[jira] [Created] (SPARK-22073) Add workaround for HIVE-15653 to avoid stats being accidentally wiped

["Alexander Behm (JIRA)" <ji...@apache.org>]

Alexander Behm created SPARK-22073:
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             Summary: Add workaround for HIVE-15653 to avoid stats being accidentally wiped
                 Key: SPARK-22073
                 URL: https://issues.apache.org/jira/browse/SPARK-22073
             Project: Spark
          Issue Type: Bug
          Components: SQL
    Affects Versions: 2.2.0
            Reporter: Alexander Behm


The alterTable() RPC to the Hive Metastore has the subtle and undesirable side-effect of sometimes wiping/recreating useful stats like 'numRows' and 'totalSize'.

Further, the alterTable() causes extra "hidden" load on the NameNode/S3/whatever to list all the files and get the 'totalSize' and 'numFiles'.

This behavior can lead to confusion, e.g., if a SparkSQL query suddenly becomes slow due to a bad plan because somebody ran an unrelated ALTER TABLE from Hive/SparkSQL which wiped the stats (not fun to do the RCA).

One way to avoid this problem is to always add a special table property DO_NOT_UPDATE_STATS to the altered table before doing the alterTable() RPC to the Metastore.

See HIVE-15653 for more details.




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