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https://issues.apache.org/jira/browse/CHUKWA-584?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13006137#comment-13006137
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Ari Rabkin commented on CHUKWA-584:
-----------------------------------
I'm happy to commit a patch if you generate one. But this seems like a low
priority; I'm skeptical that those calls use enough CPU to matter.
> Multiple replace function call can be replaced with a single for loop to
> improve performance
> ---------------------------------------------------------------------------------------------
>
> Key: CHUKWA-584
> URL: https://issues.apache.org/jira/browse/CHUKWA-584
> Project: Chukwa
> Issue Type: Bug
> Components: data collection
> Affects Versions: 0.4.0
> Reporter: Xiaoming Shi
>
> {noformat}
> ./chukwa-0.4.0/src/java/org/apache/hadoop/chukwa/datacollection/writer/SeqFileWriter.java
> line: 179
> ./chukwa-0.4.0/src/java/org/apache/hadoop/chukwa/datacollection/writer/localfs/LocalWriter.java
> line:285
> {noformat}
> 3 consecutive replace() is called to remove the special characters. It's 3+
> times slower than using a for loop
> replace them all.
> {noformat}
> e.g.
> - str.replace('a', '#');
> - str.replace('b', '%');
> + StringBuilder sb = new StringBuilder( str.length() );
> + for (int i=0; i < str.length(); i++)
> + {
> + char c = str.charAt(i);
> + if ( c == 'a' )
> + sb.append('#');
> + else if ( c== 'b' )
> + sb.append('%');
> + else
> + sb.append(c);
> + }
> + str = sb.toString();
> {noformat}
> This bug has the same problem as the MySQL bug :
> http://bugs.mysql.com/bug.php?id=45699
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