[HADOOP-12428] Fix inconsistency between log-level guards and statements

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 2.8.0, 3.0.0-alpha1
• Labels: BB2015-05-TBR
• Target Version/s: 2.8.0
• Hadoop Flags: Reviewed
• Assignee: Jagadesh Kiran N
• Reporter: Jackie Chang
• Created: 26/Sep/13 03:36
• Updated: 30/Aug/16 01:23
• Resolved: 22/Sep/15 03:57

Description

Developers use logs to do in-house debugging. These log statements are later demoted to less severe levels and usually are guarded by their matching severity levels. However, we do see inconsistencies in trunk. A log statement like

       if (LOG.isDebugEnabled()) {
        LOG.info("Assigned container (" + allocated + ") "

doesn't make much sense because the log message is actually only printed out in DEBUG-level. We do see previous issues tried to correct this inconsistency. I am proposing a comprehensive correction over trunk.

Doug Cutting pointed it out in HADOOP-312: https://issues.apache.org/jira/browse/HADOOP-312?focusedCommentId=12429498&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-12429498
HDFS-1611 also corrected this inconsistency.
This could have been avoided by switching from log4j to slf4j's {} format like CASSANDRA-625 (2010/3) and ZOOKEEPER-850 (2012/1), which gives cleaner code and slightly higher performance.

Issue Links

• is related to: HDFS-1611 Some logical issues need to address.