PGConf.Russia 2018

Developers are often challenged to deliver results that are hard to implement using simple SQL queries. Fortunately, complex SQL capabilities exist in the SQL standards — common table expressions and window functions.

SQL is a declarative language, meaning the user submits an SQL command and the database determines the optimal execution. Common Table Expressions (CTEs) allow queries to be more imperative, allowing looping and processing hierarchical structures that are normally associated only with imperative languages.

Normal SQL queries return rows where each row is independent of the other returned rows. SQL window functions allow queries to return computed columns based on values in other rows in the result set.

This tutorial will help developers use CTE queries in their applications and allow operations that normally could only be done in application code to be done via SQL queries. It also explains the many window function facilities and how they can be used to produce useful SQL query results.

Video

Part I «Programming the SQL Way with CTE»

Part II «Postgres Window Magic»

Pluggable storages is hot subject in PostgreSQL development. The period of heated debates about whether we need them is over. Skepticism about pluggable storages, based on concern that they may be source of inconsistent behavior, was weakened after criticism of PostgreSQL MVCC implementation from Uber side. It became widely understandable that pluggable storages are needed at least for an alternative MVCC implementation. And that is one of way-points for pluggable storages interface design.

At the moment, work on pluggable storages is in the practical stage. There is a thread is pgsql-hackers where few people are developing patchset and several people are doing review.

This talk will cover following subjects:

• overview of pluggable storages interface;
• changes in PostgreSQL core required to implement this interface;
• current and potential implementations of pluggable storages including heap with undo-log and in-memory OLTP engine;
• current state of patchset and prospective of its commit
• further development of interface allowing more possibilities in pluggable storages (columnar, index-organized, LSM and so on).

Transition tables, a new feature in PostgreSQL 10, offer broad new capabilities including new ways to maintain materialized views. At the end of this talk, you will have seen new ways to use this feature and have it in your tool chest for the future.

Comparison of capabilities of PostgreSQL and MS SQL to work with 1С. What does pg_restore mean for 1С user? Results of load testing for 1C database of more than 1TB size. The story of one 1C Production: 2 years, 500+ databases 1C, 4TB of data, cascading replication.