dbt enables data analysts and engineers to transform their data using the same practices that software engineers use to build applications.

dbt is the T in ELT. Organize, cleanse, denormalize, filter, rename, and pre-aggregate the raw data in your warehouse so that it's ready for analysis.

dbt-greenplum

The dbt-greenplum package contains the code enabling dbt to work with Greenplum. For more information on using dbt with Greenplum, consult the docs.

This adapter is based on dbt-postgres v1.8.2.

Compared to dbt-postgres, dbt-greenplum supports some Greenplum-Specific features.

For those Greenplum-Specific features, we reference markporoshin/dbt-greenplum which is no longer maintained.

Greenplum-Specific Features

Distribution Policy

Greenplum will choose the first column as the distribution column by default while not specifying distribution policy.

You can specify distribution policy explicitly with the following settings.

• distributed randomly by setting distributed_randomly=true in the model config.
• distributed replicated by setting distributed_replicated=true in the model config.
• distributed by (<column_name> [, ... ]) by setting distributed_by='<column_name> [, ... ]' in the model config.

Table Storage Model

• Heap Storage(Default)

  You can create heap table with the setting appendoptimized=false in the model config.

  Here is an example.

  {{
    config(
      ...
      materialized='table',
      appendoptimized=false,
      ...
    )
  }}
  
  select 1 as "id"

• Append-Optimized Storage

  You can create Append-Optimized(AO) table with the setting appendoptimized=true in the model config.

• Row or Column-Oriented Storage

  • Row-Oriented Storage

    Row-oriented storage is used by default.

    Also you can create table with row-oriented storage by setting orientation=row in the model config explicitly.

  • Column-Oriented Storage (Append-Optimized Tables Only)

    You can create table with column-oriented storage by setting orientation=column in the model config.

    NOTE: Tables that use column-oriented storage must be append-optimized tables.

• Using Compression (Append-Optimized Tables Only)

  You can specify compresstype, level and blocksize settings in the model config.

  Default values are compresstype=ZLIB, compresslevel=1 and blocksize=32768.

  NOTE: Only append-optimized tables can use compression.

Partition Tables

Greenplum can NOT create partition tables with create table as statement.

So to build model with partitions, you need to two steps.

• create table
• insert data

To build model with partitions, we need to configure

• fields_string - definition of columns name, type and constraints

  This setting is must.

• one of following way to configure partitions

  • Way 1: using the setting raw_partition

    Here is an example.

    {% set fields_string %}
       id int4 null,
       incomingdate timestamp NULL
    {% endset %}
    
    {% set raw_partition %}
      PARTITION BY RANGE (incomingdate)
      (
        START ('2021-01-01'::timestamp) INCLUSIVE
        END ('2023-01-01'::timestamp) EXCLUSIVE
        EVERY (INTERVAL '1 day'),
        DEFAULT PARTITION extra
      )
    {% endset %}
    
    {{
      config(
        materialized='table',
        fields_string=fields_string,
        raw_partition=raw_partition,
      )
    }}
    
    with source_data as (
    
        select
            1 as id,
            '2022-02-22'::timestamp as incomingdate
        union all
        select
            null as id,
            '2022-02-25'::timestamp as incomingdate
    )
    select *
    from source_data

    The generated SQL by dbt is as follows. (We mock the model name using <model_identifier>.)

    create table if not exists <model_identifier> (
       id int4 null,
       incomingdate timestamp NULL
    )
    PARTITION BY RANGE (incomingdate)
    (
       START ('2021-01-01'::timestamp) INCLUSIVE
        END ('2023-01-01'::timestamp) EXCLUSIVE
        EVERY (INTERVAL '1 day'),
        DEFAULT PARTITION extra
    );
    
    insert into <model_identifier> (
    with source_data as (
        select
            1 as id,
            '2022-02-22'::timestamp as incomingdate
        union all
        select
            null as id,
            '2022-02-25'::timestamp as incomingdate
    )
    select *
    from source_data
    );

  • Way 2: using the settings partition_type, partition_column, partition_spec

    Here is an example.

    {% set fields_string %}
        id int4 null,
        incomingdate timestamp NULL
    {% endset %}
    
    {%- set partition_type = 'RANGE' -%}
    {%- set partition_column = 'incomingdate' -%}
    {% set partition_spec %}
        START ('2021-01-01'::timestamp) INCLUSIVE
        END ('2023-01-01'::timestamp) EXCLUSIVE
        EVERY (INTERVAL '1 day'),
        DEFAULT PARTITION extra
    {% endset %}
    
    {{
        config(
            materialized='table',
            fields_string=fields_string,
            partition_type=partition_type,
            partition_column=partition_column,
            partition_spec=partition_spec,
        )
    }}
    
    with source_data as (
    
        select
            1 as id,
            '2022-02-22'::timestamp as incomingdate
        union all
        select
            null as id,
            '2022-02-25'::timestamp as incomingdate
    )
    select *
    from source_data

    Generated SQL by dbt is same as Way 1.

  • Way 3: using the settings partition_type, partition_column, partition_start, partition_end, partition_every

    Here is an example.

    {% set fields_string %}
        id int4 null,
        incomingdate timestamp NULL
    {% endset %}
    
    {%- set partition_type = 'RANGE' -%} 
    {%- set partition_column = 'incomingdate' -%}
    {%- set partition_start = "'2021-01-01'::timestamp" -%}
    {%- set partition_end = "'2023-01-01'::timestamp" -%}
    {%- set partition_every = '1 day' -%}
    
    {{
        config(
            materialized='table',
            fields_string=fields_string,
            partition_type=partition_type,
            partition_column=partition_column,
            partition_start=partition_start,
            partition_end=partition_end,
            partition_every=partition_every,
            default_partition_name='extra'
         )
    }}
    
    with source_data as (
    
        select
            1 as id,
            '2022-02-22'::timestamp as incomingdate
        union all
        select
            null as id,
            '2022-02-25'::timestamp as incomingdate
    )
    select *
    from source_data

    Generated SQL by dbt is same as Way 1.

  • Way 4: using the settings partition_type, partition_column, partition_values

    Here is an example.

    {% set fields_string %}
        id int4 null,
        incomingdate timestamp NULL
    {% endset %}
    
    {%- set partition_type = 'LIST' -%}
    {%- set partition_column = 'code' -%}
    {% set partition_values %}
        PARTITION sales VALUES ('S'),
        PARTITION returns VALUES ('R')
    {% endset %}
    
    {{
        config(
            materialized='table',
            fields_string=fields_string,
            partition_type=partition_type,
            partition_column=partition_column,
            partition_values=partition_values,
            default_partition_name='extra'
        )
    }}
    
    with source_data as (
    
        select
            1 as id,
            'S' as code
        union all
        select
            null as id,
            'N' as code
    )
    select *
    from source_data

    Generated SQL by dbt is as follows.

    create table if not exists <model_identifier> (
        id int4 null,
        code char(1)
    )
    PARTITION BY LIST (code)
        (
            PARTITION sales VALUES ('S'),
            PARTITION returns VALUES ('R'),
            DEFAULT PARTITION extra
        )
    ;
    
    insert into <model_identifier> (
    with source_data as (
        select
            1 as id,
            'S' as code
        union all
        select
            null as id,
            'N' as code
    )
    select *
    from source_data
    );

• default_partition_name - name of default partition, default value is other

Incremental Strategy

Valid incremental strategies are append, delete+insert and truncate+insert.

Getting started

• Install dbt
• Read the introduction and viewpoint

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