target-duckdb from jwills

DuckDB loader

The target-duckdb loader sends data into DuckDB after it was pulled from a source using an extractor

Getting Started


If you haven't already, follow the initial steps of the Getting Started guide:

  1. Install Meltano
  2. Create your Meltano project

Installation and configuration

  1. Add the target-duckdb loader to your project using
    meltano add
  2. meltano add loader target-duckdb
  3. Configure the target-duckdb settings using
    meltano config
  4. meltano config target-duckdb set --interactive

Next steps

If you run into any issues, learn how to get help.


This plugin currently has no capabilities defined. If you know the capabilities required by this plugin, please contribute!


The target-duckdb settings that are known to Meltano are documented below. To quickly find the setting you're looking for, click on any setting name from the list:

You can override these settings or specify additional ones in your meltano.yml by adding the settings key.

Please consider adding any settings you have defined locally to this definition on MeltanoHub by making a pull request to the YAML file that defines the settings for this plugin.

File Path (filepath)

  • Environment variable: TARGET_DUCKDB_FILEPATH

Path to the local DuckDB file.

Batch Size Rows (batch_size_rows)

  • Environment variable: TARGET_DUCKDB_BATCH_SIZE_ROWS
  • Default Value: 100000

Maximum number of rows in each batch. At the end of each batch, the rows in the batch are loaded into DuckDB.

Flush All Streams (flush_all_streams)

  • Environment variable: TARGET_DUCKDB_FLUSH_ALL_STREAMS
  • Default Value: false

Flush and load every stream into DuckDB when one batch is full. Warning - This may trigger the COPY command to use files with low number of records.

Default Target Schema (default_target_schema)


Name of the schema where the tables will be created. If schema_mapping is not defined then every stream sent by the tap is loaded into this schema.

schema_mapping (schema_mapping)

  • Environment variable: TARGET_DUCKDB_SCHEMA_MAPPING

Useful if you want to load multiple streams from one tap to multiple DuckDB schemas.

If the tap sends the stream_id in - format then this option overwrites the default_target_schema value.

Add Metadata Columns (add_metadata_columns)

  • Default Value: false

Metadata columns add extra row level information about data ingestions, (i.e. when was the row read in source, when was inserted or deleted in postgres etc.) Metadata columns are creating automatically by adding extra columns to the tables with a column prefix SDC. The column names are following the stitch naming conventions documented at Enabling metadata columns will flag the deleted rows by setting the _SDC_DELETED_AT metadata column. Without the add_metadata_columns option the deleted rows from singer taps will not be recognisable in DuckDB.

Hard Delete (hard_delete)

  • Environment variable: TARGET_DUCKDB_HARD_DELETE
  • Default Value: false

When hard_delete option is true then DELETE SQL commands will be performed in DuckDB to delete rows in tables. It's achieved by continuously checking the _SDC_DELETED_AT metadata column sent by the singer tap. Due to deleting rows requires metadata columns, hard_delete option automatically enables the add_metadata_columns option as well.

Data Flattening Max Level (data_flattening_max_level)

  • Default Value: 0

Object type RECORD items from taps can be transformed to flattened columns by creating columns automatically.

When value is 0 (default) then flattening functionality is turned off.

Primary Key Required (primary_key_required)

  • Default Value: true

Log based and Incremental replications on tables with no Primary Key cause duplicates when merging UPDATE events. When set to true, stop loading data if no Primary Key is defined.

Validate Records (validate_records)

  • Environment variable: TARGET_DUCKDB_VALIDATE_RECORDS
  • Default Value: false

Validate every single record message to the corresponding JSON schema. This option is disabled by default and invalid RECORD messages will fail only at load time by DuckDB. Enabling this option will detect invalid records earlier but could cause performance degradation.

Temporary Directory (temp_dir)

  • Environment variable: TARGET_DUCKDB_TEMP_DIR

Directory of temporary CSV files with RECORD messages.

Something missing?

This page is generated from a YAML file that you can contribute changes to.

Edit it on GitHub!

Looking for help?

If you're having trouble getting the target-duckdb loader to work, look for an existing issue in its repository, file a new issue, or join the Meltano Slack community and ask for help in the


meltano add loader target-duckdb

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