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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. This adapter based on postgres-adapter with a bit difference for a greenplum specific features

Installation

Easiest way to start use dbt-greenplum is to install it using pip pip install dbt-greenplum==<version>

Where <version> is same as your dbt version

Available versions:

  • 0.19.2
  • 1.0.4
  • 1.2.0
  • 1.4.0
  • 1.5.0

Supported Features

You can specify following settings:

  • Storage type
    • heap
    • appendoptimized
  • Distribution
    • distributed randomly by defaut
    • distributed by (column, [ ... ] ) by setting up distributed_by parameter in the model config
    • distributed replicated by setting up distributed_replicated=true parameter in the model config
  • Table orientation
    • orientation=colum by default
    • orientation=row by setting up orientation parameter in row in the model config
  • Compress type, level and blocksize with default values
     compresstype=ZLIB,
     compresslevel=1,
     blocksize=32768
    You can also specify blocksize, compresstype, compresslevel in the model config
  • appendoptimized preference by default is true, also you can override it by setting up appendoptimized field in the model config
  • Partitions (see "Partition" chapter below)
  • Additional incremental strategy
    • truncate-insert by setting up incremental_strategy="truncate+insert" parameter in the model config or +incremental_strategy: truncate_insert in the dbt_project.yml

Heap table example

To create heap table set appendoptimized parameter value to false

{{
   config(
      ...
      materialized='table',
      appendoptimized=false
      ...
   )
}}

select 1 as "id"

will produce following SQL code

create  table "<db_name>"."<schema_name>"."<table_name>"
with (
   appendoptimized=false
) as (
   select 1 as "id"
)
DISTRIBUTED RANDOMLY;

Appendoptimized table example

You can use appendopimized or appendonly(legacy) to create appendoptimized table

Such model definition

{{
    config(
        materialized='table',
        distributed_by='id',
        appendoptimized=true,
        orientation='column',
        compresstype='ZLIB',
        compresslevel=1,
        blocksize=32768
    )
}}

with source_data as (

    select 1 as id
    union all
    select null as id

)

select *
from source_data

will produce following sql code

create  table "dvault"."dv"."my_first_dbt_model__dbt_tmp"
with (
    appendoptimized=true,
    blocksize=32768,
    orientation=column,
    compresstype=ZLIB,
    compresslevel=1
)
as (
  with source_data as (
      select 1 as id
      union all
      select null as id
    )
  select *
  from source_data
)  
distributed by (id);

  
alter table "dvault"."dv"."my_first_dbt_model__dbt_tmp" rename to "my_first_dbt_model";

Partitions

Greenplum does not support partitions with create table as construction, so you need to build model in two steps

  • create table schema
  • insert data

To implement partitions into you dbt-model you need to specify on of the following config parameters:

  • fields_string - definition of columns name, type and constraints
  • one of following way to configure partitions
    • raw_partition by default
    • partition_type, partition_column, partition_spec
    • partition_type, partition_column, partition_start, partition_end, partition_every
    • partition_type, partition_column, partition_values
  • default_partition_name - name of default partition 'other' by default

Let consider examples of definition model with partitions

  • using raw_partition parameter
    {% 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',
            distributed_by='id',
            appendoptimized=true,
            orientation='column',
            compresstype='ZLIB',
            compresslevel=1,
            blocksize=32768,
            fields_string=fields_string,
            raw_partition=raw_partition,
            default_partition_name='other_data'
        )
    }}
    
    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
    will produce following sql code
    create table if not exists "database"."schema"."my_first_dbt_model__dbt_tmp" (
        id int4 null,
        incomingdate timestamp NULL
    )
    with (
        appendoptimized=true,
        blocksize=32768,
        orientation=column,
        compresstype=ZLIB,
        compresslevel=1
    )
    DISTRIBUTED BY (id)
    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 "database"."schema"."my_first_dbt_model__dbt_tmp" (
        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
    );
    alter table "dvault"."dv"."my_first_dbt_model" rename to "my_first_dbt_model__dbt_backup";
    drop table if exists "dvault"."dv"."my_first_dbt_model__dbt_backup" cascade;
    alter table "database"."schema"."my_first_dbt_model__dbt_tmp" rename to "my_first_dbt_model";
  • Same result you can get using partition_type, partition_column, partition_spec parameters
    {% 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',
            distributed_by='id',
            appendoptimized=true,
            orientation='column',
            compresstype='ZLIB',
            compresslevel=1,
            blocksize=32768,
            fields_string=fields_string,
            partition_type=partition_type,
            partition_column=partition_column,
            partition_spec=partition_spec,
            default_partition_name='other_data'
        )
    }}
    
    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
  • also, you can use third way
    {% 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 = "'2022-01-01'::timestamp" -%}
    {%- set partition_every = '1 day' -%}
    
    
    {{
        config(
            materialized='table',
            distributed_by='id',
            appendoptimized=true,
            orientation='column',
            compresstype='ZLIB',
            compresslevel=1,
            blocksize=32768,
            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='other_data'
        )
    }}
    
    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
  • example of partition_type LIST is coming soon

Table partition hints

Too check generate sql script use -d option: dbt -d run <...> -m <models>

If you want implement complex partition logic with subpartition or something else use raw_partition parameter

Truncate+insert incremental strategy

You can use this incremental strategy to safely reload models without cascade dropping dependent objects due to Greenplum's transactional TRUNCATE operation realization

Model definition example:

{{
   config(
      ...
      materialized='incremental',
      incremental_strategy='truncate+insert',
      ...
   )
}}

select *
from source_data

Getting started

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Code of Conduct

Everyone interacting in the dbt project's codebases, issue trackers, chat rooms, and mailing lists is expected to follow the dbt Code of Conduct.

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Adaptation postgres adapter for Greenplum

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