https://community.cloudera.com/t5/Support-Questions/hive-count-not-working/m-p/216895#M178804 <P><A rel="user" href="https://community.cloudera.com/users/10115/sahmad43.html" nodeid="10115">@Sami Ahmad</A> </P><P>It works after I set this in hive-site.xml</P><P>I am not sure the reason, but it was forced to run mapreduce</P><PRE>hive.compute.query.using.stats=false</PRE><P>I also found something in hive metastore (mine is MySQL).</P><PRE>mysql&gt; SELECT PARAM_VALUE FROM PARTITION_PARAMS AS A, PARTITIONS AS B WHERE A.PARAM_KEY='numRows' and A.PART_ID=B.PART_ID and A.PARAM_VALUE = 0 limit 10; </PRE><P>It seems if PARAM_VALUE is not -1, hive will return this value without running mapreduce.</P><P>If PARAM_VALUE equals to -1, mapreduce will be executed.</P> Wed, 08 Nov 2017 22:02:35 GMT sula678 2017-11-08T22:02:35Z