The maximum number of connections a PostgreSQL can accept is configured using max_connections. When attempting to connect to a server already at full capacity, logically the server complains:

Postgres 12 is bringing a game-changer regarding common table expressions (named also CTE, defined by WITH clauses in SELECT queries) with the following commit:

Partitions in Postgres are a recent concept, being introduced as of version 10 and improved a lot over the last years. It is complicated, and doable, to gather information about them with specific queries working on the system catalogs, still these may not be straight-forward. For example, getting a full partition tree leads to the use of WITH RECURSIVE when working on partitions with multiple layers.

A couple of weeks ago a bug has popped up on the community mailing lists about the use of temporary objects in two-phase commit. After discussions, the result is the following commit:

The following commit has been merged into Postgres 12, adding a new option for VACUUM and ANALYZE:

The following commit has been merged into Postgres 12 a couple of months ago, easing failover control flow:

The following bug fix has been committed to the PostgreSQL code tree, addressing an issue visibly since ON COMMIT support for CREATE TABLE has been added back in commit ebb5318 from 2002:

The following commit has reached PostgreSQL 12, which brings more flexibility in managing replication with standbys distributed geographically:

The following commit has happened in Postgres 12, adding a feature which allows to control and potentially enforce the protocol SSL connections can use when connecting to the server:

If you maintain some PostgreSQL extensions which rely on PGXS, a build infrastructure for PostgreSQL, the following commit added to Postgres 12 will be likely something interesting, because it adds new options to control more types of regression tests: