Amazon PostgreSQL RDS (v1.0)

Amazon PostgreSQL RDS feature snapshot

A high-level look at Stitch's Amazon PostgreSQL RDS (v1.0) integration, including release status, useful links, and the features supported in Stitch.

Connecting Amazon PostgreSQL RDS

Amazon PostgreSQL RDS setup requirements

To set up Amazon PostgreSQL RDS in Stitch, you need:

• Permissions in Amazon Web Services (AWS) that allow you to:

  • Create/manage Security Groups, which is required to whitelist Stitch’s IP addresses.
  • View database details, which is required for retrieving the database’s connection details

• Permissions in PostgreSQL that allow you to create users. This is required to create a database user for Stitch.

• If using Log-based Incremental Replication, you’ll need:

  • A database running PostgreSQL 9.4 or greater. Earlier versions of PostgreSQL do not include logical replication functionality, which is required for Log-based Replication.
  • The rds_superuser role in your Amazon PostgreSQL RDS database, if you want to use Log-based Replication. This role is required to grant the rds_replication privilege to Stitch’s database user.
  • To connect to the master instance. Log-based replication will only work on master instances due to a feature gap in PostgreSQL 10. Based on their forums, PostgreSQL is working on adding support for using logical replication on a read replica to a future version.

• If you’re not using Log-based Incremental Replication, you’ll need:

  • A database running PostgreSQL 9.3.x or greater. PostgreSQL 9.3.x is the minimum version Stitch supports for PostgreSQL integrations.
  • To verify if the database is a read replica, or follower. While we always recommend connecting a replica over a production database, this also means you may need to verify some of its settings - specifically the max_standby_streaming_delay and max_standby_archive_delay settings - before connecting it to Stitch. We recommend setting these parameters to 8-12 hours for an initial replication job, and then decreasing them afterwards.

Step 1: Configure database connection settings

In this step, you’ll configure the database server to allow traffic from Stitch to access it. There are two ways to connect your database:

• A direct connection will work if your database is publicly accessible.
• An SSH tunnel is required if your database isn’t publicly accessible. This method uses a publicly accessible instance, or an SSH server, to act as an intermediary between Stitch and your database. The SSH server will forward traffic from Stitch through an encrypted tunnel to the private database.

Click the option you’re using below and follow the instructions.

Step 2: Create a Stitch database user

Next, you’ll create a dedicated database user for Stitch. This will ensure Stitch is visible in any logs or audits, and allow you to maintain your privilege hierarchy.

• Instructions
• Privileges list

GRANT rds_replication TO stitch

Step 3: Configure Log-based Incremental Replication

While Log-based Incremental Replication is the most accurate and efficient method of replication, using this replication method may, at times, require manual intervention or impact the source database’s performance. Refer to the Log-based Incremental Replication documentation for more info.

You can also use one of Stitch’s other Replication Methods, which don’t require any database configuration. Replication Methods can be changed at any time.

In this section:

• Step 3.1: Configure the database parameter group

• Step 3.2: Define the backup retention period

• Step 3.3: Apply parameter changes and reboot the database

• Step 3.4: Create a replication slot

Step 3.1: Configure the database parameter group

• Instructions
• Server settings list

Step 3.2: Define the backup retention period

The backup retention period setting defines the number of days for which automated backups are retained. This ensures that data can still be replicated even if a job is interrupted, there’s database or Stitch downtime, etc.

1. Navigate back to the Databases page by using the menu on the left side of the page.

2. Select the instance you’re connecting to Stitch.
3. Click the Modify button.

4. On the Modify DB Instance page, scroll down to the Backup section.

5. Set Backup retention period to anything greater than 1 day:

   

Step 3.3: Apply parameter changes and reboot the database

1. Scroll to the bottom of the Databases page and click Continue.
2. The next page will display a summary of the modifications made to the database. In the Scheduling of Modifications section, select the Apply Immediately option.
3. Click Modify DB Instance to apply the changes.

