Infrastructure at your Service
By Franck Pachot . I have published 105 additional blog posts here since the 500th one https://blog.dbi-services.com/rollback-to-savepoint/ that I have written on my come back to dbi-services. On Oracle Database, of course, other databases as well, on clouds (OCI and AWS mainly, with a look at GCP and Azure). But also with some thoughts on the rise of the “scale-out” obsession of NoSQL. And, because I’m convinced that consistency, referential integrity, and SQL is a…
By Franck Pachot . The title is provocative on purpose because you can read in many places that you should avoid scans, and that Scan operations are less efficient than other operations in DynamoDB. I think that there is a risk, reading those message without understanding what is behind, that people will actually avoid Scans and replace them by something that is even worse. If you want to compare the efficiency of an operation, you…
By Franck Pachot . I have written about some NoSQL myths in previous posts (here and here) and I got some feedback from people mentioning that the test case was on relatively small data. This is true. In order to understand how it works, we need to explain and trace the execution, and that is easier on a small test case. Once the algorithm is understood it is easy to infer how it scales. Then,…
By Franck Pachot . The NoSQL technologies emerged for Big Data workloads where eventual consistency is acceptable and scaling out to multiple server nodes is an easy answer to increase throughput. With cloud services rising, those key-value document datastores started to be used by the web-scale companies for some transactional processing workloads as well. The solutions can provide high performance and easy partitioning capabilities thanks to the very simple API of NoSQL. Each table or…
By Franck Pachot . That’s common to any data structure, whether it is RDBMS or NoSQL, indexes are good to accelerate reads but slow the writes. This post explains the consequences of adding indexes in DynamoDB. Secondary Indexes What we call an index in DynamoDB is different from an index in RDBMS. They have the same goal: store your data with some redundancy in order to have it physically partitioned, sorted, and clustered differently than…
By Franck Pachot . In The myth of NoSQL (vs. RDBMS) “joins dont scale” I explained that joins actually scale very well with an O(logN) on the input tables size, thanks to B*Tree index access, and can even be bounded by hash partitioning with local index, like in DynamoDB single-table design. Jonathan Lewis added a comment that, given the name of the tables (USERS and ORDERS). we should expect an increasing number of rows returned…
By Franck Pachot . I have written a few blog posts about some NoSQL (vs. RDBMS) myths (“joins dont scale”, “agility: adding attributes” and “simpler API to bound resources”). And I’ll continue on other points that are claimed by some NoSQL vendors and are, in my opinion, misleading by lack of knowledge and facts about RDBMS databases. But here I’m sharing an opposite opinion: SQL being user-friendly is now a myth. Yes, that was the…
By Franck Pachot . NoSQL provides an API that is much simpler than SQL. And one advantage of it is that users cannot exceed a defined amount of resources in one call. You can read this in Alex DeBrie article https://www.alexdebrie.com/posts/dynamodb-no-bad-queries/#relational-queries-are-unbounded which I take as a base for some of my “Myth of NoSQL vs RDBMS” posts because he explains very well how SQL and NoSQL are perceived by the users. But this idea of…
By Franck Pachot . J’essaie quelque chose de nouveau. Je publie beaucoup en anglais (blog, articles, prĂ©sentations) mais cette fois quelque chose de 100% francophone. En sortant du confinement, on reprend les transports (train, voiture,…) et c’est l’occasion de se dĂ©tendre en musique mais aussi de s’informer avec des podcasts. J’ai l’impression que c’est un format qui a de l’avenir: moins contraignant que regarder une video ou ou lire un article ou une newsletter. Alors…
By Franck Pachot . I’ll reference Alex DeBrie article “SQL, NoSQL, and Scale: How DynamoDB scales where relational databases don’t“, especially the paragraph about “Why relational databases don’t scale”. But I want to make clear that my post here is not against this article, but against a very common myth that even precedes NoSQL databases. Actually, I’m taking this article as reference because the author, in his website and book, has really good points about…
