[ https://issues.apache.org/jira/browse/SPARK-14393?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15562888#comment-15562888 ]
Kevin Ushey commented on SPARK-14393: ------------------------------------- Am I correct to understand that I should simply expect `monotonicallyIncreasingId()` to _not_ produce monotonically increasing ids, sometimes? If this is the case, then how can one expect to use this function safely? > monotonicallyIncreasingId not monotonically increasing with downstream > coalesce > ------------------------------------------------------------------------------- > > Key: SPARK-14393 > URL: https://issues.apache.org/jira/browse/SPARK-14393 > Project: Spark > Issue Type: Bug > Components: SQL > Affects Versions: 1.6.0 > Reporter: Jason Piper > > When utilising monotonicallyIncreasingId with a coalesce, it appears that > every partition uses the same offset (0) leading to non-monotonically > increasing IDs. > See examples below > {code} > >>> sqlContext.range(10).select(monotonicallyIncreasingId()).show() > +---------------------------+ > |monotonicallyincreasingid()| > +---------------------------+ > | 25769803776| > | 51539607552| > | 77309411328| > | 103079215104| > | 128849018880| > | 163208757248| > | 188978561024| > | 214748364800| > | 240518168576| > | 266287972352| > +---------------------------+ > >>> sqlContext.range(10).select(monotonicallyIncreasingId()).coalesce(1).show() > +---------------------------+ > |monotonicallyincreasingid()| > +---------------------------+ > | 0| > | 0| > | 0| > | 0| > | 0| > | 0| > | 0| > | 0| > | 0| > | 0| > +---------------------------+ > >>> sqlContext.range(10).repartition(5).select(monotonicallyIncreasingId()).coalesce(1).show() > +---------------------------+ > |monotonicallyincreasingid()| > +---------------------------+ > | 0| > | 1| > | 0| > | 0| > | 1| > | 2| > | 3| > | 0| > | 1| > | 2| > +---------------------------+ > {code} -- This message was sent by Atlassian JIRA (v6.3.4#6332) --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@spark.apache.org For additional commands, e-mail: issues-h...@spark.apache.org