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Date: Thu, 5 Jan 2017 22:32:58 +0000 (UTC)
From: "Sahil Takiar (JIRA)" <jira@apache.org>
To: dev@hive.apache.org
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Subject: [jira] [Created] (HIVE-15546) Optimize Utilities.getInputPaths()
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archived-at: Thu, 05 Jan 2017 22:33:00 -0000

Sahil Takiar created HIVE-15546:
-----------------------------------

             Summary: Optimize Utilities.getInputPaths()
                 Key: HIVE-15546
                 URL: https://issues.apache.org/jira/browse/HIVE-15546
             Project: Hive
          Issue Type: Sub-task
          Components: Hive
            Reporter: Sahil Takiar
            Assignee: Sahil Takiar


When running on blobstores (like S3) where metadata operations (like listStatus) are costly, Utilities.getInputPaths() can add significant overhead when setting up the input paths for an MR / Spark / Tez job.

The method performs a listStatus on all input paths in order to check if the path is empty. If the path is empty, a dummy file is created for the given partition. This is all done sequentially. This can be really slow when there are a lot of empty partitions. Even when all partitions have input data, this can take a long time.

We should either:

(1) Just remove the logic to check if each input path is empty, and handle any edge cases accordingly.

(2) Multi-thread the listStatus calls


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