amansinha100 commented on a change in pull request #1699: DRILL-7108: Improve selectivity estimates for (NOT)LIKE, NOT_EQUALS, IS NOT NULL predicates URL: https://github.com/apache/drill/pull/1699#discussion_r267156075
########## File path: exec/java-exec/src/main/java/org/apache/drill/exec/planner/cost/DrillRelMdSelectivity.java ########## @@ -56,6 +56,12 @@ private static final DrillRelMdSelectivity INSTANCE = new DrillRelMdSelectivity(); static final org.slf4j.Logger logger = org.slf4j.LoggerFactory.getLogger(DrillRelMdSelectivity.class); public static final RelMetadataProvider SOURCE = ReflectiveRelMetadataProvider.reflectiveSource(BuiltInMethod.SELECTIVITY.method, INSTANCE); + /* + * For now, we are treating all LIKE predicates to have the same selectivity irrespective of the number or position + * of wildcard characters (%). This is no different than the present Drill/Calcite behaviour w.r.t to LIKE predicates. Review comment: There is a difference from the current behavior of Drill/Calcite because the selectivity number has been reduced to 5%. ---------------------------------------------------------------- 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: [email protected] With regards, Apache Git Services
