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26.1. Configuring the Metadata Catalog
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26.1. Configuring the Metadata Catalog #

26.1.1. Defining a Metadata Catalog Connection (define_catalog_connection)
26.1.2. Initializing the Metadata Catalog (init)

Metadata tables of pgpro_metastore are stored in the axe_catalog schema of the Postgres Pro DBMS, or in the so-called metadata catalog. This catalog can be initialized on the local Postgres Pro AXE server or on a remote server.

26.1.1. Defining a Metadata Catalog Connection (define_catalog_connection) #

You must define a metadata catalog connection regardless of whether the metadata catalog is initialized on the local Postgres Pro AXE server or on a remote server.

Required privileges: Postgres Pro AXE administrator only. For more information about stored procedures and privileges, refer to Section 18.1.

Execute the following command on the Postgres Pro AXE server: 

  SELECT metastore.define_catalog_connection('host', 'port', 'database', 'username', 'password');

Where:

  • host and port: The hostname and port for connecting to the server where to initialize the metadata catalog later.

  • database: The name of the server database where to create metadata tables.

  • username and password: The username and password for connecting to the Postgres Pro DBMS on the server.

If one of these parameters is missing, pass an empty string as a value.

Example 26.1. Defining a Metadata Catalog Connection without a Username and Password

  SELECT metastore.define_catalog_connection('localhost','5433','postgres','','');

For the changes to take effect, reconnect to the Postgres Pro AXE server (not to the server with the metadata catalog).

Postgres Pro AXE performs the following actions:

  1. Checks input parameters and user privileges.

  2. Updates the foreign server (metastore_catalog) using the specified public connection parameters of the server with the metadata catalog: 

        ALTER SERVER metastore_catalog
      OPTIONS (
        SET host     'host',
        SET port     'port',
        SET dbname   'database',
        SET user     'username'
      );

  3. Updates the user mapping for the PUBLIC role using the specified private connection parameters of the server with the metadata catalog: 

      ALTER USER MAPPING FOR PUBLIC
    SERVER metastore_catalog
    OPTIONS (
      SET password 'password'
    );

If the connection to the server with the metadata catalog fails when performing one of the stored procedures, you are automatically reconnected using the last connection parameters.

Example 26.2. 

        postgres=# SELECT metastore.remove_storage('mt_storage');
        INFO:  Connection failed! Trying to reconnect.
        INFO:  Reconnecting...1
        INFO:  Reconnect successful!
                remove_storage
        -----------------------------------
        Storage was removed successfully.
        (1 row)

26.1.2. Initializing the Metadata Catalog (init) #

When you initialize the metadata catalog, metadata tables are created in the server database.

Before performing this instruction, define a metadata catalog connection.

Required privileges: Postgres Pro AXE administrator only. For more information about stored procedures and privileges, refer to Section 18.1.

Execute the following command on the Postgres Pro AXE server: 

  SELECT metastore.init(force_init bool DEFAULT false)

Where force_init specifies whether to reinitialize the metadata catalog if it is already initialized on the server.

Postgres Pro AXE performs the following actions:

  1. Checks input parameters and user privileges.

  2. If the force_init parameter is set to false and the axe_catalog schema already exists on the server, outputs a warning that the metadata catalog is already initialized and terminates the command. Otherwise, Postgres Pro AXE initializes the metadata catalog on the server.

  3. If the force_init parameter is set to true, performs the following actions:

    1. Deletes all proxy tables from the metastore schema on the Postgres Pro AXE server.

    2. Reinitializes the metadata catalog on the server.

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Chapter 26. Metadata Catalog Home 26.2. Connecting to a Remote Server with the Metadata Catalog
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