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DML-Operations-on-Carbon.md

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  • [LOAD DATA](#LOAD DATA)
  • [SHOW LOADS](#SHOW LOADS)
  • [DELETE SEGMENT BY ID](#DELETE SEGMENT BY ID)
  • [DELETE SEGMENT BY DATE](#DELETE SEGMENT BY DATE)

LOAD DATA

Function

This command loads the user data in raw format to the Carbon specific data format store, this way Carbon provides good performance while querying the data.

Syntax

LOAD DATA [LOCAL] INPATH 'folder_path' INTO TABLE [db_name.]table_name 
            OPTIONS(property_name=property_value, ...)

Example:

LOAD DATA local inpath '/opt/rawdata/data.csv' INTO table carbontable
                       options('DELIMITER'=',', 'QUOTECHAR'='"',
                               'FILEHEADER'='empno,empname,
                                designation,doj,workgroupcategory,
                                workgroupcategoryname,deptno,deptname,projectcode,
                                projectjoindate,projectenddate,attendance,utilization,salary',
                               'MULTILINE'='true', 'ESCAPECHAR'='\', 
                               'COMPLEX_DELIMITER_LEVEL_1'='$', 
                               'COMPLEX_DELIMITER_LEVEL_2'=':',
                               'LOCAL_DICTIONARY_PATH'='/opt/localdictionary/',
                               'DICTIONARY_FILE_EXTENSION'='.dictionary')

Parameter Description

Parameter Description
folder_path Path of raw csv data folder or file.
db_name Database name, if it is not specified then it uses current database.
table_name The name of the table in provided database.

Usage Guideline

Following are the options that can be used in load data:

  • DELIMITER: Delimiters and Quote Characters can be provided in the load command.

    OPTIONS('DELIMITER'=',' , 'QUOTECHAR'='"')

  • QUOTECHAR: Delimiters and Quote Characters can be provided in the load command.

    OPTIONS('DELIMITER'=',' , 'QUOTECHAR'='"')

  • FILEHEADER: Headers can be provided in the LOAD DATA command if headers are missing in the source files.

    OPTIONS('FILEHEADER'='column1,column2')

  • MULTILINE: CSV with new line character in quotes.

    OPTIONS('MULTILINE'='true')

  • ESCAPECHAR: Escape char can be provided if user want strict validation of escape character on CSV.

    OPTIONS('ESCAPECHAR'='\')

  • COMPLEX_DELIMITER_LEVEL_1: Split the complex type data column in a row (eg., a$b$c --> Array = {a,b,c}).

    OPTIONS('COMPLEX_DELIMITER_LEVEL_1'='$')

  • COMPLEX_DELIMITER_LEVEL_2: Split the complex type nested data column in a row. Applies level_1 delimiter & applies level_2 based on complex data type (eg., a:b$c:d --> Array> = {{a,b},{c,d}}).

    OPTIONS('COMPLEX_DELIMITER_LEVEL_2'=':')

  • LOCAL_DICTIONARY_PATH: Local dictionary files path.

    OPTIONS('LOCAL_DICTIONARY_PATH'='/opt/localdictionary/')

  • DICTIONARY_FILE_EXTENSION: local Dictionary file extension.

    OPTIONS('DICTIONARY_FILE_EXTENSION'='.dictionary')

Scenarios

Load from CSV files

To load carbon table from CSV file, use the following syntax.

LOAD DATA [LOCAL] INPATH 'folder path' INTO TABLE tablename OPTIONS(property_name=property_value, ...)

Example:

LOAD DATA local inpath './src/test/resources/data.csv' INTO table carbontable 
                    options('DELIMITER'=',', 'QUOTECHAR'='"', 
                            'FILEHEADER'='empno,empname,designation,doj,
                             workgroupcategory,workgroupcategoryname,
                             deptno,deptname,projectcode,projectjoindate,
                             projectenddate,attendance,utilization,salary', 
                            'MULTILINE'='true', 'ESCAPECHAR'='\', 
                            'COMPLEX_DELIMITER_LEVEL_1'='$', 'COMPLEX_DELIMITER_LEVEL_2'=':', 
                            'LOCAL_DICTIONARY_PATH'='/opt/localdictionary/','DICTIONARY_FILE_EXTENSION'='.dictionary')

SHOW SEGMENTS

Function

This command is to show the segments of carbon table to the user.

Syntax

SHOW SEGMENTS FOR TABLE [db_name.]table_name LIMIT number_of_segments;

Example:

SHOW SEGMENTS FOR TABLE CarbonDatabase.CarbonTable LIMIT 2;

Parameter Description

Parameter Description
db_name Database name, if it is not specified then it uses current database.
table_name The name of the table in provided database.
number_of_loads limit the output to this number.

Usage Guideline

NA

Scenarios

NA

DELETE SEGMENT BY ID

Function

This command is to delete segment by using the segment ID.

Syntax

DELETE SEGMENT segment_id1,segment_id2 FROM TABLE [db_name.]table_name;

Example:

DELETE LOAD 0 FROM TABLE CarbonDatabase.CarbonTable;
DELETE LOAD 0.1,5,8 FROM TABLE CarbonDatabase.CarbonTable;
Note: Here 0.1 is compacted segment sequence id.

Parameter Description

Parameter Description
segment_id Segment Id of the load.
db_name Database name, if it is not specified then it uses current database.
table_name The name of the table in provided database.

Usage Guideline

NA

Scenarios

NA

DELETE SEGMENT BY DATE

Function

This command will allow to deletes the Carbon segment(s) from the store based on the date provided by the user in the DML command. The segment created before the particular date will be removed from the specific stores.

Syntax

DELETE SEGMENTS FROM TABLE [db_name.]table_name WHERE STARTTIME BEFORE [DATE_VALUE];

Example:

DELETE SEGMENTS FROM TABLE CarbonDatabase.CarbonTable WHERE STARTTIME BEFORE '2017-06-01 12:05:06';

Parameter Description

Parameter Description
DATE_VALUE Valid segement load start time value. All the segments before this specified date will be deleted.
db_name Database name, if it is not specified then it uses current database.
table_name The name of the table in provided database.

Usage Guideline

NA

Scenarios

NA