Google Cloud Datastream vs OpenLogReplicator

Google Cloud Datastream is a serverless change data capture and replication service for synchronizing data. Streams can capture ongoing updates and backfill historical records, while the service scales automatically without resources for users to provision or manage. Supported destinations include BigQuery, Cloud Storage, and Apache Iceberg tables. Documented sources include Oracle, MySQL, PostgreSQL, AlloyDB, SQL Server, MongoDB, Spanner, Salesforce, ServiceNow, Workday, and Microsoft Dataverse; some sources are marked as preview. Datastream can work with Dataflow templates to load data from Cloud Storage into destinations including BigQuery, Cloud SQL, and Spanner. Connectivity options include IP allowlisting, a forward SSH tunnel, and private connectivity over VPC peering. Processing is charged, idle streams incur no cost, and other Google Cloud resources are billed separately. The free tier includes 100 GiB of eligible CDC data per month per billing account. Events are delivered at least once, but ordering is not guaranteed. Datastream is administered through the Google Cloud console, CLI, or REST API.

OpenLogReplicator is a free, open-source Oracle change data capture solution written in C++ for self-hosted Linux deployments. It reads transactions directly from Oracle binary redo logs and streams changes as JSON or Protobuf. Destinations include Kafka, flat files, plain TCP/IP or ZeroMQ network streams, and a discard output for testing. The log-based design is intended to minimize impact on the source database. Archived redo logs can be processed, including offline operation while the database is shut down, and actual DDL commands can be tracked. Basic DML filters can restrict processing, such as selecting INSERT operations for a table. Direct Prometheus metrics include DML counters that can carry schema-name tags. Oracle 23c is supported; binary XMLType support for Oracle 11.2 through 21c is experimental. Debezium use is supported with version 1.3.0 as the minimum and 1.9.0 recommended for Debezium 2.x and 3.x. The GPL v3 plan costs nothing.