| Summary: | MDC is not working with AsyncAppender | ||
|---|---|---|---|
| Product: | Log4j - Now in Jira | Reporter: | Heikki Linnakangas <heikki.linnakangas> |
| Component: | Other | Assignee: | log4j-dev <log4j-dev> |
| Status: | RESOLVED FIXED | ||
| Severity: | normal | ||
| Priority: | P3 | ||
| Version: | unspecified | ||
| Target Milestone: | --- | ||
| Hardware: | All | ||
| OS: | All | ||
Hello Heikki, Thank you for the clear bug report. Your fix has been incorporated and will ship with log4j 1.2 final. |
MDC seems to work inproperly with AsyncAppender. I have a custom appender that reads some entries from the MDC, and writes them to a database. If I use it with the AsyncAppender, the MDC information is sometimes wrong. The problems seems to be that LoggingEvent.getMDCCopy() doesn't actully create a copy of the hashtable, but just gets a reference to it. If you apply the patch below... diff -b -Naur orig/org/apache/log4j/spi/LoggingEvent.java patched/org/apache/log 4j/spi/LoggingEvent.java --- orig/org/apache/log4j/spi/LoggingEvent.java Mon Jan 21 10:08:10 2002 +++ patched/org/apache/log4j/spi/LoggingEvent.java Mon Jan 21 10:07:44 2002 @@ -200,7 +200,7 @@ void getMDCCopy() { if(mdcLookupRequired) { ndcLookupRequired = false; - mdcCopy = MDC.getContext(); + mdcCopy = (Hashtable)MDC.getContext().clone(); } } ... it starts working. However, there will still be problems, if you put mutable objects in the MDC, since Hashtable.clone makes shallow clones.