Re: PostgreSQL Active-Active Clustering

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
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