Re: [soa-rm] microservice database consistency

Even if the "Single Database per Microservice pattern is a well established goal for Microservice design and aligns with the Single Responsibility Principle", this does not make it reasonable. Can you imagine a business application comprised 24 MS, or 124 MS? Easily (considering their fine-granular nature). Well, this application is supposed to have 24 (124) databases and related resource for maintenence... Thell this to anyone with the funds. This is unrealistic - no one business will pay for this. Obviously, this is a whole in the MSA and it has good potentials to become a black whole for MSA.

Also, I see more and more assumptions pointing to that MS in the application should know about each other... OOA is not that far :-)

- Michael

Sent: Thursday, February 02, 2017 at 10:23 PM
From: rexbroo <rexb@starbourne.com>
To: soa-rm@lists.oasis-open.org
Subject: Re: [soa-rm] microservice database consistency

The Single Database per Microservice pattern is a well established goal for Microservice design and aligns with the Single Responsibility Principle, though it is not as easily achieved as it seems when you consider that there may be multiple instances of a given Microservice, especially where those instances are spun up at need by load balancing in the cloud under PaaS implementations.

As the author says in an event-driven architecture a Microservice publishes an event when it’s data changes and other services consume that event and update their data. That is, of course, an oversimplification of a process where duplicate notifications must be prevented. Also, providing for eventual consistency in persistent datastores is something that has to be addressed. This is where our effort to figure out heuristics for scoping Microservices and their interactive grouping can provide value. The question is how to structure a set of interrelated Microservices such that they can work together optimally.

Lots to think about.

Rex

On 2/2/2017 12:37 PM, Ken Laskey wrote:

This has been a continuing topic of discussion and I found some info that actually covers this in the level of detail where you an envision a solution.

First see http://microservices.io/patterns/microservices.html, specially

How to maintain data consistency?

and then the link http://microservices.io/patterns/data/event-driven-architecture.html.

Thoughts? Continuing questions?

Ken

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Dr. Kenneth Laskey
MITRE Corporation, M/S F510 phone: 703-983-7934
7515 Colshire Drive fax: 703-983-1379
McLean VA 22102-7508

-- 
Rex Brooks
Starbourne Communications Design
Email: rexb@starbourne.com
GeoAddress:
1361 Addison St. Apt. A
Berkeley, CA 94702
Phone: 510-898-0670

soa-rm message

How to maintain data consistency?