Github user sachouche commented on a diff in the pull request:
https://github.com/apache/drill/pull/1001#discussion_r146708658
--- Diff:
exec/java-exec/src/main/java/org/apache/drill/exec/expr/fn/impl/SqlPatternContainsMatcher.java
---
@@ -17,37 +17,166 @@
*/
package org.apache.drill.exec.expr.fn.impl;
-public class SqlPatternContainsMatcher implements SqlPatternMatcher {
+public final class SqlPatternContainsMatcher implements SqlPatternMatcher {
final String patternString;
CharSequence charSequenceWrapper;
final int patternLength;
+ final MatcherFcn matcherFcn;
public SqlPatternContainsMatcher(String patternString, CharSequence
charSequenceWrapper) {
- this.patternString = patternString;
+ this.patternString = patternString;
this.charSequenceWrapper = charSequenceWrapper;
- patternLength = patternString.length();
+ patternLength = patternString.length();
+
+ // The idea is to write loops with simple condition checks to allow
the Java Hotspot achieve
+ // better optimizations (especially vectorization)
+ if (patternLength == 1) {
+ matcherFcn = new Matcher1();
--- End diff --
Padma, I have two reasons to follow the added complexity
1) The new code is encapsulated within the Contains matching logic; doesn't
increase code complexity
2)
o I created a test with the original match logic, pattern and input were
Strings though passed as CharSequence
o Ran the test with the new and old method (1 billion iterations) on MacOS
o pattern length
o The old match method performed in 43sec where as the new one performed in
15sec
o The reason for the speedup is the custom matcher functions have less
instructions (load and comparison)
---
