Partitioning in Hive Hadoop Online Tutorials. In this post, we will discuss about one of the most critical and important concept in Hive, Partitioning in Hive Tables. Table partitioning means dividing table data into some parts based on the values of particular columns like date or country, segregate the input records into different filesdirectories based on date or country. Partitioning can be done based on more than column which will impose multi dimensional structure on directory storage. Petaa Bytes is a leading Center of Data Science Course in Mumbai, Big Data Hadoop Training in Mumbai. Data Science course is having basic to advanced level. For Example, In addition to partitioning log records by date column, we can also sup divide the single day records into country wise separate files by including country column into partitioning. We will see more about this in the examples. Partitions are defined at the time of table creation using the PARTITIONED BY clause, with a list of column definitions for partitioning. Syntax. CREATE EXTERNAL TABLE tablename colname1 datatype1,. PARTITIONED BY colnamen datatypen COMMENT colcomment,. CREATEEXTERNALTABLEtablenamecolname1datatype1. PARTITIONEDBYcolnamendatatypenCOMMENTcolcomment. As shown in syntax, we can also add comments to partitioned columns. Advantages. Partitioning is used for distributing execution load horizontally. As the data is stored as slicesparts, query response time is faster to process the small part of the data instead of looking for a search in the entire data set.
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