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https://issues.apache.org/jira/browse/HDFS-8971?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14993829#comment-14993829
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Tsz Wo Nicholas Sze commented on HDFS-8971:
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Hi, I appreciate using the new log API in order to make the code shorter in
general but it may not be possible to remove the isDebugEnabled guards and
keeping the same debug message format at the same time.
It is hard to read the debug messages printed by ByteArrayManager after the
change here since some one-line messages are printed in multiple lines. It is
even worse when there are multiple threads. See the output of
TestByteArrayManager (or the attached log in HDFS-9383).
> Remove guards when calling LOG.debug() and LOG.trace() in client package
> ------------------------------------------------------------------------
>
> Key: HDFS-8971
> URL: https://issues.apache.org/jira/browse/HDFS-8971
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Components: build
> Reporter: Mingliang Liu
> Assignee: Mingliang Liu
> Fix For: 2.8.0
>
> Attachments: HDFS-8971.000.patch, HDFS-8971.001.patch
>
>
> We moved the {{shortcircuit}} package from {{hadoop-hdfs}} to
> {{hadoop-hdfs-client}} module in JIRA
> [HDFS-8934|https://issues.apache.org/jira/browse/HDFS-8934] and
> [HDFS-8951|https://issues.apache.org/jira/browse/HDFS-8951], and
> {{BlockReader}} in
> [HDFS-8925|https://issues.apache.org/jira/browse/HDFS-8925]. Meanwhile, we
> also replaced the _log4j_ log with _slf4j_ logger. There were existing code
> in the client package to guard the log when calling {{LOG.debug()}} and
> {{LOG.trace()}}, e.g. in {{ShortCircuitCache.java}}, we have code like this:
> {code:title=Trace with guards|borderStyle=solid}
> 724 if (LOG.isTraceEnabled()) {
> 725 LOG.trace(this + ": found waitable for " + key);
> 726 }
> {code}
> In _slf4j_, this kind of guard is not necessary. We should clean the code by
> removing the guard from the client package.
> {code:title=Trace without guards|borderStyle=solid}
> 724 LOG.trace("{}: found waitable for {}", this, key);
> {code}
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