Details
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Bug
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Status: Resolved
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Blocker
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Resolution: Not A Bug
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Impala 2.1
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None
Description
Changing a column's type by ALTER TABLE CHANGE ... leads to column stats for that column failing to persist.
Therefore every COMPUTE INCREMENTAL STATS after that turn into a full scan, because Impala believes the column doesn't have stats and needs to rescan the table, not to mention the fact that the statistics on that column are permanently wrong.