When set the DocValueContext for FetchPhase became very slow

[yunfeng_wu]

our plugins need read field value from docvalue, after query phase we set the DocValueFieldsContext contains the field we need. If field has no docvalue, we would retrieve this field value from stored_fields or _source. The whole query became very slowly, dump the proccess stack-trace we found thread stucked at sun.reflect.Reflection.getCallerClass as below depicted, can anyone explain this? Our plugins using thrift-RPC introduced slf4j-api-xxx.jar

java.lang.Thread.State: RUNNABLE
    at sun.reflect.Reflection.getCallerClass(Native Method)
    at java.lang.Class.getClassLoader(Class.java:683)
    at org.apache.logging.log4j.LogManager.getLogger(LogManager.java:551)
    at org.elasticsearch.common.logging.ESLoggerFactory.getLogger(ESLoggerFactory.java:49)
    at org.elasticsearch.common.logging.ESLoggerFactory.getLogger(ESLoggerFactory.java:57)
    at org.elasticsearch.common.logging.Loggers.getLogger(Loggers.java:101)
    at org.elasticsearch.index.fielddata.plain.DocValuesIndexFieldData.<init>(DocValuesIndexFieldData.java:55)
    at org.elasticsearch.index.fielddata.plain.SortedNumericDVIndexFieldData.<init>(SortedNumericDVIndexFieldData.java:58)
    at org.elasticsearch.index.fielddata.plain.DocValuesIndexFieldData$Builder.build(DocValuesIndexFieldData.java:99)
    at org.elasticsearch.index.fielddata.IndexFieldDataService.getForField(IndexFieldDataService.java:129)
    at org.elasticsearch.search.fetch.subphase.DocValueFieldsFetchSubPhase.hitExecute(DocValueFieldsFetchSubPhase.java:64)
    at org.elasticsearch.search.fetch.FetchPhase.execute(FetchPhase.java:162)
    at com.baidu.elasticsearch.scan.ScanService.executeFetchPhase(ScanService.java:313)
    at com.baidu.elasticsearch.scan.ScanService.getNext(ScanService.java:271)

Or

java.lang.Thread.State: RUNNABLE
    at sun.reflect.Reflection.getCallerClass(Native Method)
    at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.apache.logging.log4j.util.ReflectionUtil.getCallerClass(ReflectionUtil.java:129)
    at org.apache.logging.log4j.util.ReflectionUtil.getCallerClass(ReflectionUtil.java:212)
    at org.apache.logging.log4j.util.ReflectionUtil.getCallerClass(ReflectionUtil.java:203)
    at org.apache.logging.log4j.core.selector.ClassLoaderContextSelector.getContext(ClassLoaderContextSelector.java:72)
    at org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:227)
    at org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:45)
    at org.apache.logging.log4j.LogManager.getContext(LogManager.java:174)
    at org.apache.logging.log4j.LogManager.getLogger(LogManager.java:618)
    at org.elasticsearch.common.logging.DeprecationLogger.<init>(DeprecationLogger.java:117)
    at org.elasticsearch.common.xcontent.support.AbstractXContentParser.<init>(AbstractXContentParser.java:57)
    at org.elasticsearch.common.xcontent.json.JsonXContentParser.<init>(JsonXContentParser.java:44)
    at org.elasticsearch.common.xcontent.json.JsonXContent.createParser(JsonXContent.java:108)
    at org.elasticsearch.common.xcontent.XContentHelper.convertToMap(XContentHelper.java:140)
    at org.elasticsearch.common.xcontent.XContentHelper.convertToMap(XContentHelper.java:114)
    at org.elasticsearch.common.xcontent.XContentHelper.convertToMap(XContentHelper.java:92)
    at org.elasticsearch.search.lookup.SourceLookup.sourceAsMapAndType(SourceLookup.java:89)
    at org.elasticsearch.search.lookup.SourceLookup.sourceAsMap(SourceLookup.java:93)
    at org.elasticsearch.search.SearchHit.getSourceAsMap(SearchHit.java:344)