4. Navigate to the Instance Details page and locate the Parameter group. Initially, the Parameter group should say applying.

   When it changes to pending-reboot, you can reboot the database and apply the changes.

5. Scroll up to the top of the page and locate the Instance actions menu.
6. In this menu, click Reboot.
7. On the next page, click Reboot to confirm you want to reboot the instance.

Rebooting the instance will take a few minutes. When the status of the parameter group changes to in-sync and the DB instance status (located at the top of the Instance Details page) changes to available, the reboot will be complete:

Step 3.4: Create a replication slot

Next, you’ll create a dedicated logical replication slot for Stitch. In PostgreSQL, a logical replication slot represents a stream of database changes that can then be replayed to a client in the order they were made on the original server. Each slot streams a sequence of changes from a single database.

Note: Replication slots are specific to a given database in a cluster. If you want to connect multiple databases - whether in one integration or several - you’ll need to create a replication slot for each database.

1. Log into the master database as a superuser.
2. Using the wal2json plugin, create a logical replication slot:

   • If you’re connecting multiple databases, you’ll need to run this command for every database you want to connect, replacing <raw_database_name> with the name of the database:

     SELECT *
     FROM pg_create_logical_replication_slot('stitch_<raw_database_name>', 'wal2json');
     

     This will create a replication slot named stitch_<raw_database_name>.

   • If you’re connecting a single database, run the following command:

     SELECT *
     FROM pg_create_logical_replication_slot('stitch', 'wal2json');
     

     This will create a replication slot named stitch.

3. Log in as the Stitch user and verify you can read from the replication slot, replacing <replication_slot_name> with the name of the replication slot:

   SELECT COUNT(*)
   FROM pg_logical_slot_peek_changes('<replication_slot_name>', null, null);
   

   If connecting multiple databases, you should verify that the Stitch user can read from each of the replication slots you created.

Note: wal2json is required to use Log-based replication in Stitch for PostgreSQL-backed databases. wal2json is included by default and enabled in Step 3.1 by defining the rds.logical_replication parameter.

Step 4: Connect Stitch

In this step, you’ll complete the setup by entering the database’s connection details and defining replication settings in Stitch.

Step 4.1: Locate the database connection details in AWS

1. Sign into the AWS Console, if needed.
2. Navigate to the RDS option.

3. On the RDS Dashboard page, click the Databases option on the left side of the page. This will open the RDS Databases page.

4. In the list of databases, locate and click on the instance you want to connect to Stitch. This will open the Database Details page.

5. On the Database Details page, scroll down to the Connectivity & security section.

6. Locate the following fields:
   • Endpoint

   • DB Name: This field contains the name of the database used to launch the instance. You’ll only need this info if you want to connect this specific database to Stitch.

     You can connect this database to Stitch, or another database within Amazon PostgreSQL RDS.

   • Port: This is the port used by the database.

Leave this page open for now - you’ll need it to complete the setup.

Step 4.2: Define the database connection details in Stitch

1. If you aren’t signed into your Stitch account, sign in now.

2. On the Stitch Dashboard page, click the Add Integration button.

3. Locate and click the PostgreSQL icon.

4. Fill in the fields as follows:

   • Integration Name: Enter a name for the integration. This is the name that will display on the Stitch Dashboard for the integration; it’ll also be used to create the schema in your destination.

     For example, the name “Stitch Amazon PostgreSQL RDS” would create a schema called stitch_amazon_postgresql_rds in the destination. Note: The schema name cannot be changed after the integration is saved.

   • Host (Endpoint): Paste the Endpoint address from the Amazon PostgreSQL RDS Details page in AWS into this field. Don’t include the port number, if it’s appended to the end of the endpoint string - this will cause errors.

   • Port: Enter the port used by the instance. The default is 5432.

   • Username: Enter the Stitch Amazon PostgreSQL RDS database user’s username.

   • Password: Enter the password for the Stitch Amazon PostgreSQL RDS database user.

