Load data into Hive with custom delimiter

后端 未结 3 851
忘掉有多难
忘掉有多难 2020-12-07 05:48

I\'m trying to create an internal (managed) table in hive that can store my incremental log data. The table goes like this:

CREATE TABLE logs (foo INT, bar S         


        
相关标签:
3条回答
  • 2020-12-07 06:00

    By default, hive only allows user to use single character as field delimiter. Although there's RegexSerDe to specify multiple-character delimiter, it can be daunting to use, especially for amateurs.

    The patch (HIVE-5871) adds a new SerDe named MultiDelimitSerDe. With MultiDelimitSerDe, users can specify a multiple-character field delimiter when creating tables, in a way most similar to typical table creations.

    hive> CREATE TABLE logs (foo INT, bar STRING, created_date TIMESTAMP)
        > ROW FORMAT SERDE 'org.apache.hadoop.hive.contrib.serde2.MultiDelimitSerDe' 
        > WITH SERDEPROPERTIES ("field.delim"="<=>")
        > STORED AS TEXTFILE;
    
    hive> dfs -put /home/user1/multi_char.txt /user/hive/warehouse/logs/. ;
    
    hive> select * from logs;
    OK
    120 abcdefg 2016-01-01 12:14:11
    Time taken: 1.657 seconds, Fetched: 1 row(s)
    hive> 
    
    0 讨论(0)
  • 2020-12-07 06:12

    I suggest you to go with MultiDelimitSerDe answers mentioned earlier over mine. You can also give a try with RegexSerDe. But You need to have an additional step of parsing it to your datatypes since RegexSerde accepts String by default.

    RegexSerDe will come to handy dealing with some log files where the data that is not uniformly arranged with only one single delimiter.

    CREATE TABLE logs_tmp  (foo STRING,bar STRING, created_date STRING) 
    ROW FORMAT SERDE 'org.apache.hadoop.hive.contrib.serde2.RegexSerDe' 
    WITH SERDEPROPERTIES (
     "input.regex" = "(\\d{3})<=>(\\w+)<=>(\\d{4}-\\d{2}-\\d{2}\\s\\d{2}:\\d{2}:\\d{2})"
    ) 
    STORED AS TEXTFILE;
    
    LOAD DATA LOCAL INPATH 'logs.txt' overwrite into table logs_tmp;
    
    CREATE TABLE logs  (foo INT,bar STRING, created_date TIMESTAMP) ;
    
    INSERT INTO TABLE logs SELECT cast(foo as int) as foo,bar,cast(created_date as TIMESTAMP) as created_date from logs_tmp 
    

    output:

       OK
        Time taken: 0.213 seconds    
        hive> select * from logs;
        120     abcdefg 2016-01-01 12:14:11
    
    0 讨论(0)
  • 2020-12-07 06:14
    CREATE TABLE logs (foo INT, bar STRING, created_date TIMESTAMP)
    ROW FORMAT SERDE 'org.apache.hadoop.hive.contrib.serde2.MultiDelimitSerDe'
    WITH SERDEPROPERTIES (
        "field.delim"="<=>",
        "collection.delim"=":",
        "mapkey.delim"="@"
    );
    

    load data in table

    load data local inpath '/home/kishore/Data/input.txt' overwrite into table logs;
    
    0 讨论(0)
提交回复
热议问题