kgyrtkirk commented on a change in pull request #831: HIVE-22238 pkfk URL: https://github.com/apache/hive/pull/831#discussion_r342535997
########## File path: ql/src/java/org/apache/hadoop/hive/ql/stats/StatsUtils.java ########## @@ -1961,6 +1961,7 @@ public static void updateStats(Statistics stats, long newNumRows, newDV = (long) Math.ceil(ratio * oldDV); } cs.setCountDistint(newDV); + cs.setFilterColumn(); Review comment: I'm not sure - I don't think so...actually because we may end up filtering rows in a join as well - I think it's more accurate to fave this. I was trying to come up with some query which might be relevant...but they doesn't really made sense...query requirements: * we need to have a join condition on the FK - where we would not set it as a filterColumn * we need to have a 2. join condition on the same FK I think queries like the following make not much sense; and the filter on FK could be movedf to the PK side which has lesser number of rows anyway...so its kinda useless... ``` select 1 from torpedos t, ships s, something ???, where true -- join#1 condition(x-fk) ; it is required to use t.ship_id and t.ship_id = ??? -- the pk-fk condition and t.ship_id = s.id ``` ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: gitbox-unsubscr...@hive.apache.org For additional commands, e-mail: gitbox-h...@hive.apache.org