Today here is a highlight of a new Postgres 9.4 feature interesting for developers and companies doing packaging of Postgres on Windows as it makes possible the installation of client-only binaries and libraries using MSVC. It has been introduced by this commit:

Continuing on the series of posts about logical replication and after looking at [some basics] (/postgresql-2/postgres-9-4-feature-highlight-basics-logical-decoding/) and the concept of [REPLICA IDENTITY] (/postgresql-2/postgres-9-4-feature-highlight-replica-identity-logical-replication/) for a table, now is time to begin more serious things by having a look at how to develop an output plugin for the logical decoding facility.

Among the many things to say about logical replication features added in PostgreSQL 9.4, REPLICA IDENTITY is a new table-level parameter that can be used to control the information written to WAL to identify tuple data that is being deleted or updated (an update being a succession of an insert and a delete in MVCC).

The second huge feature coming in PostgreSQL 9.4 with [jsonb] (postgresql-2/postgres-9-4-feature-highlight-indexing-jsonb/) is called [logical decoding] (https://www.postgresql.org/docs/devel/static/logicaldecoding.html). In short, it is a new plugin facility that can be used to decode changes that happen on a database and stream them to external sources. It can be used for many things like replication, auditing or even online upgrade solutions.

Except if you have been cut from the Internet the last week, you have already heard of Heartbleed. This good candidate for the “Bug of the Year 2014” price is already costing a better-not-to-count amount of money in maintenance and development for many companies around the world.

PostgreSQL 9.4 is shipping with a new feature called [jsonb] (https://www.postgresql.org/docs/devel/static/datatype-json.html), which is a new data type able to store JSON data supporting GIN indexing (!). In short, this feature, one of the most important of the upcoming release, if not the most important, puts Postgres directly in good position in the field of document-oriented database systems.

PostgreSQL 9.4 is coming with more support for triggers, making them now firable on foreign tables. This feature has been introduced by the following commit:

A new feature is showing up in PostgreSQL 9.4 allowing to get more information about transaction lock waits and their circumstances. It has been introduced by this commit:

Replication slots is a new feature of PostgreSQL 9.4 that has been introduced by this commit:

When using COPY, there is an option called FORCE_NOT_NULL allowing to enforce a string to be not null even if it is not quoted. Here is an example of how it works: