drill-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From paul-rogers <...@git.apache.org>
Subject [GitHub] drill pull request #907: DRILL-5697: Improve performance of filter operator ...
Date Fri, 18 Aug 2017 19:17:53 GMT
Github user paul-rogers commented on a diff in the pull request:

    https://github.com/apache/drill/pull/907#discussion_r134034748
  
    --- Diff: exec/java-exec/src/main/java/org/apache/drill/exec/expr/fn/impl/RegexpUtil.java
---
    @@ -96,20 +145,46 @@ public static String sqlToRegexLike(
                 || (nextChar == '%')
                 || (nextChar == escapeChar)) {
               javaPattern.append(nextChar);
    +          simplePattern.append(nextChar);
               i++;
             } else {
               throw invalidEscapeSequence(sqlPattern, i);
             }
           } else if (c == '_') {
    +        // if we find _, it is not simple pattern, we are looking for only %
    +        notSimple = true;
             javaPattern.append('.');
           } else if (c == '%') {
    +        if (i == 0) {
    +          // % at the start could potentially be one of the simple cases i.e. ENDS_WITH.
    +          endsWith = true;
    +        } else if (i == (len-1)) {
    --- End diff --
    
    A bit of a funky way to do this. Might was well actually wait to the end. This is why
we need states (as an enum or via recursive descent.) At end:
    
    If all constants: CONST
    If one wildcard: one of the simple cases
    Otherwise: COMPLEX


---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at infrastructure@apache.org or file a JIRA ticket
with INFRA.
---

Mime
View raw message