Recently I came across a specific microservices pattern, and that in turn during research led me to a database theorem. I did not know it, so I decided collecting database theorems in one place. If you know of an additional database related theorem that is missing here, let me know…

Mind the key replication axioms — tl;dr Data consistency is in many cases the key requirement for database migration or replication: if consistency cannot be guaranteed, the (contents of the) target database might be inconsistent compared to the (contents of the) source database. …

tl;dr Cloud Spanner introduced point-in-time-recovery (PITR) as a supported database feature. This blog demonstrates how to recover a dropped table using PITR using gcloud commands. Point-in-time-recovery PITR allows you to recover data at a point in time in the past. …

tl;dr For the longest time I managed gcloud commands in documents or text files, especially during prototyping or initial research. From there I copy and paste them one-by-one or in blocks to a terminal or to the Cloud Shell for execution. This is tedious, error prone and very inefficient —…

By Christoph Bussler and Anand Jain — This blog discusses Cloud Spanner table interleaving from a developer’s perspective: what are interleaving tables, when to use this schema design concept, some edge cases and gotchas. tl;dr: interleaving tables are a query performance optimization tool for specific join query patterns. Interleaving tables are not a data modeling concept even…

Selecting Databases for Multi-cloud Use Cases — Note: this blog has the same content as the series with the same name. With medium.com series being deprecated, I post the same content unchanged as regular blog here. This series discusses various aspects of multi-cloud database management: What is multi-cloud database management? What are use cases for managing databases…

by Christoph Bussler and Sireesha Pulipati — Introduction Multi-tenancy is a software architecture pattern in which a single or few instances of an application serve multiple tenants or customers, often hundreds or thousands. This approach is fundamental to cloud computing platforms where the underlying infrastructure is shared among multiple organizations. Basically, multi-tenancy can be thought of as a…

A tutorial for setting up a multi-cloud VPN — Introduction This blog is a tutorial on how to set up a VPN between Google Cloud and AWS, create multi-zone subnetworks in each cloud and test any-to-any connectivity. For part of the setup this blog follows the community tutorial Google Cloud HA VPN interoperability guide for AWS and cites verbatim from…

by Christoph Bussler, Szabolcs Rozsnyai — What is zero downtime database migration and replication? Zero downtime database migration and replication (Database Migration — Concepts and Principles (Part 1), Database Migration — Concepts and Principles (Part 2)) refers to migrating or replicating data from a source database to a target database without impacting the client’s access of the source database in terms of availability or…