[ https://issues.apache.org/jira/browse/IMPALA-6590?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Wenzhe Zhou reassigned IMPALA-6590: ----------------------------------- Assignee: Wenzhe Zhou (was: Abhishek Rawat) > Disable expr rewrites and codegen for VALUES() statements > --------------------------------------------------------- > > Key: IMPALA-6590 > URL: https://issues.apache.org/jira/browse/IMPALA-6590 > Project: IMPALA > Issue Type: Bug > Components: Frontend > Affects Versions: Impala 2.8.0, Impala 2.9.0, Impala 2.10.0, Impala 2.11.0 > Reporter: Alexander Behm > Assignee: Wenzhe Zhou > Priority: Major > Labels: perf, planner, ramp-up, regression > > The analysis of statements with big VALUES clauses like INSERT INTO <tbl> > VALUES is slow due to expression rewrites like constant folding. The > performance of such statements has regressed since the introduction of expr > rewrites and constant folding in IMPALA-1788. > We should skip expr rewrites for VALUES altogether since it mostly provides > no benefit but can have a large overhead due to evaluation of expressions in > the backend (constant folding). These expressions are ultimately evaluated > and materialized in the backend anyway, so there's no point in folding them > during analysis. > Similarly, there is no point in doing codegen for these exprs in the backend > union node. > *Workaround* > {code} > SET ENABLE_EXPR_REWRITES=FALSE; > SET DISABLE_CODEGEN=TRUE; > {code} -- This message was sent by Atlassian Jira (v8.20.1#820001) --------------------------------------------------------------------- To unsubscribe, e-mail: issues-all-unsubscr...@impala.apache.org For additional commands, e-mail: issues-all-h...@impala.apache.org