[
https://issues.apache.org/jira/browse/SPARK-21096?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Irina Truong updated SPARK-21096:
---------------------------------
Description:
There is a pickle error when submitting a spark job that references a member
variable in a lambda, even when the member variable is a simple type that
should be serializable.
Here is a minimal example:
https://gist.github.com/j-bennet/8390c6d9a81854696f1a9b42a4ea8278
In the gist above, this method will throw an exception:
{quote}def build_fail(self):
processed = self.rdd.map(lambda row: process_row(row, self.multiplier))
return processed.collect(){quote}
While this method will run just fine:
{quote}def build_ok(self):
mult = self.multiplier
processed = self.rdd.map(lambda row: process_row(row, mult))
return processed.collect()
}}{quote}
In this example, {{self.multiplier}} is just an int. However, passing it into a
lambda throws a pickle error, because it is trying to pickle the whole
{{self}}, and that contains {{sc}}.
If this is the expected behavior, then why should re-assigning
{{self.multiplier}} to a variable make a difference?
was:
There is a pickle error when submitting a spark job that references a member
variable in a lambda, even when the member variable is a simple type that
should be serializable.
Here is a minimal example:
https://gist.github.com/j-bennet/8390c6d9a81854696f1a9b42a4ea8278
In the gist above, this method will throw an exception:
{{def build_fail(self):
processed = self.rdd.map(lambda row: process_row(row, self.multiplier))
return processed.collect()
}}
While this method will run just fine:
{{
def build_ok(self):
mult = self.multiplier
processed = self.rdd.map(lambda row: process_row(row, mult))
return processed.collect()
}}
In this example, {{self.multiplier}} is just an int. However, passing it into a
lambda throws a pickle error, because it is trying to pickle the whole
{{self}}, and that contains {{sc}}.
If this is the expected behavior, then why should re-assigning
{{self.multiplier}} to a variable make a difference?
> Pickle error when passing a member variable to Spark executors
> --------------------------------------------------------------
>
> Key: SPARK-21096
> URL: https://issues.apache.org/jira/browse/SPARK-21096
> Project: Spark
> Issue Type: Bug
> Components: Spark Core
> Affects Versions: 2.1.1
> Reporter: Irina Truong
>
> There is a pickle error when submitting a spark job that references a member
> variable in a lambda, even when the member variable is a simple type that
> should be serializable.
> Here is a minimal example:
> https://gist.github.com/j-bennet/8390c6d9a81854696f1a9b42a4ea8278
> In the gist above, this method will throw an exception:
> {quote}def build_fail(self):
> processed = self.rdd.map(lambda row: process_row(row, self.multiplier))
> return processed.collect(){quote}
> While this method will run just fine:
> {quote}def build_ok(self):
> mult = self.multiplier
> processed = self.rdd.map(lambda row: process_row(row, mult))
> return processed.collect()
> }}{quote}
> In this example, {{self.multiplier}} is just an int. However, passing it into
> a lambda throws a pickle error, because it is trying to pickle the whole
> {{self}}, and that contains {{sc}}.
> If this is the expected behavior, then why should re-assigning
> {{self.multiplier}} to a variable make a difference?
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