mapreduce - Hive map-reduce 查询失败

Question

我正在尝试运行我的第一个 Hive 查询，它可以启动 map-reduce 作业。我已按照“ http://doc.mapr.com/display/MapR/Hive ”中给出的所有步骤进行操作。

“web_log”表已被创建并且数据加载完成且没有错误。但是当尝试执行“SELECT web_log。FROM web_log WHERE web_log.url LIKE '%doc'*”时，我遇到了以下异常。

Number of reduce tasks is set to 0 since there's no reduce operator Starting Job = job_1429420954627_0002, 
Tracking URL = http://yarn-training:8088/proxy/application_1429420954627_0002/ 
Kill Command = /opt/mapr/bin/hadoop job -kill job_1429420954627_0002 Hadoop job information for Stage-1: number of mappers: 0; number of reducers: 0 2015-04-19 00:19:15,690 Stage-1 map = 0%, reduce = 0% Ended Job = job_1429420954627_0002 with errors Error during job, obtaining debugging information... FAILED: 
Hi

有人可以指导我吗？

Answer 1

您的减速器数量 = 0，因为您的工作是仅地图工作。现在这是您的查询吗？我认为您的 select 语句缺少某些内容。

SELECT web_log.* FROM web_log WHERE web_log.url LIKE '%doc';