Parquet holds min/max statistics in several levels, and it will compare the value V to the those min/max headers, and only scan blocks wheremin/max contains the valueV. This is for predicate push down. Spark Interview Question | Partition Pruning | Predicate Pushdown 36 related questions found...
根据我的阅读,spark predict push down将用于源端(简化数据扫描)。电子病历5.32.xspark版本-2.4.5配置单元版本-2.x数据量超过2 TB。我有另一个功能团队创建的配置单元/Spark表。他们还在这个表的顶部创建了视图。源表和视图之间的唯一区别是创建日期列数据类型基表->创建日期->日期查看->创建日期->时间戳问题: ...
You will find that this kind of filter is called post scan filters in the code source. They will apply after reading a row and converting it into Apache Spark's Row format. The second method returns all push down filters, so the ones executed while reading the record fro...
spark sql谓词下推逻辑优化器PushDownPredicates包含了三个规则: PushPredicateThroughNonJoin是sparksql中非join情况的谓词下推的逻辑执行计划优化器 谓词可以下推的前提:不影响查询结果,即要保证下推前和下推后两个sql执行得到的效果相同 PushPredicateThroughNonJoin优化器处理了6类可以下推的情况 处理Filter节点下为Proj...
In the meantime, i wanted to push the updates i have so far. Please go through when you have some time. Thanks a lot. Copy link SparkQA commented Mar 1, 2017 Test build #73646 has finished for PR 16954 at commit 886a744. This patch passes all tests. This patch merges cleanly....
該謂詞由Spark計算層進行過濾,Spark計算層擷取name like 'table%'的資料,val_long1 > 1由業務代碼進行過濾。 全為AND push.down.range.long=true push.down.range.string=false select * from table where val_string1 > 'string1' and name like 'table%'; 與String類型做大小比較的謂詞都不會下推。 該...
谓词下推配置的参数需要在创建Spark外表时配置。谓词下推规则如下: 当过滤条件中的逻辑谓词只存在AND和NOT时,可以自定义谓词是否下推。 当过滤条件中的逻辑谓词存在OR时,谓词全部下推,自定义的谓词下推配置(例如E-MapReduce SQL方式的参数配置push.down.range.long=false和push.down.range.string=false)不会生效。