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https://issues.apache.org/jira/browse/HUDI-1529?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Vinoth Chandar resolved HUDI-1529.
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Resolution: Fixed
> Spark-SQL drvier runs out of memory when metadata table is enabled
> ------------------------------------------------------------------
>
> Key: HUDI-1529
> URL: https://issues.apache.org/jira/browse/HUDI-1529
> Project: Apache Hudi
> Issue Type: Sub-task
> Components: Performance, Spark Integration
> Reporter: Udit Mehrotra
> Assignee: Udit Mehrotra
> Priority: Major
> Labels: pull-request-available
> Fix For: 0.7.0
>
>
> When testing a large dataset around 1.2TB data and around 20k files, we
> notice an issue where the spark driver would always run out of memory, when
> running queries with use of metadata table *enabled*. The OOM would happen on
> any query, even if it was touching a single partition, and was happening in
> the *split generation* phase before any tasks would start executing.
> Upon analyzing the heap dump, it was analyzed that input format was
> generating *millions of splits for every single file*. Upon further analysis
> of the code path, it was found that the root cause was because *metadata
> enabled* code was ignoring the *blockSize* when returning *FileStatus*
> objects and setting it to *0*. Spark by itself does not set any value for the
> property:
> {code:java}
> mapreduce.input.fileinputformat.split.minsize
> {code}
> As a result *minSize* ends up being 1, and with block size as 0 it cause
> input format to *generate splits of size 1 bytes***** because of the logic
> here:
> [https://github.com/apache/hadoop/blob/trunk/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapred/FileInputFormat.java#L417]
> This ends up in exponential file split objects being creating, causing driver
> to run out of memory.
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