[SOLR-4833] All(most all) Logger instances should be made static

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Duplicate
• Assignee: Unassigned
• Reporter: Chris M. Hostetter
• Created: 16/May/13 17:21
• Updated: 16/Nov/20 21:44
• Resolved: 09/May/17 20:48

Description

The majority of Logger usage in Solr is via static variables, but there are a few places where this pattern does not hold true - i think we should fix that and be completley consistent. if there is any specific cases where a non-static variable really makes a lot of sense, then it should be heavily commented as to why.

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The SLF4J FAQ has a list of pros and cons for why Logger variables should/shouldn't be static...

http://slf4j.org/faq.html#declared_static

...the majority of the "pros" for non-static usage don't really apply to Solr, while the pros for static usage due.

Another lucene/solr specific pro in favor of static variables for loggers is the way our test framework looks for memory leaks in tests. Having a simple test that does not null out a static reference to what seems like a small object is typically fine – but if that small object has an explicit (non-static) reference to a Logger, all of the state in that Logger is counted as part of the size of that small object leading to confusion.

Issue Links

• duplicates: SOLR-8330 Restrict logger visibility throughout the codebase to private so that only the file that declares it can use it
• is related to: SOLR-15005 RequestHandlerBase's logger name should point to the implementation class
• relates to: SOLR-4825 Port SolrLogFormatter to log4j