Using Tag History Splitter to replace previous Ignition Server History Provider Database

Ignition
1

Has anyone successfully used a Tag History Splitter to migrate tag history from MSSQL to MariaDB?

My goal is to deploy a new Ignition Gateway that uses MariaDB and configure a Tag History Splitter with:

  • MariaDB as the primary history provider/database

  • The MSSQL database used by previous Ignition Gateway as the secondary provider

The intent is to continue writing all new history to MariaDB while still being able to query historical data from MSSQL during the transition period.

I also have a question regarding the splitter's query limiter. Has anyone found a way to automatically update the primary provider's query scope (for example, using gateway scripts, tags, or another automated method) rather than manually adjusting it over time?

Any examples, documentation, or lessons learned from a similar migration would be appreciated.

2

I would not recommend the historian splitter for this, personally.
(Disclaimer: I am just a dev with no personal experience with production Ignition or database deployments)

Instead, make a complete cutover to the new historian, and consider using 'external' tables in MariaDB to transparently reference your MSSQL data:

From Ignition's standpoint, it's only connecting to one database, and MariaDB is in charge of accessing the legacy data in MSSQL. You'll have to (one-time) add the legacy tables as direct references in your MariaDB instance, and then adjust the sqlth_partitions table to ensure it includes the 'legacy' tables.