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https://issues.apache.org/jira/browse/DRILL-5899?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16243239#comment-16243239
]
ASF GitHub Bot commented on DRILL-5899:
---------------------------------------
Github user paul-rogers commented on a diff in the pull request:
https://github.com/apache/drill/pull/1015#discussion_r149555002
--- Diff:
exec/java-exec/src/main/java/org/apache/drill/exec/expr/fn/impl/SqlPatternEndsWithMatcher.java
---
@@ -17,33 +17,30 @@
*/
package org.apache.drill.exec.expr.fn.impl;
-public class SqlPatternEndsWithMatcher implements SqlPatternMatcher {
- final String patternString;
- CharSequence charSequenceWrapper;
- final int patternLength;
-
- public SqlPatternEndsWithMatcher(String patternString, CharSequence
charSequenceWrapper) {
- this.charSequenceWrapper = charSequenceWrapper;
- this.patternString = patternString;
- this.patternLength = patternString.length();
+import io.netty.buffer.DrillBuf;
+
+public class SqlPatternEndsWithMatcher extends AbstractSqlPatternMatcher {
+
+ public SqlPatternEndsWithMatcher(String patternString) {
+ super(patternString);
}
@Override
- public int match() {
- int txtIndex = charSequenceWrapper.length();
- int patternIndex = patternLength;
- boolean matchFound = true; // if pattern is empty string, we always
match.
+ public int match(int start, int end, DrillBuf drillBuf) {
+
+ if ( (end - start) < patternLength) { // No match if input string
length is less than pattern length.
+ return 0;
+ }
// simplePattern string has meta characters i.e % and _ and escape
characters removed.
// so, we can just directly compare.
- while (patternIndex > 0 && txtIndex > 0) {
- if (charSequenceWrapper.charAt(--txtIndex) !=
patternString.charAt(--patternIndex)) {
- matchFound = false;
- break;
+ for (int index = 1; index <= patternLength; index++) {
--- End diff --
```
int txtStart = end - patternLength;
if (txtStart < start) { return 0; }
for (int index = 0; index < patternLength; index++) {
... patternByteBuffer.get(index) ... drillBuf.getByte(txtStart + index)
...
```
> Simple pattern matchers can work with DrillBuf directly
> -------------------------------------------------------
>
> Key: DRILL-5899
> URL: https://issues.apache.org/jira/browse/DRILL-5899
> Project: Apache Drill
> Issue Type: Improvement
> Components: Execution - Flow
> Reporter: Padma Penumarthy
> Assignee: Padma Penumarthy
> Priority: Critical
>
> For the 4 simple patterns we have i.e. startsWith, endsWith, contains and
> constant,, we do not need the overhead of charSequenceWrapper. We can work
> with DrillBuf directly. This will save us from doing isAscii check and UTF8
> decoding for each row.
> UTF-8 encoding ensures that no UTF-8 character is a prefix of any other valid
> character. So, instead of decoding varChar from each row we are processing,
> encode the patternString once during setup and do raw byte comparison.
> Instead of bounds checking and reading one byte at a time, we get the whole
> buffer in one shot and use that for comparison.
> This improved overall performance for filter operator by around 20%.
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