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https://issues.apache.org/jira/browse/SPARK-14974?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15384188#comment-15384188
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Apache Spark commented on SPARK-14974:
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User 'baishuo' has created a pull request for this issue:
https://github.com/apache/spark/pull/14262
> spark sql job create too many files in HDFS when doing insert overwrite hive
> table
> ----------------------------------------------------------------------------------
>
> Key: SPARK-14974
> URL: https://issues.apache.org/jira/browse/SPARK-14974
> Project: Spark
> Issue Type: Improvement
> Components: SQL
> Affects Versions: 1.5.2
> Reporter: zenglinxi
> Priority: Minor
>
> Recently, we often encounter problems using spark sql for inserting data into
> a partition table (ex.: insert overwrite table $output_table partition(dt)
> select xxx from tmp_table).
> After the spark job start running on yarn, the app will create too many files
> (ex. 2,000,000, or even 10,000,000), which will make HDFS under enormous
> pressure.
> We found that the num of files created by spark job is depending on the
> partition num of hive table that will be inserted and the num of spark sql
> partitions.
> files_num = hive_table_partions_num * spark_sql_partitions_num.
> We often make the spark_sql_partitions_num(spark.sql.shuffle.partitions) >=
> 1000, and the hive_table_partions_num is very small under normal
> circumstances, but it will turn out to be more than 2000 when we input a
> wrong field as the partion field unconsciously, which will make the files_num
> >= 1000 * 2000 = 2,000,000.
> There is a configuration parameter in hive that can limit the maximum number
> of dynamic partitions allowed to be created in each mapper/reducer named
> hive.exec.max.dynamic.partitions.pernode, but this conf parameter did't work
> when we use hiveContext.
> Reducing spark_sql_partitions_num(spark.sql.shuffle.partitions) can make the
> files_num be smaller, but it will affect the concurrency.
> Can we create configuration parameters to limit the maximum number of files
> allowed to be create by each task or limit the spark_sql_partitions_num
> without affect the concurrency?
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