Amazon Database Migration Service vs pgloader

Amazon Database Migration Service (AWS DMS) is a SaaS service for moving relational databases, data warehouses, NoSQL databases and other data stores to AWS or between cloud and on-premises environments. It handles one-time migrations and continuous replication, with support for both like-for-like and cross-engine moves. AWS says more than 20 databases and data warehouses can serve as source or target endpoints. DMS Schema Conversion assesses schemas and converts many code objects, including views, stored procedures and functions, while identifying work that needs manual conversion. DMS Serverless provisions and scales capacity according to transaction volume, billed hourly. Multi-AZ deployment uses redundant replication instances, and interrupted migrations can resume. API and AWS CLI support automation, while CloudTrail and CloudWatch Logs provide integrations. TLS, VPC deployment, PrivateLink and column masking are available. At least one endpoint must be Amazon RDS or EC2; on-premises-to-on-premises replication is unsupported. The AWS Free Tier offers free with credits.

pgloader migrates database and flat-file data into PostgreSQL using schema translation, casting rules, and parallel loading. Listed sources are MySQL, MariaDB, MS SQL Server, SQLite, CSV, fixed-width files, and DBF; Oracle support is not built yet. Its pipeline fetches the source catalog, prepares the PostgreSQL target, runs parallel COPY, creates indexes in parallel, and completes the schema. MySQL handling includes enum translation, converting TINYINT(1) to boolean, zero-date handling, and looking up credentials in .my.cnf. The MS SQL Server path includes Azure AD authentication, sequence migration, and multi-column foreign keys. For file imports, rejected rows can be separated after a failed COPY transaction while accepted rows continue loading. Custom casting rules go in a .load file. Version 3 in Common Lisp is the stable packaged release; version 4 is a pre-release JAR requiring Java 21 or later. The free Community tier has best-effort GitHub support. Paid support starts at €100/mo, with higher tiers offering priority handling, SLA-triaged patches, roadmap input, or issue-based support. It is self-hosted on Linux.