PgConf.Russia 2020

When migrating data from one DBMS to another, the question arises: choose a third-party tool or to program the migration yourself? Companies, trying to grow competencies within themselves, choose the second option. And they come across the "invention of their own bicycles". However, the market has powerful free data migration tools. One such tool is Pentaho Data Integration, part of the Pentaho Community Edition. The report will discuss the use of this package for data migration between Oracle and PostgreSQL. Particular attention will be paid to the problems with using this tool, and to the tasks of testing for the completeness and integrity of migrated data.

Small video illustration:

I will share our experience of migrating a server application for Russian railways from Oracle 11g Standard Edition to vanilla PostgreSQL 11.5.
At the time of migration, the database contained about 200 stored procedures of over 60000 lines of Oracle PL/SQL code (which has been developed since 2006, that is, for more than 12 years), about 250 tables, and 50GB of data.
Starting with a prologue, we'll describe our adventures along the migration process, as well as pleasant and unpleasant surprises we encountered, and finally get to an epilogue and a happy end. The story is told on behalf of an Oracle user exploring Postgres.

pg_repack is one of the most popular instruments for removing bloat of tables and indexes in Postgres. In most cases, it works perfectly. But if you use such a feature of Postgres as deferred constraints, using pg_repack becomes more difficult or even impossible. I will talk about how we encountered the problem and will describe some workarounds - from internal instruments of Postgres to a small patch for pg_repack.

pg_probackup is a flexible tool that allows choosing the backup strategy depending on the write load of the PostgreSQL cluster, as well as offers a number of other features that can facilitate this vital aspect of database maintenance. In this tutorial, we will see how to apply this tool in practice.