PostgreSQL
Last updated
Last updated
PostgreSQL, or Postgres, is an open source relational database management system that uses and extends the SQL language. It is free to use, highly extensible, and tries to conform with the SQL standard.
This document walks you through setting up Postgres to use as a source data Store in DeltaStream.
Note In DeltaStream, in CDC pipelines you can use Postgres only as a source.
Create a user in the PostgreSQL instance (see PostgreSQL documentation).
Important If you're creating a CDC pipeline backed by a PostgreSQL source store, review these additional setup instructions.
Open DeltaStream. In the lefthand navigation, click Resources ( ). The Resources page displays, with the Stores tab active.
Click Add Store +, and from the list that displays click PostgresSQL. The Add Store window displays, with Postgres-specific fields you must complete.
Enter the following information:
Store Name – A name to identify your DeltaStream store (See Store).
Store Type – POSTGRESQL.
Access Region – DeltaStream access region to associate with the store (see Region).
URI – URI for the PostgreSQL database with /<database_name>
appended.
For example, given a postgres URI of my.postgresql.uri
and an open port on the database of 5432
, to connect DeltaStream to the demo database the URI would display as:
postgresql://my.postgresql.uri:5432/demo
Username – Username associated with the PostgreSQL database user DeltaStream should assume.
Password – The password associated with the username.
Click Add to create and save the store.
Note For instructions on creating the store using DSQL, see CREATE STORE.
Click your PostgresSQL store (in this case, Postgres_Test_Store). The Postgres store page opens with the Schemas tab active. A list displays of the existing schemas in your PostgreSQL database.
(Optional) Create a new schema To do this:
Click + Add Schema. When the Add Schema window opens, enter a name for the new schema and then click Add. Your new schema displays in the entities list.
To view the tables in a schema, click a schema name.
To view a sample of rows from that table, click a table in a schema and then click Print.
To follow the next few steps, you must already have a PostgreSQL store labeled psql_store
. You also must have a Kafka store labeled kafka_store.
Define a DeltaStream stream as your source data from PostgreSQL. Then write a query to process this data and sink it to a Kafka topic.
For more details, see Adding PostgreSQL as a DeltaStream Store.
In this step, you create a stream called pageviews_cdc
that is backed by data in a PostgreSQL table. This stream represents change data capture (CDC) events from the PostgreSQL table.
Note DeltaStream uses Debezium to capture changes in a source relation table. To learn more about how CDC works with DeltaStream, see Change Data Capture (CDC).
First, print the data for your source, which is the pageviews
PostgreSQL table. To print sample rows from the table in DeltaStream, inspect your store and navigate to the table you wish to print. (For more details, see Inspect the PostgreSQL Store).
Below is an example of how to create a stream on your pageviews
data. The fields match the Debezium standard; any insert, delete, or update to the pageviews
table becomes an event for your pageviews_cdc
stream.
In the SQL pane of your workspace, write the CREATE STREAM AS SELECT (CSAS) query to ingest from pageviews_cdc
and output to a new stream labeled pageviews_cdc_sink
. To represent a feed of upsert events, this query filters for records whose op
field is CREATE
or UPDATE
.
Click Run.
Verify that the query is properly working. To do this, write an interactive SELECT query.
In the lefthand navigation, click Resources ( ). This displays a list of the existing stores.
In the lefthand navigation, click Workspace ( ).
In the lefthand navigation, click Queries ( ) to view existing queries, including the query from step 2, above. Important It can take a small amount of time for the query to transition into the Running state. Refresh you screen occasionally until you see the query transition into the Running state.