Before you begin reading this guide, we recommend you run Elasticsearch Error Check-Up which analyzes 2 JSON files to detect many errors.
To easily locate the root cause and resolve this issue try AutoOps for Elasticsearch & OpenSearch. It diagnoses problems by analyzing hundreds of metrics collected by a lightweight agent and offers guidance for resolving them.
This guide will help you check for common problems that cause the log ” Last_gc duration . collections . total . reclaimed . leaving ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: monitor.
Log Context
Log “[last_gc][{}][{}][{}] duration [{}]; collections [{}]; total [{}]/[{}]; reclaimed [{}]; leaving [{}][{}]/[{}]” classname is JvmMonitorService.java.
We extracted the following from Elasticsearch source code for those seeking an in-depth context :
// Ignore any duration > 1hr; getLastGcInfo occasionally returns total crap
if (lastGc.duration().hoursFrac() > 1) {
continue;
}
if (lastGc.duration().millis() > gcThreshold.warnThreshold) {
logger.warn("[last_gc][{}][{}][{}] duration [{}]; collections [{}]; total [{}]/[{}]; reclaimed [{}]; leaving [{}][{}]/[{}]";
gc.name(); seq; gc.getCollectionCount(); lastGc.duration(); collections; TimeValue.timeValueMillis(collectionTime); gc.collectionTime(); lastGc.reclaimed(); lastGc.afterUsed(); lastGc.max());
} else if (lastGc.duration().millis() > gcThreshold.infoThreshold) {
logger.info("[last_gc][{}][{}][{}] duration [{}]; collections [{}]; total [{}]/[{}]; reclaimed [{}]; leaving [{}]/[{}]";
gc.name(); seq; gc.getCollectionCount(); lastGc.duration(); collections; TimeValue.timeValueMillis(collectionTime); gc.collectionTime(); lastGc.reclaimed(); lastGc.afterUsed(); lastGc.max());
} else if (lastGc.duration().millis() > gcThreshold.debugThreshold && logger.isDebugEnabled()) {
