PostgreSQL says SCRAM to MD5 authentication
Version 10 improves replication, simplifies partitioning
With the release of PostgreSQL 10, the open source database's developers are farewelling the deprecated MD5 in their authentication mechanism.
Released late last week, PostgreSQL 10 instead uses an SHA-256 implementation of the Salted Challenge-Response Authentication Mechanism (SCRAM-SHA-256, described in RFC7677).
The database has also gained the ability to distribute workloads across multiple nodes.
To handle this “divide and conquer” approach, Version 10 introduces a publish/subscribe framework for logical replication.
PostgreSQL says this means database admins can send modifications between different databases on a per-database or per-table level. Admins can also fine-tune how data is replicated across clusters, and the replication features are also designed to support zero-downtime upgrades.
Replication can be carried out at table-level granularity, and is supported across major PostgreSQL versions.
Table partitioning has been reworked to a declarative model, because users were finding the previous syntax required “a nontrivial set of rules and triggers”. Further development of the partitioning capabilities are promised for future releases.
Other high points of the release include:
- Quorum commit for synchronous replication – in a distributed environment, an admin can specify how many replicas have acknowledged a change, for it to be considered safely written. This is another part of the database's “zero downtime” plans; and
- Better parallelism: – More parts of query execution can be parallelised, along with more types of data scans; and pre-sorting helps optimise the recombination of data.