PgConf.Russia 2020

In the report, we want to talk about the experience of migrating one large system from Oracle to PostgreSQL. The system itself was built on the PHP + Oracle stack; its distinguishing feature was that all business logic was implemented in PL / SQL code. In a DBMS, there are more than 3000 packages with 4-10 functions (procedures) in each. In PHP - more than 10,000 forms with inserts of anonymous blocks used to receive data, process and save results in Oracle.

To solve this extremely voluminous work, we took ANTLR4 (a powerful parser generator for reading, processing, executing, or translating structured text), PL/SQL grammar, and created an automatic converter that allows you to convert all objects in the schema and our system from Oracle to working code for PostgreSQL.

This talk discusses the open source components we use at Adjust to manage a massive number (5+PB) of application log messages on PostgreSQL in a massively multi-parallel way. It provides both a use case for PostgreSQL in a big data (high volume/velocity/variety) environment, and can be used to show the power of PostgreSQL with JSONB, GIN, and more.

This talk covers the capabilities of the components in depth, sufficient to inspire similar solutions.

Many businesses which use Database management systems like Oracle, DB2 & MS SQL are unreliable these days. Moreover, the costs incurred in maintaining these systems and its product licenses keeps on increasing. As the competitors are migrating over to the new technologies and tools available in the market, it is necessary for these businesses to migrate to new environment which is efficient, consistent and reliable to stay in the market and the technologies used in the current environment have become obsolete or no longer serve the business purpose. PostgreSQL has emerged as a top open-source RDBMS software. Since there is no licensing cost associated with it most of the companies are planning to migrate the databases which are currently running on other RDBMS like Oracle, DB2, MS SQL server to PostgreSQL. This report summarizes the various methodologies, procedures and techniques involved in successfully migrating the data from Oracle to PostgreSQL & DB2 to PostgreSQL. Migration is not a simple effort there should be proper planning and testing involved in this right from database connectivity to performance analysis. In this paper we are going to cover most of the steps which we need to consider before the migration and after the migration like choosing the correct tools for implementing the migration, time taken to migrate ,data compatibility, code conversion, application connectivity to database, database configuration parameters, performance analysis, replication setups, database monitoring, patching and backup strategies.

We will discuss stored procedures and functions, as well as the code within the database in general. We'll take a look at stored procedures from different angles: as a DBA, a database developer, and a backend developer. We will try to understand the specifics of stored procedures that often go against the common coding guidelines, and discuss best practices for working with stored procedures.
This is mainly a motivational talk for database and backend developers, not an advanced tech talk.