Dropping a partition: Adding columns. Syntax. ALTER TABLE some_table DROP IF EXISTS PARTITION(year = 2012); This command will remove the data and metadata for this partition. Table identifier parameter. Since every line in our data is a JSON object, we need to tell hive how to comprehend it as a set of fields. You can use ALTER TABLE with DROP PARTITION option to drop a partition for a table. Most ALTER TABLE operations do not actually rewrite, move, and so on the actual data files. Hive Alter Table - SQL ALTER TABLE statement is used to rename a table.The SQL ALTER TABLE statement is used to add, modify, or drop/delete columns in a table.It is used to alter a table in Hive. Drop or Delete Hive Partition. Note: You can also you all the clauses in one query in Hive. For partitions that are not compatible with Hive, use ALTER TABLE ADD PARTITION to load the partitions so that you can query their data. MSCK REPAIR is a resource-intensive query and using it to add single partition is not recommended especially when you huge number of partitions. SHOW PARTITIONS table_name [PARTITION(partition_spec)] [WHERE where_condition] [ORDER BY column_list] [LIMIT rows]; Conclusion. The ALTER TABLE statement changes the structure or properties of an existing Impala table.. If we have a large table then queries may take long time to execute on the whole table. Most ALTER TABLE operations do not actually rewrite, move, and so on the actual data files. In Hive, we can rename a column, change its type and position. A 'S' lock on table and relevant partition is acquired when a read is being performed. Type: Bug Status: Closed. In Impala, this is primarily a logical operation that updates the table metadata in the metastore database that Impala shares with Hive. ALTER TABLE lookup_table REPLACE COLUMNS (id string,name string); Note : The ALTER command will only modify Hive metadata and not the data. Hive; HIVE-1868; ALTER TABLE ADD PARTITION can't handle partition key names that conflict with HQL keywords. The data is well divided into daily chunks. hadoop,hive,partition. ALTER TABLE table_name ADD PARTITION (partCol = 'value1') location 'loc1'; ALTER TABLE table_name ADD PARTITION (partCol = 'value2') location 'loc2';... ALTER TABLE table_name ADD PARTITION (partCol = 'valueN') location 'locN'; Dynamic Partitions 动态分区. The ALTER TABLE statement changes the structure or properties of an existing Impala table.. Details. XML Word Printable JSON. In this article, you have learned Hive table partition is used to split a larger table into smaller tables by splitting based on one or multiple partitions columns also learned the following. You can then add dynamic partitions with something like: ALTER TABLE test ADD PARTITION (dt='2014-03-05') and you can insert data with: INSERT INTO TABLE test PARTITION(dt='2014-03-05') SELECT a,b,c,d from table You can add new column to the table. Export. So, we definitely want to keep year, month, day as the partitions in our external hive table. hive > ALTER TABLE student > ADD PARTITION (year=’2013’) > location '/2012/part2012'; How to Rename a Partition? Hive ALTER TABLE command is used to update or drop a partition from a Hive Metastore and HDFS location (managed table). Priority: Major . Add partitions to the table, optionally with a custom location for each partition added. First create a table in such a way so that you don't have partition column in the table. ALTER TABLE table_identifier ADD [IF NOT EXISTS] (partition_spec [partition_spec ... ALTER TABLE SET command is used for setting the SERDE or SERDE properties in Hive tables. This is overkill when we want to add an occasional one or two partitions to the table. Log In. Log In. Since this is Hive metadata operation, your data files wont be touched. 可以使用Hive INSERT语句(或Pig STORE语句)将分区动态添加到表中。 Solved: I am using hdp 2.4.2 (hive - 1.2.1.2.4). Below are the most common uses of the ALTER TABLE command: You can rename table and column of existing Hive tables. Hive> ALTER TABLE std_details ADD PARTITION (std_class=’1’); Once the above statement successfully executed, the partition added to std_db.std_details table. ALTER table mytable ADD PARTITION (testdate=’2015-03-05′) location ‘… Donate # HDFS # Hive. Description. Uses of Hive ALTER TABLE Command. Rename Hive table column. msck repair table salesdata_ext; show partitions salesdata_ext; O/p: date_of_sale=10-27-2017. Let's see the updated schema of the table. `Alter table recover partitions` is effectively an alias for `msck repair table`. The command I tried is given below. HIVE Partition – Managed Table Partitioning. Hive - Alter Table - This chapter explains how to alter the attributes of a