May 2018
Intermediate to advanced
576 pages
30h 25m
English
An example of a tightly coupled system is the open source Postgres-XL. This supersedes the earlier Postgres-XC clustering software. These systems introduced the concept of a Global Transaction Manager (GTM), which allows nodes in a tightly coupled system to work together while guaranteeing consistency across reads and writes.
Postgres-XL spreads data across multiple nodes. Larger tables can be distributed evenly, using a hash-based distribution scheme. This feature allows Postgres-XL to scale well for both high-transaction-rate (OLTP) and business intelligence (OLAP) systems.
On Postgres-XL, smaller tables can be duplicated on all nodes. Changes to smaller tables are coordinated, so there is no possibility ...