   • Database: Enter the name of the Amazon PostgreSQL RDS database you want to connect to Stitch. Stitch will ‘find’ all databases you give the Stitch user access to - a default database is only used to complete the connection. This is required for Amazon PostgreSQL RDS integrations.

   • Include PostgreSQL schema names in destination tables: Checking this setting will include schema names from the source database in the destination table name - for example: <source_schema_name>__<table_name>.

     Stitch loads all selected replicated tables to a single schema, preserving only the table name. If two tables canonicalize to the same name - even if they’re in different source databases or schemas - name collision errors can arise. Checking this setting can prevent these issues.

     Note: This setting can not be changed after the integration is saved. Additionally, this setting may create table names that exceed your destination’s limits. For more info, refer to the Database Integration Table Name Collisions guide.

Step 4.3: Define the SSH connection details

If you’re using an SSH tunnel to connect your Amazon PostgreSQL RDS database to Stitch, you’ll also need to define the SSH settings. Refer to the Setting up an SSH Tunnel for a database in Amazon Web Services guide for assistance with completing these fields.

1. Click the SSH Tunnel checkbox.

2. Fill in the fields as follows:

   • SSH Host: Paste the Public DNS of the SSH sever (EC2 instance) into this field. Refer to the Amazon SSH guide for instructions on retrieving this info.

   • SSH Port: Enter the SSH port of the SSH server (EC2 instance) into this field. This will usually be 22.

   • SSH User: Enter the Stitch Linux (SSH) user’s username.

Step 4.4: Define the SSL connection details

Click the Connect using SSL checkbox if you’re using an SSL connection. Note: The database must support and allow SSL connections for this setting to work correctly.

Step 4.5: Define Log-based Replication setting

In the Log-based Replication section, you can set this as the integration’s default Replication Method.

When enabled, tables that are set to replicate will use Log-based Incremental Replication by default. If you don’t want a table to use Log-based Incremental Replication, you can change it in the Table Settings page for that table.

If this setting isn’t enabled, you’ll have to select a Replication Method for each table you set to replicate.

Step 4.6: Create a replication schedule

In the Replication Frequency section, you’ll create the integration’s replication schedule. An integration’s replication schedule determines how often Stitch runs a replication job, and the time that job begins.

Amazon PostgreSQL RDS integrations support the following replication scheduling methods:

• Replication Frequency

• Anchor Scheduling

• Advanced Scheduling using Cron (Enterprise plans only)

To keep your row usage low, consider setting the integration to replicate less frequently. See the Understanding and Reducing Your Row Usage guide for tips on reducing your usage.

Step 5: Select data to replicate

The last step is to select select the tables and columns you want to replicate.

When you track a table, you’ll also need to define its Replication Method and, if using Key-based Incremental Replication, its Replication Key.

You can select tables and columns by:

1. In the Integration Details page, click the Tables to Replicate tab.
2. Locate a table you want to replicate.
3. Click the checkbox next to the object’s name. A green checkmark means the object is set to replicate.
4. If there are child objects, they’ll automatically display and you’ll be prompted to select some.

5. After you set a table to replicate, the Settings page will display. Note: When you track a table, by default all columns will also be tracked.

6. In the Settings page, define the table’s Replication Method and, if using Key-based Incremental Replication, its Replication Key.

7. Repeat this process for every table you want to replicate.

8. Click the Finalize Your Selections button to save your data selections.

Initial and historical replication jobs

After you finish setting up Amazon PostgreSQL RDS, its Sync Status may show as Pending on either the Stitch Dashboard or in the Integration Details page.

For a new integration, a Pending status indicates that Stitch is in the process of scheduling the initial replication job for the integration. This may take some time to complete.

Free historical data loads

The first seven days of replication, beginning when data is first replicated, are free. Rows replicated from the new integration during this time won’t count towards your quota. Stitch offers this as a way of testing new integrations, measuring usage, and ensuring historical data volumes don’t quickly consume your quota.

Did this article help? If you have questions or feedback, feel free to submit a pull request with your suggestions, open an issue on GitHub, or reach out to us.