PgConf.Russia 2017

Currently, to execute SQL queries PostgreSQL uses interpreter, which implements Volcano-style iteration model. At the same time it’s possible to get significant speedup by dynamically JIT-compiling query “on-the-fly”. In this case it’s possible to generate code that is specialized for given SQL query, and perform compiler optimizations using the information about table structure and data types that is already known at run time. This approach is especially important for complex queries, which performance is CPU-bound.

Do you test your PostgreSQL releases prior to Production in a dedicated test environment? Are you sure that your test environment (shortly Test) is equal to Production and in an appropriate state?

In Skype we were facing multiple challenges associated with database testing:
- Simplifying complex Production architecture of thousands of PostgreSQL instances, interconnected with RPCs and replications, infrastructure servers and external DB scripts, into their Test counterparts.
- Constantly growing hardware requirements, insufficient cleanup of data generated in Test.
- Differences between Test and Production were appearing and accumulating. Recognizing and fixing them required lots of effort.

This talk is intended for Oracle DBAs whose are considering to start using PostgreSQL as another RDBMS engine in their DB portfolio or for PostgreSQL DBAs, who wants to learn some of similarities and differences between Oracle and PostgreSQL. This talk is not intended to be a migration guideline neither advocating one platform over another. General database structure overview for both platforms will be compared in terms of memory configuration parameters; logical to physical structure as well as we’ll touch some security point of view and backup & recovery tools available. Oracle container databases are not covered. The talk want’s to help create a bridge for DBA and avoid some frustrations at the first Oracle DBA step to discover, learn and start using PostgreSQL as reliable fully functional database.

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The new ISO/IEC 9075-2:2016 standard specifies JSON data and operations syntax and semantics specifics for SQL. This talk overviews the requirements of this standard, and focuses on the differences between them and the actual implementation of JSON/JSONB in PostgreSQL. Special attention will be paid to JSON Path (XPath analogue), SQL/JSON functions and our plans to make Postgres compliant with this standard.

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