hive (default)> load data local inpath '/opt/module/data/smalltable' into table smalltable; 1.2基本语法 EXPLAIN [EXTENDED | DEPENDENCY | AUTHORIZATION] query-sql 1.3案例实操 1 )查看下面这条语句的执行计划 hive (default)> explain select * from bigtable; hive (default)> explain select click_url...
hive (default)> explain select * from bigtable;hive (default)> explain select click_url, count(*) ct from bigtable groupby click_url; 2 )查看详细执行计划 hive (default)> explain extended select * from bigtable;hive (default)> explain extended select click_url, count(*) ct frombigtable ...
hive (default)> load data local inpath '/opt/module/data/smalltable' into table smalltable; 1.2基本语法 EXPLAIN [EXTENDED | DEPENDENCY | AUTHORIZATION] query-sql 1.3案例实操 1 )查看下面这条语句的执行计划 hive (default)> explain select * from bigtable; hive (default)> explain select click_url...
一个Hive 查询被转换为一个有向无环图DAG,包含一个或多个stage(阶段),不同stage之间会存在依赖关系。越复杂的查询通常会引入更多的stage,通常stage越多则需要越多时间来完成任务。 默认hive一次执行一个stage,一个stage可以是一个mapreduce任务,也可以是一个抽样阶段,或者是一个合并阶段,还可以是一个limit阶段。
Hive SQL在执行之前会将SQL转换为MapReduce任务,因此需要了解具体的转换过程。可以通过explain关键字来查看具体的执行计划。通过执行计划能看到 SQL 程序转换成相应计算引擎的执行逻辑,从而能够实现更有针对性的优化(比如有些看似等价的SQL写法实则不等价)。
读取一张parquet存储的hive表,对某列进行排序orderBy,排序结果根据filter,最终选择一列为想要的DataFrame。 scala> val df = spark.sql("select * from feature_data_xyf").orderBy($"formatted_ent_name".desc).filter($"is_listed" === 1).select($"label") ...
Amount of input data processed by the workers for this stage might be skewed Output layout: [custkey, name] Output partitioning: HASH [custkey] ScanFilterProject[table = hive:tpch_sf10_snappy_parquet:customer, filterPredicate = (nationkey = bigint '0')] ...
Above: Hive's app lets you control your heating using your phone, wherever in the world you find yourself. Below: Efergy's energy monitoring app keeps tabs on your home energy consumption. You don't have to look too far to see the Internet of Things in action. Libraries were early ...
And I know that there's a canonical or answer to that, but in the writing process I'm thinking, "Well, Adam and I had this discussion where I think it's great to be a Mind Flayer because you're part of a hive mind." AS:Chrystal instantly wants to be a squid. ...
HiveSQL MySQL HiveSQL 用explain打开的执行计划包含以下几个部分: 作业的依赖关系图,即STAG DEPENDENCIES 每个作业的详细信息,即STAG PLAINS eg: 查看简单SQL的执行计划 -- 默认使用的Spark计算引擎EXPLAINSELECTgame_code,count(1)numfromdwd.dim_app_game_dictwhereapp_id>10000andapp_namelike"%同城%"GROUPBYgame...