https://community.cloudera.com/t5/Support-Questions/Impala-3-2-0-performance-degradation-while-querying-views/m-p/301613#M220777 <P>Hi,</P><P>&nbsp;</P><P>I used Impala 2.11 before (CDH 5.14) and I noticed that query runtime used to be roughly the same when we query a table or when we query a view of that table (the view statement is a select of all columns in the table). My tables (and the respective views) have around 400 columns.</P><P>&nbsp;</P><P>However, since I moved to Impala 3.2.0 (CDH 6.3.1), I noticed a degradation while querying views of up to 6 times increase in runtime. When I created a test view that contained only the columns used in my query, I noticed that runtime becomes closer from selecting the actual table.</P><P>&nbsp;</P><P>This seems to be a regressed issue, because this was not present on previous Impala versions, as far as I know. Could you please explain what changed on Impala's behavior on 3.2.0, which started to cause this discrepancy?</P><P>&nbsp;</P><P>Since Impala 3.2.0 is the last version released in CDH, I would like to know if this problem was already tracked and handle in some Impala version after that.</P><P>&nbsp;</P><P>Thanks!</P> Tue, 18 Aug 2020 14:43:13 GMT PauloRC 2020-08-18T14:43:13Z