## Data Products - Part I: A Lego Exercise

One can define a ** data product** as

*the smallest unit of data-driven architecture that can be independently deployed and managed*(aka product quantum) [1]. In other terms one can think of a data product like a box (or Lego piece) which takes data as inputs, performs several transformations on the data from which result several output data (or even data visualizations or a hybrid between data, visualizations and other content).

At high-level each Data Analytics solution can be regarded as a set of inputs, a set of outputs and the transformations that must be performed on the inputs to generate the outputs. The inputs are the data from the operational systems, while the outputs are analytics data that can be anything from data to KPIs and other metrics. A data mart, data warehouse, lakehouse and data mesh can be abstracted in this way, though different scales apply.

For creating data products within a data mesh, given a set of inputs, outputs and transformations, the challenge is to find horizontal and vertical partitions within these areas to create something that looks like a Lego structure, in which each piece of Lego represents a data product, while its color represents the membership to a business domain. Each such piece is self-contained and contains a set of transformations, respectively intermediary inputs and outputs. Multiple such pieces can be combined in a linear or hierarchical fashion to transform the initial inputs into the final outputs.

Finding such a partition is possible though it involves a considerable effort, especially in designing the whole thing — identifying each Lego piece uniquely. When each department is on its own and develops its own Lego pieces, there’s no guarantee that the pieces from the various domains will fit together to built something cohesive, performant, secure or well-structured. Is like building a house from modules, the pieces must fit together. That would be the role of governance (federated computational governance) — to align and coordinate the effort.

Conversely, there are transformations that need to be replicated for obtaining autonomous data products, and the volume of such overlapping can be considerable high. Consider for example the logic available in reports and how often it needs to be replicated. Alternatively, one can create intermediary data products, when that’s feasible.

It’s challenging to define the inputs and outputs for a Lego piece. Now imagine in doing the same for a whole set of such pieces depending on each other! This might work for small pieces of data and entities quite stable in their lifetime (e.g. playlists, artists, songs), but with complex information systems the effort can increase by a few factors. Moreover, the complexity of the structure increases as soon the Lego pieces expand beyond their initial design. It’s like the real Lego pieces would grow within the available space but still keep the initial structure — strange constructs may result, which even if they work, change the gravity center of the edifice in other directions. There will be thus limits to growth that can easily lead to duplication of functionality to overcome such challenges.

Each new output or change in the initial input for this magic boxes involves a change of all the intermediary Lego pieces from input to output. Just recollect the last experience of defining the inputs and the outputs for an important complex report, how many iterations and how much effort was involved. This might have been an extreme case, though how realistic is the assumption that with data products everything will go smoother? No matter of the effort involved in design, there will be always changes and further iterations involved.

*References:*[1] Zhamak Dehghani (2021) Data Mesh: Delivering Data-Driven Value at Scale (book review)

*Originally published at **https://sql-troubles.blogspot.com**. Written Mar-2024.*