Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1sTaiN-000GZv-D8 for pgsql-general@arkaria.postgresql.org; Tue, 16 Jul 2024 05:27:03 +0000 Received: from localhost ([127.0.0.1] helo=malur.postgresql.org) by malur.postgresql.org with esmtp (Exim 4.94.2) (envelope-from ) id 1sTaiM-00FfBh-3d for pgsql-general@arkaria.postgresql.org; Tue, 16 Jul 2024 05:27:02 +0000 Received: from magus.postgresql.org ([2a02:c0:301:0:ffff::29]) by malur.postgresql.org with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1sTaiL-00FfBY-Om for pgsql-general@lists.postgresql.org; Tue, 16 Jul 2024 05:27:01 +0000 Received: from cloud.gatewaynet.com ([185.90.37.94]) by magus.postgresql.org with esmtps (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1sTaiI-002MKu-VT for pgsql-general@lists.postgresql.org; Tue, 16 Jul 2024 05:27:00 +0000 Content-Type: multipart/alternative; boundary="------------0plK5AHzibwXMtDjClghCET3" Message-ID: Date: Tue, 16 Jul 2024 08:26:55 +0300 MIME-Version: 1.0 Subject: Re: PostgreSQL Active-Active Clustering To: pgsql-general@lists.postgresql.org References: <0BD5E273-8E2C-4EDD-AB13-37CC3309E30E@thebuild.com> Content-Language: en-US From: Achilleas Mantzios In-Reply-To: List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Archived-At: Precedence: bulk This is a multi-part message in MIME format. --------------0plK5AHzibwXMtDjClghCET3 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Στις 15/7/24 22:55, ο/η Ron Johnson έγραψε: > On Mon, Jul 15, 2024 at 3:28 PM Christophe Pettus > wrote: > > > > On Jul 15, 2024, at 12:06, Sarkar, Subhadeep > wrote: > > > > [snip] > > >   • 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). > > [snip] > > 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). > > > This "lack of products" puzzles me, because DEC was doing this with > VAX (then Alpha and Itanium) clusters 40 years ago via a Distributed > Lock Manager integrated deep into VMS. Their Rdb and (CODASYL) DBMS > products used those functions extensively. IMHO IBM did something similar with their shared DASDi back in 70s+. There was serialization mechanism enabling concurrent writes to data sets (meaning files). Not to mention IBM had great VM technology back in the day. > > (In the late 1990s, they sold the DLM code to Oracle, which is where > RAC comes from.) > > It was shared-disk, multiple-writer, because the DLM allowed for > locking at the row level.  Thus, a half dozen cluster nodes could hold > write locks on different rows on the same data page. > -- Achilleas Mantzios IT DEV - HEAD IT DEPT Dynacom Tankers Mgmt (as agents only) --------------0plK5AHzibwXMtDjClghCET3 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: 8bit
Στις 15/7/24 22:55, ο/η Ron Johnson έγραψε:
On Mon, Jul 15, 2024 at 3:28 PM Christophe Pettus <xof@thebuild.com> wrote:

> On Jul 15, 2024, at 12:06, Sarkar, Subhadeep <subhadeepsarkar@kpmg.com> wrote:
>
[snip] 
>   • 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).
[snip] 
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).

This "lack of products" puzzles me, because DEC was doing this with VAX (then Alpha and Itanium) clusters 40 years ago via a Distributed Lock Manager integrated deep into VMS.  Their Rdb and (CODASYL) DBMS products used those functions extensively.
IMHO IBM did something similar with their shared DASDi back in 70s+. There was serialization mechanism enabling concurrent writes to data sets (meaning files). Not to mention IBM had great VM technology back in the day.

(In the late 1990s, they sold the DLM code to Oracle, which is where RAC comes from.)

It was shared-disk, multiple-writer, because the DLM allowed for locking at the row level.  Thus, a half dozen cluster nodes could hold write locks on different rows on the same data page.

-- 
Achilleas Mantzios
 IT DEV - HEAD
 IT DEPT
 Dynacom Tankers Mgmt (as agents only)
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