Hi! We just started using SolrSlf4jReporter to get hold of metrics. In Solr 8.5.2 there is a issue, when the number of cores is larger than 3 (default value of coreLoadThreads) the logged metrics for some cores are missing all MDC variables for the core.
There has been some changes concerning MDCLoggingContext by David Smiley in «SOLR-14351 Harden MDCLoggingContext.clear depth tracking», I haven't managed to check if this fixes it. What happens in 8.5.2 is that MDCLoggingContext.clear() is called at the end of CoreContainer.createFromDescriptor(...), clear decrements CALL_DEPTH, resulting in CALL_DEPTH having a value larger than 0 when the next Core is created. Maybe MDCLoggingContext.reset() should be used instead of MDCLoggingContext.clear() for a 8.5.x fix? The workaround to set a larger value of coreLoadThreads does work. -- Kind regards, Marvin B. Lillehaug
