Στις 15/7/24 22:55, ο/η Ron Johnson έγραψε:
> On Mon, Jul 15, 2024 at 3:28 PM Christophe Pettus <xof(at)thebuild(dot)com>
> wrote:
>
>
> > On Jul 15, 2024, at 12:06, Sarkar, Subhadeep
> <subhadeepsarkar(at)kpmg(dot)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)