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https://issues.apache.org/jira/browse/DRILL-5697?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16133513#comment-16133513
]
ASF GitHub Bot commented on DRILL-5697:
---------------------------------------
Github user paul-rogers commented on a diff in the pull request:
https://github.com/apache/drill/pull/907#discussion_r134035511
--- Diff:
exec/java-exec/src/main/java/org/apache/drill/exec/expr/fn/impl/StringFunctions.java
---
@@ -57,22 +57,120 @@ private StringFunctions() {}
@Output BitHolder out;
@Workspace java.util.regex.Matcher matcher;
@Workspace org.apache.drill.exec.expr.fn.impl.CharSequenceWrapper
charSequenceWrapper;
+ @Workspace
org.apache.drill.exec.expr.fn.impl.RegexpUtil.sqlPatternInfo patternInfo;
@Override
public void setup() {
- matcher =
java.util.regex.Pattern.compile(org.apache.drill.exec.expr.fn.impl.RegexpUtil.sqlToRegexLike(
//
-
org.apache.drill.exec.expr.fn.impl.StringFunctionHelpers.toStringFromUTF8(pattern.start,
pattern.end, pattern.buffer))).matcher("");
+ patternInfo =
org.apache.drill.exec.expr.fn.impl.RegexpUtil.sqlToRegexLike(
+
org.apache.drill.exec.expr.fn.impl.StringFunctionHelpers.toStringFromUTF8(pattern.start,
pattern.end, pattern.buffer));
charSequenceWrapper = new
org.apache.drill.exec.expr.fn.impl.CharSequenceWrapper();
- matcher.reset(charSequenceWrapper);
+
+ // Use java regex and compile pattern only if it is not a simple
pattern.
+ if (patternInfo.getPatternType() ==
org.apache.drill.exec.expr.fn.impl.RegexpUtil.sqlPatternType.NOT_SIMPLE) {
+ java.lang.String javaPatternString =
patternInfo.getJavaPatternString();
+ matcher =
java.util.regex.Pattern.compile(javaPatternString).matcher("");
+ matcher.reset(charSequenceWrapper);
+ }
}
@Override
public void eval() {
charSequenceWrapper.setBuffer(input.start, input.end, input.buffer);
// Reusing same charSequenceWrapper, no need to pass it in.
// This saves one method call since reset(CharSequence) calls reset()
- matcher.reset();
- out.value = matcher.matches()? 1:0;
+
+ // Not a simple case. Just use Java regex.
+ if (patternInfo.getPatternType() ==
org.apache.drill.exec.expr.fn.impl.RegexpUtil.sqlPatternType.NOT_SIMPLE) {
+ matcher.reset();
+ out.value = matcher.matches() ? 1 : 0;
+ }
+
+ // This is a simple pattern that ends with a constant string i.e.
%ABC
+ // Compare the characters starting from end.
+ if (patternInfo.getPatternType() ==
org.apache.drill.exec.expr.fn.impl.RegexpUtil.sqlPatternType.ENDS_WITH) {
--- End diff --
Chains of ifs are rather old-school. Do a switch on the enum. And, do it in
the pattern class so it can be unit tested.
> Improve performance of filter operator for pattern matching
> -----------------------------------------------------------
>
> Key: DRILL-5697
> URL: https://issues.apache.org/jira/browse/DRILL-5697
> Project: Apache Drill
> Issue Type: Improvement
> Components: Execution - Flow
> Affects Versions: 1.11.0
> Reporter: Padma Penumarthy
> Assignee: Padma Penumarthy
>
> Queries using filter with sql like operator use Java regex library for
> pattern matching. However, for cases like %abc (ends with abc), abc% (starts
> with abc), %abc% (contains abc), it is observed that implementing these cases
> with simple code instead of using regex library provides good performance
> boost (4-6x). Idea is to use special case code for simple, common cases and
> fall back to Java regex library for complicated ones. That will provide good
> performance benefit for most common cases.
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