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https://issues.apache.org/jira/browse/SPARK-22538?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
MBA Learns to Code updated SPARK-22538:
---------------------------------------
Description:
When running the below code on PySpark v2.2.0, the cached input DataFrame df
disappears from SparkUI after SQLTransformer.transform(...) is called on it.
I don't yet know whether this is only a SparkUI bug, or whether the input
DataFrame df is indeed unpersisted from memory. If the latter is true, this can
be a serious bug because any new computation using new_df would have to re-do
all the work leading up to df.
{code}
from __future__ import print_function
import pandas
import pyspark
from pyspark.ml.feature import SQLTransformer
spark = pyspark.sql.SparkSession.builder.getOrCreate()
df = spark.createDataFrame(pandas.DataFrame(dict(x=[-1, 0, 1])))
# after below step, SparkUI Storage shows 1 cached RDD
df.cache(); df.count()
# after below step, cached RDD disappears from SparkUI Storage
new_df = SQLTransformer(statement='SELECT * FROM __THIS__').transform(df)
{code}
was:
When running the below code on PySpark v2.2.0, the cached input DataFrame df
disappears from SparkUI after SQLTransformer.transform(...) is called on it.
I don't yet know whether this is only a SparkUI bug, or whether the input
DataFrame df is indeed unpersisted from memory. If the latter is true, this can
be a serious bug because any new computation using new_df would have to re-do
all the work leading up to df.
{code:python}
from __future__ import print_function
import pandas
import pyspark
from pyspark.ml.feature import SQLTransformer
spark = pyspark.sql.SparkSession.builder.getOrCreate()
df = spark.createDataFrame(pandas.DataFrame(dict(x=[-1, 0, 1])))
# after below step, SparkUI Storage shows 1 cached RDD
df.cache(); df.count()
# after below step, cached RDD disappears from SparkUI Storage
new_df = SQLTransformer(statement='SELECT * FROM __THIS__').transform(df)
{code}
> SQLTransformer.transform(inputDataFrame) uncaches inputDataFrame
> ----------------------------------------------------------------
>
> Key: SPARK-22538
> URL: https://issues.apache.org/jira/browse/SPARK-22538
> Project: Spark
> Issue Type: Bug
> Components: ML, PySpark, SQL, Web UI
> Affects Versions: 2.2.0
> Reporter: MBA Learns to Code
>
> When running the below code on PySpark v2.2.0, the cached input DataFrame df
> disappears from SparkUI after SQLTransformer.transform(...) is called on it.
> I don't yet know whether this is only a SparkUI bug, or whether the input
> DataFrame df is indeed unpersisted from memory. If the latter is true, this
> can be a serious bug because any new computation using new_df would have to
> re-do all the work leading up to df.
> {code}
> from __future__ import print_function
> import pandas
> import pyspark
> from pyspark.ml.feature import SQLTransformer
> spark = pyspark.sql.SparkSession.builder.getOrCreate()
> df = spark.createDataFrame(pandas.DataFrame(dict(x=[-1, 0, 1])))
> # after below step, SparkUI Storage shows 1 cached RDD
> df.cache(); df.count()
> # after below step, cached RDD disappears from SparkUI Storage
> new_df = SQLTransformer(statement='SELECT * FROM __THIS__').transform(df)
> {code}
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