Prerequisites

The following section lists the prerequisites for working with Qlik Replicate and a Google Cloud SQL for PostgreSQL source.

Replicate for Windows

PostgreSQL ODBC Driver psqlodbc_13_xx_xxxx-x64 must be installed on the Replicate machine.

Replicate for Linux

Download PostgreSQL 13 ODBC driver, and client programs and libraries.

• Example PostgreSQL ODBC file name: postgresql13-odbc-13.02.0000-1PGDG.rhel8.x86_64.rpm
• PostgreSQL client programs and libraries file name: postgresql13-13.8-1PGDG.rhel<version>.x86_64.rpm

Then, open a shell prompt and do the following:

1. Stop the Replicate service:

   ./areplicate stop

2. Optionally, confirm that the service has stopped:

   ./areplicate status

3. Install PostgreSQL 13 client programs and libraries.

4. Install the ODBC driver for PostgreSQL 13.

5. Change the working directory to <Replicate-Install-Dir>/bin.

6. Copy the driver location to the site_arep_login.sh file:

   echo "export LD_LIBRARY_PATH=\$LD_LIBRARY_PATH:/usr/lib:/usr/lib64:/usr/pgsql-13/lib" >> site_arep_login.sh

   This will add the driver to "LD_LIBRARY_PATH" and update the driver location in the site_arep_login.sh file.

7. Optionally, confirm that the driver location was copied:

   cat site_arep_login.sh

8. Makes sure that the /etc/odbcinst.ini file contains an entry for PostgreSQL, as in the following example:

   [PostgreSQL Unicode(x64)]

   Description = PostgreSQL ODBC driver

   Driver = /usr/pgsql-13/lib/psqlodbc.so

   Setup = /usr/pgsql-13/lib/psqlodbcw.so

   UsageCount = 1

9. Start the Replicate service:

   ./areplicate start

10. Optionally, confirm that the service has started:

    ./areplicate status

CDC prerequisites

To be able to capture changes from the database, you need to set up logical replication.

To set up logical replication:

1. On Google Cloud platform, set the following flags in the PostgreSQL settings:

   • cloudsql.logical_decoding=on
   • max_replication_slots: Every connection (that is, task) creates a new slot; this parameter configures the amount of simultaneous connections that can be established to the database. If you encounter performance issues, increasing this value might help.
   • max_wal_senders: The number of tasks that can run in parallel. If you encounter performance issues, increasing this value might help.

   For more information on these parameters, see https://www.postgresql.org/docs/current/runtime-config-replication.html

2. On the database, alter the user specified in the endpoint settings (username) to support replication:

   ALTER USER username WITH REPLICATION;