How does Hive choose a bucketing?

What are the factors to be considered while deciding the number of buckets? One factor could be the block size itself as each bucket is a separate file in HDFS. The file size should be at least the same as the block size. The other factor could be the volume of data.

How do you bucket in Hive?

bucketing = true, so that Hive knows to create the number of buckets declared in the table definition to populate the bucketed table.

1. set hive. enforce. bucketing = true;
2. INSERT OVERWRITE TABLE bucketed_user PARTITION (country)
3. set hive. enforce. bucketing = true;
4. INSERT OVERWRITE TABLE bucketed_user PARTITION (country)

Why bucketing is faster than partitioning?

If you go for bucketing, you are restricting number of buckets to store the data. This number is defined during table creation scripts. Due to equal volumes of data in each partition, joins at Map side will be quicker.

Can we do bucketing on string column?

1 Answer. Yes you need to cluster your data based on country. and you need to define the number of buckets based on the total number of countries.

Can we do bucketing without partitioning in spark?

Bucketing is a technique in both Spark and Hive used to optimize the performance of the task. In bucketing buckets (clustering columns) determine data partitioning and prevent data shuffle. Although not mandatory, using a partitioned table to do the bucketing will give the best results.

Can bucketing be done without partitioning in Hive?

Bucketing can also be done even without partitioning on Hive tables. Bucketed tables allow much more efficient sampling than the non-bucketed tables.

How is bucketing helpful?

Bucketing in hive is useful when dealing with large datasets that may need to be segregated into clusters for more efficient management and to be able to perform join queries with other large datasets. The primary use case is in joining two large datasets involving resource constraints like memory limits.

Can we do bucketing on partition column?

Bucketing can be created on just one column, you can also create bucketing on a partitioned table to further split the data which further improves the query performance of the partitioned table.

What is the difference between partitioning and bucketing in Hive?

Hive partitioning is a technique to organize hive tables in an efficient manner. Based on partition keys it divides tables into different parts. Bucketing is a technique where the tables or partitions are further sub-categorized into buckets for better structure of data and efficient querying.

Can we have bucketing without partitioning in Hive?

How does bucketing help in the faster execution of queries?

It provides faster query response like portioning. In bucketing due to equal volumes of data in each partition, joins at Map side will be quicker.