Re: PostgreSQL Active-Active Clustering

> On Jul 15, 2024, at 12:06, Sarkar, Subhadeep <subhadeepsarkar@kpmg.com> wrote:
>
>   • Does the Community edition of PostgreSQL provide NATIVE active-active high availability clustering with
objectivesof scalability, load balancing and high availability without using any extensions or external components or
usageof Kubernetes/Dockers.  
>
>   • In the Community edition of PostgreSQL is it possible to setup a database cluster in load balancing mode and
providevertical and horizontal scalability without repartitioning or changes to the database objects or 3rd party
transactionrouting mechanisms using NATIVE features only (i.e. without using any extensions or external components or
usageof Kubernetes/Dockers). 
>
>   • In the Community edition of PostgreSQL is it possible to setup  a cluster where all the nodes are able to
concurrentlyread-write the underlying database image using NATIVE features (i.e. without using any extensions or
externalcomponents or usage of Kubernetes/Dockers). 

Short answer: No.

The community version of PostgreSQL, without any extensions beyond what is available in the core distribution, supports
noneof these.  I will offer that your client is not being realistic if these are their requirements, and they expect
themto be fulfilled by the core distribution of any open-source database. 

There are commercial extensions to PostgreSQL that provide the first, but PostgreSQL does not do so out of the box.  It
ispossible, now, to build this on top of community PostgreSQL with logical replication, but there is notable
developmentwork involved, and you cannot just drop an existing database into PostgreSQL and expect this to work.  In
anyevent, you will need to make sure the schema is compatible with an active-active model. 

For the second, you can explore open-source projects such as Citus, but some attention to the schema and queries will
berequired.  

No product, either commercial or open-source, provides the last one (read-write shared storage), although there are
commercialproducts that provide for a shared-storage model single-writer, multiple-reader model (for example, Amazon
Aurora).