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Date: Tue, 25 Jul 2017 22:26:00 +0000 (UTC)
From: "ASF subversion and git services (JIRA)" <jira@apache.org>
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Message-ID: <JIRA.13081299.1498012817000.12556.1501021560220@Atlassian.JIRA>
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Subject: [jira] [Commented] (HTTPCLIENT-1858) Alleviate GC pressure due to
 wire logging
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archived-at: Tue, 25 Jul 2017 22:26:05 -0000


    [ https://issues.apache.org/jira/browse/HTTPCLIENT-1858?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16100874#comment-16100874 ] 

ASF subversion and git services commented on HTTPCLIENT-1858:
-------------------------------------------------------------

Commit 888cefb7cd39cff379321096e1c2519d6adbe93c in httpcomponents-client's branch refs/heads/master from [~garydgregory]
[ https://git-wip-us.apache.org/repos/asf?p=httpcomponents-client.git;h=888cefb ]

[HTTPCLIENT-1858] Clone some code from Log4j 2 to cache a StringBuilder
in a ThreadLocal. Update to use the StringBuilder's capacity instead of
its length to measure upper bound.

> Alleviate GC pressure due to wire logging
> -----------------------------------------
>
>                 Key: HTTPCLIENT-1858
>                 URL: https://issues.apache.org/jira/browse/HTTPCLIENT-1858
>             Project: HttpComponents HttpClient
>          Issue Type: Bug
>          Components: HttpClient (classic)
>    Affects Versions: 4.5.2
>            Reporter: Arya Ketan
>            Priority: Minor
>              Labels: performance
>             Fix For: 5.0 Alpha3
>
>         Attachments: Screen Shot 2017-06-21 at 1.11.46 pm.png
>
>
> While running performance tests, I am seeing very high GC pressure due to the following code
> in Wire.java 
> {code:java}
> private void wire(final String header, final InputStream instream)
>       throws IOException {
>         final StringBuilder buffer = new StringBuilder();
>         int ch;
>         while ((ch = instream.read()) != -1) {
>             if (ch == 13) {
>                 buffer.append("[\\r]");
>             } else if (ch == 10) {
>                     buffer.append("[\\n]\"");
>                     buffer.insert(0, "\"");
>                     buffer.insert(0, header);
>                     log.debug(id + " " + buffer.toString());
>                     buffer.setLength(0);
>             } else if ((ch < 32) || (ch > 127)) {
>                 buffer.append("[0x");
>                 buffer.append(Integer.toHexString(ch));
>                 buffer.append("]");
>             } else {
>                 buffer.append((char) ch);
>             }
>         }
>         if (buffer.length() > 0) {
>             buffer.append('\"');
>             buffer.insert(0, '\"');
>             buffer.insert(0, header);
>             log.debug(id + " " + buffer.toString());
>         }
>     }
> {code}
> This is because, we are trying to expand Stringbuffer continously , thus leading to lot of char[] garbage. 
> 2 suggestions for improvements
> a) we look into whether logging level is enabled and only then construct the message
> b) efficiently construct log message.


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