[ https://issues.apache.org/jira/browse/IMPALA-7754?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Paul Rogers reassigned IMPALA-7754: ----------------------------------- Assignee: (was: Paul Rogers) > Expressions sometimes not re-analyzed after rewrite > --------------------------------------------------- > > Key: IMPALA-7754 > URL: https://issues.apache.org/jira/browse/IMPALA-7754 > Project: IMPALA > Issue Type: Bug > Components: Frontend > Affects Versions: Impala 3.0 > Reporter: Paul Rogers > Priority: Major > > The analyzer has a chain of rules which fire in order without (as noted > above) repeats. The result of rule A (rewriting conditional functions) is fed > into rule B (simplify CASE). Each rule requires that analysis be done so that > attributes of expressions can be picked out. > As it turns out, in the current code, this is rather ad-hoc. The > {{SimplifyConditionalsRule}} re-analyzes its result as part of the fix for > IMPALA-5125, but others do not, leading to optimizations not working. In > particular, in a chain of rewrites for {{IS DISTINCT FROM}}, certain rules > didn't fire because previous rules left new expressions in an un-analyzed > state. This is a bug. > The fix is to analyze the result any time a rule fires, before passing the > result to the next rule. > {code:java} > private Expr applyRuleBottomUp(Expr expr, ExprRewriteRule rule, Analyzer > analyzer) > throws AnalysisException { > ... > Expr rewrittenExpr = rule.apply(expr, analyzer); > if (rewrittenExpr != expr) { > ++numChanges_; > rewrittenExpr.analyze(analyzer); // Add me! > }} > return rewrittenExpr; > } > {code} > There are several places that the above logic appears: make the change in all > of them. > Then, in rules that simply refused to run if an expression is to analyzed: > {code:java} > public class SimplifyDistinctFromRule implements ExprRewriteRule { > public Expr apply(Expr expr, Analyzer analyzer) { > if (!expr.isAnalyzed()) return expr; > {code} > Replace this with an assertion that analysis must have been done: > {code:java} > public class SimplifyDistinctFromRule implements ExprRewriteRule { > public Expr apply(Expr expr, Analyzer analyzer) { > assert expr.isAnalyzed(); > {code} > To be safe, the assertion fires only in "debug" mode, not in production. -- This message was sent by Atlassian JIRA (v7.6.3#76005) --------------------------------------------------------------------- To unsubscribe, e-mail: issues-all-unsubscr...@impala.apache.org For additional commands, e-mail: issues-all-h...@impala.apache.org