The target-postgres loader sends data into PostgreSQL after it was pulled from a source using an extractor
Alternate Implementations
Getting Started
Prerequisites
If you haven't already, follow the initial steps of the Getting Started guide:
Installation and configuration
-
Add the target-postgres loader to your
project using
:meltano add -
Configure the target-postgres
settings using
:meltano config
meltano add target-postgres --variant transferwisemeltano config target-postgres set --interactiveNext steps
Follow the remaining steps of the Getting Started guide:
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:
add_metadata_columnsbatch_size_rowsdata_flattening_max_leveldbnamedefault_target_schemadefault_target_schema_select_permissionflush_all_streamshard_deletehostparallelismparallelism_maxpasswordportprimary_key_requiredschema_mappingssltemp_diruservalidate_records
You can also list these settings using
with the meltano configlist
subcommand:
meltano config target-postgres 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.
Add Metadata Columns (add_metadata_columns)
-
Environment variable:
TARGET_POSTGRES_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 in the Stitch Docs. 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 Postgres. Default - False
Configure this setting directly using the following Meltano command:
meltano config target-postgres set add_metadata_columns [value]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.
Configure this setting directly using the following Meltano command:
meltano config target-postgres set batch_size_rows [value]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.
Configure this setting directly using the following Meltano command:
meltano config target-postgres set data_flattening_max_level [value]Database Name (dbname)
-
Environment variable:
TARGET_POSTGRES_DBNAME
PostgreSQL database name
Configure this setting directly using the following Meltano command:
meltano config target-postgres set dbname [value]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.
Configure this setting directly using the following Meltano command:
meltano config target-postgres set default_target_schema [value]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.
Configure this setting directly using the following Meltano command:
meltano config target-postgres set default_target_schema_select_permission [value]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.
Configure this setting directly using the following Meltano command:
meltano config target-postgres set flush_all_streams [value]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.
Configure this setting directly using the following Meltano command:
meltano config target-postgres set hard_delete [value]Host (host)
-
Environment variable:
TARGET_POSTGRES_HOST -
Default Value:
localhost
PostgreSQL host
Configure this setting directly using the following Meltano command:
meltano config target-postgres set host [value]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.
Configure this setting directly using the following Meltano command:
meltano config target-postgres set parallelism [value]Max Parallelism (parallelism_max)
-
Environment variable:
TARGET_POSTGRES_PARALLELISM_MAX -
Default Value:
16
Max number of parallel threads to use when flushing tables.
Configure this setting directly using the following Meltano command:
meltano config target-postgres set parallelism_max [value]Password (password)
-
Environment variable:
TARGET_POSTGRES_PASSWORD
PostgreSQL password
Configure this setting directly using the following Meltano command:
meltano config target-postgres set password [value]Port (port)
-
Environment variable:
TARGET_POSTGRES_PORT -
Default Value:
5432
PostgreSQL port
Configure this setting directly using the following Meltano command:
meltano config target-postgres set port [value]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.
Configure this setting directly using the following Meltano command:
meltano config target-postgres set primary_key_required [value]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.
This setting can hold an object mapping source schema names to objects with target_schema and (optionally) target_schema_select_permissions and indices keys.
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"]
Configure this setting directly using the following Meltano command:
meltano config target-postgres set schema_mapping [value]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.
Configure this setting directly using the following Meltano command:
meltano config target-postgres set ssl [value]Temporary Directory (temp_dir)
-
Environment variable:
TARGET_POSTGRES_TEMP_DIR
(Default: platform-dependent) Directory of temporary CSV files with RECORD messages.
Configure this setting directly using the following Meltano command:
meltano config target-postgres set temp_dir [value]User (user)
-
Environment variable:
TARGET_POSTGRES_USER
PostgreSQL user
Configure this setting directly using the following Meltano command:
meltano config target-postgres set user [value]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.
Configure this setting directly using the following Meltano command:
meltano config target-postgres set validate_records [value]Troubleshooting
ld, clang, lssl, or linker Errors
If you have an error message like:
ld: library not found for -lsslclang: error: linker command failed with exit code 1error: 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 (legacy) or meltano add target-postgres (Meltano 3.8+).
Something missing?
This page is generated from a YAML file that you can contribute changes to.
Edit it on GitHub!Looking for help?
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