Hive alter table concatenate example Example Only through Hive can you access and change the data in managed tables. 创建临时表（创建临时表时需和原表的表结构一致）， create table test. For example I have a table with two partition columns, date and group. delim'); Alter Table Storage Properties ALTER TABLE table_name CLUSTERED BY (col_name, col_name, ) [SORTED BY (col_name, )] INTO num_buckets BUCKETS; These statements change the table’s physical storage properties. test_table_hive_merge like test. 1. 0+: CONCATENATE [ALTER TABLE table_name [PARTITION partition_spec] CONCATENATE](#alter-table-table_name-[partition-partition_spec]-concatenate) can be used to merge small ORC files into a larger file, starting in Hive 0. I get this error: source table default. Nov 24, 2020 · ALTER TABLE command can be used to perform alterations on the tables. -- --对于非分区表 alter table tablename concatenate; --对于分区表 Jul 20, 2018 · IMPORTANT - If your table schema has evolved (e. example_orc partition (dt="20180505") concatenate; 不足点： 使用concatenate命令合并小文件时不能指定合并后的文件数量，虽然可以多次执行该命令，但显然不够优雅。 一、concatenate方法 #对于非分区表 alter table tablename concatenate; #对于分区表 alter table tablename partition(dt=20201224) concatenate; 优点： 使用方便 缺点： concatenate 命令只支持 RCFILE 和 ORC 文件类型，需要执行多次，才能把文件合并为1个。 二、insert overwrite方法 Version 0. For example, " ALTER TABLE Oct 27, 2019 · 使用concatenate命令针对20180505分区进行小文件合并： alter table app. 2 insert overwrite(常用) Dec 31, 2022 · I want to concatenate multiple files into 1 file in a partition. Create/Drop/Alter Table CREATE TABLE Apr 11, 2017 · I want to use the ALTER TABLE CONCATENATE functionality in Hive, but it seems I have to give exact partition name. Mar 11, 2022 · 本文详细介绍了Hive中CONCATENATE命令用于合并小文件的过程，分别针对事务表和非事务表进行了测试。在事务表中，CONCATENATE会触发major compaction；而在非事务表中，它会启动一个Merge Job。 Dec 17, 2018 · ALTER INDEX REBUILD; CREATE TABLE AS SELECT; ALTER TABLE CONCATENATE; ALTER TABLE ARCHIVE/UNARCHIVE PARTITION; ANALYZE TABLE COMPUTE STATISTICS; IMPORT FROM EXPORT TABLE; For information about using WebHCat for DDL commands, see URL Format and WebHCat Reference: DDL Resources. For example, " ALTER TABLE Jan 10, 2024 · 小文件产生原因 hive 中的小文件肯定是向 hive 表中导入数据时产生，所以先看下向 hive 中导入数据的几种方式 直接向表中插入数据 insertintotableAvalues(1,'zhangsan',88),(2,'lisi',61); 这种方式每次插入时都会产生一个文件，多次插入少量数据就会出现多个小文件，但是这种方式生产环境很少使用，可以说基本 Aug 27, 2024 · 1. You can concatenate an external table. I'd like to be able to do something like this: alter table mytable partition (insert_date='2017-04-11',group='%') CONCATENATE; But i can't find the way of Nov 9, 2012 · Alter Table Alter Table Skewed ALTER TABLE <T> (SCHEMA) SKEWED BY (keys) ON ('c1', 'c2') [STORED AS DIRECTORIES]; The above is supported in table level only and not partition level. Similarly, alter table partition statements allow you change the properties of a specific partition in the named table. g. Jan 24, 2017 · ALTER TABLE <tableIdentifier> [partitionSpec] CONCATENATE is on that list, and has been from Spark 1, 2 to 3. 1 concatenate #对于非分区表 alter table tablename concatenate; #对于分区表 alter table tablename partition(dt=20201224) concatenate; 优点： 使用方便; 缺点： concatenate 命令只支持 RCFILE 和 ORC 文件类型，需要执行多次，才能把文件合并为1个。 1. CONCATENATE might silently drop those files. In Hive release 0. It will impact Oct 11, 2017 · In Hive release 0. 使用 hive 自带的 concatenate 命令，自动合并小文件. Create/Drop/Alter Table CREATE TABLE Aug 22, 2024 · In Hive release 0. convert a table from a non-skewed table to a skewed table, or else; alter a skewed table’s skewed column names and/or skewed values. 使用方法： #对于非分区表 alter table A concatenate; #对于分区表 alter table B partition(day=20201224) concatenate; 举例： Aug 23, 2022 · # Hive表字段修改操作## 介绍在Hive中，通过`ALTER TABLE`语句可以对表进行多种操作，包括修改表的列。当需要修改表的列时，可以使用`MODIFY COLUMN`来实现。本文将详细介绍如何使用`hive alter table modify column`来修改Hive表的列。 Sep 2, 2018 · alter table T1 concatenate: for example in case of dynamic partitions, the list of partitions being modified is not known at compile time -- so, the list is Mar 11, 2019 · Alter Table 语句它是在Hive中用来修改的表。语法声明接受任意属性，我们希望在一个表中修改以下语法。