private StringMetaDataBo selectStringMetaData(String agentId, int cacheId, long agentStartTime) {
        final List<StringMetaDataBo> metaDataList = stringMetaDataDao.getStringMetaData(agentId, agentStartTime, cacheId);
        if (CollectionUtils.isEmpty(metaDataList)) {
            logger.warn("StringMetaData not Found agent:{}, cacheId{}, agentStartTime:{}", agentId, cacheId, agentStartTime);
            return new StringMetaDataBo(agentId, agentStartTime, cacheId, "STRING-META-DATA-NOT-FOUND");
        }
        if (metaDataList.size() == 1) {
            return metaDataList.get(0);
        } else {
            logger.warn("stringMetaData size not 1 :{}", metaDataList);
            return metaDataList.get(0);
        }
    }
@author emeroad
@author jaehong.kim
@author minwoo.jung
web/src/main/java/com/navercorp/pinpoint/web/service/SpanServiceImpl.java