Data Lake
A data lake is a centralized repository that stores raw data in its native format — structured, semi-structured, and unstructured — at any scale, until you're ready to use it. Unlike a traditional data warehouse, a data lake applies schema on read, meaning structure is defined at query time, not ingestion. This flexibility makes data lakes well-suited for analytics, AI, and machine learning workloads.
In depth
Data lakes emerged to meet the needs of modern analytics. Traditional data warehouses require you to define a structure before you load data. Data lakes use schema-on-read, which means you decide how to organize data when you query it — not when you store it.
Under the hood, a data lake relies on object storage or distributed file systems. You can ingest logs, images, audio files, and database exports side by side. This flexibility supports experimentation and machine learning projects without requiring upfront data modelling.
Without governance, a data lake can get messy. A metadata catalog, access controls, and clear data ownership are required to keep data trustworthy and reliable. Unmanaged lakes quickly become "data swamps" — full of data no one can find or trust.
Pro tip
Tag and catalogue your data as you ingest it. Retroactively applying metadata to thousands of files is slow and error-prone. Building the habit at ingestion keeps your lake navigable as it grows.
Why Data Lakes matter
Data lakes are a foundational component in modern analytics and AI. They give teams the flexibility to store everything now and extract value later — without committing to a schema that might not fit tomorrow's questions.
Here's what that flexibility enables:
Unlock new insights by combining data from diverse sources, such as logs, CRM data, and video files, in one place.
Scale storage cost-effectively on platforms like Amazon S3 or services like Google Cloud Storage.
Support AI and machine learning by preserving raw, unprocessed data that models can train on directly.
Data Lake - In practice
At a growing e-commerce retailer, raw sales transactions, clickstream logs, and customer reviews all land in a data lake. Data engineers apply transformations and perform quality checks. Then, analysts use tools like PowerMetrics to build dashboards and explore metrics on top of the clean data.
The data lake handles the volume and variety. Downstream tools handle the meaning.
Data Lakes and PowerMetrics
With Klipfolio PowerMetrics, you can retrieve data from data warehouses and from services with APIs. You can then model the data, define consistent metrics, and make trustworthy answers available to your team — in dashboards, AI, and the flow of work.
Related terms
Data Warehouse
A data warehouse is a specialized, centralized repository designed to store, organize, and filter structured data from across an organization. Unlike operational databases that handle day-to-day transactions, a warehouse is architected specifically for OLAP (Online Analytical Processing). It provides a "single source of truth" for historical data, enabling businesses to perform complex queries and generate high-level business intelligence.
Read moreData Stack
A data stack is a set of tools, services, and procedures that work together to collect, process, store, and analyze an organization’s data.
Read moreData Lineage
Data lineage maps the journey of your data from origin to destination. It visually shows where data comes from, how it’s transformed, and where it’s used.
Read moreOnline Analytical Processing (OLAP)
Online Analytical Processing (OLAP) is a technology that lets you analyze large datasets from multiple angles — by time, region, product, or any other dimension — almost instantly. It organizes information into structures called cubes, which are pre-built summaries of your data, so you can explore and compare figures without waiting on slow queries.
Read moreMeasure
A measure, in the context of data, is a quantifiable numeric value used to track and analyze data. It represents a calculation—like sum, average or count—that’s performed on raw data points.
Read more