PostgreSQL

target-postgres from transferwise

PostgreSQL database loader

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

Available Variants

Getting Started

Prerequisites

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-postgres loader to your project using
    meltano add
    :
  2. meltano add loader target-postgres
  3. Configure the target-postgres settings using
    meltano config
    :
  4. meltano config target-postgres set --interactive

Next steps

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

Capabilities

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

Settings

The target-postgres 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.

Host (host)

  • Environment variable: TARGET_POSTGRES_HOST
  • Default Value: localhost

PostgreSQL host

Port (port)

  • Environment variable: TARGET_POSTGRES_PORT
  • Default Value: 5432

PostgreSQL port

User (user)

  • Environment variable: TARGET_POSTGRES_USER

PostgreSQL user

Password (password)

  • Environment variable: TARGET_POSTGRES_PASSWORD

PostgreSQL password

Database Name (dbname)

  • Environment variable: TARGET_POSTGRES_DBNAME

PostgreSQL database name

SSL (ssl)

  • Environment variable: TARGET_POSTGRES_SSL
  • Default Value: false

Using SSL via postgres sslmode='require' option.

If the server does not accept SSL connections or the client certificate is not recognized the connection will fail.

Default Target Schema (default_target_schema)

  • Environment variable: TARGET_POSTGRES_DEFAULT_TARGET_SCHEMA
  • Default Value: $MELTANO_EXTRACT__LOAD_SCHEMA

Note that $MELTANO_EXTRACT__LOAD_SCHEMA will expand to the value of the load_schema extra for the extractor used in the pipeline, which defaults to the extractor's namespace, e.g. tap_gitlab for tap-gitlab.

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.

Batch Size Rows (batch_size_rows)

  • Environment variable: TARGET_POSTGRES_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 Postgres.

Flush All Streams (flush_all_streams)

  • Environment variable: TARGET_POSTGRES_FLUSH_ALL_STREAMS
  • Default Value: false

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

Parallelism (parallelism)

  • Environment variable: TARGET_POSTGRES_PARALLELISM
  • Default Value: 0

The number of threads used to flush tables. 0 will create a thread for each stream, up to parallelism_max. -1 will create a thread for each CPU core. Any other positive number will create that number of threads, up to parallelism_max.

Max Parallelism (parallelism_max)

  • Environment variable: TARGET_POSTGRES_PARALLELISM_MAX
  • Default Value: 16

Max number of parallel threads to use when flushing tables.

Default Target Schema Select Permission (default_target_schema_select_permission)

  • Environment variable: TARGET_POSTGRES_DEFAULT_TARGET_SCHEMA_SELECT_PERMISSION

Grant USAGE privilege on newly created schemas and grant SELECT privilege on newly created tables to a specific role or a list of roles. If schema_mapping is not defined then every stream sent by the tap is granted accordingly.

Schema Mapping (schema_mapping)

  • Environment variable: TARGET_POSTGRES_SCHEMA_MAPPING

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

If the tap sends the stream_id in <schema_name>-<table_name> format then this option overwrites the default_target_schema value. Note, that using schema_mapping you can overwrite the default_target_schema_select_permission value to grant SELECT permissions to different groups per schemas or optionally you can create indices automatically for the replicated tables.

Example structure (as YAML):

schema_mapping:
  my_tap_stream_id:
    target_schema: my_postgres_schema
    target_schema_select_permissions: [ "role_with_select_privs" ]
    indices: ["column_1", "column_2s"]

Add Metadata Columns (add_metadata_columns)

  • Environment variable: TARGET_POSTGRES_ADD_METADATA_COLUMNS
  • Default Value: false

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

If the tap sends the stream_id in <schema_name>-<table_name> format then this option overwrites the default_target_schema value.

Note, that using schema_mapping you can overwrite the default_target_schema_select_permission value to grant SELECT permissions to different groups per schemas or optionally you can create indices automatically for the replicated tables.

This setting can hold an object mapping source schema names to objects with target_schema and (optionally) target_schema_select_permissions and indices keys.

Hard Delete (hard_delete)

  • Environment variable: TARGET_POSTGRES_HARD_DELETE
  • Default Value: false

When hard_delete option is true then DELETE SQL commands will be performed in Postgres 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)

  • Environment variable: TARGET_POSTGRES_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)

  • Environment variable: TARGET_POSTGRES_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_POSTGRES_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 Postgres. Enabling this option will detect invalid records earlier but could cause performance degradation.

Temporary Directory (temp_dir)

  • Environment variable: TARGET_POSTGRES_TEMP_DIR

(Default: platform-dependent) Directory of temporary CSV files with RECORD messages.

Troubleshooting

ld, clang, lssl, or linker Errors

If you have an error message like:

  • ld: library not found for -lssl
  • clang: error: linker command failed with exit code 1
  • error: command 'clang' failed with exit status 1

These error messages indicates that there is a problem installing OpenSSL.

This Stack Overflow answer has specific recommendations on setting the LDFLAGS and/or CPPFLAGS environment variables. Set those prior to running meltano add loader target-postgres.

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-postgres 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
#plugins-general
channel.

Install

meltano add loader target-postgres

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Keywords

  • database