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Subject: Re: PostgreSQL Active-Active Clustering
From: Christophe Pettus <xof@thebuild.com>
In-Reply-To: <PN0PR01MB90693B1DF528D64769D81B91C5A12@PN0PR01MB9069.INDPRD01.PROD.OUTLOOK.COM>
Date: Mon, 15 Jul 2024 12:28:14 -0700
Cc: "pgsql-general@lists.postgresql.org" <pgsql-general@lists.postgresql.org>,
 "Sur, Sanjay" <sanjaysur@kpmg.com>
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To: "Sarkar, Subhadeep" <subhadeepsarkar@kpmg.com>
Archived-At: <https://www.postgresql.org/message-id/0BD5E273-8E2C-4EDD-AB13-37CC3309E30E%40thebuild.com>
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> On Jul 15, 2024, at 12:06, Sarkar, Subhadeep =
<subhadeepsarkar@kpmg.com> wrote:
>=20
>   =E2=80=A2 Does the Community edition of PostgreSQL provide NATIVE =
active-active high availability clustering with objectives of =
scalability, load balancing and high availability without using any =
extensions or external components or usage of Kubernetes/Dockers.=20
>=20
>   =E2=80=A2 In the Community edition of PostgreSQL is it possible to =
setup a database cluster in load balancing mode and provide vertical and =
horizontal scalability without repartitioning or changes to the database =
objects or 3rd party transaction routing mechanisms using NATIVE =
features only (i.e. without using any extensions or external components =
or usage of Kubernetes/Dockers).
>=20
>   =E2=80=A2 In the Community edition of PostgreSQL is it possible to =
setup  a cluster where all the nodes are able to concurrently read-write =
the underlying database image using NATIVE features (i.e. without using =
any extensions or external components 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 none of these.  I will =
offer that your client is not being realistic if these are their =
requirements, and they expect them to 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 is possible, now, to =
build this on top of community PostgreSQL with logical replication, but =
there is notable development work involved, and you cannot just drop an =
existing database into PostgreSQL and expect this to work.  In any =
event, 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 be required.=20

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