committer: Davies Liu <da...@gmail.com>
Committed: Wed Sep 14 13:37:35 2016 -0700

----------------------------------------------------------------------
 python/pyspark/broadcast.py   | 11 ++++++++++-
 python/pyspark/cloudpickle.py | 10 ++++++++++
 2 files changed, 20 insertions(+), 1 deletion(-)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/spark/blob/dbfc7aa4/python/pyspark/broadcast.py
----------------------------------------------------------------------
diff --git a/python/pyspark/broadcast.py b/python/pyspark/broadcast.py
index a0b8192..74dee14 100644
--- a/python/pyspark/broadcast.py
+++ b/python/pyspark/broadcast.py
@@ -20,6 +20,8 @@ import sys
 import gc
 from tempfile import NamedTemporaryFile
 
+from pyspark.cloudpickle import print_exec
+
 if sys.version < '3':
     import cPickle as pickle
 else:
@@ -75,7 +77,14 @@ class Broadcast(object):
             self._path = path
 
     def dump(self, value, f):
-        pickle.dump(value, f, 2)
+        try:
+            pickle.dump(value, f, 2)
+        except pickle.PickleError:
+            raise
+        except Exception as e:
+            msg = "Could not serialize broadcast: " + e.__class__.__name__ + ": " + e.message
+            print_exec(sys.stderr)
+            raise pickle.PicklingError(msg)
         f.close()
         return f.name
 

http://git-wip-us.apache.org/repos/asf/spark/blob/dbfc7aa4/python/pyspark/cloudpickle.py
----------------------------------------------------------------------
diff --git a/python/pyspark/cloudpickle.py b/python/pyspark/cloudpickle.py
index 822ae46..da2b2f3 100644
--- a/python/pyspark/cloudpickle.py
+++ b/python/pyspark/cloudpickle.py
@@ -109,6 +109,16 @@ class CloudPickler(Pickler):
             if 'recursion' in e.args[0]:
                 msg = """Could not pickle object as excessively deep recursion required."""
                 raise pickle.PicklingError(msg)
+        except pickle.PickleError:
+            raise
+        except Exception as e:
+            if "'i' format requires" in e.message:
+                msg = "Object too large to serialize: " + e.message
+            else:
+                msg = "Could not serialize object: " + e.__class__.__name__ + ": " + e.message
+            print_exec(sys.stderr)
+            raise pickle.PicklingError(msg)
+            
 
     def save_memoryview(self, obj):
         """Fallback to save_string"""


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