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Version: 0.15.50

How to configure a Validation Result Store to PostgreSQL

By default, Validation Results are stored in JSON format in the uncommitted/validations/ subdirectory of your great_expectations/ folder. Since Validation ResultsGenerated when data is Validated against an Expectation or Expectation Suite. may include examples of data (which could be sensitive or regulated) they should not be committed to a source control system. This guide will help you configure Great Expectations to store them in a PostgreSQL database.

Prerequisites: This how-to guide assumes you have:

Steps​

1. Configure the config_variables.yml file with your database credentials​

We recommend that database credentials be stored in the config_variables.yml file, which is located in the uncommitted/ folder by default, and is not part of source control. The following lines add database credentials under the key db_creds. Additional options for configuring the config_variables.yml file or additional environment variables can be found here. 

db_creds:
  drivername: postgres
  host: '<your_host_name>'
  port: '<your_port>'
  username: '<your_username>'
  password: '<your_password>'
  database: '<your_database_name>'

It is also possible to specify schema as an additional keyword argument if you would like to use a specific schema as the backend, but this is entirely optional. 

db_creds:
  drivername: postgres
  host: '<your_host_name>'
  port: '<your_port>'
  username: '<your_username>'
  password: '<your_password>'
  database: '<your_database_name>'
  schema: '<your_schema_name>'

2. Identify your Data Context Validation Results Store​

As with all StoresA connector to store and retrieve information about metadata in Great Expectations., you can use your Data ContextThe primary entry point for a Great Expectations deployment, with configurations and methods for all supporting components. to find your Validation Results StoreA connector to store and retrieve information about objects generated when data is Validated against an Expectation Suite.. In your great_expectations.yml, look for the following lines. The configuration tells Great Expectations to look for Validation Results in a Store called validations_store. The base_directory for validations_store is set to uncommitted/validations/ by default. 

validations_store_name: validations_store

stores:
  validations_store:
      class_name: ValidationsStore
      store_backend:
          class_name: TupleFilesystemStoreBackend
          base_directory: uncommitted/validations/

3. Update your configuration file to include a new Store for Validation Results on PostgreSQL​

In our case, the name is set to validations_postgres_store, but it can be any name you like. We also need to make some changes to the store_backend settings. The class_name will be set to DatabaseStoreBackend, and credentials will be set to ${db_creds}, which references the corresponding key in the config_variables.yml file. 

validations_store_name: validations_postgres_store

stores:
  validations_postgres_store:
      class_name: ValidationsStore
      store_backend:
          class_name: DatabaseStoreBackend
          credentials: ${db_creds}

5. Confirm that the new Validation Results Store has been added by running great_expectations store list​

Notice the output contains two Validation Result Stores: the original validations_store on the local filesystem and the validations_postgres_store we just configured. This is ok, since Great Expectations will look for Validation Results in PostgreSQL as long as we set the validations_store_name variable to validations_postgres_store. The config for validations_store can be removed if you would like. 

great_expectations store list

- name: validations_store
class_name: ValidationsStore
store_backend:
  class_name: TupleFilesystemStoreBackend
  base_directory: uncommitted/validations/

- name: validations_postgres_store
class_name: ValidationsStore
store_backend:
  class_name: DatabaseStoreBackend
  credentials:
      database: '<your_db_name>'
      drivername: postgresql
      host: '<your_host_name>'
      password: ******
      port: '<your_port>'
      username: '<your_username>'

6. Confirm that the Validation Results Store has been correctly configured​

Run a Checkpoint to store results in the new Validation Results store in PostgreSQL then visualize the results by re-building Data Docs.

Behind the scenes, Great Expectations will create a new table in your database called ge_validations_store, and populate the fields with information from the Validation Results.