Help Center/ MapReduce Service/ Component Operation Guide (LTS)/ Using Hive/ Configuring Hive Data Storage and Encryption/ Compressing Hive ORC Tables Using ZSTD_JNI
Updated on 2024-10-25 GMT+08:00
View PDF
Share

Compressing Hive ORC Tables Using ZSTD_JNI

Scenario

ZSTD_JNI is a native implementation of the ZSTD compression algorithm. Compared with ZSTD, ZSTD_JNI has higher compression read/write efficiency and compression ratio, and allows you to specify the compression level as well as the compression mode for data columns in a specific format.

Currently, only ORC tables can be compressed using ASTD_JNI. By contrast, ZSTD enables you to compress tables in the full storage format. Therefore, you are advised to use this feature only when you have high requirements on data compression.

This section applies only to MRS 3.2.0 or later.

Example

  1. Log in to the node where the client is installed as the Hive client installation user.
  2. Run the following command to switch to the client installation directory, for example, /opt/client:

    cd /opt/client

  3. Run the following command to configure environment variables:

    source bigdata_env

  4. Check whether the cluster authentication mode is in security mode.

    • If yes, run the following command to perform user authentication and then go to 5.

      kinit Hive service user

    • If no, go to 5.

  5. Run the following command to log in to the Hive client:

    beeline

  6. Create a table in ZSTD_JNI compression format as follows:

    • Run the following example command to set the orc.compress parameter to ZSTD_JNI when using this compression algorithm to create an ORC table:

      create table tab_1(...) stored as orc TBLPROPERTIES("orc.compress"="ZSTD_JNI");

    • The compression level of ZSTD_JNI ranges from 1 to 19. A larger value indicates a higher compression ratio but a slower read/write speed. A smaller value indicates a lower compression ratio but a faster compression speed compared with read/write speed and the other way around. The default value is 6. You can set the compression level through the orc.global.compress.level parameter, as shown in the follows.

      create table tab_1(...) stored as orc TBLPROPERTIES("orc.compress"="ZSTD_JNI", 'orc.global.compress.level'='3');

    • This compression algorithm allows you to compress service data and columns in a specific data format. Currently, data in the following formats is supported: JSON data columns, Base64 data columns, timestamp data columns, and UUID data columns. You can achieve this function by setting the orc.column.compress parameter during table creation.

      The following example code shows how to use ZSTD_JNI to compress data in the JSON, Base64, timestamp, and UUID formats.

      create table test_orc_zstd_jni(f1 int, f2 string, f3 string, f4 string, f5 string) stored as orc

      TBLPROPERTIES('orc.compress'='ZSTD_JNI', 'orc.column.compress'='[{"type":"cjson","columns":"f2"},{"type":"base64","columns":"f3"},{"type ":"gorilla","columns":{"format": "yyyy-MM-dd HH:mm:ss.SSS", "columns": "f4"}},{"type":"uuid","columns":"f5"}]');

      You can insert data in the corresponding format based on the site requirements to further compress the data.