In short, choose by workload. Data historians suit plant-level process data, trusted operational technology (OT) workflows, and regulated records. Time series databases suit high-frequency telemetry, cross-site analysis, and open access for analytics and AI. Many teams run both, so the real question is complement or replace.

What was each system built to do?

Industrial companies often ask one class of system to do two jobs. The first is operational historization: collecting supervisory control and data acquisition (SCADA) and programmable logic controller (PLC) data at established frequencies for process visibility, reporting, operational continuity, and compliance. Data historians were purpose-built for this. They integrate tightly with control systems, arrive with industrial features built in, and have earned deep trust in OT.

The second job is operational intelligence: collecting higher-frequency telemetry, preserving granular data, combining it across systems and sites, and feeding analytics, AI, digital twins, and predictive maintenance. Time series databases, such as InfluxDB 3, were built for scale and open access, which suits this job. They have trade-offs of their own. They aren’t specific to OT, so connectivity, asset modeling, and visualization come from integrated tools, and building a complete solution takes developer resources.

Which criteria decide where a workload belongs?

Evaluate each workload rather than the whole estate at once. These criteria usually decide it:

Criterion Favors a data historian Favors a time series database
Data frequency and fidelity Established control-system rates; approximation acceptable High-frequency data; full fidelity needed
Signals and sites One plant, stable signal set Many signals and sites, growing
Who uses the data OT engineers with historian tools Analysts, data scientists, and applications using SQL or Python
Cost model Stable tag count Growing tag count under per-tag pricing
Industrial features Needed out of the box Can be integrated from other tools

Access is often the deciding row. InfluxDB 3 Enterprise supports SQL and InfluxQL, with Arrow Flight clients for Python and other languages and connections to Grafana and Power BI, so operational data reaches analytics tools without a proprietary interface.

Should you complement or replace your historian?

When the criteria split, with some workloads favoring the historian and others a time series database, the question becomes whether to add a time series database alongside the historian or replace the historian outright.

Complementing fits when the historian still serves plant operations, regulated data, and established workflows well, but new workloads exceed what it was built for. The historian keeps its role, and the time series database takes high-frequency, cross-site, and analytics work. See when to complement your data historian with a time series database.

Replacement fits at natural break points, such as a new facility, a carve-out, or end-of-life hardware, and requires planning for everything a historian does beyond storage. See when to replace your data historian with a time series database. Many teams complement first, then replace site by site as those break points arrive.

Frequently asked questions

Can a time series database connect directly to PLCs and SCADA systems?

For basic ingestion, yes. Telegraf, InfluxData's open source collection agent, includes [Open Platform Communications Unified Architecture (OPC UA) input plugins](https://docs.influxdata.com/telegraf/v1/input-plugins/opcua/) and an MQTT consumer that read from industrial sources and write to InfluxDB 3 Enterprise. Tag mapping, standardization, and contextualization across plants typically come from industrial connectivity platforms, such as Kepware, Litmus, or HighByte, running alongside.

Is a time series database harder to run than a data historian?

It's a build-versus-buy trade-off. A data historian arrives as an end-to-end industrial product with connectivity, visualization, and asset modeling included. A time series database is more open and flexible, but OT-specific features must be integrated from other tools, and assembling a complete solution takes developer resources. Teams weigh that effort against gains in scale, access, and cost.

Where should regulated or GxP data live?

Typically on the historian or another validated system. Time series databases such as InfluxDB don't include built-in GxP compliance features. Regulated data, however, is often a fraction of what a plant's historian stores. Teams can keep batch, quality, and release records on the validated system while moving non-regulated operational data to a more flexible platform.