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Diffstat (limited to 'docs/programming-guide.md')
| -rw-r--r-- | docs/programming-guide.md | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/docs/programming-guide.md b/docs/programming-guide.md index d5ff416fe8..ae712d6274 100644 --- a/docs/programming-guide.md +++ b/docs/programming-guide.md @@ -1144,9 +1144,11 @@ generate these on the reduce side. When data does not fit in memory Spark will s to disk, incurring the additional overhead of disk I/O and increased garbage collection. Shuffle also generates a large number of intermediate files on disk. As of Spark 1.3, these files -are not cleaned up from Spark's temporary storage until Spark is stopped, which means that -long-running Spark jobs may consume available disk space. This is done so the shuffle doesn't need -to be re-computed if the lineage is re-computed. The temporary storage directory is specified by the +are preserved until the corresponding RDDs are no longer used and are garbage collected. +This is done so the shuffle files don't need to be re-created if the lineage is re-computed. +Garbage collection may happen only after a long period time, if the application retains references +to these RDDs or if GC does not kick in frequently. This means that long-running Spark jobs may +consume a large amount of disk space. The temporary storage directory is specified by the `spark.local.dir` configuration parameter when configuring the Spark context. Shuffle behavior can be tuned by adjusting a variety of configuration parameters. See the |