PostgreSQL clusters using streaming replication and pgpool-II
The talk is about PostgreSQL clusters using streaming replication and pgpool-II, which are quite popular in Japan. Plus, the next version of pgpool-II will be released this winter, so the talk will be about what's new in the version.
Kamil Islamov Stickeroid Ai
Method of automated refresh of preprocessed results of analytis reports is provided. Preprocessing and caching of reports allows ability for fast response for big data reports. Author describes the way of reports cache refreshing with minimum server loads and tuned actualization rate.
Boris Veryugin ООО "Диасофт Платформа"
Diasoft Platform company's technology solutions for migration of applications from proprietary DBMS (on the examples of Oracle and Microsoft SQL Server) to PostgreSQL will be presented in the talk. These solutions are implemented in Diasoft Database Adapter software.
Our technology solutions allow to automate: 1) migration of database schema (including translation of stored procedure and function code); 2) migration of data; 3) migration of client applications without any change in their source code.
Алексей Лесовский PostgreSQL Consulting LLC
Alexander Korotkov Postgres Professional
Postgres was initially designed to support access methods extendability. Well known citation about access method in Postgres claims: "It is imperative that a user be able to construct new access methods to provide efficient access to instances of nontraditional base types" Michael Stonebraker, Jeff Anton, Michael Hirohama. Extendability in POSTGRES, IEEE Data Eng. Bull. 10 (2) pp.16-23, 1987
Initially, heap was just one for access methods. So, extendability of access methods would also mean pluggable storage engines in modern terms. For now, only index access methods are defined in pg_am table of system catalog. Those index access methods also have well-defined interface. Therefore in order to meet initial design PostgreSQL need to support two features:
- Pluggable index access methods, i.e. ability to implement new index types by adding new tuples to pg_am;
- Pluggable storage engines, i.e. ability to implement completely different storages for tables without traditional heap.
Besides mechanical work like "CREATE ACCESS METHOD" command, extensible index access methods needs to be WAL-logged. For now, community doesn't want extensions to define their own WAL-records, because there is a chance to break both recovery and replication, which is not acceptable. Another approach is to define generic WAL-records, that specify a difference between pages in generalized way.
There are only few DBMS which support pluggable storage engines now. MySQL is the most common example here. However, dealing with different storage engines in MySQL is like dealing with different DBMS. This is not the way PostgreSQL should go from our view.
However, now PostgreSQL users realize benefits from other storages. Ideas of columnar storages and in-memory storages for PostgreSQL are very popular. Simultaneously, technical possibilities to implement them are growing. FDW and custom nodes are arrived. Generic WAL and extensible index access methods are pending for 9.6. Much work in the direction of pluggable storage engines is already done even if it had different aims.
It's time for PostgreSQL core developers to think about native support of pluggable storages without kludges. Finally, we should get "CREATE STORAGE ENGINE name ..." command as legal extendability mechanism.
In this talk we will show current state on pluggable index access method and design of pluggable storage engines.