ALTER TABLE name RENAME TO new_name ALTER TABLE name ADD COLUMNS (col_spec[, col_spec ]) ALTER TABLE name DROP [COLUMN] column_name ALTER TAB Jul 6, 2018 · select concat_ws('^',col1,col2,col3) as result from table; In the shell it will look like this: colnames=col1,col2,col3 hive -e "select concat_ws('^',${colnames}) as result from table" If columns are not string, wrap them with cast as string using shell, this will allow concat_ws work with strings and not-string columns. In Hive release For example: "ALTER TABLE Nov 5, 2023 · Hive提供了一个内置的合并文件函数ALTER TABLE <table_name> CONCATENATE。该函数可以将表中的多个小文件合并成一个文件。 下面是一个示例，演示如何使用CONCATENATE函数合并Hive表中的小文件： Jun 17, 2018 · Specifying -d in the command will cause it to dump the ORC file data rather than the metadata (Hive 1. It will likely continue to be unsupported from Spark until the day that the Hadoop ecosystem ships Hive with Spark as its default engine, and even then, this may become deprecated. See Bug report. Alteration on table modify's or changes its metadata Aug 17, 2018 · alter table dbname. test_table_hive; #如果存储在cos、ofs上，创建表后可能需要修改存储路径，默认是hdfs路径。 Mar 28, 2021 · 使用concatenate命令针对20180505分区进行小文件合并： alter table app. For example: ALTER TABLE table_name [PARTITION (partition_key = 'partition_value' [, ])] CONCATENATE Example: ALTER TABLE table_name UNSET SERDEPROPERTIES ('field. Specifying --rowindex with a comma separated list of column ids will cause it to print row indexes for the specified columns, where 0 is the top level struct containing all of the columns and 1 is the first column id (Hive 1. tblName partition (yyyy=2018, mm=7, dd=11) concatenate; all the small files got concatenated into 2 big files. 0 RCFile added support for fast block level merging of small RCFiles using concatenate command. new columns added) but still contains files using the old schema. Namely, partitions whose day=X part has an X value of 06, Oct 13, 2023 · hive小文件合并一、参数配置：在Map输入的时候,把小文件合并. Now that that's out of the way, we need to do this in two ALTER INDEX &mldr; REBUILD; CREATE TABLE &mldr; AS SELECT; ALTER TABLE &mldr; CONCATENATE; ALTER TABLE ARCHIVE/UNARCHIVE PARTITION; ANALYZE TABLE &mldr; COMPUTE STATISTICS; IMPORT FROM &mldr; EXPORT TABLE; For information about using WebHCat for DDL commands, see URL Format and WebHCat Reference: DDL Resources. clickstream_v3 partition (export_date = '2023-01-01', day = '2022-12-31') concatenate; but it doesn't work, Sep 6, 2018 · 经过网上的调研发现通过hive表使用orc格式进行存储能够通过concatenate命令对分区进行小文件合并，并且能够节省80%以上的存储空间，真是喜闻乐见！ 本文不再详细介绍orc，text，rc，parquet各种对比，具体可见网上相关文章，下面只是以举例为主。 创建一个orc hive Jan 10, 2021 · 1. 0 and later). Aug 22, 2024 · In Hive release 0. You can add columns/partitions, change SerDe, add table and SerDe properties, or rename the table itself. 14. 8. We can modify multiple numbers of properties associated with the table schema in the Hive. The merge happens at the stripe level, which avoids decompressing and decoding the data. Hive is designed to support a relatively low rate of transactions, as opposed to serving as an online analytical processing (OLAP) system. example_orc partition (dt="20180505") concatenate; 不足点： 使用concatenate命令合并小文件时不能指定合并后的文件数量，虽然可以多次执行该命令，但显然不够优雅。 Dec 25, 2015 · I am trying to concatenate smaller ORC files into larger ones using Hive's concatenate feature but am having some issues with certain partitions. vsatlmtd_prod_orc is partitioned but partition not found. It will. I do: alter table default. I want to see if I can able to concatenate further to make it as single file. Oct 11, 2017 · Alter table statements enable you to change the structure of an existing table. Strangely, It didn't convert the 2 files into 1 file in the first run. Jul 3, 2023 · #1. 0. You can use the SHOW TRANSACTIONS command . Alter Table Rename Table Dec 25, 2019 · Apache Hive ALTER TABLE Command, Syntax, Examples, Rename Hive Table , Add new column to Hive Table, Change Hive Table Column name and Type, Add and Drop Partition. Workarounds were done to fail this operation if the table is unmanaged, and was finally fixed in Hive 3. Because Hive has full control of managed tables, Hive can optimize these tables extensively. elscydg dqcsro bmkzr fcbglxs bybr woj ilemuch zmqgn aokcjmp pvu mthk jlih rbq dohlq gmoav