table such as changing its table name, changing column names, adding columns, and deleting or replacing c For the partition to reflect in the table metadata, we will either have to repair the table or add partition by using the alter command that we are discussing later. Add Hadoop archive option to Hive table. Partition is helpful when the table has one or more Partition keys. The table identifier parameter in all statements has the following form: table_identifier [database_name.] Is there a way to alter the table Let's see the updated data of the table. When I tried using the following hive command it gives me error. Partitioning allows Hive to run queries on a specific set of data in the table based on the value of partition column used in the query. delta.``: The location of an existing Delta table. If the table is created with option PARTITIONED BY it will be partitioned. To achieve this, we are going to add … Hive … If this post helps you, please consider to buy a cup of coffee for me. Partition column is a virtual column that does not exist on the file as a column. Add PARTITION after creating TABLE in hive. You can add, modify existing columns in Hive tables. One option is to delete existing external table and create new table that includes new column. The following query is used to add a partition to the employee table. New partitions must be of the same type (LIST, RANGE or HASH) as existing partitions. Without partitioning, any query on the table in Hive will read the entire data in the table. However, beginning with Spark 2.1, Alter Table Partitions is also supported for tables defined using the datasource API. Please refer to both the create and alter commands below: Hive Partitions is a way to organizes tables into partitions by dividing tables into different parts based on partition keys. Type: Bug Status: Open. Partition keys are basic elements for determining how the data is stored in the table. ADD PARTITION. Here, we are changing the name of the column by using the following signature: - The primary difference in usability is that `alter table recover partitions` works from dbcli or directly ODAS through the REST API. This is supported only for tables created using the Hive format. The `msck repair table` command must be run from Hive. ALTER TABLE ADD COLUMNS statement adds mentioned ... ALTER TABLE SET command is used for setting the SERDE or SERDE properties in Hive tables. However if you had partitioned the existing table using “PARTITIONED BY” clause, then you will be allowed you add partition using the ALTER TABLE command. HIVE-9430; NullPointerException on ALTER TABLE ADD PARTITION if no value given. In Impala, this is primarily a logical operation that updates the table metadata in the metastore database that Impala shares with Hive. The ALTER TABLE… ADD PARTITION command adds a partition to an existing partitioned table. ALTER TABLE lookup_table ADD COLUMNS (comments string); Replace all columns other than the partition columns. Add or drop table partition. Make hive be able to read JSON. table_name: A table name, optionally qualified with a database name. Also the use of where limit order by clause in Partitions which is introduced from Hive 4.0.0. Partition locations to be used with Athena must use the s3 protocol (for example, s3://bucket/folder/). Similarly, multiple partitions for each class can be set by using ADD PARTITION. ... None. This feature indirectly fixes the issue we mentioned in this post. Syntax: ALTER TABLE table_name PARTITION partition_spec RENAME TO PARTITION partition_spec; The following query is used to rename a partition: Recently I tried to add a partition to a hive table with S3 as the storage. Hive Alter Table - Learn Hive in simple and easy steps from basic to advanced concepts with clear examples including Introduction, Architecture, Installation, Data Types, Create Database, Use Database, Alter Database, Drop Database, Tables, Create Table, Alter Table, Load Data to Table, Insert Table, Drop Table, Views, Indexes, Partitioning, Show, Describe, Built-In Operators, Built-In Functions OR alter table salesdata_ext add partition (date_of_sale=’10-27-2017’); As we didn't add any data to the new column, hive consider NULL as the value. Let us discuss the HIVE partition concept for the managed table first. Change Column. There is no upper limit to the number of defined partitions in a partitioned table. HIVE queries can take advantage of the partitioned data for better performance. Export. You can also manually update or drop a Hive partition directly on HDFS using Hadoop commands, if you do so you need to run the MSCK command to synch up HDFS files with Hive …